use std::{collections::HashMap, str::FromStr};

use crate::{
    ast::types::{
        ArrayExpression, BinaryExpression, BinaryPart, BodyItem, CallExpression, CommentStyle, ExpressionStatement,
        FunctionExpression, Identifier, Literal, LiteralIdentifier, MemberExpression, MemberObject, NonCodeMeta,
        NonCodeNode, NonCodeValue, ObjectExpression, ObjectKeyInfo, ObjectProperty, PipeExpression, PipeSubstitution,
        Program, ReturnStatement, UnaryExpression, UnaryOperator, Value, VariableDeclaration, VariableDeclarator,
        VariableKind,
    },
    errors::{KclError, KclErrorDetails},
    math_parser::MathParser,
    token::{Token, TokenType},
};

mod parser_impl;

pub const PIPE_SUBSTITUTION_OPERATOR: &str = "%";
pub const PIPE_OPERATOR: &str = "|>";

#[derive(Debug, PartialEq, Clone)]
struct TokenReturn {
    token: Option<Token>,
    index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct TokenReturnWithNonCode {
    token: Option<Token>,
    index: usize,
    non_code_node: Option<NonCodeNode>,
}

#[derive(Debug, PartialEq, Clone)]
pub struct MemberExpressionReturn {
    pub expression: MemberExpression,
    pub last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ValueReturn {
    value: Value,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ArrayElementsReturn {
    elements: Vec<Value>,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ArrayReturn {
    expression: ArrayExpression,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct PipeBodyReturn {
    body: Vec<Value>,
    last_index: usize,
    non_code_meta: NonCodeMeta,
}

#[derive(Debug, PartialEq, Clone)]
struct BinaryExpressionReturn {
    expression: BinaryExpression,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ArgumentsReturn {
    arguments: Vec<Value>,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
pub struct CallExpressionResult {
    pub expression: CallExpression,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct PipeExpressionResult {
    expression: PipeExpression,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct VariableDeclaratorsReturn {
    declarations: Vec<VariableDeclarator>,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct VariableDeclarationResult {
    declaration: VariableDeclaration,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
pub struct ParamsResult {
    pub params: Vec<Identifier>,
    pub last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
pub struct UnaryExpressionResult {
    pub expression: UnaryExpression,
    pub last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ExpressionStatementResult {
    expression: ExpressionStatement,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ObjectPropertiesResult {
    properties: Vec<ObjectProperty>,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ObjectExpressionResult {
    expression: ObjectExpression,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct ReturnStatementResult {
    statement: ReturnStatement,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct BodyResult {
    body: Vec<BodyItem>,
    last_index: usize,
    non_code_meta: NonCodeMeta,
}

#[derive(Debug, PartialEq, Clone)]
struct BlockStatementResult {
    block: Program,
    last_index: usize,
}

#[derive(Debug, PartialEq, Clone)]
struct FunctionExpressionResult {
    expression: FunctionExpression,
    last_index: usize,
}

pub struct Parser {
    pub tokens: Vec<Token>,
    stdlib: crate::std::StdLib,
}

impl Parser {
    pub fn new(tokens: Vec<Token>) -> Self {
        let stdlib = crate::std::StdLib::new();
        Self { tokens, stdlib }
    }

    pub fn get_token(&self, index: usize) -> Result<&Token, KclError> {
        if self.tokens.is_empty() {
            return Err(KclError::Syntax(KclErrorDetails {
                source_ranges: vec![],
                message: "file is empty".to_string(),
            }));
        }

        let Some(token) = self.tokens.get(index) else {
            return Err(KclError::Syntax(KclErrorDetails {
                source_ranges: vec![self.tokens.last().unwrap().into()],
                message: "unexpected end".to_string(),
            }));
        };
        Ok(token)
    }

    /// Use the new Winnow parser.
    pub fn ast(&self) -> Result<Program, KclError> {
        parser_impl::run_parser(&mut self.tokens.as_slice())
    }

    /// Use the old handwritten recursive parser.
    pub fn ast_old(&self) -> Result<Program, KclError> {
        let body = self.make_body(
            0,
            vec![],
            NonCodeMeta {
                non_code_nodes: HashMap::new(),
                start: Vec::new(),
            },
        )?;
        let end = match self.get_token(body.last_index) {
            Ok(token) => token.end,
            Err(_) => self.tokens[self.tokens.len() - 1].end,
        };
        Ok(Program {
            start: 0,
            end,
            body: body.body,
            non_code_meta: body.non_code_meta,
        })
    }

    fn make_identifier(&self, index: usize) -> Result<Identifier, KclError> {
        let current_token = self.get_token(index)?;
        Ok(Identifier {
            start: current_token.start,
            end: current_token.end,
            name: current_token.value.clone(),
        })
    }

    fn make_literal(&self, index: usize) -> Result<Literal, KclError> {
        let token = self.get_token(index)?;
        let value = if token.token_type == TokenType::Number {
            if let Ok(value) = token.value.parse::<i64>() {
                serde_json::Value::Number(value.into())
            } else if let Ok(value) = token.value.parse::<f64>() {
                if let Some(n) = serde_json::Number::from_f64(value) {
                    serde_json::Value::Number(n)
                } else {
                    return Err(KclError::Syntax(KclErrorDetails {
                        source_ranges: vec![token.into()],
                        message: format!("Invalid float: {}", token.value),
                    }));
                }
            } else {
                return Err(KclError::Syntax(KclErrorDetails {
                    source_ranges: vec![token.into()],
                    message: format!("Invalid integer: {}", token.value),
                }));
            }
        } else {
            let mut str_val = token.value.clone();
            str_val.remove(0);
            str_val.pop();
            serde_json::Value::String(str_val)
        };
        Ok(Literal {
            start: token.start,
            end: token.end,
            value,
            raw: token.value.clone(),
        })
    }

    fn find_end_of_non_code_node(&self, index: usize) -> Result<usize, KclError> {
        if index == self.tokens.len() {
            return Ok(index);
        }

        let current_token = self.get_token(index)?;
        if !current_token.is_code_token() {
            return self.find_end_of_non_code_node(index + 1);
        }

        Ok(index)
    }

    fn find_start_of_non_code_node(&self, index: usize) -> Result<usize, KclError> {
        if index == 0 {
            return Ok(index);
        }

        let current_token = self.get_token(index)?;
        if !current_token.is_code_token() {
            return self.find_start_of_non_code_node(index - 1);
        }

        Ok(index + 1)
    }

    fn make_non_code_node(&self, index: usize) -> Result<(Option<NonCodeNode>, usize), KclError> {
        let end_index = self.find_end_of_non_code_node(index)?;
        let start_index = self.find_start_of_non_code_node(index)?;
        let non_code_tokens = self.tokens[index..end_index].to_vec();

        let has_comment = self.tokens[start_index..end_index]
            .iter()
            .any(|t| t.token_type == TokenType::BlockComment || t.token_type == TokenType::LineComment);

        if !has_comment
            && self.tokens[start_index..end_index]
                .iter()
                .map(|t| t.value.clone())
                .collect::<String>()
                .contains("\n\n")
        {
            return Ok((
                Some(NonCodeNode {
                    start: self.tokens[start_index].start,
                    end: self.tokens[end_index - 1].end,
                    value: NonCodeValue::NewLine,
                }),
                end_index - 1,
            ));
        }

        let is_block_style = non_code_tokens
            .first()
            .map(|tok| matches!(tok.token_type, TokenType::BlockComment))
            .unwrap_or_default();

        let full_string = non_code_tokens
            .iter()
            .map(|t| {
                if t.token_type == TokenType::BlockComment {
                    t.value
                        .trim()
                        .trim_start_matches("/*")
                        .trim_end_matches("*/")
                        .trim()
                        .to_string()
                        + "\n"
                } else {
                    t.value.trim().trim_start_matches("//").trim().to_string() + "\n"
                }
            })
            .collect::<String>()
            .trim()
            .to_string();

        if full_string.is_empty() {
            return Ok((None, end_index - 1));
        }

        let start_end_string = self.tokens[start_index..end_index]
            .iter()
            .map(|t| t.value.clone())
            .collect::<String>()
            .trim_start_matches(' ')
            .trim_end()
            .to_string();

        // Get the previous token if it exists.
        let is_new_line_comment =
            start_end_string.starts_with('\n') || start_end_string.contains('\n') || start_index == 0 || index == 0;

        let node = NonCodeNode {
            start: self.tokens[start_index].start,
            end: self.tokens[end_index - 1].end,
            value: if start_end_string.starts_with("\n\n") && is_new_line_comment {
                // Preserve if they want a whitespace line before the comment.
                // But let's just allow one.
                NonCodeValue::NewLineBlockComment {
                    value: full_string,
                    style: if is_block_style {
                        CommentStyle::Block
                    } else {
                        CommentStyle::Line
                    },
                }
            } else if is_new_line_comment {
                NonCodeValue::BlockComment {
                    value: full_string,
                    style: if is_block_style {
                        CommentStyle::Block
                    } else {
                        CommentStyle::Line
                    },
                }
            } else {
                NonCodeValue::InlineComment {
                    value: full_string,
                    style: if is_block_style {
                        CommentStyle::Block
                    } else {
                        CommentStyle::Line
                    },
                }
            },
        };
        Ok((Some(node), end_index - 1))
    }

    fn next_meaningful_token(&self, index: usize, offset: Option<usize>) -> Result<TokenReturnWithNonCode, KclError> {
        // There is no next meaningful token.
        if index >= self.tokens.len() - 1 {
            return Ok(TokenReturnWithNonCode {
                token: None,
                index: self.tokens.len() - 1,
                non_code_node: None,
            });
        }

        let new_index = index + offset.unwrap_or(1);
        let Ok(token) = self.get_token(new_index) else {
            return Ok(TokenReturnWithNonCode {
                token: Some(self.tokens[self.tokens.len() - 1].clone()),
                index: self.tokens.len() - 1,
                non_code_node: None,
            });
        };

        if !token.is_code_token() {
            let non_code_node = self.make_non_code_node(new_index)?;
            let new_new_index = non_code_node.1 + 1;
            let bonus_non_code_node = non_code_node.0;

            return Ok(TokenReturnWithNonCode {
                token: self.get_token(new_new_index).ok().cloned(),
                index: new_new_index,
                non_code_node: bonus_non_code_node,
            });
        }
        Ok(TokenReturnWithNonCode {
            token: Some(token.clone()),
            index: new_index,
            non_code_node: None,
        })
    }

    pub fn find_closing_brace(
        &self,
        index: usize,
        brace_count: usize,
        search_opening_brace: &str,
    ) -> Result<usize, KclError> {
        let closing_brace_map: HashMap<&str, &str> = [("(", ")"), ("{", "}"), ("[", "]")].iter().cloned().collect();
        let current_token = self.get_token(index)?;
        let mut search_opening_brace = search_opening_brace;
        let is_first_call = search_opening_brace.is_empty() && brace_count == 0;
        if is_first_call {
            search_opening_brace = &current_token.value;
            if !["(", "{", "["].contains(&search_opening_brace) {
                return Err(KclError::Syntax(KclErrorDetails {
                    source_ranges: vec![current_token.into()],
                    message: format!(
                        "expected to be started on a opening brace ( {{ [, instead found '{}'",
                        search_opening_brace
                    ),
                }));
            }
        }
        let found_closing_brace = brace_count == 1 && current_token.value == closing_brace_map[search_opening_brace];
        let found_another_opening_brace = current_token.value == search_opening_brace;
        let found_another_closing_brace = current_token.value == closing_brace_map[search_opening_brace];
        if found_closing_brace {
            return Ok(index);
        }
        if found_another_opening_brace {
            return self.find_closing_brace(index + 1, brace_count + 1, search_opening_brace);
        }
        if found_another_closing_brace && brace_count > 0 {
            return self.find_closing_brace(index + 1, brace_count - 1, search_opening_brace);
        }
        // non-brace token, increment and continue
        self.find_closing_brace(index + 1, brace_count, search_opening_brace)
    }

    fn is_call_expression(&self, index: usize) -> Result<Option<usize>, KclError> {
        if index + 1 >= self.tokens.len() {
            return Ok(None);
        }
        let current_token = self.get_token(index)?;
        let very_next_token = self.get_token(index + 1)?;
        if (current_token.token_type == TokenType::Word)
            && very_next_token.token_type == TokenType::Brace
            && very_next_token.value == "("
        {
            return Ok(Some(self.find_closing_brace(index + 1, 0, "")?));
        }
        Ok(None)
    }

    fn find_next_declaration_keyword(&self, index: usize) -> Result<TokenReturn, KclError> {
        if index >= self.tokens.len() - 1 {
            return Ok(TokenReturn {
                token: None,
                index: self.tokens.len() - 1,
            });
        }
        let next_token = self.next_meaningful_token(index, None)?;

