/*
 * Copyright © 2014-2021 The Android Password Store Authors. All Rights Reserved.
 * SPDX-License-Identifier: GPL-3.0-only
 */

package dev.msfjarvis.aps.ui.crypto

import android.content.Intent
import android.os.Bundle
import android.view.Menu
import android.view.MenuItem
import android.view.View
import androidx.activity.result.IntentSenderRequest
import androidx.activity.result.contract.ActivityResultContracts.StartIntentSenderForResult
import androidx.lifecycle.lifecycleScope
import com.github.ajalt.timberkt.e
import com.github.michaelbull.result.onFailure
import com.github.michaelbull.result.runCatching
import dev.msfjarvis.aps.R
import dev.msfjarvis.aps.data.password.FieldItem
import dev.msfjarvis.aps.data.password.PasswordEntry
import dev.msfjarvis.aps.databinding.DecryptLayoutBinding
import dev.msfjarvis.aps.ui.adapters.FieldItemAdapter
import dev.msfjarvis.aps.util.extensions.viewBinding
import dev.msfjarvis.aps.util.settings.PreferenceKeys
import java.io.ByteArrayOutputStream
import java.io.File
import kotlin.time.ExperimentalTime
import kotlin.time.seconds
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import me.msfjarvis.openpgpktx.util.OpenPgpApi
import me.msfjarvis.openpgpktx.util.OpenPgpServiceConnection
import org.openintents.openpgp.IOpenPgpService2

class DecryptActivity : BasePgpActivity(), OpenPgpServiceConnection.OnBound {

  private val binding by viewBinding(DecryptLayoutBinding::inflate)

  private val relativeParentPath by lazy(LazyThreadSafetyMode.NONE) { getParentPath(fullPath, repoPath) }
  private var passwordEntry: PasswordEntry? = null

  private val userInteractionRequiredResult =
    registerForActivityResult(StartIntentSenderForResult()) { result ->
      if (result.data == null) {
        setResult(RESULT_CANCELED, null)
        finish()
        return@registerForActivityResult
      }

      when (result.resultCode) {
        RESULT_OK -> decryptAndVerify(result.data)
        RESULT_CANCELED -> {
          setResult(RESULT_CANCELED, result.data)
          finish()
        }
      }
    }

  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    supportActionBar?.setDisplayHomeAsUpEnabled(true)
    bindToOpenKeychain(this)
    title = name
    with(binding) {
      setContentView(root)
      passwordCategory.text = relativeParentPath
      passwordFile.text = name
      passwordFile.setOnLongClickListener {
        copyTextToClipboard(name)
        true
      }
      passwordLastChanged.run {
        runCatching { text = resources.getString(R.string.last_changed, lastChangedString) }.onFailure {
          visibility = View.GONE
        }
      }
    }
  }

  override fun onCreateOptionsMenu(menu: Menu?): Boolean {
    menuInflater.inflate(R.menu.pgp_handler, menu)
    passwordEntry?.let { entry ->
      if (menu != null) {
        menu.findItem(R.id.edit_password).isVisible = true
        if (entry.password.isNotEmpty()) {
          menu.findItem(R.id.share_password_as_plaintext).isVisible = true
          menu.findItem(R.id.copy_password).isVisible = true
        }
      }
    }
    return true
  }

  override fun onOptionsItemSelected(item: MenuItem): Boolean {
    when (item.itemId) {
      android.R.id.home -> onBackPressed()
      R.id.edit_password -> editPassword()
      R.id.share_password_as_plaintext -> shareAsPlaintext()
      R.id.copy_password -> copyPasswordToClipboard(passwordEntry?.password)
      else -> return super.onOptionsItemSelected(item)
    }
    return true
  }

  override fun onBound(service: IOpenPgpService2) {
    super.onBound(service)
    decryptAndVerify()
  }

  override fun onError(e: Exception) {
    e(e)
  }

  /**
   * Automatically finishes the activity 60 seconds after decryption succeeded to prevent
   * information leaks from stale activities.
   */
  @OptIn(ExperimentalTime::class)
  private fun startAutoDismissTimer() {
    lifecycleScope.launch {
      delay(60.seconds)
      finish()
    }
  }

