/*

 Copyright (C) 2018 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 View controller for displaying a Question.

 */

#import "QuestionViewController.h"

#import "Quiz.h"

#import "ResultsViewController.h"

@interface QuestionViewController ()

@property (readwrite, getter = isLastQuestion) BOOL lastQuestion;

@end

@implementation QuestionViewController

//| ----------------------------------------------------------------------------

- (void)viewDidLoad

{

    [super viewDidLoad];

    // Prevent the user from returning to the previous question.

    self.navigationItem.hidesBackButton = YES;

}

//| ----------------------------------------------------------------------------

- (void)viewWillAppear:(BOOL)animated

{

    [super viewWillAppear:animated];

    self.title = [NSString stringWithFormat:@"Question %lu", self.questionIndex+1];

    self.lastQuestion = (self.questionIndex == self.currentQuiz.totalQuestions - 1);

}

//| ----------------------------------------------------------------------------

//! Unwinds from the ResultsViewController back to the first

//! QuestionViewController when the user taps the 'Start Over' button.

//

//  This is an unwind action.  Note that the sender parameter is a

//  'UIStoryboardSegue*' instead of the usual 'id'.  Like all unwind actions,

//  this method is invoked early in the unwind process, before the visual

//  transition.  Note that the receiver of this method is the

//  destinationViewController of the segue.  Your view controller should use

//  this callback to update its UI before it is redisplayed.

//

- (IBAction)exitToQuizStart:(UIStoryboardSegue *)sender

{

    // The user has restarted the quiz.

    [self.currentQuiz resetQuiz];

}

//| ----------------------------------------------------------------------------

//  We must disambiguate which QuestionViewController should handle the

//  exitToQuizStart: action as there will be several QuestionViewController

//  instances on the navigation stack when the unwind segue is triggered.  By

//  default, a UINavigationController (or QuizContainerViewController) searches 

//  its viewControllers array in reverse.  Without overriding this method, 

//  the QuestionViewController directly preceding the results screen would be

//  selected as the destination of the unwind segue.

//

- (BOOL)canPerformUnwindSegueAction:(SEL)action fromViewController:(UIViewController *)fromViewController withSender:(id)sender

{

    // Always check if the view controller implements the unwind action by

    // calling the super's implementation.

    if ([super canPerformUnwindSegueAction:action fromViewController:fromViewController withSender:sender])

        // The first QuestionViewController in the navigation stack should 

        // handle the unwind action.

        return self == ((UINavigationController*)self.parentViewController).viewControllers[0];

    return NO;

}

//| ----------------------------------------------------------------------------

//  Overriding this method allows a view controller to block the execution of a 

//  triggered segue.

//

- (BOOL)shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender

{

    // Only advance to the next question if there is a next question.

    if ([identifier isEqualToString:@"NextQuestion"])

        return !self.lastQuestion;

    return [super shouldPerformSegueWithIdentifier:identifier sender:sender];

}

//| ----------------------------------------------------------------------------

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender

{

    if ([segue.identifier isEqualToString:@"NextQuestion"])

    {

        self.currentQuiz[self.questionIndex].selectedResponse = (self.tableView).indexPathForSelectedRow.row;

        QuestionViewController *nextQuestionVC = (QuestionViewController*)segue.destinationViewController;

        nextQuestionVC.currentQuiz = self.currentQuiz;

        nextQuestionVC.questionIndex = self.questionIndex+1;

    }

    else if ([segue.identifier isEqualToString:@"ResultScreen"])

    {

        ResultsViewController *resultVC = (ResultsViewController*)segue.destinationViewController;

        resultVC.currentQuiz = self.currentQuiz;

    }

}

#pragma mark - Table view data source

//| ----------------------------------------------------------------------------

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

{

    return 2;

}

//| ----------------------------------------------------------------------------

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

{

    if (section == 0)

        return 1;

    else

        return self.currentQuiz[self.questionIndex].responses.count;

}

//| ----------------------------------------------------------------------------

//  This delegate method is implemented because the height of the

//  cell displaying the question will need to change depending on the height 

//  required to display the question text.  As the device rotates this will

//  change.

//

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

{

    if (indexPath.section == 0)

    {

        UITableViewCell *questionCell = [tableView dequeueReusableCellWithIdentifier:@"QuestionCell"];

        UILabel *questionLabel = questionCell.textLabel;

        // Use the -boundingRectWithSize:options:attributes:context: method of NSString to

        // determine the required height of the question cell in order

        // to display the question without cutting off any of the text.

        // The width must be constrained to the width of the table view minus the

        // left and right margin of a grouped style cell.

        // Unfortunately, there is no way to lookup exactly what that margin is, so

        // it must be hardcoded.

        // The height is left unconstrained.

        CGSize constrainingSize = CGSizeMake(tableView.bounds.size.width - 40*2, MAXFLOAT);

        return ceill([questionLabel.text boundingRectWithSize:constrainingSize options:NSStringDrawingUsesLineFragmentOrigin attributes:nil context:nil].size.height + 22);

    }

    return tableView.rowHeight;

}

//| ----------------------------------------------------------------------------

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

    if (indexPath.section == 0)

    {

        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"QuestionCell"];

        cell.textLabel.text = self.currentQuiz[self.questionIndex].text;

        return cell;

    }

    else

    {

        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"AnswerCell"];

        cell.textLabel.text = self.currentQuiz[self.questionIndex].responses[indexPath.row];

        return cell;

    }

}

//| ----------------------------------------------------------------------------

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath

{

    [tableView deselectRowAtIndexPath:indexPath animated:NO];

    // This method is called regardless of the value returned by 

    // -shouldPerformSegueWithIdentifier:.  Therefore, check if this view

    // controller is displaying the final question and advance to the results

    // screen only if it is.

    if (indexPath.section == 1 && self.lastQuestion)

    {

        self.currentQuiz[self.questionIndex].selectedResponse = indexPath.row;

        // Trigger the segue leading to the results screen.

        [self performSegueWithIdentifier:@"ResultScreen" sender:self];

    }

}

@end