        if next_token.index >= self.tokens.len() - 1 {
            return Ok(TokenReturn {
                token: None,
                index: self.tokens.len() - 1,
            });
        }
        if let Some(token_val) = next_token.token {
            if token_val.token_type == TokenType::Keyword && VariableKind::from_str(&token_val.value).is_ok() {
                return Ok(TokenReturn {
                    token: Some(token_val),
                    index: next_token.index,
                });
            }
            if token_val.token_type == TokenType::Brace && token_val.value == "(" {
                let closing_brace_index = self.find_closing_brace(next_token.index, 0, "")?;
                let arrow_token = self.next_meaningful_token(closing_brace_index, None)?.token;
                if let Some(arrow_token) = arrow_token {
                    if arrow_token.token_type == TokenType::Operator && arrow_token.value == "=>" {
                        return Ok(TokenReturn {
                            token: Some(token_val),
                            index: next_token.index,
                        });
                    }
                }
            }
        }
        self.find_next_declaration_keyword(next_token.index)
    }

    fn has_pipe_operator(&self, index: usize, _limit_index: Option<usize>) -> Result<TokenReturnWithNonCode, KclError> {
        let limit_index = match _limit_index {
            Some(i) => i,
            None => {
                let call_expression = self.is_call_expression(index)?;
                if let Some(ce) = call_expression {
                    let token_after_call_expression = self.next_meaningful_token(ce, None)?;

                    if let Some(token_after_call_expression_val) = token_after_call_expression.token {
                        if token_after_call_expression_val.token_type == TokenType::Operator
                            && token_after_call_expression_val.value == PIPE_OPERATOR
                        {
                            return Ok(TokenReturnWithNonCode {
                                token: Some(token_after_call_expression_val),
                                index: token_after_call_expression.index,
                                // non_code_node: None,
                                non_code_node: token_after_call_expression.non_code_node,
                            });
                        }
                        return Ok(TokenReturnWithNonCode {
                            token: None,
                            index: token_after_call_expression.index,
                            non_code_node: None,
                        });
                    }
                }
                let current_token = self.get_token(index)?;
                if current_token.token_type == TokenType::Brace && current_token.value == "{" {
                    let closing_brace_index = self.find_closing_brace(index, 0, "")?;
                    let token_after_closing_brace = self.next_meaningful_token(closing_brace_index, None)?;
                    if let Some(token_after_closing_brace_val) = token_after_closing_brace.token {
                        if token_after_closing_brace_val.token_type == TokenType::Operator
                            && token_after_closing_brace_val.value == PIPE_OPERATOR
                        {
                            return Ok(TokenReturnWithNonCode {
                                token: Some(token_after_closing_brace_val),
                                index: token_after_closing_brace.index,
                                non_code_node: token_after_closing_brace.non_code_node,
                            });
                        }
                        return Ok(TokenReturnWithNonCode {
                            token: None,
                            index: token_after_closing_brace.index,
                            non_code_node: None,
                        });
                    }
                }

                let next_declaration = self.find_next_declaration_keyword(index)?;
                next_declaration.index
            }
        };
        let next_token = self.next_meaningful_token(index, None)?;
        if next_token.index >= limit_index {
            return Ok(TokenReturnWithNonCode {
                token: None,
                index: next_token.index,
                non_code_node: None,
            });
        }
        if let Some(next_token_val) = next_token.token {
            if next_token_val.token_type == TokenType::Operator && next_token_val.value == PIPE_OPERATOR {
                return Ok(TokenReturnWithNonCode {
                    token: Some(next_token_val),
                    index: next_token.index,
                    non_code_node: next_token.non_code_node,
                });
            }
        }
        self.has_pipe_operator(next_token.index, Some(limit_index))
    }

    fn collect_object_keys(
        &self,
        index: usize,
        _previous_keys: Option<Vec<ObjectKeyInfo>>,
        has_opening_brace: bool,
    ) -> Result<Vec<ObjectKeyInfo>, KclError> {
        let previous_keys = _previous_keys.unwrap_or_default();
        let next_token = self.next_meaningful_token(index, None)?;
        if next_token.index == self.tokens.len() - 1 {
            return Ok(previous_keys);
        }
        let mut has_opening_brace = match &next_token.token {
            Some(next_token_val) => {
                if next_token_val.token_type == TokenType::Brace && next_token_val.value == "[" {
                    true
                } else {
                    has_opening_brace
                }
            }
            None => has_opening_brace,
        };
        let period_or_opening_bracket = match &next_token.token {
            Some(next_token_val) => {
                if has_opening_brace && next_token_val.token_type == TokenType::Brace && next_token_val.value == "]" {
                    // We need to reset our has_opening_brace flag, since we've closed it.
                    has_opening_brace = false;
                    let next_next_token = self.next_meaningful_token(next_token.index, None)?;
                    if let Some(next_next_token_val) = &next_next_token.token {
                        if next_next_token_val.token_type == TokenType::Brace && next_next_token_val.value == "[" {
                            // Set the opening brace flag again, since we've opened it again.
                            has_opening_brace = true;
                        }
                    }
                    next_next_token.clone()
                } else {
                    next_token.clone()
                }
            }
            None => next_token.clone(),
        };
        if let Some(period_or_opening_bracket_token) = period_or_opening_bracket.token {
            if period_or_opening_bracket_token.token_type != TokenType::Period
                && period_or_opening_bracket_token.token_type != TokenType::Brace
            {
                return Ok(previous_keys);
            }

            // We don't care if we never opened the brace.
            if !has_opening_brace && period_or_opening_bracket_token.token_type == TokenType::Brace {
                return Ok(previous_keys);
            }

            // Make sure its the right kind of brace, we don't care about ().
            if period_or_opening_bracket_token.token_type == TokenType::Brace
                && period_or_opening_bracket_token.value != "["
                && period_or_opening_bracket_token.value != "]"
            {
                return Ok(previous_keys);
            }

            let key_token = self.next_meaningful_token(period_or_opening_bracket.index, None)?;
            let next_period_or_opening_bracket = self.next_meaningful_token(key_token.index, None)?;
            let is_braced = match next_period_or_opening_bracket.token {
                Some(next_period_or_opening_bracket_val) => {
                    has_opening_brace
                        && next_period_or_opening_bracket_val.token_type == TokenType::Brace
                        && next_period_or_opening_bracket_val.value == "]"
                }
                None => false,
            };
            let end_index = if is_braced {
                next_period_or_opening_bracket.index
            } else {
                key_token.index
            };
            if let Some(key_token_token) = key_token.token {
                let key = if key_token_token.token_type == TokenType::Word {
                    LiteralIdentifier::Identifier(Box::new(self.make_identifier(key_token.index)?))
                } else {
                    LiteralIdentifier::Literal(Box::new(self.make_literal(key_token.index)?))
                };
                let computed = is_braced && key_token_token.token_type == TokenType::Word;
                let mut new_previous_keys = previous_keys;
                new_previous_keys.push(ObjectKeyInfo {
                    key,
                    index: end_index,
                    computed,
                });
                self.collect_object_keys(key_token.index, Some(new_previous_keys), has_opening_brace)
            } else {
                Err(KclError::Unimplemented(KclErrorDetails {
                    source_ranges: vec![period_or_opening_bracket_token.clone().into()],
                    message: format!("expression with token {:?}", period_or_opening_bracket_token),
                }))
            }
        } else {
            Ok(previous_keys)
        }
    }

    pub fn make_member_expression(&self, index: usize) -> Result<MemberExpressionReturn, KclError> {
        let current_token = self.get_token(index)?;
        let mut keys_info = self.collect_object_keys(index, None, false)?;
        if keys_info.is_empty() {
            return Err(KclError::Syntax(KclErrorDetails {
                source_ranges: vec![current_token.into()],
                message: "expected to be started on a identifier or literal".to_string(),
            }));
        }
        let last_key = keys_info[keys_info.len() - 1].clone();
        let first_key = keys_info.remove(0);
        let root = self.make_identifier(index)?;
        let mut member_expression = MemberExpression {
            start: current_token.start,
            end: self.get_token(first_key.index)?.end,
            object: MemberObject::Identifier(Box::new(root)),
            property: first_key.key.clone(),
            computed: first_key.computed,
        };
        for key_info_1 in keys_info.iter() {
            let end_token = self.get_token(key_info_1.index)?;
            member_expression = MemberExpression {
                start: current_token.start,
                end: end_token.end,
                object: MemberObject::MemberExpression(Box::new(member_expression)),
                property: key_info_1.key.clone(),
                computed: key_info_1.computed,
            };
        }
        Ok(MemberExpressionReturn {
            expression: member_expression,
            last_index: last_key.index,
        })
    }

    fn find_end_of_binary_expression(&self, index: usize) -> Result<usize, KclError> {
        let current_token = self.get_token(index)?;

        if current_token.token_type == TokenType::Brace && current_token.value == "(" {
            let closing_parenthesis = self.find_closing_brace(index, 0, "")?;
            let maybe_another_operator = self.next_meaningful_token(closing_parenthesis, None)?;
            return if let Some(maybe_another_operator_token) = maybe_another_operator.token {
                if maybe_another_operator_token.token_type != TokenType::Operator
                    || maybe_another_operator_token.value == PIPE_OPERATOR
                {
                    Ok(closing_parenthesis)
                } else {
                    let next_right = self.next_meaningful_token(maybe_another_operator.index, None)?;
                    self.find_end_of_binary_expression(next_right.index)
                }
            } else {
                Ok(closing_parenthesis)
            };
        }

        if current_token.token_type == TokenType::Word {
            if let Ok(next_token) = self.get_token(index + 1) {
                if next_token.token_type == TokenType::Period
                    || (next_token.token_type == TokenType::Brace && next_token.value == "[")
                {
                    let member_expression = self.make_member_expression(index)?;
                    return self.find_end_of_binary_expression(member_expression.last_index);
                }

                if next_token.token_type == TokenType::Brace && next_token.value == "(" {
                    let closing_parenthesis = self.find_closing_brace(index + 1, 0, "")?;
                    let maybe_another_operator = self.next_meaningful_token(closing_parenthesis, None)?;
                    return if let Some(maybe_another_operator_token) = maybe_another_operator.token {
                        if maybe_another_operator_token.token_type != TokenType::Operator
                            || maybe_another_operator_token.value == PIPE_OPERATOR
                        {
                            Ok(closing_parenthesis)
                        } else {
                            let next_right = self.next_meaningful_token(maybe_another_operator.index, None)?;
                            self.find_end_of_binary_expression(next_right.index)
                        }
                    } else {
                        Ok(closing_parenthesis)
                    };
                }
            }
        }

        let maybe_operator = self.next_meaningful_token(index, None)?;
        if let Some(maybe_operator_token) = maybe_operator.token {
            if maybe_operator_token.token_type == TokenType::Number
                || maybe_operator_token.token_type == TokenType::Word
            {
                return self.find_end_of_binary_expression(maybe_operator.index);
            } else if maybe_operator_token.token_type != TokenType::Operator
                || maybe_operator_token.value == PIPE_OPERATOR
            {
                return Ok(index);
            }
            let next_right = self.next_meaningful_token(maybe_operator.index, None)?;
            if next_right.index != index {
                self.find_end_of_binary_expression(next_right.index)
            } else {
                Ok(index)
            }
        } else {
            Ok(index)
        }
    }

    fn make_value(&self, index: usize) -> Result<ValueReturn, KclError> {
        let current_token = self.get_token(index)?;
        let next = self.next_meaningful_token(index, None)?;
        if let Some(next_token) = &next.token {
            if next_token.token_type == TokenType::Brace && next_token.value == "(" {
                let end_index = self.find_closing_brace(next.index, 0, "")?;
                let token_after_call_expression = self.next_meaningful_token(end_index, None)?;
                if let Some(token_after_call_expression_token) = token_after_call_expression.token {
                    if token_after_call_expression_token.token_type == TokenType::Operator
                        && token_after_call_expression_token.value != PIPE_OPERATOR
                    {
                        let binary_expression = self.make_binary_expression(index)?;
                        return Ok(ValueReturn {
                            value: Value::BinaryExpression(Box::new(binary_expression.expression)),
                            last_index: binary_expression.last_index,
                        });
                    }
                }

                let call_expression = self.make_call_expression(index)?;
                return Ok(ValueReturn {
                    value: Value::CallExpression(Box::new(call_expression.expression)),
                    last_index: call_expression.last_index,
                });
            }
        }

        if current_token.token_type == TokenType::Word
            || current_token.token_type == TokenType::Number
            || current_token.token_type == TokenType::String
        {
            if let Some(next_token) = &next.token {
                if next_token.token_type == TokenType::Operator {
                    let binary_expression = self.make_binary_expression(index)?;
                    return Ok(ValueReturn {
                        value: Value::BinaryExpression(Box::new(binary_expression.expression)),
                        last_index: binary_expression.last_index,
                    });
                }
            }
        }

