/*
 * Copyright 2017 Google
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#import "UIViewController+Alerts.h"

#import <objc/runtime.h>

/*! @var kPleaseWaitAssociatedObjectKey
    @brief Key used to identify the "please wait" spinner associated object.
 */
static NSString *const kPleaseWaitAssociatedObjectKey =
    @"_UIViewControllerAlertCategory_PleaseWaitScreenAssociatedObject";

/*! @var kUseStatusBarSpinnerAssociatedObjectKey
    @brief The address of this constant is the key used to identify the "use status bar spinner"
        associated object.
 */
static const void *const kUseStatusBarSpinnerAssociatedObjectKey;

/*! @var kOK
    @brief Text for an 'OK' button.
 */
static NSString *const kOK = @"OK";

/*! @var kCancel
    @brief Text for an 'Cancel' button.
 */
static NSString *const kCancel = @"Cancel";

/*! @class SimpleTextPromptDelegate
    @brief A @c UIAlertViewDelegate which allows @c UIAlertView to be used with blocks more easily.
 */
@interface SimpleTextPromptDelegate : NSObject <UIAlertViewDelegate>

/*! @fn init
    @brief Please use initWithCompletionHandler.
 */
- (nullable instancetype)init NS_UNAVAILABLE;

/*! @fn initWithCompletionHandler:
    @brief Designated initializer.
    @param completionHandler The block to call when the alert view is dismissed.
 */
- (nullable instancetype)initWithCompletionHandler:(AlertPromptCompletionBlock)completionHandler
    NS_DESIGNATED_INITIALIZER;

@end

@implementation UIViewController (Alerts)

- (void)setUseStatusBarSpinner:(BOOL)useStatusBarSpinner {
  objc_setAssociatedObject(self,
                           &kUseStatusBarSpinnerAssociatedObjectKey,
                           useStatusBarSpinner ? @(YES) : nil,
                           OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (BOOL)useStatusBarSpinner {
  return objc_getAssociatedObject(self, &kUseStatusBarSpinnerAssociatedObjectKey) ? YES : NO;
}

/*! @fn supportsAlertController
    @brief Determines if the current platform supports @c UIAlertController.
    @return YES if the current platform supports @c UIAlertController.
 */
- (BOOL)supportsAlertController {
  return NSClassFromString(@"UIAlertController") != nil;
}

- (void)showMessagePrompt:(NSString *)message {
  [self showMessagePromptWithTitle:nil message:message showCancelButton:NO completion:nil];
}

- (void)showMessagePromptWithTitle:(nullable NSString *)title
                           message:(NSString *)message
                  showCancelButton:(BOOL)showCancelButton
                        completion:(nullable AlertPromptCompletionBlock)completion {
  if (message) {
    [UIPasteboard generalPasteboard].string = message;
  }
  if ([self supportsAlertController]) {
    UIAlertController *alert =
        [UIAlertController alertControllerWithTitle:title
                                            message:message
                                     preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *okAction =
        [UIAlertAction actionWithTitle:kOK
                                 style:UIAlertActionStyleDefault
                               handler:^(UIAlertAction * _Nonnull action) {
          if (completion) {
            completion(YES, nil);
          }
        }];
    [alert addAction:okAction];

    if (showCancelButton) {
      UIAlertAction *cancelAction =
          [UIAlertAction actionWithTitle:kCancel
                                   style:UIAlertActionStyleCancel
                                 handler:^(UIAlertAction * _Nonnull action) {
            completion(NO, nil);
          }];
      [alert addAction:cancelAction];
    }
    [self presentViewController:alert animated:YES completion:nil];
  } else {
    UIAlertView *alert =
        [[UIAlertView alloc] initWithTitle:title
                                   message:message
                                  delegate:nil
                         cancelButtonTitle:nil
                         otherButtonTitles:kOK, nil];
    [alert show];
  }
}

