// Copyright 2019 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package io.flutter.plugins.imagepicker;

import android.Manifest;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.media.MediaScannerConnection;
import android.net.Uri;
import android.provider.MediaStore;
import androidx.annotation.VisibleForTesting;
import androidx.core.app.ActivityCompat;
import androidx.core.content.FileProvider;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.PluginRegistry;
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import java.util.UUID;

/**
 * A delegate class doing the heavy lifting for the plugin.
 *
 * <p>When invoked, both the {@link #chooseImageFromGallery} and {@link #takeImageWithCamera}
 * methods go through the same steps:
 *
 * <p>1. Check for an existing {@link #pendingResult}. If a previous pendingResult exists, this
 * means that the chooseImageFromGallery() or takeImageWithCamera() method was called at least
 * twice. In this case, stop executing and finish with an error.
 *
 * <p>2. Check that a required runtime permission has been granted. The chooseImageFromGallery()
 * method checks if the {@link Manifest.permission#READ_EXTERNAL_STORAGE} permission has been
 * granted. Similarly, the takeImageWithCamera() method checks that {@link
 * Manifest.permission#CAMERA} has been granted.
 *
 * <p>The permission check can end up in two different outcomes:
 *
 * <p>A) If the permission has already been granted, continue with picking the image from gallery or
 * camera.
 *
 * <p>B) If the permission hasn't already been granted, ask for the permission from the user. If the
 * user grants the permission, proceed with step #3. If the user denies the permission, stop doing
 * anything else and finish with a null result.
 *
 * <p>3. Launch the gallery or camera for picking the image, depending on whether
 * chooseImageFromGallery() or takeImageWithCamera() was called.
 *
 * <p>This can end up in three different outcomes:
 *
 * <p>A) User picks an image. No maxWidth or maxHeight was specified when calling {@code
 * pickImage()} method in the Dart side of this plugin. Finish with full path for the picked image
 * as the result.
 *
 * <p>B) User picks an image. A maxWidth and/or maxHeight was provided when calling {@code
 * pickImage()} method in the Dart side of this plugin. A scaled copy of the image is created.
 * Finish with full path for the scaled image as the result.
 *
 * <p>C) User cancels picking an image. Finish with null result.
 */
public class ImagePickerDelegate
    implements PluginRegistry.ActivityResultListener,
        PluginRegistry.RequestPermissionsResultListener {
  @VisibleForTesting static final int REQUEST_CODE_CHOOSE_IMAGE_FROM_GALLERY = 2342;
  @VisibleForTesting static final int REQUEST_CODE_TAKE_IMAGE_WITH_CAMERA = 2343;
  @VisibleForTesting static final int REQUEST_EXTERNAL_IMAGE_STORAGE_PERMISSION = 2344;
  @VisibleForTesting static final int REQUEST_CAMERA_IMAGE_PERMISSION = 2345;
  @VisibleForTesting static final int REQUEST_CODE_CHOOSE_VIDEO_FROM_GALLERY = 2352;
  @VisibleForTesting static final int REQUEST_CODE_TAKE_VIDEO_WITH_CAMERA = 2353;
  @VisibleForTesting static final int REQUEST_EXTERNAL_VIDEO_STORAGE_PERMISSION = 2354;
  @VisibleForTesting static final int REQUEST_CAMERA_VIDEO_PERMISSION = 2355;