        // Account for negative numbers.
        if current_token.token_type == TokenType::Operator || current_token.value == "-" {
            if let Some(next_token) = &next.token {
                if next_token.token_type == TokenType::Word
                    || next_token.token_type == TokenType::Number
                    || next_token.token_type == TokenType::String
                {
                    // See if the next token is an operator.
                    let next_right = self.next_meaningful_token(next.index, None)?;
                    if let Some(next_right_token) = next_right.token {
                        if next_right_token.token_type == TokenType::Operator {
                            let binary_expression = self.make_binary_expression(index)?;
                            return Ok(ValueReturn {
                                value: Value::BinaryExpression(Box::new(binary_expression.expression)),
                                last_index: binary_expression.last_index,
                            });
                        }
                    }
                }
            }
        }

        if current_token.token_type == TokenType::Brace && current_token.value == "{" {
            let object_expression = self.make_object_expression(index)?;
            return Ok(ValueReturn {
                value: Value::ObjectExpression(Box::new(object_expression.expression)),
                last_index: object_expression.last_index,
            });
        }
        if current_token.token_type == TokenType::Brace && current_token.value == "[" {
            let array_expression = self.make_array_expression(index)?;
            return Ok(ValueReturn {
                value: Value::ArrayExpression(Box::new(array_expression.expression)),
                last_index: array_expression.last_index,
            });
        }

        if let Some(next_token) = next.token {
            if (current_token.token_type == TokenType::Word)
                && (next_token.token_type == TokenType::Period
                    || (next_token.token_type == TokenType::Brace && next_token.value == "["))
            {
                let member_expression = self.make_member_expression(index)?;
                // If the next token is an operator, we need to make a binary expression.
                let next_right = self.next_meaningful_token(member_expression.last_index, None)?;
                if let Some(next_right_token) = next_right.token {
                    if next_right_token.token_type == TokenType::Operator
                        || next_right_token.token_type == TokenType::Number
                    {
                        let binary_expression = self.make_binary_expression(index)?;
                        return Ok(ValueReturn {
                            value: Value::BinaryExpression(Box::new(binary_expression.expression)),
                            last_index: binary_expression.last_index,
                        });
                    }
                }

                return Ok(ValueReturn {
                    value: Value::MemberExpression(Box::new(member_expression.expression)),
                    last_index: member_expression.last_index,
                });
            }
        }
        if current_token.token_type == TokenType::Word || current_token.token_type == TokenType::Keyword {
            let identifier = self.make_identifier(index)?;
            return Ok(ValueReturn {
                value: Value::Identifier(Box::new(identifier)),
                last_index: index,
            });
        }
        if current_token.token_type == TokenType::Number || current_token.token_type == TokenType::String {
            let literal = self.make_literal(index)?;
            return Ok(ValueReturn {
                value: Value::Literal(Box::new(literal)),
                last_index: index,
            });
        }

        if current_token.token_type == TokenType::Brace && current_token.value == "(" {
            let closing_brace_index = self.find_closing_brace(index, 0, "")?;
            return if let Some(arrow_token) = self.next_meaningful_token(closing_brace_index, None)?.token {
                if arrow_token.token_type == TokenType::Operator && arrow_token.value == "=>" {
                    let function_expression = self.make_function_expression(index)?;
                    Ok(ValueReturn {
                        value: Value::FunctionExpression(Box::new(function_expression.expression)),
                        last_index: function_expression.last_index,
                    })
                } else {
                    // This is likely a binary expression that starts with a parenthesis.
                    let binary_expression = self.make_binary_expression(index)?;
                    Ok(ValueReturn {
                        value: Value::BinaryExpression(Box::new(binary_expression.expression)),
                        last_index: binary_expression.last_index,
                    })
                }
            } else {
                return Err(KclError::Unimplemented(KclErrorDetails {
                    source_ranges: vec![current_token.into()],
                    message: "expression with braces".to_string(),
                }));
            };
        }

        if current_token.token_type == TokenType::Operator && current_token.value == "-" {
            let unary_expression = self.make_unary_expression(index)?;
            return Ok(ValueReturn {
                value: Value::UnaryExpression(Box::new(unary_expression.expression)),
                last_index: unary_expression.last_index,
            });
        }

        Err(KclError::Unexpected(KclErrorDetails {
            source_ranges: vec![current_token.into()],
            message: format!("Unexpected token {:?}", current_token),
        }))
    }

    fn make_array_elements(
        &self,
        index: usize,
        previous_elements: Vec<Value>,
    ) -> Result<ArrayElementsReturn, KclError> {
        let first_element_token = self.get_token(index)?;
        if first_element_token.token_type == TokenType::Brace && first_element_token.value == "]" {
            return Ok(ArrayElementsReturn {
                elements: previous_elements,
                last_index: index,
            });
        }
        let current_element = self.make_value(index)?;
        let next_token = self.next_meaningful_token(current_element.last_index, None)?;
        if let Some(next_token_token) = next_token.token {
            let is_closing_brace = next_token_token.token_type == TokenType::Brace && next_token_token.value == "]";
            let is_comma = next_token_token.token_type == TokenType::Comma;
            // Check if we have a double period, which would act as an expansion operator.
            let is_double_period = next_token_token.token_type == TokenType::DoublePeriod;
            if !is_closing_brace && !is_comma && !is_double_period {
                return Err(KclError::Syntax(KclErrorDetails {
                    source_ranges: vec![next_token_token.clone().into()],
                    message: format!("Expected a `,`, `]`, or `..`, found {:?}", next_token_token.value),
                }));
            }
            let next_call_index = if is_closing_brace {
                next_token.index
            } else {
                self.next_meaningful_token(next_token.index, None)?.index
            };

            if is_double_period {
                // We want to expand the array.
                // Make sure the previous element is a number literal.
                if first_element_token.token_type != TokenType::Number {
                    return Err(KclError::Syntax(KclErrorDetails {
                        source_ranges: vec![first_element_token.into()],
                        message: "`..` expansion operator requires a number literal on both sides".to_string(),
                    }));
                }

                // Make sure the next element is a number literal.
                let last_element_token = self.get_token(next_call_index)?;
                if last_element_token.token_type != TokenType::Number {
                    return Err(KclError::Syntax(KclErrorDetails {
                        source_ranges: vec![last_element_token.into()],
                        message: "`..` expansion operator requires a number literal on both sides".to_string(),
                    }));
                }

                // Expand the array.
                let mut previous_elements = previous_elements.clone();
                let first_element = first_element_token.value.parse::<i64>().map_err(|_| {
                    KclError::Syntax(KclErrorDetails {
                        source_ranges: vec![first_element_token.into()],
                        message: "expected a number literal".to_string(),
                    })
                })?;
                let last_element = last_element_token.value.parse::<i64>().map_err(|_| {
                    KclError::Syntax(KclErrorDetails {
                        source_ranges: vec![last_element_token.into()],
                        message: "expected a number literal".to_string(),
                    })
                })?;
                if first_element > last_element {
                    return Err(KclError::Syntax(KclErrorDetails {
                        source_ranges: vec![first_element_token.into(), last_element_token.into()],
                        message: "first element must be less than or equal to the last element".to_string(),
                    }));
                }
                for i in first_element..=last_element {
                    previous_elements.push(Value::Literal(Box::new(Literal {
                        start: first_element_token.start,
                        end: first_element_token.end,
                        value: i.into(),
                        raw: i.to_string(),
                    })));
                }
                return self.make_array_elements(next_call_index + 1, previous_elements);
            }

            let mut previous_elements = previous_elements.clone();
            previous_elements.push(current_element.value);
            self.make_array_elements(next_call_index, previous_elements)
        } else {
            Err(KclError::Unimplemented(KclErrorDetails {
                source_ranges: vec![first_element_token.into()],
                message: "no next token".to_string(),
            }))
        }
    }

    fn make_array_expression(&self, index: usize) -> Result<ArrayReturn, KclError> {
        let opening_brace_token = self.get_token(index)?;
        let first_element_token = self.next_meaningful_token(index, None)?;
        // Make sure there is a closing brace.
        let closing_brace_index = self.find_closing_brace(index, 0, "").map_err(|_| {
            KclError::Syntax(KclErrorDetails {
                source_ranges: vec![opening_brace_token.into()],
                message: "missing a closing brace for the array".to_string(),
            })
        })?;
        let closing_brace_token = self.get_token(closing_brace_index)?;
        let array_elements = self.make_array_elements(first_element_token.index, Vec::new())?;
        Ok(ArrayReturn {
            expression: ArrayExpression {
                start: opening_brace_token.start,
                end: closing_brace_token.end,
                elements: array_elements.elements,
            },
            last_index: array_elements.last_index,
        })
    }

    fn make_pipe_body(
        &self,
        index: usize,
        previous_values: Vec<Value>,
        previous_non_code_meta: Option<NonCodeMeta>,
    ) -> Result<PipeBodyReturn, KclError> {
        let non_code_meta = match previous_non_code_meta {
            Some(meta) => meta,
            None => NonCodeMeta {
                start: Vec::new(),
                non_code_nodes: HashMap::new(),
            },
        };
        let current_token = self.get_token(index)?;
        let expression_start = self.next_meaningful_token(index, None)?;
        let value: Value;
        let last_index: usize;
        if current_token.token_type == TokenType::Operator {
            let val = self.make_value(expression_start.index)?;
            value = val.value;
            last_index = val.last_index;
        } else {
            return Err(KclError::Syntax(KclErrorDetails {
                source_ranges: vec![current_token.into()],
                message: format!("Expected a pipe value, found {:?}", current_token.token_type),
            }));
        }
        let next_pipe = self.has_pipe_operator(index, None)?;
        if next_pipe.token.is_none() {
            let mut _previous_values = previous_values;
            _previous_values.push(value);
            return Ok(PipeBodyReturn {
                body: _previous_values,
                last_index,
                non_code_meta,
            });
        }
        let mut _non_code_meta: NonCodeMeta;
        if let Some(node) = next_pipe.non_code_node {
            _non_code_meta = non_code_meta;
            _non_code_meta.insert(previous_values.len(), node);
        } else {
            _non_code_meta = non_code_meta;
        }
        let mut _previous_values = previous_values;
        _previous_values.push(value);
        self.make_pipe_body(next_pipe.index, _previous_values, Some(_non_code_meta))
    }

    fn make_binary_expression(&self, index: usize) -> Result<BinaryExpressionReturn, KclError> {
        let end_index = self.find_end_of_binary_expression(index)?;
        let mut math_parser = MathParser::new(&self.tokens[index..end_index + 1]);
        let expression = math_parser.parse()?;
        Ok(BinaryExpressionReturn {
            expression,
            last_index: end_index,
        })
    }

    fn make_arguments(&self, index: usize, previous_args: Vec<Value>) -> Result<ArgumentsReturn, KclError> {
        let brace_or_comma_token = self.get_token(index)?;
        let should_finish_recursion =
            brace_or_comma_token.token_type == TokenType::Brace && brace_or_comma_token.value == ")";
        if should_finish_recursion {
            return Ok(ArgumentsReturn {
                arguments: previous_args,
                last_index: index,
            });
        }
        let argument_token = self.next_meaningful_token(index, None)?;

        if let Some(argument_token_token) = argument_token.token {
            let next_brace_or_comma = self.next_meaningful_token(argument_token.index, None)?;
            if let Some(next_brace_or_comma_token) = next_brace_or_comma.token {
                if (argument_token_token.token_type == TokenType::Word)
                    && (next_brace_or_comma_token.token_type == TokenType::Period
                        || (next_brace_or_comma_token.token_type == TokenType::Brace
                            && next_brace_or_comma_token.value == "["))
                {
                    let member_expression = self.make_member_expression(argument_token.index)?;
                    let mut _previous_args = previous_args;
                    _previous_args.push(Value::MemberExpression(Box::new(member_expression.expression)));
                    let next_comma_or_brace_token_index =
                        self.next_meaningful_token(member_expression.last_index, None)?.index;
                    return self.make_arguments(next_comma_or_brace_token_index, _previous_args);
                }

                let is_identifier_or_literal = next_brace_or_comma_token.token_type == TokenType::Comma
                    || next_brace_or_comma_token.token_type == TokenType::Brace;
                if argument_token_token.token_type == TokenType::Brace && argument_token_token.value == "[" {
                    let array_expression = self.make_array_expression(argument_token.index)?;
                    let next_comma_or_brace_token_index =
                        self.next_meaningful_token(array_expression.last_index, None)?.index;
                    let mut _previous_args = previous_args;
                    _previous_args.push(Value::ArrayExpression(Box::new(array_expression.expression)));
                    return self.make_arguments(next_comma_or_brace_token_index, _previous_args);
                }

