package expo.modules

import android.annotation.SuppressLint
import android.app.Activity
import android.content.Context
import android.content.Intent
import android.content.pm.ActivityInfo
import android.content.res.Configuration
import android.os.Build
import android.os.Build.VERSION
import android.os.Bundle
import android.util.Log
import android.view.KeyEvent
import android.view.ViewGroup
import androidx.annotation.VisibleForTesting
import androidx.collection.ArrayMap
import androidx.lifecycle.lifecycleScope
import com.facebook.react.ReactActivity
import com.facebook.react.ReactActivityDelegate
import com.facebook.react.ReactDelegate
import com.facebook.react.ReactHost
import com.facebook.react.ReactInstanceManager
import com.facebook.react.ReactRootView
import com.facebook.react.modules.core.PermissionListener
import expo.modules.core.interfaces.ReactActivityHandler.DelayLoadAppHandler
import expo.modules.core.interfaces.ReactActivityLifecycleListener
import expo.modules.kotlin.Utils
import kotlinx.coroutines.CompletableDeferred
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.CoroutineStart
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import kotlinx.coroutines.sync.Mutex
import kotlinx.coroutines.sync.withLock
import java.lang.reflect.Field
import java.lang.reflect.Method
import java.lang.reflect.Modifier
import kotlin.coroutines.resume
import kotlin.coroutines.suspendCoroutine

class ReactActivityDelegateWrapper(
  private val activity: ReactActivity,
  private val isNewArchitectureEnabled: Boolean, // TODO(@lukmccall): Unused since SDK 55, remove in SDK 56
  @get:VisibleForTesting internal var delegate: ReactActivityDelegate
) : ReactActivityDelegate(activity, null) {
  constructor(activity: ReactActivity, delegate: ReactActivityDelegate) :
    this(activity, false, delegate)

  private val reactActivityLifecycleListeners = ExpoModulesPackage.packageList
    .flatMap { it.createReactActivityLifecycleListeners(activity) }
  private val reactActivityHandlers = ExpoModulesPackage.packageList
    .flatMap { it.createReactActivityHandlers(activity) }
  private val methodMap: ArrayMap<String, Method> = ArrayMap()
  private val _reactHost: ReactHost? by lazy {
    delegate.reactHost
  }
  private val delayLoadAppHandler: DelayLoadAppHandler? by lazy {
    reactActivityHandlers.asSequence()
      .mapNotNull { it.getDelayLoadAppHandler(activity, reactHost) }
      .firstOrNull()
  }

  /**
   * A deferred that indicates when the app loading is ready
   */
  private val loadAppReady = CompletableDeferred<Unit>()

  /**
   * A mutex to ensure all coroutines in a scope are running in atomic way.
   *
   * This is to act like [Activity] lifecycle,
   * e.g. all work in [onResume] should be executed after all work in [onCreate] finished.
   */
  private val mutex = Mutex()

  /**
   * A [CoroutineScope] that binds its lifecycle as [ReactActivityDelegateWrapper].
   * This is used for [onDestroy] because we need a longer lifecycle scope to call [onDestroy]
   */
  private val applicationCoroutineScope: CoroutineScope by lazy {
    CoroutineScope(Dispatchers.Main)
  }

  //region ReactActivityDelegate

  override fun getLaunchOptions(): Bundle? {
    return invokeDelegateMethod("getLaunchOptions")
  }

  override fun createRootView(): ReactRootView? {
    return invokeDelegateMethod("createRootView")
  }

  override fun getReactDelegate(): ReactDelegate? {
    return invokeDelegateMethod("getReactDelegate")
  }

  override fun getReactHost(): ReactHost? {
    return _reactHost
  }

  override fun getReactInstanceManager(): ReactInstanceManager {
    return delegate.reactInstanceManager
  }

  override fun getMainComponentName(): String? {
    return delegate.mainComponentName
  }

  override fun loadApp(appKey: String?) {
    launchLifecycleScopeWithLock(start = CoroutineStart.UNDISPATCHED) {
      loadAppImpl(appKey, supportsDelayLoad = true)
    }
  }