  @VisibleForTesting final String fileProviderName;

  private final Activity activity;
  private final File externalFilesDirectory;
  private final ImageResizer imageResizer;
  private final ImagePickerCache cache;
  private final PermissionManager permissionManager;
  private final IntentResolver intentResolver;
  private final FileUriResolver fileUriResolver;
  private final FileUtils fileUtils;

  interface PermissionManager {
    boolean isPermissionGranted(String permissionName);

    void askForPermission(String permissionName, int requestCode);

    boolean needRequestCameraPermission();
  }

  interface IntentResolver {
    boolean resolveActivity(Intent intent);
  }

  interface FileUriResolver {
    Uri resolveFileProviderUriForFile(String fileProviderName, File imageFile);

    void getFullImagePath(Uri imageUri, OnPathReadyListener listener);
  }

  interface OnPathReadyListener {
    void onPathReady(String path);
  }

  private Uri pendingCameraMediaUri;
  private MethodChannel.Result pendingResult;
  private MethodCall methodCall;

  public ImagePickerDelegate(
      final Activity activity,
      final File externalFilesDirectory,
      final ImageResizer imageResizer,
      final ImagePickerCache cache) {
    this(
        activity,
        externalFilesDirectory,
        imageResizer,
        null,
        null,
        cache,
        new PermissionManager() {
          @Override
          public boolean isPermissionGranted(String permissionName) {
            return ActivityCompat.checkSelfPermission(activity, permissionName)
                == PackageManager.PERMISSION_GRANTED;
          }

          @Override
          public void askForPermission(String permissionName, int requestCode) {
            ActivityCompat.requestPermissions(activity, new String[] {permissionName}, requestCode);
          }

          @Override
          public boolean needRequestCameraPermission() {
            return ImagePickerUtils.needRequestCameraPermission(activity);
          }
        },
        new IntentResolver() {
          @Override
          public boolean resolveActivity(Intent intent) {
            return intent.resolveActivity(activity.getPackageManager()) != null;
          }
        },
        new FileUriResolver() {
          @Override
          public Uri resolveFileProviderUriForFile(String fileProviderName, File file) {
            return FileProvider.getUriForFile(activity, fileProviderName, file);
          }

          @Override
          public void getFullImagePath(final Uri imageUri, final OnPathReadyListener listener) {
            MediaScannerConnection.scanFile(
                activity,
                new String[] {(imageUri != null) ? imageUri.getPath() : ""},
                null,
                new MediaScannerConnection.OnScanCompletedListener() {
                  @Override
                  public void onScanCompleted(String path, Uri uri) {
                    listener.onPathReady(path);
                  }
                });
          }
        },
        new FileUtils());
  }

  /**
   * This constructor is used exclusively for testing; it can be used to provide mocks to final
   * fields of this class. Otherwise those fields would have to be mutable and visible.
   */
  @VisibleForTesting
  ImagePickerDelegate(
      final Activity activity,
      final File externalFilesDirectory,
      final ImageResizer imageResizer,
      final MethodChannel.Result result,
      final MethodCall methodCall,
      final ImagePickerCache cache,
      final PermissionManager permissionManager,
      final IntentResolver intentResolver,
      final FileUriResolver fileUriResolver,
      final FileUtils fileUtils) {
    this.activity = activity;
    this.externalFilesDirectory = externalFilesDirectory;
    this.imageResizer = imageResizer;
    this.fileProviderName = activity.getPackageName() + ".flutter.image_provider";
    this.pendingResult = result;
    this.methodCall = methodCall;
    this.permissionManager = permissionManager;
    this.intentResolver = intentResolver;
    this.fileUriResolver = fileUriResolver;
    this.fileUtils = fileUtils;
    this.cache = cache;
  }

  void saveStateBeforeResult() {
    if (methodCall == null) {
      return;
    }

    cache.saveTypeWithMethodCallName(methodCall.method);
    cache.saveDimensionWithMethodCall(methodCall);
    if (pendingCameraMediaUri != null) {
      cache.savePendingCameraMediaUriPath(pendingCameraMediaUri);
    }
  }

  void retrieveLostImage(MethodChannel.Result result) {
    Map<String, Object> resultMap = cache.getCacheMap();
    String path = (String) resultMap.get(cache.MAP_KEY_PATH);
    if (path != null) {
      Double maxWidth = (Double) resultMap.get(cache.MAP_KEY_MAX_WIDTH);
      Double maxHeight = (Double) resultMap.get(cache.MAP_KEY_MAX_HEIGHT);
      int imageQuality =
          resultMap.get(cache.MAP_KEY_IMAGE_QUALITY) == null
              ? 100
              : (int) resultMap.get(cache.MAP_KEY_IMAGE_QUALITY);