                if argument_token_token.token_type == TokenType::Operator && argument_token_token.value == "-" {
                    let value = self.make_value(argument_token.index)?;
                    let next_comma_or_brace_token_index = self.next_meaningful_token(value.last_index, None)?.index;
                    let mut _previous_args = previous_args;
                    _previous_args.push(value.value);
                    return self.make_arguments(next_comma_or_brace_token_index, _previous_args);
                }
                if argument_token_token.token_type == TokenType::Brace && argument_token_token.value == "{" {
                    let object_expression = self.make_object_expression(argument_token.index)?;
                    let next_comma_or_brace_token_index =
                        self.next_meaningful_token(object_expression.last_index, None)?.index;
                    let mut _previous_args = previous_args;
                    _previous_args.push(Value::ObjectExpression(Box::new(object_expression.expression)));
                    return self.make_arguments(next_comma_or_brace_token_index, _previous_args);
                }
                if (argument_token_token.token_type == TokenType::Word
                    || argument_token_token.token_type == TokenType::Number
                    || argument_token_token.token_type == TokenType::String)
                    && next_brace_or_comma_token.token_type == TokenType::Operator
                {
                    let binary_expression = self.make_binary_expression(argument_token.index)?;
                    let next_comma_or_brace_token_index =
                        self.next_meaningful_token(binary_expression.last_index, None)?.index;
                    let mut _previous_args = previous_args;
                    _previous_args.push(Value::BinaryExpression(Box::new(binary_expression.expression)));
                    return self.make_arguments(next_comma_or_brace_token_index, _previous_args);
                }

                if !is_identifier_or_literal {
                    let binary_expression = self.make_binary_expression(next_brace_or_comma.index)?;
                    let mut _previous_args = previous_args;
                    _previous_args.push(Value::BinaryExpression(Box::new(binary_expression.expression)));
                    return self.make_arguments(binary_expression.last_index, _previous_args);
                }

                if argument_token_token.token_type == TokenType::Operator
                    && argument_token_token.value == PIPE_SUBSTITUTION_OPERATOR
                {
                    let value = Value::PipeSubstitution(Box::new(PipeSubstitution {
                        start: argument_token_token.start,
                        end: argument_token_token.end,
                    }));

                    let mut _previous_args = previous_args;
                    _previous_args.push(value);
                    return self.make_arguments(next_brace_or_comma.index, _previous_args);
                }
                if argument_token_token.token_type == TokenType::Word
                    && next_brace_or_comma_token.token_type == TokenType::Brace
                    && next_brace_or_comma_token.value == "("
                {
                    let closing_brace = self.find_closing_brace(next_brace_or_comma.index, 0, "")?;
                    return if let Some(token_after_closing_brace) =
                        self.next_meaningful_token(closing_brace, None)?.token
                    {
                        if token_after_closing_brace.token_type == TokenType::Operator
                            && token_after_closing_brace.value != PIPE_OPERATOR
                        {
                            let binary_expression = self.make_binary_expression(argument_token.index)?;
                            let next_comma_or_brace_token_index =
                                self.next_meaningful_token(binary_expression.last_index, None)?.index;
                            let mut _previous_args = previous_args;
                            _previous_args.push(Value::BinaryExpression(Box::new(binary_expression.expression)));
                            self.make_arguments(next_comma_or_brace_token_index, _previous_args)
                        } else {
                            let call_expression = self.make_call_expression(argument_token.index)?;
                            let next_comma_or_brace_token_index =
                                self.next_meaningful_token(call_expression.last_index, None)?.index;
                            let mut _previous_args = previous_args;
                            _previous_args.push(Value::CallExpression(Box::new(call_expression.expression)));
                            self.make_arguments(next_comma_or_brace_token_index, _previous_args)
                        }
                    } else {
                        return Err(KclError::Unimplemented(KclErrorDetails {
                            source_ranges: vec![argument_token_token.clone().into()],
                            message: format!("Unexpected token {}", argument_token_token.value),
                        }));
                    };
                }

                if argument_token_token.token_type == TokenType::Keyword
                    || argument_token_token.token_type == TokenType::Word
                {
                    let identifier = Value::Identifier(Box::new(self.make_identifier(argument_token.index)?));
                    let mut _previous_args = previous_args;
                    _previous_args.push(identifier);
                    return self.make_arguments(next_brace_or_comma.index, _previous_args);
                } else if argument_token_token.token_type == TokenType::Number
                    || argument_token_token.token_type == TokenType::String
                {
                    let literal = Value::Literal(Box::new(self.make_literal(argument_token.index)?));
                    let mut _previous_args = previous_args;
                    _previous_args.push(literal);
                    return self.make_arguments(next_brace_or_comma.index, _previous_args);
                } else if argument_token_token.token_type == TokenType::Brace && argument_token_token.value == ")" {
                    return self.make_arguments(argument_token.index, previous_args);
                }

                Err(KclError::Unimplemented(KclErrorDetails {
                    source_ranges: vec![argument_token_token.clone().into()],
                    message: format!("Unexpected token {}", argument_token_token.value),
                }))
            } else {
                Err(KclError::Unimplemented(KclErrorDetails {
                    source_ranges: vec![brace_or_comma_token.into()],
                    message: format!("Unexpected token {}", brace_or_comma_token.value),
                }))
            }
        } else {
            Err(KclError::Unimplemented(KclErrorDetails {
                source_ranges: vec![brace_or_comma_token.into()],
                message: format!("Unexpected token {}", brace_or_comma_token.value),
            }))
        }
    }

    pub fn make_call_expression(&self, index: usize) -> Result<CallExpressionResult, KclError> {
        let current_token = self.get_token(index)?;
        let brace_token = self.next_meaningful_token(index, None)?;
        let callee = self.make_identifier(index)?;
        // Make sure there is a closing brace.
        let closing_brace_index = self.find_closing_brace(brace_token.index, 0, "").map_err(|_| {
            KclError::Syntax(KclErrorDetails {
                source_ranges: vec![current_token.into()],
                message: "missing a closing brace for the function call".to_string(),
            })
        })?;
        let closing_brace_token = self.get_token(closing_brace_index)?;
        // Account for if we have no args.
        let args = if brace_token.index + 1 == closing_brace_index {
            ArgumentsReturn {
                arguments: vec![],
                last_index: closing_brace_index,
            }
        } else {
            self.make_arguments(brace_token.index, vec![])?
        };
        let function = if let Some(stdlib_fn) = self.stdlib.get(&callee.name) {
            crate::ast::types::Function::StdLib { func: stdlib_fn }
        } else {
            crate::ast::types::Function::InMemory
        };
        Ok(CallExpressionResult {
            expression: CallExpression {
                start: current_token.start,
                end: closing_brace_token.end,
                callee,
                arguments: args.arguments,
                optional: false,
                function,
            },
            last_index: args.last_index,
        })
    }

    fn make_pipe_expression(&self, index: usize) -> Result<PipeExpressionResult, KclError> {
        let current_token = self.get_token(index)?;
        let pipe_body_result = self.make_pipe_body(index, vec![], None)?;
        let end_token = self.get_token(pipe_body_result.last_index)?;
        Ok(PipeExpressionResult {
            expression: PipeExpression {
                start: pipe_body_result
                    .body
                    .first()
                    .map(|v| v.start())
                    .unwrap_or(current_token.start),
                end: end_token.end,
                body: pipe_body_result.body,
                non_code_meta: pipe_body_result.non_code_meta,
            },
            last_index: pipe_body_result.last_index,
        })
    }

    fn make_variable_declarators(
        &self,
        index: usize,
        previous_declarators: Vec<VariableDeclarator>,
    ) -> Result<VariableDeclaratorsReturn, KclError> {
        let current_token = self.get_token(index)?;

        // Make sure they are not assigning a variable to a reserved keyword.
        // Or a stdlib function.
        if current_token.token_type == TokenType::Keyword || self.stdlib.fns.contains_key(&current_token.value) {
            return Err(KclError::Syntax(KclErrorDetails {
                source_ranges: vec![current_token.into()],
                message: format!(
                    "Cannot assign a variable to a reserved keyword: {}",
                    current_token.value
                ),
            }));
        }

        let assignment = self.next_meaningful_token(index, None)?;
        let Some(assignment_token) = assignment.token else {
            return Err(KclError::Unimplemented(KclErrorDetails {
                source_ranges: vec![current_token.clone().into()],
                message: format!("Unexpected token {}", current_token.value),
            }));
        };

        let contents_start_token = self.next_meaningful_token(assignment.index, None)?;
        let pipe_start_index = if assignment_token.token_type == TokenType::Operator {
            contents_start_token.index
        } else {
            assignment.index
        };
        let next_pipe_operator = self.has_pipe_operator(pipe_start_index, None)?;
        let init: Value;
        let last_index = if next_pipe_operator.token.is_some() {
            let pipe_expression_result = self.make_pipe_expression(assignment.index)?;
            init = Value::PipeExpression(Box::new(pipe_expression_result.expression));
            pipe_expression_result.last_index
        } else {
            let value_result = self.make_value(contents_start_token.index)?;
            init = value_result.value;
            value_result.last_index
        };
        let current_declarator = VariableDeclarator {
            start: current_token.start,
            end: self.get_token(last_index)?.end,
            id: self.make_identifier(index)?,
            init,
        };
        let mut declarations = previous_declarators;
        declarations.push(current_declarator);
        Ok(VariableDeclaratorsReturn {
            declarations,
            last_index,
        })
    }

    fn make_variable_declaration(&self, index: usize) -> Result<VariableDeclarationResult, KclError> {
        let current_token = self.get_token(index)?;
        let declaration_start_token = self.next_meaningful_token(index, None)?;
        let kind = VariableKind::from_str(&current_token.value).map_err(|_| {
            KclError::Syntax(KclErrorDetails {
                source_ranges: vec![current_token.into()],
                message: format!("Unexpected token: {}", current_token.value),
            })
        })?;
        let variable_declarators_result = self.make_variable_declarators(declaration_start_token.index, vec![])?;

        // Check if we have a fn variable kind but are not assigning a function.
        if !variable_declarators_result.declarations.is_empty() {
            if let Some(declarator) = variable_declarators_result.declarations.get(0) {
                if let Value::FunctionExpression(_) = declarator.init {
                    if kind != VariableKind::Fn {
                        return Err(KclError::Syntax(KclErrorDetails {
                            source_ranges: vec![current_token.into()],
                            message: format!("Expected a `fn` variable kind, found: `{}`", current_token.value),
                        }));
                    }
                } else {
                    // If we have anything other than a function, make sure we are not using the `fn` variable kind.
                    if kind == VariableKind::Fn {
                        return Err(KclError::Syntax(KclErrorDetails {
                            source_ranges: vec![current_token.into()],
                            message: format!("Expected a `let` variable kind, found: `{}`", current_token.value),
                        }));
                    }
                }
            }
        }
        Ok(VariableDeclarationResult {
            declaration: VariableDeclaration {
                start: current_token.start,
                end: variable_declarators_result.declarations[variable_declarators_result.declarations.len() - 1].end,
                kind,
                declarations: variable_declarators_result.declarations,
            },
            last_index: variable_declarators_result.last_index,
        })
    }

    fn make_params(&self, index: usize, previous_params: Vec<Identifier>) -> Result<ParamsResult, KclError> {
        let brace_or_comma_token = self.get_token(index)?;
        let argument = self.next_meaningful_token(index, None)?;
        let Some(argument_token) = argument.token else {
            return Err(KclError::Unimplemented(KclErrorDetails {
                source_ranges: vec![brace_or_comma_token.into()],
                message: format!("expected a function parameter, found: {}", brace_or_comma_token.value),
            }));
        };

        let should_finish_recursion = (argument_token.token_type == TokenType::Brace && argument_token.value == ")")
            || (brace_or_comma_token.token_type == TokenType::Brace && brace_or_comma_token.value == ")");
        if should_finish_recursion {
            return Ok(ParamsResult {
                params: previous_params,
                last_index: index,
            });
        }

