use crate::syn::ast::*;
use crate::syn::token::*;
use pest::{error::Error, iterators::Pair, Parser};

#[derive(pest_derive::Parser)]
#[grammar = "syn/parser.pest"]
pub struct SybilParser;

pub type Result<T, E = Error<Rule>> = std::result::Result<T, E>;

fn parse_atom(pair: Pair<Rule>) -> Result<SpAtom> {
    match pair.as_rule() {
        Rule::float => todo!(),
        Rule::int => todo!(),
        Rule::assign => todo!(),
        Rule::word => todo!(),
        Rule::str => todo!(),
        _ => unreachable!(),
    }
}

fn parse_expr(pair: Pair<Rule>) -> Result<SpExpr> {
    match pair.as_rule() {
        Rule::atom => {
            todo!()
        }
        Rule::quote => {
            todo!()
        }
        Rule::apply => {
            todo!()
        }
        _ => unreachable!(),
    }
}

fn parse_stmt(pair: Pair<Rule>) -> Result<SpStmt> {
    match pair.as_rule() {
        Rule::expr => {
            todo!()
        }
        _ => unreachable!(),
    }
}

pub fn parse_file(text: &str) -> Result<Vec<SpStmt>> {
    let input = SybilParser::parse(Rule::file, text)?.next().unwrap();
    let mut stmts = Vec::new();
    for pair in input.into_inner() {
        stmts.push(parse_stmt(pair)?);
    }
    Ok(stmts)
}