fervid_parser 0.2.0

use fervid_core::{
    AttributeOrBinding, FervidAtom, StrOrExpr, VBindDirective, VCustomDirective, VForDirective,
    VModelDirective, VOnDirective, VSlotDirective, VueDirectives,
};
use swc_core::{common::{BytePos, Span}, ecma::ast::Expr};
use swc_ecma_parser::Syntax;
use swc_html_ast::Attribute;

use crate::{
    error::{ParseError, ParseErrorKind},
    SfcParser,
};

impl SfcParser<'_, '_, '_> {
    /// Returns `true` when `v-pre` is discovered
    pub fn process_element_attributes(
        &mut self,
        raw_attributes: Vec<Attribute>,
        attrs_or_bindings: &mut Vec<AttributeOrBinding>,
        vue_directives: &mut Option<Box<VueDirectives>>,
    ) -> bool {
        // Skip any kind of processing for `v-pre` mode
        if self.is_pre {
            attrs_or_bindings.extend(raw_attributes.into_iter().map(create_regular_attribute));
            return false;
        }

        // Check existence of `v-pre` in attributes
        let has_v_pre = raw_attributes.iter().any(|attr| attr.name == "v-pre");
        if has_v_pre {
            attrs_or_bindings.extend(
                raw_attributes
                    .into_iter()
                    .filter(|attr| attr.name != "v-pre")
                    .map(create_regular_attribute),
            );
            return true;
        }

        for mut raw_attribute in raw_attributes.into_iter() {
            // Use raw names for attributes, otherwise SWC transforms them to lowercase
            // `-1` is needed because SWC spans start from 1
            let raw_idx_start = raw_attribute.span.lo.0 as usize - 1;
            let raw_idx_end = raw_idx_start + raw_attribute.name.len();
            raw_attribute.name = FervidAtom::from(&self.input[raw_idx_start..raw_idx_end]);

            match self.try_parse_directive(raw_attribute, attrs_or_bindings, vue_directives) {
                Ok(()) => {
                    // do nothing, we are good already
                }

                // parse as a raw attribute
                Err(raw_attribute) => {
                    attrs_or_bindings.push(create_regular_attribute(raw_attribute))
                }
            }
        }

        // No `v-pre` found in attributes
        false
    }

    /// Returns `true` if it was recognized as a directive (regardless if it was successfully parsed)
    pub fn try_parse_directive(
        &mut self,
        raw_attribute: Attribute,
        attrs_or_bindings: &mut Vec<AttributeOrBinding>,
        vue_directives: &mut Option<Box<VueDirectives>>,
    ) -> Result<(), Attribute> {
        macro_rules! bail {
            // Everything is okay, this is just not a directive
            () => {
                return Err(raw_attribute);
            };
            // Parsing directive failed
            ($err_kind: expr) => {
                self.errors.push(ParseError {
                    kind: $err_kind,
                    span: raw_attribute.span,
                });
                return Err(raw_attribute);
            };
            (js, $parse_error: expr) => {
                self.errors.push($parse_error);
                return Err(raw_attribute);
            };
        }

        macro_rules! ts {
            () => {
                Syntax::Typescript(Default::default())
            };
        }

        // TODO Fix and test parsing of directives

        // TODO Should the span be narrower? (It can be narrowed with lo = lo + name.len() + 1 and hi = hi - 1)
        let span = raw_attribute.span;
        let raw_name: &str = &raw_attribute.name;
        let mut chars_iter = raw_name.chars().enumerate().peekable();

        // Every directive starts with a prefix: `@`, `:`, `.`, `#` or `v-`
        let Some((_, prefix)) = chars_iter.next() else {
            bail!(ParseErrorKind::DirectiveSyntax);
        };