        // Make sure they are not assigning a variable to a reserved keyword.
        // Or a stdlib function.
        if argument_token.token_type == TokenType::Keyword || self.stdlib.fns.contains_key(&argument_token.value) {
            return Err(KclError::Syntax(KclErrorDetails {
                source_ranges: vec![argument_token.clone().into()],
                message: format!(
                    "Cannot assign a variable to a reserved keyword: {}",
                    argument_token.value
                ),
            }));
        }

        let next_brace_or_comma_token = self.next_meaningful_token(argument.index, None)?;
        let identifier = self.make_identifier(argument.index)?;
        let mut _previous_params = previous_params;
        _previous_params.push(identifier);
        self.make_params(next_brace_or_comma_token.index, _previous_params)
    }

    fn make_unary_expression(&self, index: usize) -> Result<UnaryExpressionResult, KclError> {
        let current_token = self.get_token(index)?;
        let next_token = self.next_meaningful_token(index, None)?;
        if next_token.token.is_none() {
            return Err(KclError::Syntax(KclErrorDetails {
                source_ranges: vec![current_token.into()],
                message: "expected another token".to_string(),
            }));
        }
        let argument = self.make_value(next_token.index)?;
        let argument_token = self.get_token(argument.last_index)?;
        Ok(UnaryExpressionResult {
            expression: UnaryExpression {
                operator: UnaryOperator::from_str(&current_token.value).map_err(|err| {
                    KclError::Syntax(KclErrorDetails {
                        source_ranges: vec![current_token.into()],
                        message: err.to_string(),
                    })
                })?,
                start: current_token.start,
                end: argument_token.end,
                argument: match argument.value {
                    Value::BinaryExpression(binary_expression) => BinaryPart::BinaryExpression(binary_expression),
                    Value::Identifier(identifier) => BinaryPart::Identifier(identifier),
                    Value::Literal(literal) => BinaryPart::Literal(literal),
                    Value::UnaryExpression(unary_expression) => BinaryPart::UnaryExpression(unary_expression),
                    Value::CallExpression(call_expression) => BinaryPart::CallExpression(call_expression),
                    Value::MemberExpression(member_expression) => BinaryPart::MemberExpression(member_expression),
                    _ => {
                        return Err(KclError::Syntax(KclErrorDetails {
                            source_ranges: vec![current_token.into()],
                            message: format!("Invalid argument for unary expression: {:?}", argument.value),
                        }));
                    }
                },
            },
            last_index: argument.last_index,
        })
    }

    fn make_expression_statement(&self, index: usize) -> Result<ExpressionStatementResult, KclError> {
        let current_token = self.get_token(index)?;
        let next = self.next_meaningful_token(index, None)?;
        if let Some(next_token) = &next.token {
            if next_token.token_type == TokenType::Brace && next_token.value == "(" {
                let call_expression = self.make_call_expression(index)?;
                let end = self.get_token(call_expression.last_index)?.end;
                return Ok(ExpressionStatementResult {
                    expression: ExpressionStatement {
                        start: current_token.start,
                        end,
                        expression: Value::CallExpression(Box::new(call_expression.expression)),
                    },
                    last_index: call_expression.last_index,
                });
            }
            let binary_expression = self.make_binary_expression(index)?;
            Ok(ExpressionStatementResult {
                expression: ExpressionStatement {
                    start: current_token.start,
                    end: binary_expression.expression.end,
                    expression: Value::BinaryExpression(Box::new(binary_expression.expression)),
                },
                last_index: binary_expression.last_index,
            })
        } else {
            Err(KclError::Unimplemented(KclErrorDetails {
                source_ranges: vec![current_token.into()],
                message: "make_expression_statement".to_string(),
            }))
        }
    }

    fn make_object_properties(
        &self,
        index: usize,
        previous_properties: Vec<ObjectProperty>,
    ) -> Result<ObjectPropertiesResult, KclError> {
        let property_key_token = self.get_token(index)?;
        if property_key_token.token_type == TokenType::Brace && property_key_token.value == "}" {
            return Ok(ObjectPropertiesResult {
                properties: previous_properties,
                last_index: index,
            });
        }
        let colon_token = self.next_meaningful_token(index, None)?;
        let value_start_token = self.next_meaningful_token(colon_token.index, None)?;
        let val = self.make_value(value_start_token.index)?;
        let value = val.value;
        let value_last_index = val.last_index;
        let comma_or_closing_brace_token = self.next_meaningful_token(value_last_index, None)?;
        let object_property = ObjectProperty {
            start: property_key_token.start,
            end: match &value {
                Value::BinaryExpression(binary_expression) => binary_expression.end,
                Value::Identifier(identifier) => identifier.end,
                Value::Literal(literal) => literal.end,
                Value::CallExpression(call_expression) => call_expression.end,
                Value::UnaryExpression(unary_expression) => unary_expression.end,
                Value::ObjectExpression(object_expression) => object_expression.end,
                Value::ArrayExpression(array_expression) => array_expression.end,
                Value::FunctionExpression(function_expression) => function_expression.end,
                Value::PipeExpression(pipe_expression) => pipe_expression.end,
                Value::PipeSubstitution(pipe_substitution) => pipe_substitution.end,
                Value::MemberExpression(member_expression) => member_expression.end,
            },
            key: self.make_identifier(index)?,
            value,
        };
        let next_key_token = self.next_meaningful_token(comma_or_closing_brace_token.index, None)?;
        if let Some(comma_or_closing_brace_token_token) = &comma_or_closing_brace_token.token {
            let next_key_index = if comma_or_closing_brace_token_token.token_type == TokenType::Brace
                && comma_or_closing_brace_token_token.value == "}"
            {
                comma_or_closing_brace_token.index
            } else {
                next_key_token.index
            };
            let mut _previous_properties = previous_properties;
            _previous_properties.push(object_property);
            self.make_object_properties(next_key_index, _previous_properties)
        } else {
            Err(KclError::Unimplemented(KclErrorDetails {
                source_ranges: vec![property_key_token.into()],
                message: "make_object_properties".to_string(),
            }))
        }
    }

    fn make_object_expression(&self, index: usize) -> Result<ObjectExpressionResult, KclError> {
        let opening_brace_token = self.get_token(index)?;
        // Make sure there is a closing brace.
        let _closing_brace = self.find_closing_brace(index, 0, "")?;
        let first_property_token = self.next_meaningful_token(index, None)?;
        let object_properties = self.make_object_properties(first_property_token.index, vec![])?;
        Ok(ObjectExpressionResult {
            expression: ObjectExpression {
                start: opening_brace_token.start,
                end: self.get_token(object_properties.last_index)?.end,
                properties: object_properties.properties,
            },
            last_index: object_properties.last_index,
        })
    }

    fn make_return_statement(&self, index: usize) -> Result<ReturnStatementResult, KclError> {
        let current_token = self.get_token(index)?;
        let next_token = self.next_meaningful_token(index, None)?;
        let val = self.make_value(next_token.index)?;
        let value = val.value;
        let last_index = val.last_index;
        Ok(ReturnStatementResult {
            statement: ReturnStatement {
                start: current_token.start,
                end: self.get_token(last_index)?.end,
                argument: value,
            },
            last_index,
        })
    }

    fn make_body(
        &self,
        token_index: usize,
        previous_body: Vec<BodyItem>,
        previous_non_code_meta: NonCodeMeta,
    ) -> Result<BodyResult, KclError> {
        let mut non_code_meta = previous_non_code_meta;
        if self.tokens.is_empty() {
            return Err(KclError::Semantic(KclErrorDetails {
                source_ranges: vec![],
                message: "file is empty".to_string(),
            }));
        }

        if token_index >= self.tokens.len() - 1 {
            return Ok(BodyResult {
                body: previous_body,
                last_index: token_index,
                non_code_meta,
            });
        }

        let token = self.get_token(token_index)?;
        if token.token_type == TokenType::Brace && token.value == "}" {
            return Ok(BodyResult {
                body: previous_body,
                last_index: token_index,
                non_code_meta,
            });
        }

        if !token.is_code_token() {
            let next_token = self.next_meaningful_token(token_index, Some(0))?;
            if let Some(node) = &next_token.non_code_node {
                if previous_body.is_empty() {
                    if let Some(next) = next_token.non_code_node {
                        non_code_meta.start.push(next);
                    }
                } else {
                    non_code_meta.insert(previous_body.len(), node.clone());
                }
            }
            return self.make_body(next_token.index, previous_body, non_code_meta);
        }

        let next = self.next_meaningful_token(token_index, None)?;
        if let Some(node) = &next.non_code_node {
            non_code_meta.insert(previous_body.len(), node.clone());
        }

        if token.token_type == TokenType::Keyword && VariableKind::from_str(&token.value).is_ok() {
            let declaration = self.make_variable_declaration(token_index)?;
            let next_thing = self.next_meaningful_token(declaration.last_index, None)?;
            if let Some(node) = &next_thing.non_code_node {
                non_code_meta.insert(previous_body.len(), node.clone());
            }
            let mut _previous_body = previous_body;
            _previous_body.push(BodyItem::VariableDeclaration(VariableDeclaration {
                start: declaration.declaration.start,
                end: declaration.declaration.end,
                kind: declaration.declaration.kind,
                declarations: declaration.declaration.declarations,
            }));
            let body = self.make_body(next_thing.index, _previous_body, non_code_meta)?;
            return Ok(BodyResult {
                body: body.body,
                last_index: body.last_index,
                non_code_meta: body.non_code_meta,
            });
        }

        if token.token_type == TokenType::Keyword && token.value == "return" {
            let statement = self.make_return_statement(token_index)?;
            let next_thing = self.next_meaningful_token(statement.last_index, None)?;
            if let Some(node) = &next_thing.non_code_node {
                non_code_meta.insert(previous_body.len(), node.clone());
            }
            let mut _previous_body = previous_body;
            _previous_body.push(BodyItem::ReturnStatement(ReturnStatement {
                start: statement.statement.start,
                end: statement.statement.end,
                argument: statement.statement.argument,
            }));
            let body = self.make_body(next_thing.index, _previous_body, non_code_meta)?;
            return Ok(BodyResult {
                body: body.body,
                last_index: body.last_index,
                non_code_meta: body.non_code_meta,
            });
        }

        if let Some(next_token) = next.token {
            if token.token_type == TokenType::Word
                && next_token.token_type == TokenType::Brace
                && next_token.value == "("
            {
                let expression = self.make_expression_statement(token_index)?;
                let next_thing = self.next_meaningful_token(expression.last_index, None)?;
                if let Some(node) = &next_thing.non_code_node {
                    non_code_meta.insert(previous_body.len(), node.clone());
                }
                let mut _previous_body = previous_body;
                _previous_body.push(BodyItem::ExpressionStatement(ExpressionStatement {
                    start: expression.expression.start,
                    end: expression.expression.end,
                    expression: expression.expression.expression,
                }));
                let body = self.make_body(next_thing.index, _previous_body, non_code_meta)?;
                return Ok(BodyResult {
                    body: body.body,
                    last_index: body.last_index,
                    non_code_meta: body.non_code_meta,
                });
            }
        }

        let next_thing = self.next_meaningful_token(token_index, None)?;
        if let Some(next_thing_token) = next_thing.token {
            if (token.token_type == TokenType::Number || token.token_type == TokenType::Word)
                && next_thing_token.token_type == TokenType::Operator
            {
                if let Some(node) = &next_thing.non_code_node {
                    non_code_meta.insert(previous_body.len(), node.clone());
                }
                let expression = self.make_expression_statement(token_index)?;
                let mut _previous_body = previous_body;
                _previous_body.push(BodyItem::ExpressionStatement(ExpressionStatement {
                    start: expression.expression.start,
                    end: expression.expression.end,
                    expression: expression.expression.expression,
                }));
                return Ok(BodyResult {
                    body: _previous_body,
                    last_index: expression.last_index,
                    non_code_meta,
                });
            }
        }

        Err(KclError::Syntax(KclErrorDetails {
            source_ranges: vec![token.into()],
            message: format!("unexpected token {}", token.value),
        }))
    }

    fn make_block_statement(&self, index: usize) -> Result<BlockStatementResult, KclError> {
        let opening_curly = self.get_token(index)?;
        let next_token = self.get_token(index + 1)?;
        let next_token_index = index + 1;
        let body = if next_token.value == "}" {
            BodyResult {
                body: vec![],
                last_index: next_token_index,
                non_code_meta: NonCodeMeta {
                    non_code_nodes: HashMap::new(),
                    start: Vec::new(),
                },
            }
        } else {
            self.make_body(
                next_token_index,
                vec![],
                NonCodeMeta {
                    non_code_nodes: HashMap::new(),
                    start: Vec::new(),
                },
            )?
        };
        Ok(BlockStatementResult {
            block: Program {
                start: opening_curly.start,
                end: self.get_token(body.last_index)?.end,
                body: body.body,
                non_code_meta: body.non_code_meta,
            },
            last_index: body.last_index,
        })
    }

    fn make_function_expression(&self, index: usize) -> Result<FunctionExpressionResult, KclError> {
        let current_token = self.get_token(index)?;
        let closing_brace_index = self.find_closing_brace(index, 0, "")?;
        let arrow_token = self.next_meaningful_token(closing_brace_index, None)?;
        let body_start_token = self.next_meaningful_token(arrow_token.index, None)?;
        let params = self.make_params(index, vec![])?;
        let block = self.make_block_statement(body_start_token.index)?;
        Ok(FunctionExpressionResult {
            expression: FunctionExpression {
                start: current_token.start,
                end: self.get_token(block.last_index)?.end,
                params: params.params,
                body: block.block,
            },
            last_index: block.last_index,
        })
    }
}

