use std::time::{Duration, Instant};

use julid::Julid;
use sqlx::{query_scalar, SqlitePool};

use crate::{util::year_to_epoch, ShowKind, User, Watch, WatchQuest};

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

const MOVIE_QUERY: &str = "select * from movie_titles order by year, title asc limit ?";

//-************************************************************************
// the omega user is the system ID, but has no actual power in the app
//-************************************************************************
const OMEGA_ID: Julid = Julid::omega();
const BULK_INSERT: usize = 2_000;

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

impl From<ImportMovieOmega> for Watch {
    fn from(value: ImportMovieOmega) -> Self {
        Watch {
            id: OMEGA_ID, // this is ignored by the inserter
            title: value.title,
            release_date: year_to_epoch(value.year.as_deref()),
            length: value.runtime.and_then(|v| v.parse::<i64>().ok()),
            kind: ShowKind::Movie,
            metadata_url: None,
            added_by: OMEGA_ID,
        }
    }
}

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

//-************************************************************************
// utility functions for building CLI tools, currently just for benchmarking
//-************************************************************************
pub async fn add_watch_quests(pool: &SqlitePool, quests: &[WatchQuest]) -> Result<(), ()> {
    let mut builder = sqlx::QueryBuilder::new("insert into watch_quests (user, watch) ");
    builder.push_values(quests, |mut b, quest| {
        let user = quest.user;
        let watch = quest.watch;
        //eprintln!("{user}, {watch}");
        b.push_bind(user).push_bind(watch);
    });

    let q = builder.build();
    q.execute(pool).await.map_err(|e| {
        dbg!(e);
    })?;

    Ok(())
}

pub async fn add_users(db_pool: &SqlitePool, users: &[User]) -> Result<Duration, ()> {
    let mut builder =
        sqlx::QueryBuilder::new("insert into users (username, displayname, email, pwhash)");

    let start = Instant::now();
    builder.push_values(users.iter(), |mut b, user| {
        b.push_bind(&user.username)
            .push_bind(&user.displayname)
            .push_bind(&user.email)
            .push_bind(&user.pwhash);
    });
    let q = builder.build();
    q.execute(db_pool).await.map_err(|_| ())?;
    let end = Instant::now();
    let dur = end - start;

    Ok(dur)
}

pub async fn add_omega_watches(
    w2w_db: &SqlitePool,
    movie_db: &SqlitePool,
    num: u32,
) -> Result<Duration, ()> {
    let omega = ensure_omega(w2w_db).await;

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

    let start = Instant::now();
    for movies in movies.as_slice().chunks(BULK_INSERT) {
        let mut builder = sqlx::QueryBuilder::new(
            "insert into watches (kind, title, length, release_date, added_by) ",
        );

        builder.push_values(movies, |mut b, movie| {
            let title = &movie.title;
            b.push_bind(ShowKind::Movie)
                .push_bind(title)
                .push_bind(movie.runtime.as_ref().and_then(|l| l.parse::<i64>().ok()))
                .push_bind(year_to_epoch(movie.year.as_deref()))
                .push_bind(omega);
        });
        let q = builder.build();
        q.execute(w2w_db).await.map_err(|_| ())?;
    }
    let end = Instant::now();
    let dur = end - start;

    Ok(dur)
}

pub async fn ensure_omega(db_pool: &SqlitePool) -> Julid {
    if !check_omega_exists(db_pool).await {
        sqlx::query("insert into users (id, username, pwhash) values (?, 'the omega user', 'you shall not password')").bind(OMEGA_ID).execute(db_pool).await.unwrap();
    }
    OMEGA_ID
}

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

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

#[cfg(test)]
mod test {
    use tokio::runtime::Runtime;

    use super::*;

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

        assert!(rt.block_on(check_omega_exists(&p)));
    }
}