use crate::errors::Error;
use postgres::{Client, NoTls};
use rand::prelude::*;
use std::sync::{Arc, Mutex};

lazy_static! {
    static ref CLIENT: Arc<Mutex<Client>> = Arc::new(Mutex::new(
        Client::connect(
            "host=127.0.0.1 user=spotify_intersect password=example dbname=track_db",
            NoTls
        )
        .expect("failed to connect to database")
    ));
}

pub fn initialize_db() -> Result<(), Error> {
    let mut client = CLIENT.lock()?;
    client.batch_execute(
        r#"
        CREATE TABLE IF NOT EXISTS track (
            track_id      SERIAL PRIMARY KEY,
            track_code    TEXT NOT NULL UNIQUE,
            name          TEXT NOT NULL,
            artist        TEXT NOT NULL,
            popularity    int DEFAULT 50
        );
        CREATE TABLE IF NOT EXISTS lobby (
            lobby_id       SERIAL PRIMARY KEY,
            token          TEXT NOT NULL UNIQUE,
            lobby_name     TEXT NOT NULL
        );
        CREATE TABLE IF NOT EXISTS suser (
            user_id       SERIAL PRIMARY KEY,
            user_name     TEXT NOT NULL,
            lobby_id         int REFERENCES lobby (lobby_id) ON UPDATE CASCADE ON DELETE CASCADE,
            CONSTRAINT suser_name_lobby UNIQUE (lobby_id, user_name)
        );
        CREATE TABLE IF NOT EXISTS user_track_raw (
            track_id      int REFERENCES track (track_id) ON UPDATE CASCADE ON DELETE CASCADE,
            user_id       int REFERENCES suser (user_id) ON UPDATE CASCADE ON DELETE CASCADE,
            count         int NOT NULL DEFAULT 1,
            CONSTRAINT track_user_pkey PRIMARY KEY (track_id, user_id)
        );

        CREATE OR REPLACE VIEW user_track AS (
            SELECT *, "count" / (
                SELECT SUM("count")
                FROM user_track_raw AS ut
                WHERE ut.user_id = user_id
            )::decimal AS score
            FROM user_track_raw
        );
    "#,
    )?;
    Ok(())
}

use rspotify::model::track::FullTrack;
pub fn insert_track(user_id: i32, track: FullTrack, weight: i32) -> Result<(), Error> {
    let mut client = CLIENT.lock()?;

    if track.id.is_none() {
        println!("{:#?}", track);
        return Err("failed to load get track information".into());
    }
    print!(" {} ", track.id.clone()?);
    client.execute(
        "INSERT INTO track (track_code, name, artist, popularity)
            VALUES ($1, $2, $3, $4)
                ON CONFLICT DO NOTHING",
        &[
            &(track.id.clone()?),
            &track.name,
            &track.artists[0].name,
            &(track.popularity as i32),
        ],
    )?;
    let track_id: i32 = client.query(
        "SELECT track_id FROM track where track_code = $1;",
        &[&(track.id?)],
    )?[0]
        .get(0);
    println!("uid: {} tid: {}", user_id, track_id);
    client.execute(
        "
        INSERT INTO user_track_raw (track_id, user_id, count)
                VALUES ($1, $2, $3)
                ON CONFLICT
                     ON CONSTRAINT track_user_pkey
                         DO NOTHING;
            ",
        &[&track_id, &user_id, &0],
    )?;
    client.execute(
        "UPDATE user_track SET count = count + $3 WHERE track_id = $1 AND user_id = $2;",
        &[&track_id, &user_id, &weight],
    )?;
    Ok(())
}

pub fn insert_user(name: &str, lobby: &str) -> Result<i32, Error> {
    let mut client = CLIENT.lock()?;
    let x = get_lid(lobby, &mut *client)?;
    client.execute(
        "INSERT INTO suser (user_name, lobby_id) VALUES ($1, $2) ON CONFLICT (user_name, lobby_id) DO NOTHING;",
        &[&name, &x],
    )?;
    let db_user_id = get_uid(name, lobby, &mut *client)?;
    client.execute("DELETE FROM user_track WHERE user_id = $1;", &[&db_user_id])?;
    Ok(db_user_id)
}

fn get_lid(lobby: &str, client: &mut postgres::Client) -> Result<i32, Error> {
    let x: i32 = client
        .query_one("SELECT lobby_id FROM lobby WHERE token = $1;", &[&lobby])?
        .get(0);
    Ok(x)
}

fn get_uid(name: &str, lobby: &str, client: &mut postgres::Client) -> Result<i32, Error> {
    let x: i32 = client
        .query_one("SELECT user_id FROM suser JOIN lobby USING (lobby_id) WHERE user_name = $1 AND token = $2;", &[&name, &lobby])?
        .get(0);
    Ok(x)
}

pub fn match_users(lobby: String, names: &[&str]) -> Result<String, Error> {
    let mut client = CLIENT.lock()?;
    let mut songs = String::new();
    let names: Vec<String> = names.iter().map(|x| x.to_string()).collect();
    let users = names
        .iter()
        .fold(String::new(), |a, name| format!("{}, ({})", a, name));
    let users: String = users.chars().skip(2).collect();
    for row in client.query(
        "
			WITH users AS (
			    SELECT *
			    FROM ( VALUES $1 AS _ (user_id)
			)
			SELECT track_id, name, artist
			FROM track
			JOIN (
	        SELECT track_id
			FROM user_track
			JOIN suser USING (user_id)
			JOIN track USING (track_id)
            JOIN lobby USING (lobby_id)
			WHERE suser.user_name IN (SELECT * FROM users) AND track = $2
			GROUP BY track_id
			HAVING COUNT(track_id) = (SELECT COUNT(*) FROM users)
			ORDER BY SUM(score) DESC
			) AS _ USING (track_id)
			;
            ",
        &[&users, &lobby],
    )? {
        let name: String = row.get(1);
        let artist: String = row.get(2);
        songs = format!("{}{} by {}\n", songs, name, artist);
    }
    Ok(songs)
}

pub fn get_users(lobby: &str) -> Result<String, Error> {
    let mut client = CLIENT.lock()?;
    let mut users = String::new();
    for row in client.query(
        "SELECT user_name FROM suser JOIN lobby USING (lobby_id) WHERE token = $1",
        &[&lobby],
    )? {
        let user: String = row.get(0);
        users = format!("{}{}\n", users, user);
    }
    Ok(users)
}

pub fn create_lobby(name: &str) -> Result<String, Error> {
    let mut client = CLIENT.lock()?;
    let mut token = String::new();
    while token.is_empty()
        || client
            .query_one("SELECT lobby_id FROM lobby WHERE token = $1", &[&token])
            .is_ok()
    {
        let rand: [u8; 20] = rand::thread_rng().gen();
        token = base64::encode_config(&rand, base64::URL_SAFE);
    }
    client.execute(
        "INSERT INTO lobby (token, lobby_name) VALUES ($1, $2);",
        &[&token, &name],
    )?;
    Ok(token)
}