#import "OpenFilePlugin.h"

@interface OpenFilePlugin ()<UIDocumentInteractionControllerDelegate>
@end

static NSString *const CHANNEL_NAME = @"open_file";

// Returns the root view controller of the app,
// or nil if the app has no root view controller.
static UIViewController *RootViewController() {
  // If the app is running on iOS 13 or higher, then use the new `connectedScenes`
  // API to get the root view controller of the key window.
  if (@available(iOS 13, *)) {
    // Get a list of all the connected scenes in the app.
    NSSet *scenes = [[UIApplication sharedApplication] connectedScenes];
    // Iterate over the scenes and check if each one is a UIWindowScene.
    for (UIScene *scene in scenes) {
      if ([scene isKindOfClass:[UIWindowScene class]]) {
        // Get a list of all the windows in the scene.
        NSArray *windows = ((UIWindowScene *)scene).windows;
        // Iterate over the windows and check if each one is the key window.
        for (UIWindow *window in windows) {
          if (window.isKeyWindow) {
            // Return the root view controller of the key window.
            return window.rootViewController;
          }
        }
      }
    }
    // If we couldn't find a key window, then return nil.
    return nil;
  } else {
    // Simply return the root view controller of the key window.
    return [UIApplication sharedApplication].keyWindow.rootViewController;
  }
}

// Returns the top view controller in a view controller hierarchy.
static UIViewController *
TopViewControllerForViewController(UIViewController *viewController) {
  // If the view controller has a presented view controller, then return the top
  // view controller in that hierarchy.
  if (viewController.presentedViewController) {
    return TopViewControllerForViewController(
        viewController.presentedViewController);
  }
  // If the view controller is a navigation controller, then return the top
  // view controller in the navigation controller's stack.
  if ([viewController isKindOfClass:[UINavigationController class]]) {
    return TopViewControllerForViewController(
        ((UINavigationController *)viewController).visibleViewController);
  }
  // Otherwise, return the given view controller.
  return viewController;
}

@implementation OpenFilePlugin{
    FlutterResult _result;
    UIViewController *_viewController;
    UIDocumentInteractionController *_documentController;
    UIDocumentInteractionController *_interactionController;
}

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
    FlutterMethodChannel* channel = [FlutterMethodChannel
                                     methodChannelWithName:CHANNEL_NAME
                                     binaryMessenger:[registrar messenger]];
    UIViewController *rootViewController = RootViewController();
    UIViewController *viewController =
              TopViewControllerForViewController(rootViewController);
    OpenFilePlugin* instance = [[OpenFilePlugin alloc] initWithViewController:viewController];
    [registrar addMethodCallDelegate:instance channel:channel];
}

- (instancetype)initWithViewController:(UIViewController *)viewController {
    self = [super init];
    if (self) {
        _viewController = viewController;
    }
    return self;
}

- (void)handleMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
    if ([@"open_file" isEqualToString:call.method]) {
        _result = result;
        NSString *msg = call.arguments[@"file_path"];
        if(msg==nil){
            NSDictionary * dict = @{@"message":@"the file path cannot be null", @"type":@-4};
            NSData * jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];
            NSString * json = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
            result(json);
            return;
        }
        NSFileManager *fileManager=[NSFileManager defaultManager];
        BOOL fileExist=[fileManager fileExistsAtPath:msg];
        if(fileExist){
            _documentController = [UIDocumentInteractionController interactionControllerWithURL:[NSURL fileURLWithPath:msg]];
            _documentController.delegate = self;
            NSString *uti = call.arguments[@"uti"];
            BOOL isBlank = [self isBlankString:uti];
            if(!isBlank){
                _documentController.UTI = uti;
            }
            @try {
                BOOL previewSucceeded = [_documentController presentPreviewAnimated:YES];
                if(!previewSucceeded){
                    UIViewController *rootViewController = RootViewController();
                    UIViewController *viewController =
                                TopViewControllerForViewController(rootViewController);
                    [_documentController presentOpenInMenuFromRect:CGRectMake(500,20,100,100) inView:viewController.view animated:YES];
                }
            }@catch (NSException *exception) {
                NSDictionary * dict = @{@"message":@"File opened incorrectly。", @"type":@-4};
                NSData * jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];
                NSString * json = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
                result(json);
            }
        }else{
            NSDictionary * dict = @{@"message":@"the file does not exist", @"type":@-2};
            NSData * jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];
            NSString * json = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

            result(json);
        }
    } else {
        result(FlutterMethodNotImplemented);
    }
}

- (void)documentInteractionControllerDidEndPreview:(UIDocumentInteractionController *)controller {
    NSDictionary * dict = @{@"message":@"done", @"type":@0};
    NSData * jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];
    NSString * json = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

    _result(json);
}

- (void)documentInteractionControllerDidDismissOpenInMenu:(UIDocumentInteractionController *)controller {
      NSDictionary * dict = @{@"message":@"done", @"type":@0};
      NSData * jsonData = [NSJSONSerialization dataWithJSONObject:dict options:NSJSONWritingPrettyPrinted error:nil];
      NSString * json = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];

      _result(json);
}

- (UIViewController *)documentInteractionControllerViewControllerForPreview:(UIDocumentInteractionController *)controller {
    UIViewController *rootViewController = RootViewController();
    UIViewController *viewController =
                        TopViewControllerForViewController(rootViewController);
    return  viewController;
}

- (BOOL) isBlankString:(NSString *)string {
    if (string == nil || string == NULL) {
        return YES;
    }
    if ([string isKindOfClass:[NSNull class]]) {
        return YES;
    }
    if ([[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length]==0){
        return YES;
    }
    return NO;
}
@end