PlayerAndroid/app/src/main/java/code/name/monkey/retromusic/repository/GenreRepository.kt

/*
 * Copyright (c) 2019 Hemanth Savarala.
 *
 * Licensed under the GNU General Public License v3
 *
 * This is free software: you can redistribute it and/or modify it under
 * the terms of the GNU General Public License as published by
 *  the Free Software Foundation either version 3 of the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 */

package code.name.monkey.retromusic.repository

import android.content.ContentResolver
import android.database.Cursor
import android.provider.BaseColumns
import android.provider.MediaStore.Audio.Genres
import code.name.monkey.retromusic.Constants.IS_MUSIC
import code.name.monkey.retromusic.Constants.baseProjection
import code.name.monkey.retromusic.extensions.getLong
import code.name.monkey.retromusic.extensions.getString
import code.name.monkey.retromusic.extensions.getStringOrNull
import code.name.monkey.retromusic.model.Genre
import code.name.monkey.retromusic.model.Song
import code.name.monkey.retromusic.util.PreferenceUtil

interface GenreRepository {
    fun genres(): List<Genre>

    fun songs(genreId: Long): List<Song>

    fun song(genreId: Long): Song
}

// TODO: move genre info into song model
class RealGenreRepository(
    private val contentResolver: ContentResolver,
    private val songRepository: RealSongRepository
) : GenreRepository {

    override fun genres(): List<Genre> {
        return getGenresFromCursor(makeGenreCursor())
    }

    override fun songs(genreId: Long): List<Song> {
        // The genres table only stores songs that have a genre specified,
        // so we need to get songs without a genre a different way.
        return if (genreId == -1L) {
            getSongsWithNoGenre()
        } else songRepository.songs()
    }

    override fun song(genreId: Long): Song {
        return songRepository.song(SongQuery())
    }

    private fun getGenreFromCursor(cursor: Cursor): Genre {
        val id = cursor.getLong(Genres._ID)
        val name = cursor.getStringOrNull(Genres.NAME)
        val songCount = songs(id).size
        return Genre(id, name ?: "", songCount)

    }

    private fun getGenreFromCursorWithOutSongs(cursor: Cursor): Genre {
        val id = cursor.getLong(Genres._ID)
        val name = cursor.getString(Genres.NAME)
        return Genre(id, name, -1)
    }

    private fun getSongsWithNoGenre(): List<Song> {
        // TODO: do this somehow (probably by actually storing genres on songs in our model)
        val selection =
            BaseColumns._ID + " NOT IN " + "(SELECT " + Genres.Members.AUDIO_ID + " FROM audio_genres_map)"
        return songRepository.songs()
    }

    private fun makeGenreSongCursor(genreId: Long): Cursor? {
        return try {
            contentResolver.query(
                Genres.Members.getContentUri("external", genreId),
                baseProjection,
                IS_MUSIC,
                null,
                PreferenceUtil.songSortOrder
            )
        } catch (e: SecurityException) {
            return null
        }
    }

    private fun getGenresFromCursor(cursor: Cursor?): ArrayList<Genre> {
        val genres = arrayListOf<Genre>()
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {
                    val genre = getGenreFromCursor(cursor)
                    if (genre.songCount > 0) {
                        genres.add(genre)
                    } else {
                        // try to remove the empty genre from the media store
                        try {
                            contentResolver.delete(
                                Genres.EXTERNAL_CONTENT_URI,
                                Genres._ID + " == " + genre.id,
                                null
                            )
                        } catch (e: Exception) {
                            e.printStackTrace()
                        }

                    }
                } while (cursor.moveToNext())
            }
            cursor.close()
        }
        return genres
    }

    private fun getGenresFromCursorForSearch(cursor: Cursor?): List<Genre> {
        val genres = mutableListOf<Genre>()
        if (cursor != null && cursor.moveToFirst()) {
            do {
                genres.add(getGenreFromCursorWithOutSongs(cursor))
            } while (cursor.moveToNext())
        }
        cursor?.close()
        return genres
    }

    private fun makeGenreCursor(): Cursor? {
        val projection = arrayOf(Genres._ID, Genres.NAME)
        return try {
            contentResolver.query(
                Genres.EXTERNAL_CONTENT_URI,
                projection,
                null,
                null,
                PreferenceUtil.genreSortOrder
            )
        } catch (e: SecurityException) {
            return null
        }
    }
}