LibreTube/app/src/main/java/com/github/libretube/helpers/BackupHelper.kt

package com.github.libretube.helpers

import android.content.Context
import android.net.Uri
import android.util.Log
import androidx.core.content.edit
import androidx.preference.PreferenceManager
import com.github.libretube.api.JsonHelper
import com.github.libretube.constants.PreferenceKeys
import com.github.libretube.db.DatabaseHolder.Database
import com.github.libretube.extensions.TAG
import com.github.libretube.obj.BackupFile
import com.github.libretube.obj.PreferenceItem
import kotlinx.serialization.ExperimentalSerializationApi
import kotlinx.serialization.json.booleanOrNull
import kotlinx.serialization.json.decodeFromStream
import kotlinx.serialization.json.encodeToStream
import kotlinx.serialization.json.floatOrNull
import kotlinx.serialization.json.intOrNull
import kotlinx.serialization.json.longOrNull

/**
 * Backup and restore the preferences
 */
object BackupHelper {
    /**
     * Write a [BackupFile] containing the database content as well as the preferences
     */
    @OptIn(ExperimentalSerializationApi::class)
    fun createAdvancedBackup(context: Context, uri: Uri, backupFile: BackupFile) {
        try {
            context.contentResolver.openOutputStream(uri)?.use { outputStream ->
                JsonHelper.json.encodeToStream(backupFile, outputStream)
            }
        } catch (e: Exception) {
            Log.e(TAG(), "Error while writing backup: $e")
        }
    }

    /**
     * Restore data from a [BackupFile]
     */
    @OptIn(ExperimentalSerializationApi::class)
    suspend fun restoreAdvancedBackup(context: Context, uri: Uri) {
        val backupFile = context.contentResolver.openInputStream(uri)?.use {
            JsonHelper.json.decodeFromStream<BackupFile>(it)
        } ?: return

        Database.watchHistoryDao().insertAll(backupFile.watchHistory.orEmpty())
        Database.searchHistoryDao().insertAll(backupFile.searchHistory.orEmpty())
        Database.watchPositionDao().insertAll(backupFile.watchPositions.orEmpty())
        Database.localSubscriptionDao().insertAll(backupFile.localSubscriptions.orEmpty())
        Database.customInstanceDao().insertAll(backupFile.customInstances.orEmpty())
        Database.playlistBookmarkDao().insertAll(backupFile.playlistBookmarks.orEmpty())
        Database.subscriptionGroupsDao().insertAll(backupFile.channelGroups.orEmpty())

        backupFile.localPlaylists?.forEach {
            Database.localPlaylistsDao().createPlaylist(it.playlist)
            val playlistId = Database.localPlaylistsDao().getAll().last().playlist.id
            it.videos.forEach { playlistItem ->
                playlistItem.playlistId = playlistId
                Database.localPlaylistsDao().addPlaylistVideo(playlistItem)
            }
        }

        restorePreferences(context, backupFile.preferences)
    }

    /**
     * Restore the shared preferences from a backup file
     */
    private fun restorePreferences(context: Context, preferences: List<PreferenceItem>?) {
        if (preferences == null) return
        PreferenceManager.getDefaultSharedPreferences(context).edit(commit = true) {
            // clear the previous settings
            clear()

            // decide for each preference which type it is and save it to the preferences
            preferences.forEach { (key, jsonValue) ->
                val value = if (jsonValue.isString) {
                    jsonValue.content
                } else {
                    jsonValue.booleanOrNull
                        ?: jsonValue.intOrNull
                        ?: jsonValue.longOrNull
                        ?: jsonValue.floatOrNull
                }
                when (value) {
                    is Boolean -> putBoolean(key, value)
                    is Float -> putFloat(key, value)
                    is Long -> putLong(key, value)
                    is Int -> {
                        when (key) {
                            PreferenceKeys.START_FRAGMENT -> putInt(key, value)
                            else -> putLong(key, value.toLong())
                        }
                    }
                    is String -> putString(key, value)
                }
            }
        }
    }
}