/*
* Nextcloud application
*
* @author Mario Danic
* @author Chris Narkiewicz
* Copyright (C) 2017-2018 Mario Danic <mario@lovelyhq.com>
* Copyright (C) 2020 Chris Narkiewicz <hello@ezaquarii.com>
*
* This program 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 program 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.
*
* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package com.nextcloud.client.jobs

import android.accounts.AuthenticatorException
import android.accounts.OperationCanceledException
import android.app.Activity
import android.app.NotificationManager
import android.app.PendingIntent
import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.graphics.BitmapFactory
import android.media.RingtoneManager
import android.os.Build
import android.text.TextUtils
import android.util.Base64
import android.util.Log
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import androidx.work.Worker
import androidx.work.WorkerParameters
import com.google.gson.Gson
import com.nextcloud.client.account.User
import com.nextcloud.client.account.UserAccountManager
import com.owncloud.android.R
import com.owncloud.android.datamodel.DecryptedPushMessage
import com.owncloud.android.lib.common.OwnCloudClient
import com.owncloud.android.lib.common.OwnCloudClientManagerFactory
import com.owncloud.android.lib.common.operations.RemoteOperation
import com.owncloud.android.lib.common.utils.Log_OC
import com.owncloud.android.lib.resources.notifications.DeleteNotificationRemoteOperation
import com.owncloud.android.lib.resources.notifications.GetNotificationRemoteOperation
import com.owncloud.android.lib.resources.notifications.models.Notification
import com.owncloud.android.ui.activity.FileDisplayActivity
import com.owncloud.android.ui.activity.NotificationsActivity
import com.owncloud.android.ui.notifications.NotificationUtils
import com.owncloud.android.utils.PushUtils
import com.owncloud.android.utils.ThemeUtils
import dagger.android.AndroidInjection
import org.apache.commons.httpclient.HttpMethod
import org.apache.commons.httpclient.HttpStatus
import org.apache.commons.httpclient.methods.DeleteMethod
import org.apache.commons.httpclient.methods.GetMethod
import org.apache.commons.httpclient.methods.PutMethod
import org.apache.commons.httpclient.methods.Utf8PostMethod
import java.io.IOException
import java.security.GeneralSecurityException
import java.security.PrivateKey
import java.security.SecureRandom
import javax.crypto.Cipher
import javax.inject.Inject

class NotificationWork constructor(
    private val context: Context,
    params: WorkerParameters,
    private val notificationManager: NotificationManager,
    private val accountManager: UserAccountManager
) : Worker(context, params) {

    companion object {
        const val TAG = "NotificationJob"
        const val KEY_NOTIFICATION_ACCOUNT = "KEY_NOTIFICATION_ACCOUNT"
        const val KEY_NOTIFICATION_SUBJECT = "subject"
        const val KEY_NOTIFICATION_SIGNATURE = "signature"
        private const val KEY_NOTIFICATION_ACTION_LINK = "KEY_NOTIFICATION_ACTION_LINK"
        private const val KEY_NOTIFICATION_ACTION_TYPE = "KEY_NOTIFICATION_ACTION_TYPE"
        private const val PUSH_NOTIFICATION_ID = "PUSH_NOTIFICATION_ID"
        private const val NUMERIC_NOTIFICATION_ID = "NUMERIC_NOTIFICATION_ID"
    }

    @Suppress("TooGenericExceptionCaught", "NestedBlockDepth", "ComplexMethod", "LongMethod") // legacy code
    override fun doWork(): Result {
        val subject = inputData.getString(KEY_NOTIFICATION_SUBJECT) ?: ""
        val signature = inputData.getString(KEY_NOTIFICATION_SIGNATURE) ?: ""
        if (!TextUtils.isEmpty(subject) && !TextUtils.isEmpty(signature)) {
            try {
                val base64DecodedSubject = Base64.decode(subject, Base64.DEFAULT)
                val base64DecodedSignature = Base64.decode(signature, Base64.DEFAULT)
                val privateKey = PushUtils.readKeyFromFile(false) as PrivateKey
                try {
                    val signatureVerification = PushUtils.verifySignature(context,
                        accountManager,
                        base64DecodedSignature,
                        base64DecodedSubject)
                    if (signatureVerification != null && signatureVerification.isSignatureValid) {
                        val cipher = Cipher.getInstance("RSA/None/PKCS1Padding")
                        cipher.init(Cipher.DECRYPT_MODE, privateKey)
                        val decryptedSubject = cipher.doFinal(base64DecodedSubject)
                        val gson = Gson()
                        val decryptedPushMessage = gson.fromJson(String(decryptedSubject),
                            DecryptedPushMessage::class.java)
                        if (decryptedPushMessage.delete) {
                            notificationManager.cancel(decryptedPushMessage.nid)
                        } else if (decryptedPushMessage.deleteAll) {
                            notificationManager.cancelAll()
                        } else {
                            val user = accountManager.getUser(signatureVerification.getAccount().name)
                                .orElseThrow { RuntimeException() }
                            fetchCompleteNotification(user, decryptedPushMessage)
                        }
                    }
                } catch (e1: GeneralSecurityException) {
                    Log.d(TAG, "Error decrypting message ${e1.javaClass.name} ${e1.localizedMessage}")
                }
            } catch (exception: Exception) {
                Log.d(TAG, "Something went very wrong" + exception.localizedMessage)
            }
        }
        return Result.success()
    }