  @SuppressLint("DiscouragedPrivateApi")
  override fun onCreate(savedInstanceState: Bundle?) {
    // Give handlers a chance as early as possible to replace the wrapped delegate object.
    // If they do, we call the new wrapped delegate's `onCreate` instead of overriding it here.
    val newDelegate = reactActivityHandlers.asSequence()
      .mapNotNull { it.onDidCreateReactActivityDelegate(activity, this) }
      .firstOrNull()

    reactActivityHandlers.forEach { handler ->
      handler.onDidCreateReactActivityDelegateNotification(activity, newDelegate)
    }

    if (newDelegate != null && newDelegate != this) {
      val mDelegateField = ReactActivity::class.java.getDeclaredField("mDelegate")
      mDelegateField.isAccessible = true
      val modifiers = Field::class.java.getDeclaredField("accessFlags")
      modifiers.isAccessible = true
      modifiers.setInt(mDelegateField, mDelegateField.modifiers and Modifier.FINAL.inv())
      mDelegateField.set(activity, newDelegate)
      delegate = newDelegate

      delegate.onCreate(savedInstanceState)
    } else {
      // Since we just wrap `ReactActivityDelegate` but not inherit it, in its `onCreate`,
      // the calls to `createRootView()` or `getMainComponentName()` have no chances to be our wrapped methods.
      // Instead we intercept `ReactActivityDelegate.onCreate` and replace the `mReactDelegate` with our version.
      // That's not ideal but works.

      launchLifecycleScopeWithLock(start = CoroutineStart.UNDISPATCHED) {
        awaitDelayLoadAppWhenReady(delayLoadAppHandler)
        loadAppReady.complete(Unit)

        if (VERSION.SDK_INT >= Build.VERSION_CODES.O && isWideColorGamutEnabled) {
          activity.window.colorMode = ActivityInfo.COLOR_MODE_WIDE_COLOR_GAMUT
        }

        val launchOptions = composeLaunchOptions()
        val reactDelegate = ReactDelegate(
          plainActivity,
          reactHost,
          mainComponentName,
          launchOptions
        )

        val mReactDelegate = ReactActivityDelegate::class.java.getDeclaredField("mReactDelegate")
        mReactDelegate.isAccessible = true
        mReactDelegate.set(delegate, reactDelegate)
        if (mainComponentName != null) {
          loadAppImpl(mainComponentName, supportsDelayLoad = false)
        }
      }
    }

    reactActivityLifecycleListeners.forEach { listener ->
      listener.onCreate(activity, savedInstanceState)
    }
  }

  override fun onResume() {
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      delegate.onResume()
      reactActivityLifecycleListeners.forEach { listener ->
        listener.onResume(activity)
      }
    }
  }

  override fun onPause() {
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      reactActivityLifecycleListeners.forEach { listener ->
        listener.onPause(activity)
      }
      if (delayLoadAppHandler != null) {
        try {
          // For the delay load case, we may enter a different call flow than react-native.
          // For example, Activity stopped before delay load finished.
          // We stop before the ReactActivityDelegate gets a chance to set up.
          // In this case, we should catch the exceptions.
          delegate.onPause()
        } catch (e: Exception) {
          Log.e(TAG, "Exception occurred during onPause with delayed app loading", e)
        }
      } else {
        delegate.onPause()
      }
    }
  }

  override fun onUserLeaveHint() {
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      reactActivityLifecycleListeners.forEach { listener ->
        listener.onUserLeaveHint(activity)
      }
      delegate.onUserLeaveHint()
    }
  }

  override fun onDestroy() {
    // Note: use our `coroutineScope` for onDestroy here
    // because the lifecycleScope destroyed before the executions.
    applicationCoroutineScope.launch {
      mutex.withLock {
        loadAppReady.await()
        reactActivityLifecycleListeners.forEach { listener ->
          listener.onDestroy(activity)
        }
        if (delayLoadAppHandler != null) {
          try {
            // For the delay load case, we may enter a different call flow than react-native.
            // For example, Activity stopped before delay load finished.
            // We stop before the ReactActivityDelegate gets a chance to set up.
            // In this case, we should catch the exceptions.
            delegate.onDestroy()
          } catch (e: Exception) {
            Log.e(TAG, "Exception occurred during onDestroy with delayed app loading", e)
          }
        } else {
          delegate.onDestroy()
        }
      }
    }
  }

