solidb 1.0.2

//! Operator precedence chain for SDBQL expression parsing.
//!
//! Precedence (lowest to highest):
//! 1. Ternary: `?:`
//! 2. Null coalesce: `??`
//! 3. Logical OR: `||`
//! 4. Pipeline: `|>`
//! 5. Boolean OR: `OR`
//! 6. Boolean AND: `AND`
//! 7. Bitwise OR: `|`
//! 8. Bitwise XOR: `^`
//! 9. Bitwise AND: `&`
//! 10. Comparison: `==`, `!=`, `<`, `<=`, `>`, `>=`, `IN`, `LIKE`, etc.
//! 11. Range: `..`
//! 12. Shift: `<<`, `>>`
//! 13. Additive: `+`, `-`
//! 14. Multiplicative: `*`, `/`, `%`
//! 15. Unary: `!`, `-`, `~`
//! 16. Postfix: `.`, `?.`, `[]`
//! 17. Primary: literals, variables, function calls, etc.

use crate::error::{DbError, DbResult};
use crate::sdbql::ast::{BinaryOperator, Expression, UnaryOperator};
use crate::sdbql::lexer::Token;
use crate::sdbql::parser::Parser;

impl Parser {
    /// Parse ternary expression: condition ? true_expr : false_expr
    /// Lowest precedence, right-associative
    pub(super) fn parse_ternary_expression(&mut self) -> DbResult<Expression> {
        let condition = self.parse_null_coalesce_expression()?;

        if matches!(self.current_token(), Token::Question) {
            self.advance(); // consume '?'
            let true_expr = self.parse_ternary_expression()?; // right-associative
            self.expect(Token::Colon)?;
            let false_expr = self.parse_ternary_expression()?;
            Ok(Expression::Ternary {
                condition: Box::new(condition),
                true_expr: Box::new(true_expr),
                false_expr: Box::new(false_expr),
            })
        } else {
            Ok(condition)
        }
    }

    /// Parse null coalescing expression: left ?? right
    /// Returns left if left is not null, otherwise evaluates and returns right
    fn parse_null_coalesce_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_logical_or_expression()?;

        while matches!(self.current_token(), Token::NullCoalesce) {
            self.advance(); // consume ??
            let right = self.parse_logical_or_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op: BinaryOperator::NullCoalesce,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse logical OR expression: left || right
    fn parse_logical_or_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_pipeline_expression()?;

        while matches!(self.current_token(), Token::DoublePipe) {
            self.advance(); // consume ||
            let right = self.parse_pipeline_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op: BinaryOperator::LogicalOr,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse pipeline expression: expr |> FUNC(args) |> FUNC2(args)
    fn parse_pipeline_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_or_expression()?;

        while matches!(self.current_token(), Token::PipeRight) {
            self.advance(); // consume |>

            let func_name = self.parse_pipeline_function_name()?;
            self.expect(Token::LeftParen)?;
            let args = self.parse_function_call_args()?;

            let right = Expression::FunctionCall {
                name: func_name,
                args,
            };

            left = Expression::Pipeline {
                left: Box::new(left),
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse function name in pipeline context - allows keywords that double as functions
    fn parse_pipeline_function_name(&mut self) -> DbResult<String> {
        let name = match self.current_token() {
            Token::Identifier(name) => name.clone(),
            Token::Filter => "FILTER".to_string(),
            Token::Sort => "SORT".to_string(),
            Token::Count => "COUNT".to_string(),
            Token::Any => "ANY".to_string(),
            Token::Return => "RETURN".to_string(),
            Token::In => "IN".to_string(),
            _ => {
                return Err(DbError::ParseError(format!(
                    "Expected function name after |>, got {:?}",
                    self.current_token()
                )));
            }
        };
        self.advance();
        Ok(name)
    }

