use std::sync::{Arc, Mutex};

use sqlx::{query, query_scalar, SqlitePool};
use tokio::task::JoinSet;
use tokio_retry::Retry;

use crate::{
    db_id::DbId,
    util::year_to_epoch,
    watches::handlers::{add_new_watch_impl, add_watch_quest_impl},
    ShowKind, Watch, WatchQuest,
};

const USER_EXISTS_QUERY: &str = "select count(*) from witches where id = $1";

const MOVIE_QUERY: &str = "select * from movies order by random() limit 10000";

//-************************************************************************
// the omega user is the system ID, but has no actual power in the app
//-************************************************************************
const OMEGA_ID: u128 = u128::MAX;

#[derive(Debug, sqlx::FromRow, Clone)]
pub struct ImportMovieOmega {
    pub title: String,
    pub year: Option<String>,
    pub length: Option<String>,
}

impl From<ImportMovieOmega> for Watch {
    fn from(value: ImportMovieOmega) -> Self {
        Watch {
            title: value.title,
            release_date: year_to_epoch(value.year.as_deref()),
            length: value.length.and_then(|v| v.parse::<i64>().ok()),
            id: DbId::new(),
            kind: ShowKind::Movie,
            metadata_url: None,
            added_by: OMEGA_ID.into(),
        }
    }
}

impl From<&ImportMovieOmega> for Watch {
    fn from(value: &ImportMovieOmega) -> Self {
        Watch {
            title: value.title.to_string(),
            release_date: year_to_epoch(value.year.as_deref()),
            length: value.length.as_ref().and_then(|v| v.parse::<i64>().ok()),
            id: DbId::new(),
            kind: ShowKind::Movie,
            metadata_url: None,
            added_by: OMEGA_ID.into(),
        }
    }
}

//-************************************************************************
// utility functions for building CLI tools, currently just for benchmarking
//-************************************************************************
pub async fn add_watch_omega(db_pool: &SqlitePool, movie: &ImportMovieOmega) -> Result<DbId, ()> {
    let watch: Watch = movie.into();
    if add_new_watch_impl(db_pool, &watch, None).await.is_ok() {
        Ok(watch.id)
    } else {
        eprintln!("failed to add \"{}\"", watch.title);
        Err(())
    }
}

pub async fn add_watch_quest(db_pool: &SqlitePool, quest: WatchQuest) -> Result<(), ()> {
    if add_watch_quest_impl(db_pool, &quest).await.is_ok() {
        Ok(())
    } else {
        eprintln!("failed to add {}", quest.id);
        Err(())
    }
}

pub async fn add_user(
    db_pool: &SqlitePool,
    username: &str,
    displayname: Option<&str>,
    email: Option<&str>,
    id: Option<DbId>,
) {
    let pwhash = "you shall not password";
    let id: DbId = id.unwrap_or_else(DbId::new);
    if query(crate::signup::CREATE_QUERY)
        .bind(id)
        .bind(username)
        .bind(displayname)
        .bind(email)
        .bind(pwhash)
        .execute(db_pool)
        .await
        .is_ok()
    {
        println!("{id}");
    } else {
        eprintln!("failed to add user \"{username}\"");
    }
}

pub async fn add_omega_watches(ww_db: &SqlitePool, movie_db: &SqlitePool) -> Vec<DbId> {
    ensure_omega(ww_db).await;

    let movies: Vec<ImportMovieOmega> = sqlx::query_as(MOVIE_QUERY)
        .fetch_all(movie_db)
        .await
        .unwrap();

    let mut set = JoinSet::new();
    let movie_set = Vec::with_capacity(10_000);
    let movie_set = Arc::new(Mutex::new(movie_set));

    let retry_strategy = tokio_retry::strategy::ExponentialBackoff::from_millis(100)
        .map(tokio_retry::strategy::jitter)
        .take(4);

    for movie in movies {
        let db = ww_db.clone();
        let title = movie.title.as_str();
        let year = movie.year.clone().unwrap();
        let len = movie.length.clone().unwrap();
        let retry_strategy = retry_strategy.clone();
        let movie_set = movie_set.clone();

        let key = format!("{title}{year}{len}");
        set.spawn(async move {
            (
                key,
                Retry::spawn(retry_strategy, || async {
                    if let Ok(id) = add_watch_omega(&db, &movie).await {
                        let mut mset = movie_set.lock().unwrap();
                        mset.push(id);
                        Ok(())
                    } else {
                        Err(())
                    }
                })
                .await,
            )
        });
    }
    // stragglers
    while (set.join_next().await).is_some() {}
    let movies = movie_set.lock().unwrap().clone();
    movies
}

pub async fn ensure_omega(db_pool: &SqlitePool) -> DbId {
    if !check_omega_exists(db_pool).await {
        add_user(
            db_pool,
            "The Omega User",
            Some("I am the end of all watches."),
            None,
            Some(OMEGA_ID.into()),
        )
        .await
    }
    OMEGA_ID.into()
}

async fn check_omega_exists(db_pool: &SqlitePool) -> bool {
    let id: DbId = OMEGA_ID.into();
    let count = query_scalar(USER_EXISTS_QUERY)
        .bind(id)
        .fetch_one(db_pool)
        .await
        .unwrap_or(0);
    count > 0
}

//-************************************************************************
//tests
//-************************************************************************

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

    #[tokio::test]
    async fn ensure_omega_user() {
        let p = crate::db::get_db_pool().await;
        assert!(!check_omega_exists(&p).await);
        ensure_omega(&p).await;
        assert!(check_omega_exists(&p).await);
    }
}