  override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    /**
     * Workaround for a problem when results from [onActivityResult] are not properly delivered to modules.
     * It happens when Android kills the [Activity] upon low memory scenario and recreates it later on.
     *
     * In [com.facebook.react.ReactInstanceManager.onActivityResult] you can see that if
     * [com.facebook.react.bridge.ReactContext] is null then React would not broadcast the result to the modules
     * and thus [expo.modules.kotlin.AppContext] would not be triggered properly.
     *
     * If [com.facebook.react.bridge.ReactContext] is not available when [onActivityResult] is called then
     * let us wait for it and invoke [onActivityResult] once it's available.
     *
     * TODO (@bbarthec): fix it upstream?
     */
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      delegate.onActivityResult(requestCode, resultCode, data)
    }
  }

  override fun onKeyDown(keyCode: Int, event: KeyEvent): Boolean {
    if (!loadAppReady.isCompleted) {
      return false
    }
    // if any of the handlers return true, intentionally consume the event instead of passing it
    // through to the delegate
    return reactActivityHandlers
      .map { it.onKeyDown(keyCode, event) }
      .fold(false) { accu, current -> accu || current } || delegate.onKeyDown(keyCode, event)
  }

  override fun onKeyUp(keyCode: Int, event: KeyEvent): Boolean {
    if (!loadAppReady.isCompleted) {
      return false
    }
    // if any of the handlers return true, intentionally consume the event instead of passing it
    // through to the delegate
    return reactActivityHandlers
      .map { it.onKeyUp(keyCode, event) }
      .fold(false) { accu, current -> accu || current } || delegate.onKeyUp(keyCode, event)
  }

  override fun onKeyLongPress(keyCode: Int, event: KeyEvent): Boolean {
    if (!loadAppReady.isCompleted) {
      return false
    }
    // if any of the handlers return true, intentionally consume the event instead of passing it
    // through to the delegate
    return reactActivityHandlers
      .map { it.onKeyLongPress(keyCode, event) }
      .fold(false) { accu, current -> accu || current } || delegate.onKeyLongPress(keyCode, event)
  }

  override fun onBackPressed(): Boolean {
    if (!loadAppReady.isCompleted) {
      return false
    }
    val listenerResult = reactActivityLifecycleListeners
      .map(ReactActivityLifecycleListener::onBackPressed)
      .fold(false) { accu, current -> accu || current }
    val delegateResult = delegate.onBackPressed()
    return listenerResult || delegateResult
  }

  override fun onNewIntent(intent: Intent?): Boolean {
    if (!loadAppReady.isCompleted) {
      return false
    }
    val listenerResult = reactActivityLifecycleListeners
      .map { it.onNewIntent(intent) }
      .fold(false) { accu, current -> accu || current }
    val delegateResult = delegate.onNewIntent(intent)
    return listenerResult || delegateResult
  }

  override fun onWindowFocusChanged(hasFocus: Boolean) {
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      delegate.onWindowFocusChanged(hasFocus)
    }
  }

  override fun requestPermissions(permissions: Array<out String>, requestCode: Int, listener: PermissionListener?) {
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      delegate.requestPermissions(permissions, requestCode, listener)
    }
  }

  override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      delegate.onRequestPermissionsResult(requestCode, permissions, grantResults)
    }
  }

  override fun getContext(): Context {
    return invokeDelegateMethod("getContext")
  }

  override fun getPlainActivity(): Activity {
    return invokeDelegateMethod("getPlainActivity")
  }

  override fun isFabricEnabled(): Boolean {
    return invokeDelegateMethod("isFabricEnabled")
  }

  override fun isWideColorGamutEnabled(): Boolean {
    return invokeDelegateMethod("isWideColorGamutEnabled")
  }

  override fun composeLaunchOptions(): Bundle? {
    return invokeDelegateMethod("composeLaunchOptions")
  }

  override fun onConfigurationChanged(newConfig: Configuration) {
    launchLifecycleScopeWithLock {
      loadAppReady.await()
      delegate.onConfigurationChanged(newConfig)
    }
  }