        // https://vuejs.org/api/built-in-directives.html#v-bind
        let mut is_bind_prop = false;
        let mut expect_argument = true;
        let mut argument_start = 0;
        let mut argument_end = raw_name.len();

        let directive_name = match prefix {
            '@' => "on",
            ':' => "bind",
            '.' => {
                is_bind_prop = true;
                "bind"
            }
            '#' => "slot",
            'v' if matches!(chars_iter.next(), Some((_, '-'))) => {
                // Read directive name
                let mut start = 0;
                let mut end = raw_name.len();
                while let Some((idx, c)) = chars_iter.next() {
                    if c == '.' {
                        expect_argument = false;
                        argument_end = idx;
                        end = idx;
                        break;
                    }
                    if c == ':' {
                        end = idx;
                        break;
                    }
                    if start == 0 {
                        // `idx` is never 0 because zero-th char is `prefix`
                        start = idx;
                    }
                }

                // Directive syntax is bad if we could not read the directive name
                if start == 0 {
                    bail!(ParseErrorKind::DirectiveSyntax);
                }

                &raw_name[start..end]
            }
            _ => {
                bail!();
            }
        };

        // Try parsing argument (it is optional and may be empty though)
        let mut argument: Option<StrOrExpr> = None;
        if expect_argument {
            while let Some((idx, c)) = chars_iter.next() {
                if c == '.' {
                    argument_end = idx;
                    break;
                }
                if argument_start == 0 {
                    argument_start = idx;
                }
            }

            if argument_start != 0 {
                let mut raw_argument = &raw_name[argument_start..argument_end];
                let mut is_dynamic_argument = false;

                // Dynamic argument: `:[dynamic-argument]`
                if raw_argument.starts_with('[') {
                    // Check syntax
                    if !raw_argument.ends_with(']') {
                        bail!(ParseErrorKind::DynamicArgument);
                    }

                    raw_argument =
                        &raw_argument['['.len_utf8()..(raw_argument.len() - ']'.len_utf8())];
                    if raw_argument.is_empty() {
                        bail!(ParseErrorKind::DynamicArgument);
                    }

                    is_dynamic_argument = true;
                }

                if is_dynamic_argument {
                    // TODO Narrower span?
                    let parsed_argument = match self.parse_expr(raw_argument, ts!(), span) {
                        Ok(parsed) => parsed,
                        Err(expr_err) => {
                            bail!(js, expr_err);
                        }
                    };

                    argument = Some(StrOrExpr::Expr(parsed_argument));
                } else {
                    argument = Some(StrOrExpr::Str(FervidAtom::from(raw_argument)));
                }
            }
        }

        // Try parsing modifiers, it is a simple string split
        let mut modifiers = Vec::<FervidAtom>::new();
        if argument_end != 0 {
            for modifier in raw_name[argument_end..]
                .split('.')
                .filter(|m| !m.is_empty())
            {
                modifiers.push(FervidAtom::from(modifier));
            }
        }

        /// Unwrapping the value or failing
        macro_rules! expect_value {
            () => {
                if let Some(ref value) = raw_attribute.value {
                    value
                } else {
                    bail!(ParseErrorKind::DirectiveSyntax);
                }
            };
        }

        macro_rules! get_directives {
            () => {
                vue_directives.get_or_insert_with(|| Box::new(VueDirectives::default()))
            };
        }

        macro_rules! push_directive {
            ($key: ident, $value: expr) => {
                let directives = get_directives!();
                directives.$key = Some($value);
            };
        }

        macro_rules! push_directive_js {
            ($key: ident, $value: expr) => {
                match self.parse_expr($value, ts!(), span) {
                    Ok(parsed) => {
                        let directives = get_directives!();
                        directives.$key = Some(parsed);
                    }
                    Result::Err(expr_err) => self.report_error(expr_err),
                }
            };
        }

