/*
 * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
 * SPDX-License-Identifier: GPL-3.0-only
 */
package dev.msfjarvis.aps.ui.autofill

import android.app.PendingIntent
import android.content.Context
import android.content.Intent
import android.content.IntentSender
import android.os.Build
import android.os.Bundle
import android.view.autofill.AutofillManager
import android.widget.Toast
import androidx.activity.result.IntentSenderRequest
import androidx.activity.result.contract.ActivityResultContracts.StartIntentSenderForResult
import androidx.annotation.RequiresApi
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import com.github.androidpasswordstore.autofillparser.AutofillAction
import com.github.androidpasswordstore.autofillparser.Credentials
import com.github.michaelbull.result.getOrElse
import com.github.michaelbull.result.onFailure
import com.github.michaelbull.result.onSuccess
import com.github.michaelbull.result.runCatching
import dagger.hilt.android.AndroidEntryPoint
import dev.msfjarvis.aps.data.passfile.PasswordEntry
import dev.msfjarvis.aps.util.autofill.AutofillPreferences
import dev.msfjarvis.aps.util.autofill.AutofillResponseBuilder
import dev.msfjarvis.aps.util.autofill.DirectoryStructure
import dev.msfjarvis.aps.util.extensions.OPENPGP_PROVIDER
import dev.msfjarvis.aps.util.extensions.asLog
import java.io.ByteArrayOutputStream
import java.io.File
import java.io.InputStream
import java.io.OutputStream
import javax.inject.Inject
import kotlin.coroutines.Continuation
import kotlin.coroutines.resume
import kotlin.coroutines.resumeWithException
import kotlin.coroutines.suspendCoroutine
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import logcat.LogPriority.ERROR
import logcat.asLog
import logcat.logcat
import me.msfjarvis.openpgpktx.util.OpenPgpApi
import me.msfjarvis.openpgpktx.util.OpenPgpServiceConnection
import org.openintents.openpgp.IOpenPgpService2
import org.openintents.openpgp.OpenPgpError

@RequiresApi(Build.VERSION_CODES.O)
@AndroidEntryPoint
class AutofillDecryptActivity : AppCompatActivity() {

  companion object {

    private const val EXTRA_FILE_PATH = "dev.msfjarvis.aps.autofill.oreo.EXTRA_FILE_PATH"
    private const val EXTRA_SEARCH_ACTION = "dev.msfjarvis.aps.autofill.oreo.EXTRA_SEARCH_ACTION"

    private var decryptFileRequestCode = 1

    fun makeDecryptFileIntent(file: File, forwardedExtras: Bundle, context: Context): Intent {
      return Intent(context, AutofillDecryptActivity::class.java).apply {
        putExtras(forwardedExtras)
        putExtra(EXTRA_SEARCH_ACTION, true)
        putExtra(EXTRA_FILE_PATH, file.absolutePath)
      }
    }

    fun makeDecryptFileIntentSender(file: File, context: Context): IntentSender {
      val intent =
        Intent(context, AutofillDecryptActivity::class.java).apply {
          putExtra(EXTRA_SEARCH_ACTION, false)
          putExtra(EXTRA_FILE_PATH, file.absolutePath)
        }
      return PendingIntent.getActivity(
          context,
          decryptFileRequestCode++,
          intent,
          PendingIntent.FLAG_CANCEL_CURRENT
        )
        .intentSender
    }
  }

  @Inject lateinit var passwordEntryFactory: PasswordEntry.Factory

  private val decryptInteractionRequiredAction =
    registerForActivityResult(StartIntentSenderForResult()) { result ->
      if (continueAfterUserInteraction != null) {
        val data = result.data
        if (result.resultCode == RESULT_OK && data != null) {
          continueAfterUserInteraction?.resume(data)
        } else {
          continueAfterUserInteraction?.resumeWithException(
            Exception("OpenPgpApi ACTION_DECRYPT_VERIFY failed to continue after user interaction")
          )
        }
        continueAfterUserInteraction = null
      }
    }

  private var continueAfterUserInteraction: Continuation<Intent>? = null
  private lateinit var directoryStructure: DirectoryStructure