    @Suppress("LongMethod") // legacy code
    private fun sendNotification(notification: Notification, user: User) {
        val randomId = SecureRandom()
        val file = notification.subjectRichParameters["file"]
        val intent: Intent
        if (file == null) {
            intent = Intent(context, NotificationsActivity::class.java)
        } else {
            intent = Intent(context, FileDisplayActivity::class.java)
            intent.action = Intent.ACTION_VIEW
            intent.putExtra(FileDisplayActivity.KEY_FILE_ID, file.id)
        }
        intent.putExtra(KEY_NOTIFICATION_ACCOUNT, user.accountName)
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
        val pendingIntent = PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_ONE_SHOT)
        val pushNotificationId = randomId.nextInt()
        val notificationBuilder = NotificationCompat.Builder(context, NotificationUtils.NOTIFICATION_CHANNEL_PUSH)
            .setSmallIcon(R.drawable.notification_icon)
            .setLargeIcon(BitmapFactory.decodeResource(context.resources, R.drawable.notification_icon))
            .setColor(ThemeUtils.primaryColor(user.toPlatformAccount(), false, context))
            .setShowWhen(true)
            .setSubText(user.accountName)
            .setContentTitle(notification.getSubject())
            .setContentText(notification.getMessage())
            .setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))
            .setAutoCancel(true)
            .setVisibility(NotificationCompat.VISIBILITY_PRIVATE)
            .setContentIntent(pendingIntent)
        // Remove
        if (notification.getActions().isEmpty()) {
            val disableDetection = Intent(context, NotificationReceiver::class.java)
            disableDetection.putExtra(NUMERIC_NOTIFICATION_ID, notification.getNotificationId())
            disableDetection.putExtra(PUSH_NOTIFICATION_ID, pushNotificationId)
            disableDetection.putExtra(KEY_NOTIFICATION_ACCOUNT, user.accountName)
            val disableIntent = PendingIntent.getBroadcast(context, pushNotificationId, disableDetection,
                PendingIntent.FLAG_CANCEL_CURRENT)
            notificationBuilder.addAction(NotificationCompat.Action(R.drawable.ic_close,
                context.getString(R.string.remove_push_notification), disableIntent))
        } else { // Actions
            for (action in notification.getActions()) {
                val actionIntent = Intent(context, NotificationReceiver::class.java)
                actionIntent.putExtra(NUMERIC_NOTIFICATION_ID, notification.getNotificationId())
                actionIntent.putExtra(PUSH_NOTIFICATION_ID, pushNotificationId)
                actionIntent.putExtra(KEY_NOTIFICATION_ACCOUNT, user.accountName)
                actionIntent.putExtra(KEY_NOTIFICATION_ACTION_LINK, action.link)
                actionIntent.putExtra(KEY_NOTIFICATION_ACTION_TYPE, action.type)
                val actionPendingIntent = PendingIntent.getBroadcast(context, randomId.nextInt(),
                    actionIntent,
                    PendingIntent.FLAG_CANCEL_CURRENT)
                var icon: Int
                icon = if (action.primary) {
                    R.drawable.ic_check_circle
                } else {
                    R.drawable.ic_check_circle_outline
                }
                notificationBuilder.addAction(NotificationCompat.Action(icon, action.label, actionPendingIntent))
            }
        }
        notificationBuilder.setPublicVersion(
            NotificationCompat.Builder(context, NotificationUtils.NOTIFICATION_CHANNEL_PUSH)
                .setSmallIcon(R.drawable.notification_icon)
                .setLargeIcon(BitmapFactory.decodeResource(context.resources, R.drawable.notification_icon))
                .setColor(ThemeUtils.primaryColor(user.toPlatformAccount(), false, context))
                .setShowWhen(true)
                .setSubText(user.accountName)
                .setContentTitle(context.getString(R.string.new_notification))
                .setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))
                .setAutoCancel(true)
                .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
                .setContentIntent(pendingIntent).build())
        val notificationManager = NotificationManagerCompat.from(context)
        notificationManager.notify(notification.getNotificationId(), notificationBuilder.build())
    }