      String newPath = imageResizer.resizeImageIfNeeded(path, maxWidth, maxHeight, imageQuality);
      resultMap.put(cache.MAP_KEY_PATH, newPath);
    }
    if (resultMap.isEmpty()) {
      result.success(null);
    } else {
      result.success(resultMap);
    }
    cache.clear();
  }

  public void chooseVideoFromGallery(MethodCall methodCall, MethodChannel.Result result) {
    if (!setPendingMethodCallAndResult(methodCall, result)) {
      finishWithAlreadyActiveError(result);
      return;
    }

    if (!permissionManager.isPermissionGranted(Manifest.permission.READ_EXTERNAL_STORAGE)) {
      permissionManager.askForPermission(
          Manifest.permission.READ_EXTERNAL_STORAGE, REQUEST_EXTERNAL_VIDEO_STORAGE_PERMISSION);
      return;
    }

    launchPickVideoFromGalleryIntent();
  }

  private void launchPickVideoFromGalleryIntent() {
    Intent pickVideoIntent = new Intent(Intent.ACTION_GET_CONTENT);
    pickVideoIntent.setType("video/*");

    activity.startActivityForResult(pickVideoIntent, REQUEST_CODE_CHOOSE_VIDEO_FROM_GALLERY);
  }

  public void takeVideoWithCamera(MethodCall methodCall, MethodChannel.Result result) {
    if (!setPendingMethodCallAndResult(methodCall, result)) {
      finishWithAlreadyActiveError(result);
      return;
    }

    if (needRequestCameraPermission()
        && !permissionManager.isPermissionGranted(Manifest.permission.CAMERA)) {
      permissionManager.askForPermission(
          Manifest.permission.CAMERA, REQUEST_CAMERA_VIDEO_PERMISSION);
      return;
    }

    launchTakeVideoWithCameraIntent();
  }

  private void launchTakeVideoWithCameraIntent() {
    Intent intent = new Intent(MediaStore.ACTION_VIDEO_CAPTURE);
    boolean canTakePhotos = intentResolver.resolveActivity(intent);

    if (!canTakePhotos) {
      finishWithError("no_available_camera", "No cameras available for taking pictures.");
      return;
    }

    File videoFile = createTemporaryWritableVideoFile();
    pendingCameraMediaUri = Uri.parse("file:" + videoFile.getAbsolutePath());

    Uri videoUri = fileUriResolver.resolveFileProviderUriForFile(fileProviderName, videoFile);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, videoUri);
    grantUriPermissions(intent, videoUri);

    activity.startActivityForResult(intent, REQUEST_CODE_TAKE_VIDEO_WITH_CAMERA);
  }

  public void chooseImageFromGallery(MethodCall methodCall, MethodChannel.Result result) {
    if (!setPendingMethodCallAndResult(methodCall, result)) {
      finishWithAlreadyActiveError(result);
      return;
    }

    if (!permissionManager.isPermissionGranted(Manifest.permission.READ_EXTERNAL_STORAGE)) {
      permissionManager.askForPermission(
          Manifest.permission.READ_EXTERNAL_STORAGE, REQUEST_EXTERNAL_IMAGE_STORAGE_PERMISSION);
      return;
    }

    launchPickImageFromGalleryIntent();
  }

  private void launchPickImageFromGalleryIntent() {
    Intent pickImageIntent = new Intent(Intent.ACTION_GET_CONTENT);
    pickImageIntent.setType("image/*");

    activity.startActivityForResult(pickImageIntent, REQUEST_CODE_CHOOSE_IMAGE_FROM_GALLERY);
  }

  public void takeImageWithCamera(MethodCall methodCall, MethodChannel.Result result) {
    if (!setPendingMethodCallAndResult(methodCall, result)) {
      finishWithAlreadyActiveError(result);
      return;
    }