  /**
   * Edit the current password and hide all the fields populated by encrypted data so that when the
   * result triggers they can be repopulated with new data.
   */
  private fun editPassword() {
    val intent = Intent(this, PasswordCreationActivity::class.java)
    intent.putExtra("FILE_PATH", relativeParentPath)
    intent.putExtra("REPO_PATH", repoPath)
    intent.putExtra(PasswordCreationActivity.EXTRA_FILE_NAME, name)
    intent.putExtra(PasswordCreationActivity.EXTRA_PASSWORD, passwordEntry?.password)
    intent.putExtra(PasswordCreationActivity.EXTRA_EXTRA_CONTENT, passwordEntry?.extraContent)
    intent.putExtra(PasswordCreationActivity.EXTRA_EDITING, true)
    startActivity(intent)
    finish()
  }

  private fun shareAsPlaintext() {
    val sendIntent =
      Intent().apply {
        action = Intent.ACTION_SEND
        putExtra(Intent.EXTRA_TEXT, passwordEntry?.password)
        type = "text/plain"
      }
    // Always show a picker to give the user a chance to cancel
    startActivity(Intent.createChooser(sendIntent, resources.getText(R.string.send_plaintext_password_to)))
  }

  @OptIn(ExperimentalTime::class)
  private fun decryptAndVerify(receivedIntent: Intent? = null) {
    if (api == null) {
      bindToOpenKeychain(this)
      return
    }
    val data = receivedIntent ?: Intent()
    data.action = OpenPgpApi.ACTION_DECRYPT_VERIFY

    val inputStream = File(fullPath).inputStream()
    val outputStream = ByteArrayOutputStream()

    lifecycleScope.launch(Dispatchers.IO) {
      api?.executeApiAsync(data, inputStream, outputStream) { result ->
        when (result?.getIntExtra(OpenPgpApi.RESULT_CODE, OpenPgpApi.RESULT_CODE_ERROR)) {
          OpenPgpApi.RESULT_CODE_SUCCESS -> {
            startAutoDismissTimer()
            runCatching {
              val showPassword = settings.getBoolean(PreferenceKeys.SHOW_PASSWORD, true)
              val entry = PasswordEntry(outputStream)
              val items = arrayListOf<FieldItem>()
              val adapter = FieldItemAdapter(emptyList(), showPassword) { text -> copyTextToClipboard(text) }

              if (settings.getBoolean(PreferenceKeys.COPY_ON_DECRYPT, false)) {
                copyPasswordToClipboard(entry.password)
              }

              passwordEntry = entry
              invalidateOptionsMenu()

              if (entry.password.isNotEmpty()) {
                items.add(FieldItem.createPasswordField(entry.password))
              }

              if (entry.hasTotp()) {
                launch(Dispatchers.IO) {
                  // Calculate the actual remaining time for the first pass
                  // then return to the standard 30 second affair.
                  val remainingTime = entry.totpPeriod - (System.currentTimeMillis() % entry.totpPeriod)
                  withContext(Dispatchers.Main) {
                    val code = entry.calculateTotpCode() ?: "Error"
                    items.add(FieldItem.createOtpField(code))
                  }
                  delay(remainingTime.seconds)
                  repeat(Int.MAX_VALUE) {
                    val code = entry.calculateTotpCode() ?: "Error"
                    withContext(Dispatchers.Main) { adapter.updateOTPCode(code) }
                    delay(30.seconds)
                  }
                }
              }

              if (!entry.username.isNullOrEmpty()) {
                items.add(FieldItem.createUsernameField(entry.username))
              }

              if (entry.hasExtraContentWithoutAuthData()) {
                entry.extraContentMap.forEach { (key, value) ->
                  items.add(FieldItem(key, value, FieldItem.ActionType.COPY))
                }
              }

              binding.recyclerView.adapter = adapter
              adapter.updateItems(items)
            }
              .onFailure { e -> e(e) }
          }
          OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED -> {
            val sender = getUserInteractionRequestIntent(result)
            userInteractionRequiredResult.launch(IntentSenderRequest.Builder(sender).build())
          }
          OpenPgpApi.RESULT_CODE_ERROR -> handleError(result)
        }
      }
    }
  }
}