/*

 Copyright (C) 2017 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Table view controller to manage an editable table view that displays information about a recipe.

  The table view uses different cell types for different row types.

 */

#import "RecipeDetailViewController.h"

#import "Recipe.h"

#import "Ingredient.h"

#import "InstructionsViewController.h"

#import "TypeSelectionViewController.h"

#import "RecipePhotoViewController.h"

#import "IngredientDetailViewController.h"

@interface IngredientCell : UITableViewCell

@end

@implementation IngredientCell

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier

{ return [super initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:reuseIdentifier]; }

@end

#pragma mark -

@interface RecipeDetailViewController () <UINavigationControllerDelegate, UIImagePickerControllerDelegate, UITextFieldDelegate>

@property (nonatomic, strong) NSMutableArray *ingredients;

@property (nonatomic, strong) IBOutlet UIView *tableHeaderView;

@property (nonatomic, strong) IBOutlet UIButton *photoButton;

@property (nonatomic, strong) IBOutlet UITextField *nameTextField;

@property (nonatomic, strong) IBOutlet UITextField *overviewTextField;

@property (nonatomic, strong) IBOutlet UITextField *prepTimeTextField;

@property (assign) BOOL singleEdit; // Indicates user is swipe-deleting a particular ingredient.

- (void)updatePhotoButton;

@end

#pragma mark -

@implementation RecipeDetailViewController

// Table's section indexes.

#define TYPE_SECTION            0

#define INGREDIENTS_SECTION     1

#define INSTRUCTIONS_SECTION    2

// Segue ID when "Add Ingredient" cell is tapped.

static NSString *kAddIngredientSegueID = @"addIngredient";

// Segue ID when "Instructions" cell is tapped.

static NSString *kShowInstructionsSegueID = @"showInstructions";

// Segue ID when the recipe (category) cell is tapped.

static NSString *kShowRecipeTypeSegueID = @"showRecipeType";

#pragma mark - View controller

- (void)viewDidLoad {

    [super viewDidLoad];

    self.navigationItem.rightBarButtonItem = self.editButtonItem;

}

- (void)viewWillAppear:(BOOL)animated {

    [super viewWillAppear:animated];

    [self.photoButton setImage:self.recipe.thumbnailImage forState:UIControlStateNormal];

    self.navigationItem.title = self.recipe.name;

    self.nameTextField.text = self.recipe.name;

    self.overviewTextField.text = self.recipe.overview;

    self.prepTimeTextField.text = self.recipe.prepTime;

    [self updatePhotoButton];

    /*

     Create a mutable array that contains the recipe's ingredients ordered by displayOrder.

     The table view uses this array to display the ingredients.

     Core Data relationships are represented by sets, so have no inherent order.

     Order is "imposed" using the displayOrder attribute, but it would be inefficient to create

     and sort a new array each time the ingredients section had to be laid out or updated.

     */

    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"displayOrder" ascending:YES];

    NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:&sortDescriptor count:1];

    NSMutableArray *sortedIngredients = [[NSMutableArray alloc] initWithArray:[self.recipe.ingredients allObjects]];

    [sortedIngredients sortUsingDescriptors:sortDescriptors];

    self.ingredients = sortedIngredients;

    // update recipe type and ingredients on return

    [self.tableView reloadData]; 

}

#pragma mark - Editing

- (void)setEditing:(BOOL)editing animated:(BOOL)animated {

    [super setEditing:editing animated:animated];

    if (!self.singleEdit) {

        [self updatePhotoButton];

        self.nameTextField.enabled = editing;

        self.overviewTextField.enabled = editing;

        self.prepTimeTextField.enabled = editing;

        [self.navigationItem setHidesBackButton:editing animated:YES];

        [self.tableView beginUpdates];

        NSUInteger ingredientsCount = self.recipe.ingredients.count;

        NSArray *ingredientsInsertIndexPath = [NSArray arrayWithObject:[NSIndexPath indexPathForRow:ingredientsCount inSection:INGREDIENTS_SECTION]];

        if (editing) {

            [self.tableView insertRowsAtIndexPaths:ingredientsInsertIndexPath withRowAnimation:UITableViewRowAnimationTop];

            self.overviewTextField.placeholder = NSLocalizedString(@"Overview", "");

        } else {

            [self.tableView deleteRowsAtIndexPaths:ingredientsInsertIndexPath withRowAnimation:UITableViewRowAnimationTop];

            self.overviewTextField.placeholder = @"";

        }

        [self.tableView endUpdates];

    }

    /*

     If editing is finished, save the managed object context.