    @Suppress("TooGenericExceptionCaught") // legacy code
    private fun fetchCompleteNotification(account: User, decryptedPushMessage: DecryptedPushMessage) {
        val optionalUser = accountManager.getUser(account.accountName)
        if (!optionalUser.isPresent) {
            Log_OC.e(this, "Account may not be null")
            return
        }
        val user = optionalUser.get()
        try {
            val client = OwnCloudClientManagerFactory.getDefaultSingleton()
                .getClientFor(user.toOwnCloudAccount(), context)
            val result = GetNotificationRemoteOperation(decryptedPushMessage.nid)
                .execute(client)
            if (result.isSuccess) {
                val notification = result.notificationData[0]
                sendNotification(notification, account)
            }
        } catch (e: Exception) {
            Log_OC.e(this, "Error creating account", e)
        }
    }

    class NotificationReceiver : BroadcastReceiver() {
        private lateinit var accountManager: UserAccountManager

        /**
         * This is a workaround for a Dagger compiler bug - it cannot inject
         * into a nested Kotlin class for some reason, but the helper
         * works.
         */
        @Inject
        fun inject(accountManager: UserAccountManager) {
            this.accountManager = accountManager
        }

        @Suppress("ComplexMethod") // legacy code
        override fun onReceive(context: Context, intent: Intent) {
            AndroidInjection.inject(this, context)
            val numericNotificationId = intent.getIntExtra(NUMERIC_NOTIFICATION_ID, 0)
            val accountName = intent.getStringExtra(KEY_NOTIFICATION_ACCOUNT)
            if (numericNotificationId != 0) {
                Thread(Runnable {
                    val notificationManager = context.getSystemService(
                        Activity.NOTIFICATION_SERVICE) as NotificationManager
                    var oldNotification: android.app.Notification? = null
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && notificationManager != null) {
                        for (statusBarNotification in notificationManager.activeNotifications) {
                            if (numericNotificationId == statusBarNotification.id) {
                                oldNotification = statusBarNotification.notification
                                break
                            }
                        }
                        cancel(context, numericNotificationId)
                    }
                    try {
                        val optionalUser = accountManager.getUser(accountName)
                        if (optionalUser.isPresent) {
                            val user = optionalUser.get()
                            val client = OwnCloudClientManagerFactory.getDefaultSingleton()
                                .getClientFor(user.toOwnCloudAccount(), context)
                            val actionType = intent.getStringExtra(KEY_NOTIFICATION_ACTION_TYPE)
                            val actionLink = intent.getStringExtra(KEY_NOTIFICATION_ACTION_LINK)
                            val success: Boolean
                            success = if (!TextUtils.isEmpty(actionType) && !TextUtils.isEmpty(actionLink)) {
                                val resultCode = executeAction(actionType, actionLink, client)
                                resultCode == HttpStatus.SC_OK || resultCode == HttpStatus.SC_ACCEPTED
                            } else {
                                DeleteNotificationRemoteOperation(numericNotificationId)
                                    .execute(client).isSuccess
                            }
                            if (success) {
                                if (oldNotification == null) {
                                    cancel(context, numericNotificationId)
                                }
                            } else {
                                notificationManager.notify(numericNotificationId, oldNotification)
                            }
                        }
                    } catch (e: IOException) {
                        Log_OC.e(TAG, "Error initializing client", e)
                    } catch (e: OperationCanceledException) {
                        Log_OC.e(TAG, "Error initializing client", e)
                    } catch (e: AuthenticatorException) {
                        Log_OC.e(TAG, "Error initializing client", e)
                    }
                }).start()
            }
        }

        @Suppress("ReturnCount") // legacy code
        private fun executeAction(actionType: String, actionLink: String, client: OwnCloudClient): Int {
            val method: HttpMethod
            method = when (actionType) {
                "GET" -> GetMethod(actionLink)
                "POST" -> Utf8PostMethod(actionLink)
                "DELETE" -> DeleteMethod(actionLink)
                "PUT" -> PutMethod(actionLink)
                else -> return 0 // do nothing
            }
            method.setRequestHeader(RemoteOperation.OCS_API_HEADER, RemoteOperation.OCS_API_HEADER_VALUE)
            try {
                return client.executeMethod(method)
            } catch (e: IOException) {
                Log_OC.e(TAG, "Execution of notification action failed: $e")
            }
            return 0
        }

        private fun cancel(context: Context, notificationId: Int) {
            val notificationManager = context.getSystemService(Activity.NOTIFICATION_SERVICE) as NotificationManager
            notificationManager.cancel(notificationId)
        }
    }
}