  //endregion

  //region Internals

  @Suppress("UNCHECKED_CAST")
  private fun <T> invokeDelegateMethod(name: String): T {
    var method = methodMap[name]
    if (method == null) {
      method = ReactActivityDelegate::class.java.getDeclaredMethod(name)
      method.isAccessible = true
      methodMap[name] = method
    }
    return method!!.invoke(delegate) as T
  }

  @VisibleForTesting
  @Suppress("UNCHECKED_CAST")
  internal fun <T, A> invokeDelegateMethod(
    name: String,
    argTypes: Array<Class<*>>,
    args: Array<A>
  ): T {
    var method = methodMap[name]
    if (method == null) {
      method = ReactActivityDelegate::class.java.getDeclaredMethod(name, *argTypes)
      method.isAccessible = true
      methodMap[name] = method
    }
    return method!!.invoke(delegate, *args) as T
  }

  private suspend fun loadAppImpl(appKey: String?, supportsDelayLoad: Boolean) {
    // Give modules a chance to wrap the ReactRootView in a container ViewGroup. If some module
    // wants to do this, we override the functionality of `loadApp` and call `setContentView` with
    // the new container view instead.
    val rootViewContainer = reactActivityHandlers.asSequence()
      .mapNotNull { it.createReactRootViewContainer(activity) }
      .firstOrNull()
    if (rootViewContainer != null) {
      val mReactDelegate = ReactActivityDelegate::class.java.getDeclaredField("mReactDelegate")
      mReactDelegate.isAccessible = true
      val reactDelegate = mReactDelegate[delegate] as ReactDelegate

      reactDelegate.loadApp(requireNotNull(appKey))
      val reactRootView = reactDelegate.reactRootView
      (reactRootView?.parent as? ViewGroup)?.removeView(reactRootView)
      rootViewContainer.addView(reactRootView, ViewGroup.LayoutParams.MATCH_PARENT)
      activity.setContentView(rootViewContainer)
      reactActivityLifecycleListeners.forEach { listener ->
        listener.onContentChanged(activity)
      }
      return
    }

    if (supportsDelayLoad) {
      awaitDelayLoadAppWhenReady(delayLoadAppHandler)
      invokeDelegateMethod<Unit, String?>("loadApp", arrayOf(String::class.java), arrayOf(appKey))
      reactActivityLifecycleListeners.forEach { listener ->
        listener.onContentChanged(activity)
      }
      return
    }

    invokeDelegateMethod<Unit, String?>("loadApp", arrayOf(String::class.java), arrayOf(appKey))
    reactActivityLifecycleListeners.forEach { listener ->
      listener.onContentChanged(activity)
    }
  }

  private suspend fun awaitDelayLoadAppWhenReady(delayLoadAppHandler: DelayLoadAppHandler?) {
    if (delayLoadAppHandler == null) {
      return
    }
    suspendCoroutine { continuation ->
      delayLoadAppHandler.whenReady {
        Utils.assertMainThread()
        continuation.resume(Unit)
      }
    }
  }

  private fun launchLifecycleScopeWithLock(
    start: CoroutineStart = CoroutineStart.DEFAULT,
    block: suspend CoroutineScope.() -> Unit
  ) {
    activity.lifecycleScope.launch(start = start) {
      mutex.withLock {
        block()
      }
    }
  }

  /**
   * Set the [loadAppReady] to completed state.
   * This is only for unit tests when a test setups mocks and skips the [Activity] lifecycle.
   */
  @VisibleForTesting
  internal fun setLoadAppReadyForTesting() {
    loadAppReady.complete(Unit)
  }

  //endregion

  companion object {
    private val TAG = ReactActivityDelegate::class.simpleName
  }
}