mod disk_db;
mod types;

use std::path::Path;

use async_std::channel::{bounded, Sender};
use async_trait::async_trait;
use disk_db::{db_handler, DiskDb};
pub use types::{CharacterId, CharsheetRow, GameRow, SessionId, UserId, UserRow};

use crate::types::FatalError;

#[derive(Debug)]
enum Request {
    Charsheet(CharacterId),
    CreateSession(UserId),
    Games,
    SaveUser(Option<UserId>, String, String, bool, bool),
    Session(SessionId),
    User(UserId),
    UserByUsername(String),
    Users,
}

#[derive(Debug)]
struct DatabaseRequest {
    tx: Sender<DatabaseResponse>,
    req: Request,
}

#[derive(Debug)]
enum DatabaseResponse {
    Charsheet(Option<CharsheetRow>),
    CreateSession(SessionId),
    Games(Vec<GameRow>),
    SaveUser(UserId),
    Session(Option<UserRow>),
    User(Option<UserRow>),
    Users(Vec<UserRow>),
}

#[async_trait]
pub trait Database: Send + Sync {
    async fn user(&self, _: &UserId) -> Result<Option<UserRow>, FatalError>;

    async fn user_by_username(&self, _: &str) -> Result<Option<UserRow>, FatalError>;

    async fn save_user(
        &self,
        user_id: Option<UserId>,
        name: &str,
        password: &str,
        admin: bool,
        enabled: bool,
    ) -> Result<UserId, FatalError>;

    async fn users(&mut self) -> Result<Vec<UserRow>, FatalError>;

    async fn games(&mut self) -> Result<Vec<GameRow>, FatalError>;

    async fn character(&mut self, id: &CharacterId) -> Result<Option<CharsheetRow>, FatalError>;

    async fn session(&self, id: &SessionId) -> Result<Option<UserRow>, FatalError>;

    async fn create_session(&self, id: &UserId) -> Result<SessionId, FatalError>;
}

pub struct DbConn {
    conn: Sender<DatabaseRequest>,
    handle: tokio::task::JoinHandle<()>,
}

impl DbConn {
    pub fn new<P>(path: Option<P>) -> Self
    where
        P: AsRef<Path>,
    {
        let (tx, rx) = bounded::<DatabaseRequest>(5);
        let db = DiskDb::new(path).unwrap();

        let handle = tokio::spawn(async move {
            db_handler(db, rx).await;
        });

        Self { conn: tx, handle }
    }
}

macro_rules! send_request {
    ($s:expr, $req:expr, $resp_h:pat => $block:expr) => {{
        let (tx, rx) = bounded::<DatabaseResponse>(1);
        let request = DatabaseRequest { tx, req: $req };
        match $s.conn.send(request).await {
            Ok(()) => (),
            Err(_) => return Err(FatalError::DatabaseConnectionLost),
        };

        match rx
            .recv()
            .await
            .map_err(|_| FatalError::DatabaseConnectionLost)
        {
            Ok($resp_h) => $block,
            Ok(_) => Err(FatalError::MessageMismatch),
            Err(_) => Err(FatalError::DatabaseConnectionLost),
        }
    }};
}

#[async_trait]
impl Database for DbConn {
    async fn user(&self, uid: &UserId) -> Result<Option<UserRow>, FatalError> {
        send_request!(self, Request::User(uid.clone()), DatabaseResponse::User(user) => Ok(user))
    }

    async fn user_by_username(&self, username: &str) -> Result<Option<UserRow>, FatalError> {
        send_request!(self, Request::UserByUsername(username.to_owned()), DatabaseResponse::User(user) => Ok(user))
    }

    async fn save_user(
        &self,
        user_id: Option<UserId>,
        name: &str,
        password: &str,
        admin: bool,
        enabled: bool,
    ) -> Result<UserId, FatalError> {
        send_request!(self,
            Request::SaveUser(
                user_id,
                name.to_owned(),
                password.to_owned(),
                admin,
                enabled,
            ),
            DatabaseResponse::SaveUser(user_id) => Ok(user_id))
    }

