/*
 * Copyright 2021 Google LLC
 *
 * 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 "SignInViewController.h"

@import GoogleSignIn;

#import "AuthInspectorViewController.h"
#import "DataPickerState.h"
#import "DataPickerViewController.h"

static NSString *const kSignInViewTitle = @"Sign-In Sample";
static NSString *const kPlaceholderUserName = @"<Name>";
static NSString *const kPlaceholderEmailAddress = @"<Email>";
static NSString *const kPlaceholderAvatarImageName = @"PlaceholderAvatar.png";

// Labels for the cells that have in-cell control elements.
static NSString *const kButtonWidthCellLabel = @"Width";

// Labels for the cells that drill down to data pickers.
static NSString *const kColorSchemeCellLabel = @"Color scheme";
static NSString *const kStyleCellLabel = @"Style";

// Accessibility Identifiers.
static NSString *const kCredentialsButtonAccessibilityIdentifier = @"Credentials";

@implementation SignInViewController {
  // This is an array of arrays, each one corresponding to the cell
  // labels for its respective section.
  NSArray *_sectionCellLabels;

  // These sets contain the labels corresponding to cells that have various types (each cell either
  // drills down to another table view or contains a slider).
  NSArray *_drillDownCells;
  NSArray *_sliderCells;

  // States storing the current set of selected elements for each data picker.
  DataPickerState *_colorSchemeState;
  DataPickerState *_styleState;

  // Map that keeps track of which cell corresponds to which DataPickerState.
  NSDictionary *_drilldownCellState;
}

#pragma mark - View lifecycle

- (void)setUp {
  _sectionCellLabels = @[
    @[ kColorSchemeCellLabel, kStyleCellLabel, kButtonWidthCellLabel ]
  ];

  // Groupings of cell types.
  _drillDownCells = @[
    kColorSchemeCellLabel,
    kStyleCellLabel
  ];
  _sliderCells = @[ kButtonWidthCellLabel ];

  // Initialize data picker states.
  NSString *dictionaryPath =
      [[NSBundle mainBundle] pathForResource:@"DataPickerDictionary"
                                      ofType:@"plist"];
  NSDictionary *configOptionsDict = [NSDictionary dictionaryWithContentsOfFile:dictionaryPath];

  NSDictionary *colorSchemeDict = [configOptionsDict objectForKey:kColorSchemeCellLabel];
  NSDictionary *styleDict = [configOptionsDict objectForKey:kStyleCellLabel];

  _colorSchemeState = [[DataPickerState alloc] initWithDictionary:colorSchemeDict];
  _styleState = [[DataPickerState alloc] initWithDictionary:styleDict];

  _drilldownCellState = @{
    kColorSchemeCellLabel :   _colorSchemeState,
    kStyleCellLabel :         _styleState
  };

  // Make sure the GIDSignInButton class is linked in because references from
  // xib file doesn't count.
  [GIDSignInButton class];
}

- (id)initWithNibName:(NSString *)nibNameOrNil
               bundle:(NSBundle *)nibBundleOrNil {
  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  if (self) {
    [self setUp];
    self.title = kSignInViewTitle;
  }
  return self;
}

- (id)initWithCoder:(NSCoder *)aDecoder {
  self = [super initWithCoder:aDecoder];
  if (self) {
    [self setUp];
    self.title = kSignInViewTitle;
  }
  return self;
}

- (void)viewDidLoad {
  [super viewDidLoad];

  self.credentialsButton.accessibilityIdentifier = kCredentialsButtonAccessibilityIdentifier;
}

- (void)viewWillAppear:(BOOL)animated {
  [self adoptUserSettings];
  [self reportAuthStatus];
  [self updateButtons];
  [self.tableView reloadData];

  [super viewWillAppear:animated];
}

#pragma mark - Helper methods

// Updates the GIDSignIn shared instance and the GIDSignInButton
// to reflect the configuration settings that the user set
- (void)adoptUserSettings {
  // There should only be one selected color scheme
  for (NSString *scheme in _colorSchemeState.selectedCells) {
    if ([scheme isEqualToString:@"Light"]) {
      _signInButton.colorScheme = kGIDSignInButtonColorSchemeLight;
    } else {
      _signInButton.colorScheme = kGIDSignInButtonColorSchemeDark;
    }
  }

  // There should only be one selected style
  for (NSString *style in _styleState.selectedCells) {
    GIDSignInButtonStyle newStyle;
    if ([style isEqualToString:@"Standard"]) {
      newStyle = kGIDSignInButtonStyleStandard;
      self.signInButtonWidthSlider.enabled = YES;
    } else if ([style isEqualToString:@"Wide"]) {
      newStyle = kGIDSignInButtonStyleWide;
      self.signInButtonWidthSlider.enabled = YES;
    } else {
      newStyle = kGIDSignInButtonStyleIconOnly;
      self.signInButtonWidthSlider.enabled = NO;
    }
    if (self.signInButton.style != newStyle) {
      self.signInButton.style = newStyle;
      self.signInButtonWidthSlider.minimumValue = [self minimumButtonWidth];
    }
    self.signInButtonWidthSlider.value = _signInButton.frame.size.width;
  }
}