#[cfg(test)]
mod tests {
    use pretty_assertions::assert_eq;

    use super::*;
    use crate::ast::types::BinaryOperator;

    #[test]
    fn test_make_identifier() {
        let tokens = crate::token::lexer("a");
        let parser = Parser::new(tokens);
        let identifier = parser.make_identifier(0).unwrap();
        assert_eq!(
            Identifier {
                start: 0,
                end: 1,
                name: "a".to_string()
            },
            identifier
        );
    }

    #[test]
    fn test_make_identifier_with_const_myvar_equals_5_and_index_2() {
        let tokens = crate::token::lexer("const myVar = 5");
        let parser = Parser::new(tokens);
        let identifier = parser.make_identifier(2).unwrap();
        assert_eq!(
            Identifier {
                start: 6,
                end: 11,
                name: "myVar".to_string()
            },
            identifier
        );
    }

    #[test]
    fn test_make_identifier_multiline() {
        let tokens = crate::token::lexer("const myVar = 5\nconst newVar = myVar + 1");
        let parser = Parser::new(tokens);
        let identifier = parser.make_identifier(2).unwrap();
        assert_eq!(
            Identifier {
                start: 6,
                end: 11,
                name: "myVar".to_string()
            },
            identifier
        );
        let identifier = parser.make_identifier(10).unwrap();
        assert_eq!(
            Identifier {
                start: 22,
                end: 28,
                name: "newVar".to_string()
            },
            identifier
        );
    }

    #[test]
    fn test_make_identifier_call_expression() {
        let tokens = crate::token::lexer("log(5, \"hello\", aIdentifier)");
        let parser = Parser::new(tokens);
        let identifier = parser.make_identifier(0).unwrap();
        assert_eq!(
            Identifier {
                start: 0,
                end: 3,
                name: "log".to_string()
            },
            identifier
        );
        let identifier = parser.make_identifier(8).unwrap();
        assert_eq!(
            Identifier {
                start: 16,
                end: 27,
                name: "aIdentifier".to_string()
            },
            identifier
        );
    }
    #[test]
    fn test_make_non_code_node() {
        let tokens = crate::token::lexer("log(5, \"hello\", aIdentifier)");
        let parser = Parser::new(tokens);
        let index = 4;
        let expected_output = (None, 4);
        assert_eq!(parser.make_non_code_node(index).unwrap(), expected_output);

        let index = 7;
        let expected_output = (None, 7);
        assert_eq!(parser.make_non_code_node(index).unwrap(), expected_output);
        let tokens = crate::token::lexer(
            r#"
const yo = { a: { b: { c: '123' } } }
// this is a comment
const key = 'c'"#,
        );
        let parser = Parser::new(tokens);
        let index = 0;
        let expected_output = (None, 0);
        assert_eq!(parser.make_non_code_node(index).unwrap(), expected_output);

        let index = 2;
        let expected_output = (None, 2);
        assert_eq!(parser.make_non_code_node(index).unwrap(), expected_output);

        let index = 2;
        let expected_output = (None, 2);
        assert_eq!(parser.make_non_code_node(index).unwrap(), expected_output);

        let index = 29;
        let expected_output = (
            Some(NonCodeNode {
                start: 38,
                end: 60,
                value: NonCodeValue::BlockComment {
                    value: "this is a comment".to_string(),
                    style: CommentStyle::Line,
                },
            }),
            31,
        );
        assert_eq!(parser.make_non_code_node(index).unwrap(), expected_output);
    }

    #[test]
    fn test_collect_object_keys() {
        let tokens = crate::token::lexer("const prop = yo.one[\"two\"]");
        let parser = Parser::new(tokens);
        let keys_info = parser.collect_object_keys(6, None, false).unwrap();
        assert_eq!(keys_info.len(), 2);
        let first_key = match keys_info[0].key.clone() {
            LiteralIdentifier::Identifier(identifier) => format!("identifier-{}", identifier.name),
            _ => panic!("Expected first key to be an identifier"),
        };
        assert_eq!(first_key, "identifier-one");
        assert!(!keys_info[0].computed);
        let second_key = match keys_info[1].key.clone() {
            LiteralIdentifier::Literal(literal) => format!("literal-{}", literal.value),
            _ => panic!("Expected second key to be a literal"),
        };
        assert_eq!(second_key, "literal-\"two\"");
        assert!(!keys_info[1].computed);
    }

    #[test]
    fn test_make_literal_call_expression() {
        let tokens = crate::token::lexer("log(5, \"hello\", aIdentifier)");
        let parser = Parser::new(tokens);
        let literal = parser.make_literal(2).unwrap();
        assert_eq!(
            Literal {
                start: 4,
                end: 5,
                value: serde_json::Value::Number(5.into()),
                raw: "5".to_string()
            },
            literal
        );
        let literal = parser.make_literal(5).unwrap();
        assert_eq!(
            Literal {
                start: 7,
                end: 14,
                value: serde_json::Value::String("hello".to_string()),
                raw: "\"hello\"".to_string()
            },
            literal
        );
    }

    #[test]
    fn test_math_parse() {
        let tokens = crate::token::lexer(r#"5 + "a""#);
        let actual = Parser::new(tokens).ast().unwrap().body;
        let expr = BinaryExpression {
            start: 0,
            end: 7,
            operator: BinaryOperator::Add,
            left: BinaryPart::Literal(Box::new(Literal {
                start: 0,
                end: 1,
                value: serde_json::Value::Number(serde_json::Number::from(5)),
                raw: "5".to_owned(),
            })),
            right: BinaryPart::Literal(Box::new(Literal {
                start: 4,
                end: 7,
                value: serde_json::Value::String("a".to_owned()),
                raw: r#""a""#.to_owned(),
            })),
        };
        let expected = vec![BodyItem::ExpressionStatement(ExpressionStatement {
            start: 0,
            end: 7,
            expression: Value::BinaryExpression(Box::new(expr)),
        })];
        assert_eq!(expected, actual);
    }

    #[test]
    fn test_is_code_token() {
        let tokens = [
            Token {
                token_type: TokenType::Word,
                start: 0,
                end: 3,
                value: "log".to_string(),
            },
            Token {
                token_type: TokenType::Brace,
                start: 3,
                end: 4,
                value: "(".to_string(),
            },
            Token {
                token_type: TokenType::Number,
                start: 4,
                end: 5,
                value: "5".to_string(),
            },
            Token {
                token_type: TokenType::Comma,
                start: 5,
                end: 6,
                value: ",".to_string(),
            },
            Token {
                token_type: TokenType::String,
                start: 7,
                end: 14,
                value: "\"hello\"".to_string(),
            },
            Token {
                token_type: TokenType::Word,
                start: 16,
                end: 27,
                value: "aIdentifier".to_string(),
            },
            Token {
                token_type: TokenType::Brace,
                start: 27,
                end: 28,
                value: ")".to_string(),
            },
        ];
        for (i, token) in tokens.iter().enumerate() {
            assert!(token.is_code_token(), "failed test {i}: {token:?}")
        }
    }

    #[test]
    fn test_is_not_code_token() {
        let tokens = [
            Token {
                token_type: TokenType::Whitespace,
                start: 6,
                end: 7,
                value: " ".to_string(),
            },
            Token {
                token_type: TokenType::BlockComment,
                start: 28,
                end: 30,
                value: "/* abte */".to_string(),
            },
            Token {
                token_type: TokenType::LineComment,
                start: 30,
                end: 33,
                value: "// yoyo a line".to_string(),
            },
        ];
        for (i, token) in tokens.iter().enumerate() {
            assert!(!token.is_code_token(), "failed test {i}: {token:?}")
        }
    }

    #[test]
    fn test_next_meaningful_token() {
        let _offset = 1;
        let tokens = crate::token::lexer(
            r#"const mySketch = startSketchOn('XY')
  |> startProfileAt([0,0], %)
  |> lineTo({ to: [0, 1], tag: 'myPath' }, %)
  |> lineTo([1, 1], %) /* this is
      a comment
      spanning a few lines */
  |> lineTo({ to: [1,0], tag: "rightPath" }, %)
  |> close(%)"#,
        );
        let parser = Parser::new(tokens);
        let index = 17;
        let expected_output = TokenReturnWithNonCode {
            token: Some(Token {
                token_type: TokenType::Number,
                start: 60,
                end: 61,
                value: "0".to_string(),
            }),
            index: 18,
            non_code_node: None,
        };
        assert_eq!(parser.next_meaningful_token(index, None).unwrap(), expected_output);
        let index = 18;
        let expected_output = TokenReturnWithNonCode {
            token: Some(Token {
                token_type: TokenType::Brace,
                start: 61,
                end: 62,
                value: "]".to_string(),
            }),
            index: 19,
            non_code_node: None,
        };
        assert_eq!(parser.next_meaningful_token(index, None).unwrap(), expected_output);
        let index = 21;
        let expected_output = TokenReturnWithNonCode {
            token: Some(Token {
                token_type: TokenType::Operator,
                start: 64,
                end: 65,
                value: "%".to_string(),
            }),
            index: 22,
            non_code_node: None,
        };
        assert_eq!(parser.next_meaningful_token(index, None).unwrap(), expected_output);
        let index = 24;
        let expected_output = TokenReturnWithNonCode {
            token: Some(Token {
                token_type: TokenType::Operator,
                start: 69,
                end: 71,
                value: "|>".to_string(),
            }),
            index: 25,
            non_code_node: None,
        };
        assert_eq!(parser.next_meaningful_token(index, None).unwrap(), expected_output);
        let index = 25;
        let expected_output = TokenReturnWithNonCode {
            token: Some(Token {
                token_type: TokenType::Word,
                start: 72,
                end: 78,
                value: "lineTo".to_string(),
            }),
            index: 27,
            non_code_node: None,
        };
        assert_eq!(parser.next_meaningful_token(index, None).unwrap(), expected_output);
    }

    #[test]
    fn test_find_closing_brace() {
        let tokens = crate::token::lexer(
            r#"const mySketch = startSketchOn('XY')
  |> startProfileAt([0,0], %)
|> lineTo({ to: [0, 1], tag: 'myPath' }, %)
|> lineTo([1, 1], %) /* this is
  a comment
  spanning a few lines */
|> lineTo({ to: [1,0], tag: "rightPath" }, %)
|> close(%)"#,
        );
        let parser = Parser::new(tokens);
        assert_eq!(parser.find_closing_brace(7, 0, "").unwrap(), 9);
        assert_eq!(parser.find_closing_brace(14, 0, "").unwrap(), 23);
        assert_eq!(parser.find_closing_brace(29, 0, "").unwrap(), 47);
        assert_eq!(parser.find_closing_brace(57, 0, "").unwrap(), 62);

        let basic = "( hey )";
        let parser = Parser::new(crate::token::lexer(basic));
        assert_eq!(parser.find_closing_brace(0, 0, "").unwrap(), 4);

        let handles_non_zero_index = "(indexForBracketToRightOfThisIsTwo(shouldBeFour)AndNotThisSix)";
        let parser = Parser::new(crate::token::lexer(handles_non_zero_index));
        assert_eq!(parser.find_closing_brace(2, 0, "").unwrap(), 4);
        assert_eq!(parser.find_closing_brace(0, 0, "").unwrap(), 6);

        let handles_nested = "{a{b{c(}d]}eathou athoeu tah u} thatOneToTheLeftIsLast }";
        let parser = Parser::new(crate::token::lexer(handles_nested));
        assert_eq!(parser.find_closing_brace(0, 0, "").unwrap(), 18);

        // TODO expect error when not started on a brace
    }

    #[test]
    fn test_is_call_expression() {
        let tokens = crate::token::lexer(
            r#"const mySketch = startSketchOn('XY')
  |> startProfileAt([0,0], %)
|> lineTo({ to: [0, 1], tag: 'myPath' }, %)
|> lineTo([1, 1], %) /* this is
  a comment
  spanning a few lines */
|> lineTo({ to: [1,0], tag: "rightPath" }, %)
|> close(%)"#,
        );
        let parser = Parser::new(tokens);

        assert_eq!(parser.is_call_expression(4).unwrap(), None);
        assert_eq!(parser.is_call_expression(6).unwrap(), Some(9));
        assert_eq!(parser.is_call_expression(9).unwrap(), None);
        assert_eq!(parser.is_call_expression(43).unwrap(), None);
        assert_eq!(parser.is_call_expression(60).unwrap(), None);
        assert_eq!(parser.is_call_expression(87).unwrap(), None);
    }