    /// Parse boolean OR expression
    pub(super) fn parse_or_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_and_expression()?;

        while matches!(self.current_token(), Token::Or) {
            self.advance();
            let right = self.parse_and_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op: BinaryOperator::Or,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse boolean AND expression
    fn parse_and_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_bitwise_or_expression()?;

        while matches!(self.current_token(), Token::And) {
            self.advance();
            let right = self.parse_bitwise_or_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op: BinaryOperator::And,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse bitwise OR expression
    fn parse_bitwise_or_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_bitwise_xor_expression()?;

        while matches!(self.current_token(), Token::Pipe) {
            self.advance();
            let right = self.parse_bitwise_xor_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op: BinaryOperator::BitwiseOr,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse bitwise XOR expression
    fn parse_bitwise_xor_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_bitwise_and_expression()?;

        while matches!(self.current_token(), Token::Caret) {
            self.advance();
            let right = self.parse_bitwise_and_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op: BinaryOperator::BitwiseXor,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse bitwise AND expression
    fn parse_bitwise_and_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_comparison_expression()?;

        while matches!(self.current_token(), Token::Ampersand) {
            self.advance();
            let right = self.parse_comparison_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op: BinaryOperator::BitwiseAnd,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse comparison expression
    pub(super) fn parse_comparison_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_range_expression()?;

        while let Some(op) = self.parse_comparison_operator()? {
            let right = self.parse_range_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse range expressions (e.g., 1..5 produces [1, 2, 3, 4, 5])
    pub(super) fn parse_range_expression(&mut self) -> DbResult<Expression> {
        let left = self.parse_shift_expression()?;

        if matches!(self.current_token(), Token::DotDot) {
            self.advance(); // consume '..'
            let right = self.parse_shift_expression()?;
            Ok(Expression::Range(Box::new(left), Box::new(right)))
        } else {
            Ok(left)
        }
    }

    /// Parse shift expression
    fn parse_shift_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_additive_expression()?;

        while matches!(self.current_token(), Token::LeftShift | Token::RightShift) {
            let op = match self.current_token() {
                Token::LeftShift => BinaryOperator::LeftShift,
                Token::RightShift => BinaryOperator::RightShift,
                _ => unreachable!(),
            };
            self.advance();
            let right = self.parse_additive_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse additive expression (+, -)
    fn parse_additive_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_multiplicative_expression()?;

        while matches!(self.current_token(), Token::Plus | Token::Minus) {
            let op = match self.current_token() {
                Token::Plus => BinaryOperator::Add,
                Token::Minus => BinaryOperator::Subtract,
                _ => unreachable!(),
            };
            self.advance();
            let right = self.parse_multiplicative_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse multiplicative expression (*, /, %)
    fn parse_multiplicative_expression(&mut self) -> DbResult<Expression> {
        let mut left = self.parse_unary_expression()?;

        while matches!(
            self.current_token(),
            Token::Star | Token::Slash | Token::Percent
        ) {
            let op = match self.current_token() {
                Token::Star => BinaryOperator::Multiply,
                Token::Slash => BinaryOperator::Divide,
                Token::Percent => BinaryOperator::Modulus,
                _ => unreachable!(),
            };
            self.advance();
            let right = self.parse_unary_expression()?;
            left = Expression::BinaryOp {
                left: Box::new(left),
                op,
                right: Box::new(right),
            };
        }

        Ok(left)
    }

    /// Parse unary expression (!, -, ~)
    pub(super) fn parse_unary_expression(&mut self) -> DbResult<Expression> {
        match self.current_token() {
            Token::Not => {
                self.advance();
                let operand = self.parse_unary_expression()?;
                Ok(Expression::UnaryOp {
                    op: UnaryOperator::Not,
                    operand: Box::new(operand),
                })
            }
            Token::Minus => {
                self.advance();
                let operand = self.parse_unary_expression()?;
                Ok(Expression::UnaryOp {
                    op: UnaryOperator::Negate,
                    operand: Box::new(operand),
                })
            }
            Token::Tilde => {
                self.advance();
                let operand = self.parse_unary_expression()?;
                Ok(Expression::UnaryOp {
                    op: UnaryOperator::BitwiseNot,
                    operand: Box::new(operand),
                })
            }
            _ => self.parse_postfix_expression(),
        }
    }
}