// Temporarily force the sign in button to adopt its minimum allowed frame
// so that we can find out its minimum allowed width (used for setting the
// range of the width slider).
- (CGFloat)minimumButtonWidth {
  CGRect frame = self.signInButton.frame;
  self.signInButton.frame = CGRectZero;

  CGFloat minimumWidth = self.signInButton.frame.size.width;
  self.signInButton.frame = frame;

  return minimumWidth;
}

- (void)reportAuthStatus {
  GIDGoogleUser *googleUser = [GIDSignIn.sharedInstance currentUser];
  if (googleUser) {
    _signInAuthStatus.text = @"Status: Authenticated";
  } else {
    // To authenticate, use Google Sign-In button.
    _signInAuthStatus.text = @"Status: Not authenticated";
  }

  [self refreshUserInfo];
}

// Update the interface elements containing user data to reflect the
// currently signed in user.
- (void)refreshUserInfo {
  if (!GIDSignIn.sharedInstance.currentUser) {
    self.userName.text = kPlaceholderUserName;
    self.userEmailAddress.text = kPlaceholderEmailAddress;
    self.userAvatar.image = [UIImage imageNamed:kPlaceholderAvatarImageName];
    return;
  }
  self.userEmailAddress.text = GIDSignIn.sharedInstance.currentUser.profile.email;
  self.userName.text = GIDSignIn.sharedInstance.currentUser.profile.name;

  if (!GIDSignIn.sharedInstance.currentUser.profile.hasImage) {
    // There is no Profile Image to be loaded.
    return;
  }
  // Load avatar image asynchronously, in background
  dispatch_queue_t backgroundQueue =
      dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
  __weak SignInViewController *weakSelf = self;
  NSUInteger dimension = round(self.userAvatar.frame.size.width * [[UIScreen mainScreen] scale]);
  NSURL *imageURL =
      [GIDSignIn.sharedInstance.currentUser.profile imageURLWithDimension:dimension];

  dispatch_async(backgroundQueue, ^{
    NSData *avatarData = [NSData dataWithContentsOfURL:imageURL];

    if (avatarData) {
      // Update UI from the main thread when available
      dispatch_async(dispatch_get_main_queue(), ^{
        SignInViewController *strongSelf = weakSelf;
        if (strongSelf) {
          strongSelf.userAvatar.image = [UIImage imageWithData:avatarData];
        }
      });
    }
  });
}

// Adjusts "Sign in", "Sign out", "Disconnect", and "Add Scopes" buttons to reflect the current
// sign-in state (ie, the "Sign in" button becomes disabled when a user is already signed in).
- (void)updateButtons {
  BOOL hasCurrentUser = (GIDSignIn.sharedInstance.currentUser != nil);

  self.signInButton.enabled = !hasCurrentUser;
  self.signOutButton.enabled = hasCurrentUser;
  self.disconnectButton.enabled = hasCurrentUser;
  self.addScopesButton.enabled = hasCurrentUser;
  self.credentialsButton.hidden = !hasCurrentUser;

  if (hasCurrentUser) {
    self.signInButton.alpha = 0.5;
    self.signOutButton.alpha = self.disconnectButton.alpha = self.addScopesButton.alpha = 1.0;
  } else {
    self.signInButton.alpha = 1.0;
    self.signOutButton.alpha = self.disconnectButton.alpha = self.addScopesButton.alpha = 0.5;
  }
}

#pragma mark - IBActions

- (IBAction)signIn:(id)sender {
  [GIDSignIn.sharedInstance signInWithPresentingViewController:self
                                                    completion:^(GIDUserAuth *userAuth,
                                                                 NSError *error) {
    if (error) {
      self->_signInAuthStatus.text =
          [NSString stringWithFormat:@"Status: Authentication error: %@", error];
      return;
    }
    [self reportAuthStatus];
    [self updateButtons];
  }];
}

- (IBAction)signOut:(id)sender {
  [GIDSignIn.sharedInstance signOut];
  [self reportAuthStatus];
  [self updateButtons];
}

- (IBAction)disconnect:(id)sender {
  [GIDSignIn.sharedInstance disconnectWithCompletion:^(NSError *error) {
    if (error) {
      self->_signInAuthStatus.text = [NSString stringWithFormat:@"Status: Failed to disconnect: %@",
                                      error];
    } else {
      self->_signInAuthStatus.text = [NSString stringWithFormat:@"Status: Disconnected"];
    }
    [self reportAuthStatus];
    [self updateButtons];
  }];
}