     */

    if (!editing) {

        NSManagedObjectContext *context = self.recipe.managedObjectContext;

        NSError *error = nil;

        if (![context save:&error]) {

            /*

             Replace this implementation with code to handle the error appropriately.

             abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.

             */

            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);

            abort();

        }

    }

}

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField {

    if (textField == self.nameTextField) {

        self.recipe.name = self.nameTextField.text;

        self.navigationItem.title = self.recipe.name;

    }

    else if (textField == self.overviewTextField) {

        self.recipe.overview = self.overviewTextField.text;

    }

    else if (textField == self.prepTimeTextField) {

        self.recipe.prepTime = self.prepTimeTextField.text;

    }

    return YES;

}

- (BOOL)textFieldShouldReturn:(UITextField *)textField {

    [textField resignFirstResponder];

    return YES;

}

#pragma mark - UITableViewDataSource

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

    return 4;

}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {

    NSString *title = nil;

    // return a title or nil as appropriate for the section

    switch (section) {

        case TYPE_SECTION:

            title = @"Category";

            break;

        case INGREDIENTS_SECTION:

            title = @"Ingredients";

            break;

        default:

            break;

    }

    return title;

}

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

    NSInteger rows = 0;

    /*

     The number of rows depends on the section.

     In the case of ingredients, if editing, add a row in editing mode to present an "Add Ingredient" cell.

     */

    switch (section) {

        case TYPE_SECTION:

        case INSTRUCTIONS_SECTION:

            // These sections have only one row.

            rows = 1;

            break;

        case INGREDIENTS_SECTION:

            rows = self.recipe.ingredients.count;

            if (self.editing) {

                rows++;

            }

            break;

        default:

            break;

    }

    return rows;

}

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

    UITableViewCell *cell = nil;

    // For the Ingredients section, if necessary create a new cell and configure it with

    // an additional label for the amount.  Give the cell a different identifier from that

    // used for cells in other sections so that it can be dequeued separately.

    //

    if (indexPath.section == INGREDIENTS_SECTION) {

        NSUInteger ingredientCount = self.recipe.ingredients.count;

        NSInteger row = indexPath.row;

        if (indexPath.row < (NSInteger)ingredientCount) {

            // If the row is within the range of the number of ingredients for the current recipe,

            // then configure the cell to show the ingredient name and amount.

            //

            cell = [tableView dequeueReusableCellWithIdentifier:@"IngredientsCell" forIndexPath:indexPath];

            Ingredient *ingredient = [self.ingredients objectAtIndex:row];

            cell.textLabel.text = ingredient.name;

            cell.detailTextLabel.text = ingredient.amount;

        } else {

            // If the row is outside the range, it's the row that was added to allow insertion.

            // (see tableView:numberOfRowsInSection:) so give it an appropriate label.

            //

            cell = [tableView dequeueReusableCellWithIdentifier:@"AddIngredientCellIdentifier" forIndexPath:indexPath];

        }

    } else {

        switch (indexPath.section) {

            case TYPE_SECTION:  // recipe type cell

                cell = [tableView dequeueReusableCellWithIdentifier:@"RecipeType" forIndexPath:indexPath];

                cell.textLabel.text = [self.recipe.type valueForKey:@"name"];

                break;

            default:

                cell = [tableView dequeueReusableCellWithIdentifier:@"Instructions" forIndexPath:indexPath];

                break;

        }

    }

    return cell;

}

#pragma mark - UITableViewDelegate

- (void)tableView:(UITableView *)tableView willBeginEditingRowAtIndexPath:(NSIndexPath *)indexPath {

    // User has started a swipe to delete operation.

    self.singleEdit = YES;

}

- (void)tableView:(UITableView*)tableView didEndEditingRowAtIndexPath:(NSIndexPath *)indexPath {

    // Swipe to delete operation has ended.

    self.singleEdit = NO;

}

- (Ingredient *)ingredientByName:(NSString *)ingredientName {

    Ingredient *ingredient = nil;

    NSArray *ingredients = [self.recipe.ingredients allObjects];

    for (ingredient in ingredients) {

        if ([ingredient.name isEqualToString:ingredientName])

            break;  // We found the right ingredient by title.

