use std::collections::VecDeque;

use crate::{
    command::{Command, CommandParseError},
    statements::Statement,
    tokens::tokenize,
};

pub fn parse(file: String, input: String) -> Result<Vec<Command>, Vec<CommandParseError>> {
    let mut tokens: VecDeque<_> = tokenize(input, file)
        .map_err(|x| x.into_iter().map(|x| x.into()).collect::<Vec<_>>())?
        .into();
    let mut cmds = Vec::new();
    let errs = Vec::new();
    while let Some(token) = tokens.pop_front() {
        match token.data {
            crate::tokens::TokenData::Insert => cmds.push(Command::Statement(Statement::Insert)),
            crate::tokens::TokenData::Select => cmds.push(Command::Statement(Statement::Select)),
            crate::tokens::TokenData::MetaCommand(meta_command) => {
                cmds.push(Command::MetaCommand(meta_command))
            }
            crate::tokens::TokenData::EndOfFile => (),
        }
    }
    if errs.is_empty() { Ok(cmds) } else { Err(errs) }
}

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

    #[test]
    fn test_parse_single_correct() {
        let file = String::from("<stdin>");
        assert_debug_snapshot!(parse(file.clone(), String::from(".exit")));
        assert_debug_snapshot!(parse(file.clone(), String::from("select")));
        assert_debug_snapshot!(parse(file.clone(), String::from("sElEcT")));
        assert_debug_snapshot!(parse(file.clone(), String::from("INSERT")));
        assert_debug_snapshot!(parse(file.clone(), String::from("InSErT")));
    }

    #[test]
    fn test_parse_single_incorrect() {
        let file = String::from("<stdin>");
        assert_debug_snapshot!(parse(file.clone(), String::from(".halp")));
        assert_debug_snapshot!(parse(file.clone(), String::from("salect")));
        assert_debug_snapshot!(parse(file.clone(), String::from("sAlEcT")));
        assert_debug_snapshot!(parse(file.clone(), String::from("INSART")));
        assert_debug_snapshot!(parse(file.clone(), String::from("InSArT")));
    }

    #[test]
    fn test_parse_multiple_correct() {
        let file = String::from("<stdin>");
        assert_debug_snapshot!(parse(
            file.clone(),
            String::from(".exit select select insert select")
        ));
    }

    #[test]
    fn test_parse_multiple_incorrect() {
        let file = String::from("<stdin>");
        assert_debug_snapshot!(parse(
            file.clone(),
            String::from(".halp salect selact inset seiect")
        ));
    }

    #[test]
    fn test_parse_multiple_mixed() {
        let file = String::from("<stdin>");
        assert_debug_snapshot!(parse(
            file.clone(),
            String::from(".exit selct select nsert select")
        ));
    }
}