        // Construct the directives from parts
        match directive_name {
            // Directives arranged by estimated usage frequency
            "bind" => {
                // Get flags
                let mut is_camel = false;
                let mut is_prop = is_bind_prop;
                let mut is_attr = false;
                for modifier in modifiers.iter() {
                    match modifier.as_ref() {
                        "camel" => is_camel = true,
                        "prop" => is_prop = true,
                        "attr" => is_attr = true,
                        _ => {}
                    }
                }

                let value = expect_value!();

                let parsed_expr = match self.parse_expr(&value, ts!(), span) {
                    Ok(parsed) => parsed,
                    Err(expr_err) => {
                        bail!(js, expr_err);
                    }
                };

                attrs_or_bindings.push(AttributeOrBinding::VBind(VBindDirective {
                    argument,
                    value: parsed_expr,
                    is_camel,
                    is_prop,
                    is_attr,
                    span,
                }));
            }

            "on" => {
                let handler = match raw_attribute.value {
                    Some(ref value) => match self.parse_expr(&value, ts!(), span) {
                        Ok(parsed) => Some(parsed),
                        Err(expr_err) => {
                            bail!(js, expr_err);
                        }
                    },
                    None => None,
                };

                attrs_or_bindings.push(AttributeOrBinding::VOn(VOnDirective {
                    event: argument,
                    handler,
                    modifiers,
                    span,
                }));
            }

            "if" => {
                let value = expect_value!();
                push_directive_js!(v_if, &value);
            }

            "else-if" => {
                let value = expect_value!();
                push_directive_js!(v_else_if, &value);
            }

            "else" => {
                push_directive!(v_else, ());
            }

            "for" => {
                let value = expect_value!();

                let Some(((itervar, itervar_span), (iterable, iterable_span))) =
                    split_itervar_and_iterable(&value, span)
                else {
                    bail!(ParseErrorKind::DirectiveSyntax);
                };

                match self.parse_expr(itervar, ts!(), itervar_span) {
                    Ok(itervar) => match self.parse_expr(iterable, ts!(), iterable_span) {
                        Ok(iterable) => {
                            push_directive!(
                                v_for,
                                VForDirective {
                                    iterable,
                                    itervar,
                                    patch_flags: Default::default(),
                                    span
                                }
                            );
                        }
                        Result::Err(expr_err) => self.report_error(expr_err),
                    },
                    Result::Err(expr_err) => self.report_error(expr_err),
                };
            }

            "model" => {
                let value = expect_value!();

                match self.parse_expr(&value, ts!(), span) {
                    Ok(model_binding) => {
                        // v-model value must be a valid JavaScript member expression
                        if !matches!(*model_binding, Expr::Member(_) | Expr::Ident(_)) {
                            // TODO Report an error
                            bail!();
                        }

                        let directives = get_directives!();
                        directives.v_model.push(VModelDirective {
                            argument,
                            value: model_binding,
                            update_handler: None,
                            modifiers,
                            span,
                        });
                    }
                    Result::Err(_) => {}
                }
            }

            "slot" => {
                let value =
                    raw_attribute
                        .value
                        .and_then(|v| match self.parse_pat(&v, ts!(), span) {
                            Ok(value) => Some(Box::new(value)),
                            Result::Err(_) => None,
                        });
                push_directive!(
                    v_slot,
                    VSlotDirective {
                        slot_name: argument,
                        value,
                    }
                );
            }

            "show" => {
                let value = expect_value!();
                push_directive_js!(v_show, &value);
            }

            "html" => {
                let value = expect_value!();
                push_directive_js!(v_html, &value);
            }

            "text" => {
                let value = expect_value!();
                push_directive_js!(v_text, &value);
            }

            "once" => {
                push_directive!(v_once, ());
            }

            "pre" => {
                push_directive!(v_pre, ());
            }

            "memo" => {
                let value = expect_value!();
                push_directive_js!(v_memo, &value);
            }

            "cloak" => {
                push_directive!(v_cloak, ());
            }

            // Custom
            _ => 'custom: {
                // If no value, include as is
                let Some(value) = raw_attribute.value else {
                    let directives = get_directives!();
                    directives.custom.push(VCustomDirective {
                        name: directive_name.into(),
                        argument,
                        modifiers,
                        value: None,
                    });
                    break 'custom;
                };