    #[test]
    fn test_find_next_declaration_keyword() {
        let tokens = crate::token::lexer(
            r#"const mySketch = startSketchOn('XY')
  |> startProfileAt([0,0], %)
|> lineTo({ to: [0, 1], tag: 'myPath' }, %)
|> lineTo([1, 1], %) /* this is
  a comment
  spanning a few lines */
|> lineTo({ to: [1,0], tag: "rightPath" }, %)
|> close(%)"#,
        );
        let parser = Parser::new(tokens);
        assert_eq!(
            parser.find_next_declaration_keyword(4).unwrap(),
            TokenReturn {
                token: None,
                index: 102
            }
        );

        let tokens = crate::token::lexer(
            r#"const myVar = 5
const newVar = myVar + 1
"#,
        );
        let parser = Parser::new(tokens);
        assert_eq!(
            parser.find_next_declaration_keyword(6).unwrap(),
            TokenReturn {
                token: Some(Token {
                    token_type: TokenType::Keyword,
                    start: 16,
                    end: 21,
                    value: "const".to_string(),
                }),
                index: 8,
            }
        );
        assert_eq!(
            parser.find_next_declaration_keyword(14).unwrap(),
            TokenReturn { token: None, index: 19 }
        );
    }

    #[test]
    fn test_has_pipe_operator() {
        let code = r#"sketch mySketch {
  lineTo(2, 3)
} |> rx(45, %)
"#;
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens);
        assert_eq!(
            parser.has_pipe_operator(0, None).unwrap(),
            TokenReturnWithNonCode {
                token: Some(Token {
                    token_type: TokenType::Operator,
                    start: 35,
                    end: 37,
                    value: "|>".to_string(),
                }),
                index: 16,
                non_code_node: None,
            }
        );
        let code = r#"sketch mySketch {
  lineTo(2, 3)
} |> rx(45, %) |> rx(45, %)
"#;
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens);
        assert_eq!(
            parser.has_pipe_operator(0, None).unwrap(),
            TokenReturnWithNonCode {
                token: Some(Token {
                    token_type: TokenType::Operator,
                    start: 35,
                    end: 37,
                    value: "|>".to_string(),
                }),
                index: 16,
                non_code_node: None,
            }
        );

        let code = r#"sketch mySketch {
  lineTo(2, 3)
}
const yo = myFunc(9()
  |> rx(45, %)
"#;
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens);
        assert_eq!(
            parser.has_pipe_operator(0, None).unwrap(),
            TokenReturnWithNonCode {
                token: None,
                index: 16,
                non_code_node: None,
            }
        );

        let code = "const myVar2 = 5 + 1 |> myFn(%)";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens);
        assert_eq!(
            parser.has_pipe_operator(1, None).unwrap(),
            TokenReturnWithNonCode {
                token: Some(Token {
                    token_type: TokenType::Operator,
                    start: 21,
                    end: 23,
                    value: "|>".to_string(),
                }),
                index: 12,
                non_code_node: None,
            }
        );

        let code = r#"sketch mySk1 {
  lineTo(1,1)
  path myPath = lineTo(0, 1)
  lineTo(1,1)
} |> rx(90, %)
show(mySk1)"#;
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let token_with_my_path_index = tokens.iter().position(|token| token.value == "myPath").unwrap();
        // loop through getting the token and it's index
        let token_with_line_to_index_for_var_dec_index = tokens
            .iter()
            .enumerate()
            .find(|(index, token)| token.value == "lineTo" && index > &token_with_my_path_index)
            .unwrap()
            .0;
        // expect to return None,
        assert_eq!(
            parser
                .has_pipe_operator(token_with_line_to_index_for_var_dec_index, None)
                .unwrap(),
            TokenReturnWithNonCode {
                token: None,
                index: 27,
                non_code_node: None,
            }
        );

        let brace_token_index = tokens.iter().position(|token| token.value == "{").unwrap();
        assert_eq!(
            parser.has_pipe_operator(brace_token_index, None).unwrap(),
            TokenReturnWithNonCode {
                token: Some(Token {
                    token_type: TokenType::Operator,
                    start: 74,
                    end: 76,
                    value: "|>".to_string(),
                }),
                index: 36,
                non_code_node: None,
            }
        );
    }

    #[test]
    fn test_make_member_expression() {
        let tokens = crate::token::lexer("const prop = yo.one[\"two\"]");
        let parser = Parser::new(tokens);
        let member_expression_return = parser.make_member_expression(6).unwrap();
        let member_expression = member_expression_return.expression;
        let last_index = member_expression_return.last_index;
        assert_eq!(member_expression.start, 13);
        assert_eq!(member_expression.end, 26);
        let member_object = match member_expression.object {
            MemberObject::MemberExpression(member_expression) => member_expression,
            _ => panic!("Expected member expression"),
        };
        assert_eq!(member_object.start, 13);
        assert_eq!(member_object.end, 19);
        let member_object_object = match member_object.object {
            MemberObject::Identifier(identifier) => identifier,
            _ => panic!("Expected identifier"),
        };
        assert_eq!(member_object_object.start, 13);
        assert_eq!(member_object_object.end, 15);
        assert_eq!(member_object_object.name, "yo");
        let member_object_property = match member_object.property {
            LiteralIdentifier::Identifier(identifier) => identifier,
            _ => panic!("Expected identifier"),
        };
        assert_eq!(member_object_property.start, 16);
        assert_eq!(member_object_property.end, 19);
        assert_eq!(member_object_property.name, "one");
        assert!(!member_object.computed);
        let member_expression_property = match member_expression.property {
            LiteralIdentifier::Literal(literal) => literal,
            _ => panic!("Expected literal"),
        };
        assert_eq!(member_expression_property.start, 20);
        assert_eq!(member_expression_property.end, 25);
        assert_eq!(member_expression_property.value, "two");
        assert!(!member_expression.computed);
        assert_eq!(last_index, 11);
    }

    #[test]
    fn test_find_end_of_binary_expression() {
        let code = "1 + 2 * 3\nconst yo = 5";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(0).unwrap();
        assert_eq!(tokens[end].value, "3");

        let code = "(1 + 25) / 5 - 3\nconst yo = 5";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(0).unwrap();
        assert_eq!(tokens[end].value, "3");
        let index_of_5 = code.find('5').unwrap();
        let end_starting_at_the_5 = parser.find_end_of_binary_expression(index_of_5).unwrap();
        assert_eq!(end_starting_at_the_5, end);
        // whole thing wrapped
        let code = "((1 + 2) / 5 - 3)\nconst yo = 5";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(0).unwrap();
        assert_eq!(tokens[end].end, code.find("3)").unwrap() + 2);
        // whole thing wrapped but given index after the first brace
        let code = "((1 + 2) / 5 - 3)\nconst yo = 5";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(1).unwrap();
        assert_eq!(tokens[end].value, "3");
        // given the index of a small wrapped section i.e. `1 + 2` in ((1 + 2) / 5 - 3)'
        let code = "((1 + 2) / 5 - 3)\nconst yo = 5";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(2).unwrap();
        assert_eq!(tokens[end].value, "2");
        // lots of silly nesting
        let code = "(1 + 2) / (5 - (3))\nconst yo = 5";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(0).unwrap();
        assert_eq!(tokens[end].end, code.find("))").unwrap() + 2);
        // with pipe operator at the end
        let code = "(1 + 2) / (5 - (3))\n  |> fn(%)";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(0).unwrap();
        assert_eq!(tokens[end].end, code.find("))").unwrap() + 2);
        // with call expression at the start of binary expression
        let code = "yo(2) + 3\n  |> fn(%)";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(0).unwrap();
        assert_eq!(tokens[end].value, "3");
        // with call expression at the end of binary expression
        let code = "3 + yo(2)\n  |> fn(%)";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens);
        let _end = parser.find_end_of_binary_expression(0).unwrap();
        // with call expression at the end of binary expression
        let code = "-legX + 2, ";
        let tokens = crate::token::lexer(code);
        let parser = Parser::new(tokens.clone());
        let end = parser.find_end_of_binary_expression(0).unwrap();
        assert_eq!(tokens[end].value, "2");
    }

    #[test]
    fn test_make_array_expression() {
        // input_index: 6, output_index: 14, output: {"type":"ArrayExpression","start":11,"end":26,"elements":[{"type":"Literal","start":12,"end":15,"value":"1","raw":"\"1\""},{"type":"Literal","start":17,"end":18,"value":2,"raw":"2"},{"type":"Identifier","start":20,"end":25,"name":"three"}]}
        let tokens = crate::token::lexer("const yo = [\"1\", 2, three]");
        let parser = Parser::new(tokens);
        let array_expression = parser.make_array_expression(6).unwrap();
        let expression = array_expression.expression;
        assert_eq!(array_expression.last_index, 14);
        assert_eq!(expression.start, 11);
        assert_eq!(expression.end, 26);
        let elements = expression.elements;
        assert_eq!(elements.len(), 3);
        match &elements[0] {
            Value::Literal(literal) => {
                assert_eq!(literal.start, 12);
                assert_eq!(literal.end, 15);
                assert_eq!(literal.value, serde_json::Value::String("1".to_string()));
                assert_eq!(literal.raw, "\"1\"".to_string());
            }
            _ => panic!("Expected literal"),
        }
        match &elements[1] {
            Value::Literal(literal) => {
                assert_eq!(literal.start, 17);
                assert_eq!(literal.end, 18);
                assert_eq!(literal.value, serde_json::Value::Number(2.into()));
                assert_eq!(literal.raw, "2".to_string());
            }
            _ => panic!("Expected literal"),
        }
        match &elements[2] {
            Value::Identifier(identifier) => {
                assert_eq!(identifier.start, 20);
                assert_eq!(identifier.end, 25);
                assert_eq!(identifier.name, "three".to_string());
            }
            _ => panic!("Expected identifier"),
        }
    }

    #[test]
    fn test_make_call_expression() {
        let tokens = crate::token::lexer("foo(\"a\", a, 3)");
        let parser = Parser::new(tokens);
        let result = parser.make_call_expression(0).unwrap();
        assert_eq!(result.last_index, 9);
        assert_eq!(result.expression.start, 0);
        assert_eq!(result.expression.end, 14);
        assert_eq!(result.expression.callee.name, "foo");
        assert_eq!(result.expression.arguments.len(), 3);
        assert!(!result.expression.optional);
        let arguments = result.expression.arguments;
        match arguments[0] {
            Value::Literal(ref literal) => {
                assert_eq!(literal.value, "a");
                assert_eq!(literal.raw, "\"a\"");
            }
            _ => panic!("Expected literal"),
        }
        match arguments[1] {
            Value::Identifier(ref identifier) => {
                assert_eq!(identifier.name, "a");
            }
            _ => panic!("Expected identifier"),
        }
        match arguments[2] {
            Value::Literal(ref literal) => {
                assert_eq!(literal.value, 3);
                assert_eq!(literal.raw, "3");
            }
            _ => panic!("Expected literal"),
        }
    }

    #[test]
    fn test_make_variable_declaration() {
        let tokens = crate::token::lexer(
            r#"const yo = startSketch([0, 0])
  |> lineTo([1, myVar], %)
  |> foo(myVar2, %)
  |> close(%)"#,
        );
        let parser = Parser::new(tokens);
        let result = parser.make_variable_declaration(0).unwrap();
        assert_eq!(result.declaration.kind.to_string(), "const");
        assert_eq!(result.declaration.declarations.len(), 1);
        assert_eq!(result.declaration.declarations[0].id.name, "yo");
        let declaration = result.declaration.declarations[0].clone();
        let body = match declaration.init {
            Value::PipeExpression(body) => body,
            _ => panic!("expected pipe expression"),
        };
        assert_eq!(body.body.len(), 4);
        let first_call_expression = match &body.body[0] {
            Value::CallExpression(call_expression) => call_expression,
            _ => panic!("expected call expression"),
        };
        assert_eq!(first_call_expression.callee.name, "startSketch");
        assert_eq!(first_call_expression.arguments.len(), 1);
        let first_argument = &first_call_expression.arguments[0];
        let first_argument_array_expression = match first_argument {
            Value::ArrayExpression(array_expression) => array_expression,
            _ => panic!("expected array expression"),
        };
        assert_eq!(first_argument_array_expression.elements.len(), 2);
        let second_call_expression = match &body.body[1] {
            Value::CallExpression(call_expression) => call_expression,
            _ => panic!("expected call expression"),
        };
        assert_eq!(second_call_expression.callee.name, "lineTo");
        assert_eq!(second_call_expression.arguments.len(), 2);
        let first_argument = &second_call_expression.arguments[0];
        let first_argument_array_expression = match first_argument {
            Value::ArrayExpression(array_expression) => array_expression,
            _ => panic!("expected array expression"),
        };
        assert_eq!(first_argument_array_expression.elements.len(), 2);
        let second_argument = &second_call_expression.arguments[1];
        let second_argument_pipe_substitution = match second_argument {
            Value::PipeSubstitution(pipe_substitution) => pipe_substitution,
            _ => panic!("expected pipe substitution"),
        };
        assert_eq!(second_argument_pipe_substitution.start, 55);
        let third_call_expression = match &body.body[2] {
            Value::CallExpression(call_expression) => call_expression,
            _ => panic!("expected call expression"),
        };
        assert_eq!(third_call_expression.callee.name, "foo");
        assert_eq!(third_call_expression.arguments.len(), 2);
        let first_argument = &third_call_expression.arguments[0];
        let first_argument_identifier = match first_argument {
            Value::Identifier(identifier) => identifier,
            _ => panic!("expected identifier"),
        };
        assert_eq!(first_argument_identifier.name, "myVar2");

        let fourth_call_expression = match &body.body[3] {
            Value::CallExpression(call_expression) => call_expression,
            _ => panic!("expected call expression"),
        };
        assert_eq!(fourth_call_expression.callee.name, "close");
        assert_eq!(fourth_call_expression.arguments.len(), 1);
    }