- (void)showTextInputPromptWithMessage:(NSString *)message
                       completionBlock:(AlertPromptCompletionBlock)completion {
  [self showTextInputPromptWithMessage:message
                          keyboardType:UIKeyboardTypeDefault
                       completionBlock:completion];
}

- (void)showTextInputPromptWithMessage:(NSString *)message
                          keyboardType:(UIKeyboardType)keyboardType
                       completionBlock:(nonnull AlertPromptCompletionBlock)completion {
  if ([self supportsAlertController]) {
      UIAlertController *prompt =
          [UIAlertController alertControllerWithTitle:nil
                                              message:message
                                       preferredStyle:UIAlertControllerStyleAlert];
      __weak UIAlertController *weakPrompt = prompt;
      UIAlertAction *cancelAction =
          [UIAlertAction actionWithTitle:kCancel
                                   style:UIAlertActionStyleCancel
                                 handler:^(UIAlertAction * _Nonnull action) {
            completion(NO, nil);
          }];
      UIAlertAction *okAction = [UIAlertAction actionWithTitle:kOK
                                                         style:UIAlertActionStyleDefault
                                                       handler:^(UIAlertAction * _Nonnull action) {
            UIAlertController *strongPrompt = weakPrompt;
            completion(YES, strongPrompt.textFields[0].text);
      }];
      [prompt addTextFieldWithConfigurationHandler:^(UITextField *_Nonnull textField) {
        textField.keyboardType = keyboardType;
      }];
      [prompt addAction:cancelAction];
      [prompt addAction:okAction];
      [self presentViewController:prompt animated:YES completion:nil];
  } else {
    SimpleTextPromptDelegate *prompt =
        [[SimpleTextPromptDelegate alloc] initWithCompletionHandler:completion];
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:nil
                                                        message:message
                                                       delegate:prompt
                                              cancelButtonTitle:@"Cancel"
                                              otherButtonTitles:@"Ok", nil];
    alertView.alertViewStyle = UIAlertViewStylePlainTextInput;
    [alertView show];
  }
}

- (void)showSpinner:(nullable void(^)(void))completion {
  if (self.useStatusBarSpinner) {
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    completion();
    return;
  }
  if ([self supportsAlertController]) {
    [self showModernSpinner:completion];
  } else {
    [self showIOS7Spinner:completion];
  }
}

- (void)showModernSpinner:(nullable void (^)(void))completion {
  UIAlertController *pleaseWaitAlert =
      objc_getAssociatedObject(self,
                               (__bridge const void *)kPleaseWaitAssociatedObjectKey);
  if (pleaseWaitAlert) {
    if (completion) {
      completion();
    }
    return;
  }
  pleaseWaitAlert = [UIAlertController alertControllerWithTitle:nil
                                                        message:@"Please Wait...\n\n\n\n"
                                                 preferredStyle:UIAlertControllerStyleAlert];

  UIActivityIndicatorView *spinner =
      [[UIActivityIndicatorView alloc]
          initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
  spinner.color = [UIColor blackColor];
  spinner.center = CGPointMake(pleaseWaitAlert.view.bounds.size.width / 2,
      pleaseWaitAlert.view.bounds.size.height / 2);
  spinner.autoresizingMask = UIViewAutoresizingFlexibleBottomMargin |
      UIViewAutoresizingFlexibleTopMargin |
      UIViewAutoresizingFlexibleLeftMargin |
      UIViewAutoresizingFlexibleRightMargin;
  [spinner startAnimating];
  [pleaseWaitAlert.view addSubview:spinner];

  objc_setAssociatedObject(self,
      (__bridge const void *)(kPleaseWaitAssociatedObjectKey),
      pleaseWaitAlert,
      OBJC_ASSOCIATION_RETAIN_NONATOMIC);
  [self presentViewController:pleaseWaitAlert animated:YES completion:completion];
}

