#![allow(dead_code)]

/// Manage UCI messages and link into chess component
pub mod uci_engine {
    use itertools::join;

    mod chess_move {
        pub struct Move {}
    }
    mod chess_info{
        pub struct Info {}
    }
    mod chess_option{
        pub struct Opt{}
    }

    pub struct UciEngine {
        name: String,
        author: String,
    }

    impl UciEngine {
        pub fn new(name: &str, author: &str) -> UciEngine {
            UciEngine{name: name.to_string(), author: author.to_string()}
        }

        pub fn name(&self) -> String {
            self.name.clone()
        }

        pub fn author(&self) -> String {
            self.author.clone()
        }

        pub fn update(&mut self, id: &Id){
            match &id.name {
                Some(name) => self.name = name.clone(),
                None => {}
            }

            match &id.author {
                Some(author) => self.author = author.clone(),
                None => {}
            }
        }
    }

    pub struct Id {name: Option<String>, author: Option<String>}
    impl Id {
        pub fn new(name: Option<&str>, author: Option<&str>) -> Id {
            Id{
                name: if let Some(name) = name {Some(name.to_string())} else {None},
                author: if let Some(author) = author {Some(author.to_string())} else {None}
            }
        }
        pub fn update(&mut self, name: Option<&str>, author: Option<&str>){
            match &name {
                Some(name) => self.name = Some(name.to_string()),
                None => {}
            }

            match &author {
                Some(author) => self.author = Some(author.to_string()),
                None => {}
            }
        }
    }

    pub enum UciCommand {
        Id{id: Id},
        UciOk,
        ReadyOk,
        BestMove{best_move: chess_move::Move, ponder: chess_move::Move},
        CopyProtection, // unimplemented
        Registration, // unimplemented
        Info{infos: Vec<chess_info::Info>},
        Opt{options: Vec<chess_option::Opt>},
    }

    /// Parse UCI commands
    ///
    /// * id
    ///   * name *x*
    ///
    ///     this must be sent after receiving the "uci" command to identify the engine,
    ///     e.g. "id name Shredder X.Y\n"
    ///   * author *x*
    ///
    ///     this must be sent after receiving the "uci" command to identify the engine,
    ///     e.g. "id author Stefan MK\n"
    ///
    /// ```rust
    /// use chess_uci::uci_engine::{parse, UciCommand, Id, UciEngine};
    /// let mut engine = UciEngine::new("Test", "Bat");
    ///
    /// engine.exec(&parse(&mut "id name Baptiste".to_string()).expect("simple id name command"));
    /// assert_eq!(engine.name(), "Baptiste");
    ///
    /// engine.exec(&parse(&mut "id author   Monique       Jouve".to_string()).expect("simple id author command"));
    /// assert_eq!(engine.author(), "Monique Jouve");
    ///
    /// ```
    pub fn parse(message: &mut String) -> Result<UciCommand,&'static str> {
        let mut message_iter = message.split_whitespace();

        match message_iter.next() {
            None => Err("No command provided"),

            Some("id") =>
                match message_iter.collect::<Vec<&str>>().as_slice() {
                    [] => Err("Empty id command"),
                    ["name"] => Err("Empty id name command"),
                    ["author"] => Err("Empty id author command"),
                    ["name", tail @ ..] => Ok(UciCommand::Id{id: Id::new(Some(&join(tail, " ")), None)}),
                    ["author", tail @ ..] => Ok(UciCommand::Id{id: Id::new(None, Some(&join(tail, " ")))}),
                    _ => Err("Invalid id subcommand")
                },
            Some("uciok") => unimplemented!(),
            Some("readyok") => unimplemented!(),
            Some("bestmove") => unimplemented!(),
            Some("copyprotection") => unimplemented!(),
            Some("registration") => unimplemented!(),
            Some("info") => unimplemented!(),
            Some("option") => unimplemented!(),
            Some(_) => Err("Unknown command provided"),
        }
    }

    impl UciEngine {
        pub fn exec(&mut self, command: &UciCommand){
            match command {
                UciCommand::Id{id} => self.update(&id),
                _ => unimplemented!(),
            }
        }
    }
}

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

    #[test]
    fn new_uci() {
        let mut engine = UciEngine::new("Test", "Bat");
        assert_eq!(engine.name(), "Test");
        assert_eq!(engine.author(), "Bat");
        let new_id = Id::new(Some("Test 1"), None);
        engine.update(&new_id);
        assert_eq!(engine.name(), "Test 1");
        assert_eq!(engine.author(), "Bat");
        let new_id = Id::new(Some("Test 2"), Some("Bat 1"));
        engine.update(&new_id);
        assert_eq!(engine.name(), "Test 2");
        assert_eq!(engine.author(), "Bat 1");
    }
}