/*
 * Copyright (C) 2025 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.privatespace.filetransfer

import android.app.Service
import android.content.Intent
import android.net.Uri
import android.os.Environment
import android.os.IBinder
import android.util.Log
import androidx.annotation.OpenForTesting
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch

/**
 * An object responsible for starting a foreground service to copy/move the user selected files into
 * private space.
 */
@OpenForTesting
open class FileTransferService(
    private val serviceScope: CoroutineScope = CoroutineScope(Dispatchers.IO)
) : Service() {
    companion object {
        /**
         * A boolean extra noting whether this transfer is a copy(true) or a move(false) operation.
         */
        const val KEEP_ORIGINAL_EXTRA: String = "keep_original_extra"
        /** An array extra to get the uris of the file to transfer. */
        const val SOURCE_URIS_EXTRA: String = "source_uris_extra"
        /**
         * Target relative path where the given file(s) should be saved. This path should be inline
         * with guidelines for {@link MediaStore.MediaColumns.RELATIVE_PATH}
         */
        const val DESTINATION_PATH_EXTRA: String = "destination_path"
        private var keepOriginal: Boolean = true
        private const val TAG: String = "FileTransferService"
    }

    private lateinit var notificationsHelper: NotificationsHelper
    private lateinit var fileTransferManager: IFileTransferManager
    private lateinit var fileTransferStateRepository: FileTransferStateRepository
    private var uris: List<Uri>? = null

    override fun onCreate() {
        super.onCreate()
        notificationsHelper = initializeNotificationsHelper()
        fileTransferStateRepository = initializeFileTransferStateRepository()
        fileTransferManager = initializeFileTransferManager(notificationsHelper)
    }

    override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
        val uris: ArrayList<Uri>? =
            intent.getParcelableArrayListExtra(SOURCE_URIS_EXTRA, Uri::class.java)
        keepOriginal = intent.getBooleanExtra(KEEP_ORIGINAL_EXTRA, true)
        val destinationPath =
            intent.getStringExtra(DESTINATION_PATH_EXTRA) ?: Environment.DIRECTORY_DOWNLOADS

        this.uris = uris
        uris?.let {
            val numberOfFiles = it.size
            if (numberOfFiles == 0) {
                Log.e(TAG, "No files to transfer")
                return@let
            }

            notificationsHelper.createNotificationChannel()

            serviceScope.launch {
                startForeground(
                    notificationsHelper.notificationId,
                    notificationsHelper.buildProgressNotification(0, numberOfFiles, keepOriginal),
                )
                fileTransferManager.transferFiles(it, keepOriginal, destinationPath)
                fileTransferStateRepository.saveState(
                    applicationContext,
                    keepOriginal,
                    transferInProgress = false,
                )
                stopForeground(STOP_FOREGROUND_REMOVE)
                stopSelf()
                fileTransferManager.postEndOfTransferNotification(numberOfFiles, keepOriginal)
            }
        } ?: Log.e(TAG, "Unable to parse uris from the intent: $intent")

        return START_NOT_STICKY
    }

    override fun onBind(intent: Intent?): IBinder? {
        return null
    }

    override fun onDestroy() {
        if (keepOriginal) {
            uris?.forEach { uri ->
                try {
                    applicationContext.contentResolver.releasePersistableUriPermission(
                        uri,
                        Intent.FLAG_GRANT_READ_URI_PERMISSION or
                            Intent.FLAG_GRANT_WRITE_URI_PERMISSION,
                    )
                } catch (se: SecurityException) {
                    Log.e(TAG, "Failed to release persisted Uri grant", se)
                }
            }
        }
    }

    @OpenForTesting
    open fun initializeNotificationsHelper(): NotificationsHelper {
        return NotificationsHelper(applicationContext)
    }

    @OpenForTesting
    open fun initializeFileTransferStateRepository(): FileTransferStateRepository {
        return FileTransferStateRepository
    }

    @OpenForTesting
    open fun initializeFileTransferManager(
        notificationsHelper: NotificationsHelper
    ): IFileTransferManager {
        return FileTransferManagerImpl(
            notificationsHelper,
            applicationContext,
            FileTransferStateRepository,
        )
    }
}