- (void)showIOS7Spinner:(nullable void (^)(void))completion {
  UIWindow *pleaseWaitWindow =
      objc_getAssociatedObject(self,
                               (__bridge const void *)kPleaseWaitAssociatedObjectKey);

  if (pleaseWaitWindow) {
    if (completion) {
      completion();
    }
    return;
  }

  pleaseWaitWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
  pleaseWaitWindow.backgroundColor = [UIColor clearColor];
  pleaseWaitWindow.windowLevel = UIWindowLevelStatusBar - 1;

  UIView *pleaseWaitView = [[UIView alloc] initWithFrame:pleaseWaitWindow.bounds];
  pleaseWaitView.autoresizingMask = UIViewAutoresizingFlexibleWidth |
      UIViewAutoresizingFlexibleHeight;
  pleaseWaitView.backgroundColor = [UIColor colorWithWhite:0 alpha:0.5];
  UIActivityIndicatorView *spinner =
      [[UIActivityIndicatorView alloc]
          initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
  spinner.center = pleaseWaitView.center;
  [pleaseWaitView addSubview:spinner];
  [spinner startAnimating];

  pleaseWaitView.layer.opacity = 0.0;
  [self.view addSubview:pleaseWaitView];

  [pleaseWaitWindow addSubview:pleaseWaitView];

  [pleaseWaitWindow makeKeyAndVisible];

  objc_setAssociatedObject(self,
      (__bridge const void *)(kPleaseWaitAssociatedObjectKey),
      pleaseWaitWindow,
      OBJC_ASSOCIATION_RETAIN_NONATOMIC);

  [UIView animateWithDuration:0.5f animations:^{
    pleaseWaitView.layer.opacity = 1.0f;
  } completion:^(BOOL finished) {
    if (completion) {
      completion();
    }
  }];
}

- (void)hideSpinner:(nullable void(^)(void))completion {
  if (self.useStatusBarSpinner) {
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    completion();
    return;
  }
  if ([self supportsAlertController]) {
    [self hideModernSpinner:completion];
  } else {
    [self hideIOS7Spinner:completion];
  }
}

- (void)hideModernSpinner:(nullable void(^)(void))completion {
  UIAlertController *pleaseWaitAlert =
      objc_getAssociatedObject(self,
                               (__bridge const void *)kPleaseWaitAssociatedObjectKey);

  [pleaseWaitAlert dismissViewControllerAnimated:YES completion:completion];

  objc_setAssociatedObject(self,
      (__bridge const void *)(kPleaseWaitAssociatedObjectKey),
      nil,
      OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (void)hideIOS7Spinner:(nullable void(^)(void))completion {
  UIWindow *pleaseWaitWindow =
      objc_getAssociatedObject(self,
                               (__bridge const void *)kPleaseWaitAssociatedObjectKey);

  UIView *pleaseWaitView;
  pleaseWaitView = pleaseWaitWindow.subviews.firstObject;

  [UIView animateWithDuration:0.5f animations:^{
    pleaseWaitView.layer.opacity = 0.0f;
  } completion:^(BOOL finished) {
    [pleaseWaitWindow resignKeyWindow];
    objc_setAssociatedObject(self,
        (__bridge const void *)(kPleaseWaitAssociatedObjectKey),
        nil,
        OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    if (completion) {
      completion();
    }
  }];
}

@end

@implementation SimpleTextPromptDelegate {
  AlertPromptCompletionBlock _completionHandler;
  SimpleTextPromptDelegate *_retainedSelf;
}

- (instancetype)initWithCompletionHandler:(AlertPromptCompletionBlock)completionHandler {
  self = [super init];
  if (self) {
    _completionHandler = completionHandler;
    _retainedSelf = self;
  }
  return self;
}

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
  if (buttonIndex == alertView.firstOtherButtonIndex) {
    _completionHandler(YES, [alertView textFieldAtIndex:0].text);
  } else {
    _completionHandler(NO, nil);
  }
  _completionHandler = nil;
  _retainedSelf = nil;
}

@end