use serde::{Deserialize, Serialize};

use crate::{
    Request,
    commands::{Command, RequestParserError, RequestParserResult, ResponseParserError},
    common::SongPosition,
    request_tokenizer::RequestTokenizer,
    response_tokenizer::ResponseAttributes,
};

pub struct Swap;

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct SwapRequest {
    pub songpos1: SongPosition,
    pub songpos2: SongPosition,
}

impl Command for Swap {
    type Request = SwapRequest;
    type Response = ();
    const COMMAND: &'static str = "swap";

    fn serialize_request(&self, request: Self::Request) -> String {
        format!(
            "{} {} {}",
            Self::COMMAND,
            request.songpos1,
            request.songpos2
        )
    }

    fn parse_request(mut parts: RequestTokenizer<'_>) -> RequestParserResult<'_> {
        let songpos1 = parts.next().ok_or(RequestParserError::UnexpectedEOF)?;
        let songpos1 = songpos1
            .parse()
            .map_err(|_| RequestParserError::SyntaxError(0, songpos1.to_string()))?;

        let songpos2 = parts.next().ok_or(RequestParserError::UnexpectedEOF)?;
        let songpos2 = songpos2
            .parse()
            .map_err(|_| RequestParserError::SyntaxError(0, songpos2.to_string()))?;

        debug_assert!(parts.next().is_none());

        Ok((Request::Swap(songpos1, songpos2), ""))
    }

    fn parse_response(
        parts: ResponseAttributes<'_>,
    ) -> Result<Self::Response, ResponseParserError<'_>> {
        debug_assert!(parts.is_empty());
        Ok(())
    }
}