  override fun onStart() {
    super.onStart()
    val filePath =
      intent?.getStringExtra(EXTRA_FILE_PATH)
        ?: run {
          logcat(ERROR) { "AutofillDecryptActivity started without EXTRA_FILE_PATH" }
          finish()
          return
        }
    val clientState =
      intent?.getBundleExtra(AutofillManager.EXTRA_CLIENT_STATE)
        ?: run {
          logcat(ERROR) { "AutofillDecryptActivity started without EXTRA_CLIENT_STATE" }
          finish()
          return
        }
    val isSearchAction = intent?.getBooleanExtra(EXTRA_SEARCH_ACTION, true)!!
    val action = if (isSearchAction) AutofillAction.Search else AutofillAction.Match
    directoryStructure = AutofillPreferences.directoryStructure(this)
    logcat { action.toString() }
    lifecycleScope.launch {
      val credentials = decryptCredential(File(filePath))
      if (credentials == null) {
        setResult(RESULT_CANCELED)
      } else {
        val fillInDataset =
          AutofillResponseBuilder.makeFillInDataset(
            this@AutofillDecryptActivity,
            credentials,
            clientState,
            action
          )
        withContext(Dispatchers.Main) {
          setResult(
            RESULT_OK,
            Intent().apply { putExtra(AutofillManager.EXTRA_AUTHENTICATION_RESULT, fillInDataset) }
          )
        }
      }
      withContext(Dispatchers.Main) { finish() }
    }
  }

  override fun onDestroy() {
    super.onDestroy()
  }

  private suspend fun executeOpenPgpApi(
    data: Intent,
    input: InputStream,
    output: OutputStream
  ): Intent? {
    var openPgpServiceConnection: OpenPgpServiceConnection? = null
    val openPgpService =
      suspendCoroutine<IOpenPgpService2> { cont ->
        openPgpServiceConnection =
          OpenPgpServiceConnection(
              this,
              OPENPGP_PROVIDER,
              object : OpenPgpServiceConnection.OnBound {
                override fun onBound(service: IOpenPgpService2) {
                  cont.resume(service)
                }

                override fun onError(e: Exception) {
                  cont.resumeWithException(e)
                }
              }
            )
            .also { it.bindToService() }
      }
    return OpenPgpApi(this, openPgpService).executeApi(data, input, output).also {
      openPgpServiceConnection?.unbindFromService()
    }
  }

  private suspend fun decryptCredential(file: File, resumeIntent: Intent? = null): Credentials? {
    val command = resumeIntent ?: Intent().apply { action = OpenPgpApi.ACTION_DECRYPT_VERIFY }
    runCatching { file.inputStream() }
      .onFailure { e ->
        logcat(ERROR) { e.asLog("File to decrypt not found") }
        return null
      }
      .onSuccess { encryptedInput ->
        val decryptedOutput = ByteArrayOutputStream()
        runCatching { executeOpenPgpApi(command, encryptedInput, decryptedOutput) }
          .onFailure { e ->
            logcat(ERROR) { e.asLog("OpenPgpApi ACTION_DECRYPT_VERIFY failed") }
            return null
          }
          .onSuccess { result ->
            return when (val resultCode =
                result?.getIntExtra(OpenPgpApi.RESULT_CODE, OpenPgpApi.RESULT_CODE_ERROR)
            ) {
              OpenPgpApi.RESULT_CODE_SUCCESS -> {
                runCatching {
                  val entry =
                    withContext(Dispatchers.IO) {
                      @Suppress("BlockingMethodInNonBlockingContext")
                      passwordEntryFactory.create(lifecycleScope, decryptedOutput.toByteArray())
                    }
                  AutofillPreferences.credentialsFromStoreEntry(
                    this,
                    file,
                    entry,
                    directoryStructure
                  )
                }
                  .getOrElse { e ->
                    logcat(ERROR) { e.asLog("Failed to parse password entry") }
                    return null
                  }
              }
              OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED -> {
                val pendingIntent: PendingIntent =
                  result.getParcelableExtra(OpenPgpApi.RESULT_INTENT)!!
                runCatching {
                  val intentToResume =
                    withContext(Dispatchers.Main) {
                      suspendCoroutine<Intent> { cont ->
                        continueAfterUserInteraction = cont
                        decryptInteractionRequiredAction.launch(
                          IntentSenderRequest.Builder(pendingIntent.intentSender).build()
                        )
                      }
                    }
                  decryptCredential(file, intentToResume)
                }
                  .getOrElse { e ->
                    logcat(ERROR) {
                      e.asLog("OpenPgpApi ACTION_DECRYPT_VERIFY failed with user interaction")
                    }
                    return null
                  }
              }
              OpenPgpApi.RESULT_CODE_ERROR -> {
                val error = result.getParcelableExtra<OpenPgpError>(OpenPgpApi.RESULT_ERROR)
                if (error != null) {
                  withContext(Dispatchers.Main) {
                    Toast.makeText(
                        applicationContext,
                        "Error from OpenKeyChain: ${error.message}",
                        Toast.LENGTH_LONG
                      )
                      .show()
                  }
                  logcat(ERROR) {
                    "OpenPgpApi ACTION_DECRYPT_VERIFY failed (${error.errorId}): ${error.message}"
                  }
                }
                null
              }
              else -> {
                logcat(ERROR) { "Unrecognized OpenPgpApi result: $resultCode" }
                null
              }
            }
          }
      }
    return null
  }
}