    if (needRequestCameraPermission()
        && !permissionManager.isPermissionGranted(Manifest.permission.CAMERA)) {
      permissionManager.askForPermission(
          Manifest.permission.CAMERA, REQUEST_CAMERA_IMAGE_PERMISSION);
      return;
    }

    launchTakeImageWithCameraIntent();
  }

  private boolean needRequestCameraPermission() {
    if (permissionManager == null) {
      return false;
    }
    return permissionManager.needRequestCameraPermission();
  }

  private void launchTakeImageWithCameraIntent() {
    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    boolean canTakePhotos = intentResolver.resolveActivity(intent);

    if (!canTakePhotos) {
      finishWithError("no_available_camera", "No cameras available for taking pictures.");
      return;
    }

    File imageFile = createTemporaryWritableImageFile();
    pendingCameraMediaUri = Uri.parse("file:" + imageFile.getAbsolutePath());

    Uri imageUri = fileUriResolver.resolveFileProviderUriForFile(fileProviderName, imageFile);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
    grantUriPermissions(intent, imageUri);

    activity.startActivityForResult(intent, REQUEST_CODE_TAKE_IMAGE_WITH_CAMERA);
  }

  private File createTemporaryWritableImageFile() {
    return createTemporaryWritableFile(".jpg");
  }

  private File createTemporaryWritableVideoFile() {
    return createTemporaryWritableFile(".mp4");
  }

  private File createTemporaryWritableFile(String suffix) {
    String filename = UUID.randomUUID().toString();
    File image;

    try {
      image = File.createTempFile(filename, suffix, externalFilesDirectory);
    } catch (IOException e) {
      throw new RuntimeException(e);
    }

    return image;
  }

  private void grantUriPermissions(Intent intent, Uri imageUri) {
    PackageManager packageManager = activity.getPackageManager();
    List<ResolveInfo> compatibleActivities =
        packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);

    for (ResolveInfo info : compatibleActivities) {
      activity.grantUriPermission(
          info.activityInfo.packageName,
          imageUri,
          Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
    }
  }

  @Override
  public boolean onRequestPermissionsResult(
      int requestCode, String[] permissions, int[] grantResults) {
    boolean permissionGranted =
        grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED;

    switch (requestCode) {
      case REQUEST_EXTERNAL_IMAGE_STORAGE_PERMISSION:
        if (permissionGranted) {
          launchPickImageFromGalleryIntent();
        }
        break;
      case REQUEST_EXTERNAL_VIDEO_STORAGE_PERMISSION:
        if (permissionGranted) {
          launchPickVideoFromGalleryIntent();
        }
        break;
      case REQUEST_CAMERA_IMAGE_PERMISSION:
        if (permissionGranted) {
          launchTakeImageWithCameraIntent();
        }
        break;
      case REQUEST_CAMERA_VIDEO_PERMISSION:
        if (permissionGranted) {
          launchTakeVideoWithCameraIntent();
        }
        break;
      default:
        return false;
    }

    if (!permissionGranted) {
      switch (requestCode) {
        case REQUEST_EXTERNAL_IMAGE_STORAGE_PERMISSION:
        case REQUEST_EXTERNAL_VIDEO_STORAGE_PERMISSION:
          finishWithError("photo_access_denied", "The user did not allow photo access.");
          break;
        case REQUEST_CAMERA_IMAGE_PERMISSION:
        case REQUEST_CAMERA_VIDEO_PERMISSION:
          finishWithError("camera_access_denied", "The user did not allow camera access.");
          break;
      }
    }