- (IBAction)addScopes:(id)sender {
  GIDGoogleUser *currentUser = GIDSignIn.sharedInstance.currentUser;
  [currentUser addScopes:@[ @"https://www.googleapis.com/auth/user.birthday.read" ]
      presentingViewController:self
                    completion:^(GIDUserAuth *_Nullable userAuth,
                                 NSError *_Nullable error) {
    if (error) {
      self->_signInAuthStatus.text = [NSString stringWithFormat:@"Status: Failed to add scopes: %@",
                                      error];
    } else {
      self->_signInAuthStatus.text = [NSString stringWithFormat:@"Status: Scopes added"];
    }
    [self refreshUserInfo];
  }];
}

- (IBAction)showAuthInspector:(id)sender {
  AuthInspectorViewController *authInspector = [[AuthInspectorViewController alloc] init];
  [[self navigationController] pushViewController:authInspector animated:YES];
}

- (IBAction)checkSignIn:(id)sender {
  [self reportAuthStatus];
}

- (void)changeSignInButtonWidth:(UISlider *)sender {
  CGRect frame = self.signInButton.frame;
  frame.size.width = sender.value;
  self.signInButton.frame = frame;
}

#pragma mark - UITableView Data Source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
  return [_sectionCellLabels count];
}

- (NSInteger)tableView:(UITableView *)tableView
 numberOfRowsInSection:(NSInteger)section {
  return [_sectionCellLabels[section] count];
}

- (NSString *)tableView:(UITableView *)tableView
    titleForHeaderInSection:(NSInteger)section {
  if (section == 0) {
    return @"Sign-In Button Options";
  } else if (section == 1) {
    return @"Other Options";
  } else {
    return nil;
  }
}

- (BOOL)tableView:(UITableView *)tableView
    shouldHighlightRowAtIndexPath:(NSIndexPath *)indexPath {
  // Cells that drill down to other table views should be highlight-able.
  // The other cells contain control elements, so they should not be selectable.
  NSString *label = _sectionCellLabels[indexPath.section][indexPath.row];
  if ([_drillDownCells containsObject:label]) {
    return YES;
  } else {
    return NO;
  }
}

- (UITableViewCell *)tableView:(UITableView *)tableView
         cellForRowAtIndexPath:(NSIndexPath *)indexPath {
  static NSString * const kDrilldownCell = @"DrilldownCell";
  static NSString * const kSliderCell = @"SliderCell";

  NSString *label = _sectionCellLabels[indexPath.section][indexPath.row];
  UITableViewCell *cell;
  NSString *identifier;

  if ([_drillDownCells containsObject:label]) {
    identifier = kDrilldownCell;
  } else if ([_sliderCells containsObject:label]) {
    identifier = kSliderCell;
  }

  cell = [tableView dequeueReusableCellWithIdentifier:identifier];

  if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1
                                  reuseIdentifier:identifier];
  }
  // Assign accessibility labels to each cell row.
  cell.accessibilityLabel = label;

  if (identifier == kDrilldownCell) {
    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
    DataPickerState *dataState = _drilldownCellState[label];
    if (dataState.multipleSelectEnabled) {
      cell.detailTextLabel.text = @"";
    } else {
      cell.detailTextLabel.text = [dataState.selectedCells anyObject];
    }
    cell.accessibilityValue = cell.detailTextLabel.text;
  } else if (identifier == kSliderCell) {

    UISlider *slider = [[UISlider alloc] initWithFrame:CGRectMake(0, 0, 150, 0)];
    slider.minimumValue = [self minimumButtonWidth];
    slider.maximumValue = 268.0;
    slider.value = self.signInButton.frame.size.width;
    slider.enabled = self.signInButton.style != kGIDSignInButtonStyleIconOnly;

    [slider addTarget:self
                  action:@selector(changeSignInButtonWidth:)
        forControlEvents:UIControlEventValueChanged];

    slider.accessibilityIdentifier = [NSString stringWithFormat:@"%@ Slider", label];
    self.signInButtonWidthSlider = slider;
    cell.accessoryView = slider;
    [self.signInButtonWidthSlider sizeToFit];
  }

  cell.textLabel.text = label;

  return cell;
}

- (void)tableView:(UITableView *)tableView
    didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
  [tableView deselectRowAtIndexPath:indexPath animated:YES];
  UITableViewCell *selectedCell = [tableView cellForRowAtIndexPath:indexPath];
  NSString *label = selectedCell.textLabel.text;

  DataPickerState *dataState = [_drilldownCellState objectForKey:label];
  if (!dataState) {
    return;
  }

  DataPickerViewController *dataPicker =
      [[DataPickerViewController alloc] initWithNibName:nil
                                                 bundle:nil
                                              dataState:dataState];
  dataPicker.navigationItem.title = label;

  // Force the back button title to be 'Back'
  UIBarButtonItem *newBackButton =
      [[UIBarButtonItem alloc] initWithTitle:@"Back"
                                       style:UIBarButtonItemStylePlain
                                      target:nil
                                      action:nil];
  [[self navigationItem] setBackBarButtonItem:newBackButton];
  [self.navigationController pushViewController:dataPicker animated:YES];
}

@end