                // If there is a value, try parsing it and only include the successfully parsed values
                match self.parse_expr(&value, ts!(), span) {
                    Ok(parsed) => {
                        let directives = get_directives!();
                        directives.custom.push(VCustomDirective {
                            name: directive_name.into(),
                            argument,
                            modifiers,
                            value: Some(parsed),
                        });
                    }
                    Result::Err(expr_err) => self.report_error(expr_err),
                }
            }
        }

        Ok(())
    }
}

/// Creates `AttributeOrBinding::RegularAttribute`
#[inline]
pub fn create_regular_attribute(raw_attribute: Attribute) -> AttributeOrBinding {
    AttributeOrBinding::RegularAttribute {
        name: raw_attribute.name,
        value: raw_attribute.value.unwrap_or_default(),
        span: raw_attribute.span,
    }
}

fn split_itervar_and_iterable<'a>(
    raw: &'a str,
    original_span: Span,
) -> Option<((&'a str, Span), (&'a str, Span))> {
    // `item in iterable` or `item of iterable`
    let Some(split_idx) = raw.find(" in ").or_else(|| raw.find(" of ")) else {
        return None;
    };
    const SPLIT_LEN: usize = " in ".len();

    // Get the trimmed itervar and its span
    let mut offset = original_span.lo.0;
    let mut itervar = &raw[..split_idx];
    let mut itervar_old_len = itervar.len();
    itervar = itervar.trim_start();
    let itervar_lo = BytePos(offset + (itervar_old_len - itervar.len()) as u32);
    itervar_old_len = itervar.len();
    itervar = itervar.trim_end();
    let itervar_hi = BytePos(offset + (split_idx - (itervar_old_len - itervar.len())) as u32);

    let iterable_start = split_idx + SPLIT_LEN;
    offset += iterable_start as u32;

    let mut iterable = &raw[iterable_start..];
    let iterable_old_len = iterable.len();
    iterable = iterable.trim_start();
    let iterable_lo = BytePos(offset + (iterable_old_len - iterable.len()) as u32);
    iterable = iterable.trim_end();
    let iterable_hi = BytePos(iterable_lo.0 + iterable.len() as u32);

    if itervar.is_empty() || iterable.is_empty() {
        return None;
    }

    let new_span_itervar = Span {
        lo: itervar_lo,
        hi: itervar_hi,
        ctxt: original_span.ctxt,
    };

    let new_span_iterable = Span {
        lo: iterable_lo,
        hi: iterable_hi,
        ctxt: original_span.ctxt,
    };

    Some(((itervar, new_span_itervar), (iterable, new_span_iterable)))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_correctly_splits_itervar_iterable() {
        macro_rules! check {
            ($input: expr, $itervar: expr, $itervar_lo: expr, $itervar_hi: expr, $iterable: expr, $iterable_lo: expr, $iterable_hi: expr) => {
                let input = $input;
                let span = Span {
                    lo: BytePos(1),
                    hi: BytePos((input.len() + 1) as u32),
                    ctxt: Default::default(),
                };

                let Some(((itervar, itervar_span), (iterable, iterable_span))) =
                    split_itervar_and_iterable(input, span)
                else {
                    panic!("Did not manage to split")
                };
                assert_eq!($itervar, itervar);
                assert_eq!($itervar_lo, itervar_span.lo.0);
                assert_eq!($itervar_hi, itervar_span.hi.0);
                assert_eq!($iterable, iterable);
                assert_eq!($iterable_lo, iterable_span.lo.0);
                assert_eq!($iterable_hi, iterable_span.hi.0);
            };
        }

        // Trivial (all `Span`s start from 1)
        check!("item in list", "item", 1, 5, "list", 9, 13);
        check!("item of list", "item", 1, 5, "list", 9, 13);
        check!("i in 3", "i", 1, 2, "3", 6, 7);

        // A bit harder
        check!("   item   in \n \t  list   ", "item", 4, 8, "list", 19, 23);
    }
}