package main

import (
	"database/sql"
	_ "embed"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
)

//go:embed mm.cred
var mmDbCred string

func GetMmConnString() (string, error) {
	pw, err := base64.StdEncoding.DecodeString(mmDbCred)
	if err != nil {
		return "", err
	}
	return fmt.Sprintf("%s:%s@tcp(%s)/moviemanager?parseTime=true", *mmDbUser, pw, *mmDbServer), err
}

func MmReadOracle() ([]MmOracle, error) {
	key := "oracle"
	var oracles []MmOracle
	data, err := mmCache.Get(key)
	if err == nil {
		err = json.Unmarshal(data, &oracles)
		if err == nil {
			return oracles, err
		}
	}

	if mmDb == nil {
		return oracles, errors.New("no DB connection")
	}

	oracleQuery := `SELECT m.id, m.title, m.mal_id, COALESCE(SUM(pv.score), 0) AS avgScore FROM movie m
	JOIN vote pv ON (m.id = pv.movie_id)
	JOIN promise pp ON (pp.user_id = pv.user_id)
	JOIN evening me ON (pp.evening_id = me.id)
	WHERE m.id NOT IN (
		SELECT m2.id FROM movie m2
			JOIN evening_movie em2 ON (m2.id = em2.movie_id)
			JOIN evening e2 ON (em2.evening_id = e2.id)
			WHERE e2.date < CURDATE()
	) AND (
		m.id IN (
			SELECT mm.movie_source FROM movie m3
			JOIN movie_movie mm ON (m3.id = mm.movie_target)
			JOIN evening_movie em3 ON (mm.movie_target = em3.movie_id)
			JOIN evening e3 ON (em3.evening_id = e3.id)
			WHERE e3.date < CURDATE() GROUP BY m3.id
		)
		OR
		m.id NOT IN (
			SELECT mm.movie_source FROM movie m4
			JOIN movie_movie mm ON (m4.id = mm.movie_source)
		)
	)
	AND pp.promised = 1 AND m.aired = 1 AND me.date >= CURDATE() AND me.date < DATE_ADD(CURDATE(), INTERVAL 1 WEEK) GROUP BY m.id ORDER BY avgScore DESC, m.id ASC;`
	rows, err := mmDb.Query(oracleQuery)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	oracles = make([]MmOracle, 0)
	for rows.Next() {
		var oracle MmOracle
		var qMalId sql.NullInt64
		err = rows.Scan(&oracle.Id, &oracle.Title, &qMalId, &oracle.AvgScore)
		if err != nil {
			return oracles, err
		}
		if qMalId.Valid {
			oracle.Anime = qMalId.Int64
		}
		oracles = append(oracles, oracle)
	}

	err = rows.Err()

	if err == nil {
		bytes, err := json.Marshal(oracles)
		if err == nil {
			mmCache.Set(key, bytes)
		}
	}

	return oracles, err
}

func MmReadCharts() ([]MmOracle, error) {
	if mmDb == nil {
		return nil, errors.New("no DB connection")
	}

	chartsQuery := `SELECT m.id, m.title, m.mal_id FROM movie m
	JOIN evening_movie em ON em.movie_id = m.id
	JOIN evening e ON em.evening_id = e.id
	WHERE e.date <= CURDATE() AND m.mal_id IS NOT NULL;`
	rows, err := mmDb.Query(chartsQuery)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	charts := make([]MmOracle, 0)
	for rows.Next() {
		var chart MmOracle
		err = rows.Scan(&chart.Id, &chart.Title, &chart.Anime)
		if err != nil {
			return charts, err
		}
		charts = append(charts, chart)
	}

	err = rows.Err()

	return charts, err
}