package goscrobble

import (
	"database/sql"
	"errors"
	"log"
)

type Album struct {
	UUID          string `json:"uuid"`
	Name          string `json:"name"`
	Desc          string `json:"desc"`
	Img           string `json:"img"`
	MusicBrainzID string `json:"mbid"`
	SpotifyID     string `json:"spotify_id"`
}

// insertAlbum - This will return if it exists or create it based on MBID > Name
func insertAlbum(name string, mbid string, spotifyId string, artists []string, img string, tx *sql.Tx) (Album, error) {
	album := Album{}

	// Try locate our album
	if mbid != "" {
		album = getAlbumByCol("mbid", mbid, tx)
	} else if spotifyId != "" {
		album = getAlbumByCol("spotify_id", spotifyId, tx)
	}

	// If it didn't match above, lookup by name
	if album.UUID == "" {
		album = getAlbumByCol("name", name, tx)
	}

	// If we can't find it. Lets add it!
	if album.UUID == "" {
		err := insertNewAlbum(&album, name, mbid, spotifyId, img, tx)
		if err != nil {
			return album, errors.New("Failed to insert album")
		}

		if album.UUID == "" {
			return album, errors.New("Failed to fetch album")
		}

		// Try linkem up
		err = album.linkAlbumToArtists(artists, tx)
		if err != nil {
			return album, errors.New("Unable to link albums!")
		}
	}

	// Updates these values if we match earlier!
	if album.MusicBrainzID != mbid {
		album.MusicBrainzID = mbid
		album.updateAlbum("mbid", mbid, tx)
	}

	if album.SpotifyID != spotifyId {
		album.SpotifyID = spotifyId
		album.updateAlbum("spotify_id", spotifyId, tx)
	}

	if album.Img == "" {
		if img != "" {
			album.Img = img
			album.updateAlbum("img", img, tx)
		}
	}

	return album, nil
}

func getAlbumByCol(col string, val string, tx *sql.Tx) Album {
	var album Album
	err := tx.QueryRow(
		`SELECT uuid, name, COALESCE(desc, ''), COALESCE(img,''), mbid, spotify_id FROM albums WHERE "`+col+`" = $1`,
		val).Scan(&album.UUID, &album.Name, &album.Desc, &album.Img, &album.MusicBrainzID, &album.SpotifyID)

	if err != nil {
		if err != sql.ErrNoRows {
			log.Printf("Error fetching albums: %+v", err)
		}
	}

	return album
}

func insertNewAlbum(album *Album, name string, mbid string, spotifyId string, img string, tx *sql.Tx) error {
	album.UUID = newUUID()
	album.Name = name
	album.MusicBrainzID = mbid
	album.SpotifyID = spotifyId
	album.Img = img

	_, err := tx.Exec(`INSERT INTO albums (uuid, name, mbid, spotify_id, img) `+
		`VALUES ($1,$2,$3,$4,$5)`, album.UUID, album.Name, album.MusicBrainzID, album.SpotifyID, album.Img)

	return err
}

func (album *Album) linkAlbumToArtists(artists []string, tx *sql.Tx) error {
	var err error
	for _, artist := range artists {
		_, err = tx.Exec(`INSERT INTO album_artist (album, artist) `+
			`VALUES ($1,$2)`, album.UUID, artist)
		if err != nil {
			return err
		}
	}

	return err
}

func (album *Album) updateAlbum(col string, val string, tx *sql.Tx) error {
	_, err := tx.Exec(`UPDATE albums SET "`+col+`" = $1 WHERE uuid = $2`, val, album.UUID)

	return err
}

func getAlbumByUUID(uuid string) (Album, error) {
	var album Album
	err := db.QueryRow(`SELECT uuid, name, COALESCE(desc,''), COALESCE(img,''), mbid, spotify_id FROM albums WHERE uuid = $1`,
		uuid).Scan(&album.UUID, &album.Name, &album.Desc, &album.Img, &album.MusicBrainzID, &album.SpotifyID)

	if err != nil {
		return album, errors.New("Invalid UUID")
	}

	return album, nil
}