    #[test]
    fn test_make_body() {
        let tokens = crate::token::lexer("const myVar = 5");
        let parser = Parser::new(tokens);
        let body = parser
            .make_body(
                0,
                vec![],
                NonCodeMeta {
                    non_code_nodes: HashMap::new(),
                    start: Vec::new(),
                },
            )
            .unwrap();
        assert_eq!(body.body.len(), 1);
    }

    #[test]
    fn test_abstract_syntax_tree() {
        let code = "5 +6";
        let parser = Parser::new(crate::token::lexer(code));
        let result = parser.ast().unwrap();
        let expected_result = Program {
            start: 0,
            end: 4,
            body: vec![BodyItem::ExpressionStatement(ExpressionStatement {
                start: 0,
                end: 4,
                expression: Value::BinaryExpression(Box::new(BinaryExpression {
                    start: 0,
                    end: 4,
                    left: BinaryPart::Literal(Box::new(Literal {
                        start: 0,
                        end: 1,
                        value: serde_json::Value::Number(serde_json::Number::from(5)),
                        raw: "5".to_string(),
                    })),
                    operator: BinaryOperator::Add,
                    right: BinaryPart::Literal(Box::new(Literal {
                        start: 3,
                        end: 4,
                        value: serde_json::Value::Number(serde_json::Number::from(6)),
                        raw: "6".to_string(),
                    })),
                })),
            })],
            non_code_meta: NonCodeMeta::default(),
        };

        assert_eq!(result, expected_result);
    }

    #[test]
    fn test_empty_file() {
        let some_program_string = r#""#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert!(result.err().unwrap().to_string().contains("file is empty"));
    }

    #[test]
    fn test_parse_half_pipe_small() {
        let tokens = crate::token::lexer(
            "const secondExtrude = startSketchOn('XY')
  |> startProfileAt([0,0], %)
  |",
        );
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
    }

    #[test]
    fn test_parse_member_expression_double_nested_braces() {
        let tokens = crate::token::lexer(r#"const prop = yo["one"][two]"#);
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_parse_member_expression_binary_expression_period_number_first() {
        let tokens = crate::token::lexer(
            r#"const obj = { a: 1, b: 2 }
const height = 1 - obj.a"#,
        );
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_parse_member_expression_binary_expression_brace_number_first() {
        let tokens = crate::token::lexer(
            r#"const obj = { a: 1, b: 2 }
const height = 1 - obj["a"]"#,
        );
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_parse_member_expression_binary_expression_brace_number_second() {
        let tokens = crate::token::lexer(
            r#"const obj = { a: 1, b: 2 }
const height = obj["a"] - 1"#,
        );
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_parse_member_expression_binary_expression_in_array_number_first() {
        let tokens = crate::token::lexer(
            r#"const obj = { a: 1, b: 2 }
const height = [1 - obj["a"], 0]"#,
        );
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_parse_member_expression_binary_expression_in_array_number_second() {
        let tokens = crate::token::lexer(
            r#"const obj = { a: 1, b: 2 }
const height = [obj["a"] - 1, 0]"#,
        );
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_parse_member_expression_binary_expression_in_array_number_second_missing_space() {
        let tokens = crate::token::lexer(
            r#"const obj = { a: 1, b: 2 }
const height = [obj["a"] -1, 0]"#,
        );
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_parse_half_pipe() {
        let tokens = crate::token::lexer(
            "const height = 10

const firstExtrude = startSketchOn('XY')
  |> startProfileAt([0,0], %)
  |> line([0, 8], %)
  |> line([20, 0], %)
  |> line([0, -8], %)
  |> close(%)
  |> extrude(2, %)

show(firstExtrude)

const secondExtrude = startSketchOn('XY')
  |> startProfileAt([0,0], %)
  |",
        );
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
    }

    #[test]
    fn test_parse_greater_bang() {
        let tokens = crate::token::lexer(">!");
        let parser = Parser::new(tokens);
        let err = parser.ast().unwrap_err();
        // TODO: Better errors when program cannot tokenize.
        // https://github.com/KittyCAD/modeling-app/issues/696
        assert!(err.to_string().contains("file is empty"));
    }

    #[test]
    fn test_parse_z_percent_parens() {
        let tokens = crate::token::lexer("z%)");
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
    }

    #[test]
    fn test_parse_parens_unicode() {
        let tokens = crate::token::lexer("(ޜ");
        let parser = Parser::new(tokens);
        let result = parser.ast();
        // TODO: Better errors when program cannot tokenize.
        // https://github.com/KittyCAD/modeling-app/issues/696
        assert!(result.is_err());
    }

    #[test]
    fn test_parse_negative_in_array_binary_expression() {
        let tokens = crate::token::lexer(
            r#"const leg1 = 5
const thickness = 0.56

const bracket = [-leg2 + thickness, 0]
"#,
        );
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_ok());
    }

    #[test]
    fn test_parse_nested_open_brackets() {
        let tokens = crate::token::lexer(
            r#"
z(-[["#,
        );
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
    }

    #[test]
    fn test_parse_weird_new_line_function() {
        let tokens = crate::token::lexer(
            r#"z
 (--#"#,
        );
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        // TODO: Better errors when program cannot tokenize.
        // https://github.com/KittyCAD/modeling-app/issues/696
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [], message: "file is empty" }"#
        );
    }

    #[test]
    fn test_parse_weird_lots_of_fancy_brackets() {
        let tokens = crate::token::lexer(r#"zz({{{{{{{{)iegAng{{{{{{{##"#);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        // TODO: Better errors when program cannot tokenize.
        // https://github.com/KittyCAD/modeling-app/issues/696
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [], message: "file is empty" }"#
        );
    }

    #[test]
    fn test_parse_weird_close_before_open() {
        let tokens = crate::token::lexer(
            r#"fn)n
e
["#,
        );
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert!(result
            .err()
            .unwrap()
            .to_string()
            .contains("expected whitespace, found ')' which is brace"));
    }

    #[test]
    fn test_parse_weird_close_before_nada() {
        let tokens = crate::token::lexer(r#"fn)n-"#);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert!(result
            .err()
            .unwrap()
            .to_string()
            .contains("expected whitespace, found ')' which is brace"));
    }

    #[test]
    fn test_parse_weird_lots_of_slashes() {
        let tokens = crate::token::lexer(
            r#"J///////////o//+///////////P++++*++++++P///////˟
++4"#,
        );
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert!(result.err().unwrap().to_string().contains("Unexpected token"));
    }

    #[test]
    fn test_parse_expand_array() {
        let code = "const myArray = [0..10]";
        let parser = Parser::new(crate::token::lexer(code));
        let result = parser.ast().unwrap();
        let expected_result = Program {
            start: 0,
            end: 23,
            body: vec![BodyItem::VariableDeclaration(VariableDeclaration {
                start: 0,
                end: 23,
                declarations: vec![VariableDeclarator {
                    start: 6,
                    end: 23,
                    id: Identifier {
                        start: 6,
                        end: 13,
                        name: "myArray".to_string(),
                    },
                    init: Value::ArrayExpression(Box::new(ArrayExpression {
                        start: 16,
                        end: 23,
                        elements: vec![
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 0.into(),
                                raw: "0".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 1.into(),
                                raw: "1".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 2.into(),
                                raw: "2".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 3.into(),
                                raw: "3".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 4.into(),
                                raw: "4".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 5.into(),
                                raw: "5".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 6.into(),
                                raw: "6".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 7.into(),
                                raw: "7".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 8.into(),
                                raw: "8".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 9.into(),
                                raw: "9".to_string(),
                            })),
                            Value::Literal(Box::new(Literal {
                                start: 17,
                                end: 18,
                                value: 10.into(),
                                raw: "10".to_string(),
                            })),
                        ],
                    })),
                }],
                kind: VariableKind::Const,
            })],
            non_code_meta: NonCodeMeta::default(),
        };

        assert_eq!(result, expected_result);
    }

    #[test]
    fn test_error_keyword_in_variable() {
        let some_program_string = r#"const let = "thing""#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([6, 9])], message: "Cannot assign a variable to a reserved keyword: let" }"#
        );
    }

    #[test]
    fn test_error_keyword_in_fn_name() {
        let some_program_string = r#"fn let = () {}"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([3, 6])], message: "Cannot assign a variable to a reserved keyword: let" }"#
        );
    }

    #[test]
    fn test_error_stdlib_in_fn_name() {
        let some_program_string = r#"fn cos = () => {
            return 1
        }"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([3, 6])], message: "Cannot assign a variable to a reserved keyword: cos" }"#
        );
    }

    #[test]
    fn test_error_keyword_in_fn_args() {
        let some_program_string = r#"fn thing = (let) => {
    return 1
}"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([12, 15])], message: "Cannot assign a variable to a reserved keyword: let" }"#
        );
    }

    #[test]
    fn test_error_stdlib_in_fn_args() {
        let some_program_string = r#"fn thing = (cos) => {
    return 1
}"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([12, 15])], message: "Cannot assign a variable to a reserved keyword: cos" }"#
        );
    }

    #[test]
    fn zero_param_function() {
        let program = r#"
        fn firstPrimeNumber = () => {
            return 2
        }
        firstPrimeNumber()
        "#;
        let tokens = crate::token::lexer(program);
        let parser = Parser::new(tokens);
        let _ast = parser.ast().unwrap();
    }

    #[test]
    fn test_keyword_ok_in_fn_args_return() {
        let some_program_string = r#"fn thing = (param) => {
    return true
}

thing(false)
"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_error_define_function_as_var() {
        for name in ["var", "let", "const"] {
            let some_program_string = format!(
                r#"{} thing = (param) => {{
    return true
}}

thing(false)
"#,
                name
            );
            let tokens = crate::token::lexer(&some_program_string);
            let parser = Parser::new(tokens);
            let result = parser.ast();
            assert!(result.is_err());
            assert_eq!(
                result.err().unwrap().to_string(),
                format!(
                    r#"syntax: KclErrorDetails {{ source_ranges: [SourceRange([0, {}])], message: "Expected a `fn` variable kind, found: `{}`" }}"#,
                    name.len(),
                    name
                )
            );
        }
    }

    #[test]
    fn test_error_define_var_as_function() {
        let some_program_string = r#"fn thing = "thing""#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        let result = parser.ast();
        assert!(result.is_err());
        // TODO: https://github.com/KittyCAD/modeling-app/issues/784
        // Improve this error message.
        // It should say that the compiler is expecting a function expression on the RHS.
        assert_eq!(
            result.err().unwrap().to_string(),
            r#"syntax: KclErrorDetails { source_ranges: [SourceRange([11, 18])], message: "Unexpected token" }"#
        );
    }

    #[test]
    fn test_member_expression_sketch_group() {
        let some_program_string = r#"fn cube = (pos, scale) => {
  const sg = startSketchOn('XY')
  |> startProfileAt(pos, %)
    |> line([0, scale], %)
    |> line([scale, 0], %)
    |> line([0, -scale], %)

  return sg
}

const b1 = cube([0,0], 10)
const b2 = cube([3,3], 4)

const pt1 = b1[0]
const pt2 = b2[0]

show(b1)
show(b2)"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_math_with_stdlib() {
        let some_program_string = r#"const d2r = pi() / 2
let other_thing = 2 * cos(3)"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }

    #[test]
    fn test_negative_arguments() {
        let some_program_string = r#"fn box = (p, h, l, w) => {
 const myBox = startSketchOn('XY')
    |> startProfileAt(p, %)
    |> line([0, l], %)
    |> line([w, 0], %)
    |> line([0, -l], %)
    |> close(%)
    |> extrude(h, %)

  return myBox
}
let myBox = box([0,0], -3, -16, -10)
show(myBox)"#;
        let tokens = crate::token::lexer(some_program_string);
        let parser = Parser::new(tokens);
        parser.ast().unwrap();
    }
}