    async fn users(&mut self) -> Result<Vec<UserRow>, FatalError> {
        send_request!(self, Request::Users, DatabaseResponse::Users(lst) => Ok(lst))
    }

    async fn games(&mut self) -> Result<Vec<GameRow>, FatalError> {
        send_request!(self, Request::Games, DatabaseResponse::Games(lst) => Ok(lst))
    }

    async fn character(&mut self, id: &CharacterId) -> Result<Option<CharsheetRow>, FatalError> {
        send_request!(self, Request::Charsheet(id.to_owned()), DatabaseResponse::Charsheet(row) => Ok(row))
    }

    async fn session(&self, id: &SessionId) -> Result<Option<UserRow>, FatalError> {
        send_request!(self, Request::Session(id.to_owned()), DatabaseResponse::Session(row) => Ok(row))
    }

    async fn create_session(&self, id: &UserId) -> Result<SessionId, FatalError> {
        send_request!(self, Request::CreateSession(id.to_owned()), DatabaseResponse::CreateSession(session_id) => Ok(session_id))
    }
}

#[cfg(test)]
mod test {
    use std::path::PathBuf;

    use cool_asserts::assert_matches;
    use disk_db::DiskDb;
    use types::GameId;

    use super::*;

    const SOREN: &'static str = r#"{ "type_": "Candela", "name": "Soren Jensen", "pronouns": "he/him", "circle": "Circle of the Bluest Sky", "style": "dapper gentleman", "catalyst": "a cursed book", "question": "What were the contents of that book?", "nerve": { "type_": "nerve", "drives": { "current": 1, "max": 2 }, "resistances": { "current": 0, "max": 3 }, "move": { "gilded": false, "score": 2 }, "strike": { "gilded": false, "score": 1 }, "control": { "gilded": true, "score": 0 } }, "cunning": { "type_": "cunning", "drives": { "current": 1, "max": 1 }, "resistances": { "current": 0, "max": 3 }, "sway": { "gilded": false, "score": 0 }, "read": { "gilded": false, "score": 0 }, "hide": { "gilded": false, "score": 0 } }, "intuition": { "type_": "intuition", "drives": { "current": 0, "max": 0 }, "resistances": { "current": 0, "max": 3 }, "survey": { "gilded": false, "score": 0 }, "focus": { "gilded": false, "score": 0 }, "sense": { "gilded": false, "score": 0 } }, "role": "Slink", "role_abilities": [ "Scout: If you have time to observe a location, you can spend 1 Intuition to ask a question: What do I notice here that others do not see? What in this place might be of use to us? What path should we follow?" ], "specialty": "Detective", "specialty_abilities": [ "Mind Palace: When you want to figure out how two clues might relate or what path they should point you towards, burn 1 Intution resistance. The GM will give you the information you have deduced." ] }"#;

    fn setup_db() -> (DiskDb, GameId) {
        let no_path: Option<PathBuf> = None;
        let db = DiskDb::new(no_path).unwrap();

        db.save_user(Some(UserId::from("admin")), "admin", "abcdefg", true, true).unwrap();
        let game_id = db.save_game(None, "Candela").unwrap();
        (db, game_id)
    }

    #[test]
    fn it_can_retrieve_a_character() {
        let (db, game_id) = setup_db();

        assert_matches!(db.character(CharacterId::from("1")), Ok(None));

        let js: serde_json::Value = serde_json::from_str(SOREN).unwrap();
        let soren_id = db.save_character(None, game_id, js.clone()).unwrap();
        assert_matches!(db.character(soren_id).unwrap(), Some(CharsheetRow{ data, .. }) => assert_eq!(js, data));
    }

    #[tokio::test]
    async fn it_can_retrieve_a_character_through_conn() {
        let memory_db: Option<PathBuf> = None;
        let mut conn = DbConn::new(memory_db);

        assert_matches!(conn.character(&CharacterId::from("1")).await, Ok(None));
    }
}