use std::str::FromStr;
use crate::parser::{lexer::Token, ast::Ast, parse_error};
use eww_shared_util::Span;
use simplexpr::ast::SimplExpr;
use simplexpr;
use lalrpop_util::ParseError;

grammar(file_id: usize);

extern {
    type Location = usize;
    type Error = parse_error::ParseError;

    enum Token {
        "(" => Token::LPren,
        ")" => Token::RPren,
        "[" => Token::LBrack,
        "]" => Token::RBrack,
        "true" => Token::True,
        "false" => Token::False,
        "number" => Token::NumLit(<String>),
        "symbol" => Token::Symbol(<String>),
        "keyword" => Token::Keyword(<String>),
        "simplexpr" => Token::SimplExpr(<Vec<(usize, simplexpr::parser::lexer::Token, usize)>>),
        "comment" => Token::Comment,
    }
}

pub Toplevel: (Span, Vec<Ast>) = {
    <l:@L> <elems:(<Ast>)*> <r:@R> => (Span(l, r, file_id), elems)
}

pub Ast: Ast = {
    <l:@L> "(" <elems:(<Ast>)*> ")" <r:@R> => Ast::List(Span(l, r, file_id), elems),
    <l:@L> "[" <elems:(<Ast>)*> "]" <r:@R> => Ast::Array(Span(l, r, file_id), elems),
    <l:@L> <expr:SimplExpr> <r:@R> => Ast::SimplExpr(Span(l, r, file_id), expr),
    <x:Keyword> => x,
    <x:Symbol> => x,
    <l:@L> <x:Literal> <r:@R> => Ast::SimplExpr(Span(l, r, file_id), SimplExpr::literal(Span(l, r, file_id), x.into())),
    <l:@L> "comment" <r:@R> => Ast::Comment(Span(l, r, file_id)),
};

Keyword: Ast = <l:@L> <x:"keyword"> <r:@R> => Ast::Keyword(Span(l, r, file_id), x[1..].to_string());
Symbol: Ast = <l:@L> <x:"symbol"> <r:@R> => Ast::Symbol(Span(l, r, file_id), x.to_string());

Literal: String = {
    <Num> => <>,
    <Bool> => <>,
};

SimplExpr: SimplExpr = {
   <l:@L> <x:"simplexpr"> =>? {
        let parser = simplexpr::simplexpr_parser::ExprParser::new();
        parser.parse(file_id, x.into_iter().map(Ok))
            .map_err(|e| ParseError::User {
                error: parse_error::ParseError::SimplExpr(simplexpr::error::Error::from_parse_error(file_id, e))
            })
   }
}


Num: String = <"number"> => <>.to_string();
Bool: String = {
    "true" => "true".to_string(),
    "false" => "false".to_string(),
}


// vim:shiftwidth=4