    return true;
  }

  @Override
  public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
      case REQUEST_CODE_CHOOSE_IMAGE_FROM_GALLERY:
        handleChooseImageResult(resultCode, data);
        break;
      case REQUEST_CODE_TAKE_IMAGE_WITH_CAMERA:
        handleCaptureImageResult(resultCode);
        break;
      case REQUEST_CODE_CHOOSE_VIDEO_FROM_GALLERY:
        handleChooseVideoResult(resultCode, data);
        break;
      case REQUEST_CODE_TAKE_VIDEO_WITH_CAMERA:
        handleCaptureVideoResult(resultCode);
        break;
      default:
        return false;
    }

    return true;
  }

  private void handleChooseImageResult(int resultCode, Intent data) {
    if (resultCode == Activity.RESULT_OK && data != null) {
      String path = fileUtils.getPathFromUri(activity, data.getData());
      handleImageResult(path, false);
      return;
    }

    // User cancelled choosing a picture.
    finishWithSuccess(null);
  }

  private void handleChooseVideoResult(int resultCode, Intent data) {
    if (resultCode == Activity.RESULT_OK && data != null) {
      String path = fileUtils.getPathFromUri(activity, data.getData());
      handleVideoResult(path);
      return;
    }

    // User cancelled choosing a picture.
    finishWithSuccess(null);
  }

  private void handleCaptureImageResult(int resultCode) {
    if (resultCode == Activity.RESULT_OK) {
      fileUriResolver.getFullImagePath(
          pendingCameraMediaUri != null
              ? pendingCameraMediaUri
              : Uri.parse(cache.retrievePendingCameraMediaUriPath()),
          new OnPathReadyListener() {
            @Override
            public void onPathReady(String path) {
              handleImageResult(path, true);
            }
          });
      return;
    }

    // User cancelled taking a picture.
    finishWithSuccess(null);
  }

  private void handleCaptureVideoResult(int resultCode) {
    if (resultCode == Activity.RESULT_OK) {
      fileUriResolver.getFullImagePath(
          pendingCameraMediaUri != null
              ? pendingCameraMediaUri
              : Uri.parse(cache.retrievePendingCameraMediaUriPath()),
          new OnPathReadyListener() {
            @Override
            public void onPathReady(String path) {
              handleVideoResult(path);
            }
          });
      return;
    }

    // User cancelled taking a picture.
    finishWithSuccess(null);
  }

  private void handleImageResult(String path, boolean shouldDeleteOriginalIfScaled) {
    if (methodCall != null) {
      Double maxWidth = methodCall.argument("maxWidth");
      Double maxHeight = methodCall.argument("maxHeight");
      Integer imageQuality = methodCall.argument("imageQuality");

      String finalImagePath =
          imageResizer.resizeImageIfNeeded(path, maxWidth, maxHeight, imageQuality);

      finishWithSuccess(finalImagePath);

      //delete original file if scaled
      if (finalImagePath != null && !finalImagePath.equals(path) && shouldDeleteOriginalIfScaled) {
        new File(path).delete();
      }
    } else {
      finishWithSuccess(path);
    }
  }

  private void handleVideoResult(String path) {
    finishWithSuccess(path);
  }

  private boolean setPendingMethodCallAndResult(
      MethodCall methodCall, MethodChannel.Result result) {
    if (pendingResult != null) {
      return false;
    }

    this.methodCall = methodCall;
    pendingResult = result;

    // Clean up cache if a new image picker is launched.
    cache.clear();

    return true;
  }

  private void finishWithSuccess(String imagePath) {
    if (pendingResult == null) {
      cache.saveResult(imagePath, null, null);
      return;
    }
    pendingResult.success(imagePath);
    clearMethodCallAndResult();
  }

  private void finishWithAlreadyActiveError(MethodChannel.Result result) {
    result.error("already_active", "Image picker is already active", null);
  }

  private void finishWithError(String errorCode, String errorMessage) {
    if (pendingResult == null) {
      cache.saveResult(null, errorCode, errorMessage);
      return;
    }
    pendingResult.error(errorCode, errorMessage, null);
    clearMethodCallAndResult();
  }

  private void clearMethodCallAndResult() {
    methodCall = null;
    pendingResult = null;
  }
}