    }

    return ingredient;

}

- (void)tableView:(UITableView *)tableView accessoryButtonTappedForRowWithIndexPath:(NSIndexPath *)indexPath {

    if (indexPath.section == TYPE_SECTION && indexPath.row == 0) {

        // Edit the recipe "type"- pass the recipe.

        //

        TypeSelectionViewController *typeSelectionViewController =

            [[TypeSelectionViewController alloc] initWithStyle:UITableViewStylePlain];

        typeSelectionViewController.recipe = self.recipe;

        // Present modally the recipe type view controller.

        UINavigationController *navController =

            [[UINavigationController alloc] initWithRootViewController:typeSelectionViewController];

        navController.modalPresentationStyle = UIModalPresentationFullScreen;

        [self.navigationController presentViewController:navController animated:YES completion:nil];

    }

    else if (indexPath.section == INGREDIENTS_SECTION) {

        // Edit the recipe "ingredient" - pass the ingredient.

        //

        IngredientDetailViewController *ingredientDetailViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"IngredientDetailViewController"];

        ingredientDetailViewController.recipe = self.recipe;

        // Find the selected ingredient table cell (based on indexPath),

        // use it's ingredient title to find the right ingredient object in this recipe.

        // note: you can't use indexPath.row to lookup the recipe's ingredient object because NSSet is not ordered.

        //

        UITableViewCell *ingredientCell = [tableView cellForRowAtIndexPath:indexPath];

        ingredientDetailViewController.ingredient = [self ingredientByName:ingredientCell.textLabel.text];

        // Present modally the ingredient detail view controller.

        UINavigationController *navController =

            [[UINavigationController alloc] initWithRootViewController:ingredientDetailViewController];

        navController.modalPresentationStyle = UIModalPresentationFullScreen;

        [self.navigationController presentViewController:navController animated:YES completion:nil];

    }

}

- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    NSIndexPath *rowToSelect = indexPath;

    NSInteger section = indexPath.section;

    BOOL isEditing = self.editing;

    // If editing, don't allow instructions to be selected

    // Not editing: Only allow instructions to be selected

    //

    if ((isEditing && section == INSTRUCTIONS_SECTION) || (!isEditing && section != INSTRUCTIONS_SECTION)) {

        [tableView deselectRowAtIndexPath:indexPath animated:YES];

        rowToSelect = nil;    

    }

    return rowToSelect;

}

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

    if ([segue.identifier isEqualToString:kAddIngredientSegueID]) {

        // Add an ingredient.

        //

        Recipe *recipe = nil;

        if ([sender isKindOfClass:[Recipe class]]) {

            // The sender is the actual recipe send from "didAddRecipe" delegate (user created a new recipe)

            // pass the recipe.

            recipe = (Recipe *)sender;

            UINavigationController *navController = (UINavigationController *)segue.destinationViewController;

            IngredientDetailViewController *ingredientDetailViewController = (IngredientDetailViewController *)navController.topViewController;

            ingredientDetailViewController.recipe = recipe;

        }

    }

    else if ([segue.identifier isEqualToString:kShowInstructionsSegueID]) {

        // Show and/or edit the instructions - pass the recipe.

        //

        InstructionsViewController *instructionsViewController = (InstructionsViewController *)segue.destinationViewController;

        instructionsViewController.recipe = self.recipe;

    }

}

- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath {

    UITableViewCellEditingStyle style = UITableViewCellEditingStyleNone;

    // Only allow editing in the ingredients section.

    // In the ingredients section, the last row (row number equal to the count of ingredients)

    // is added automatically (see tableView:cellForRowAtIndexPath:) to provide an insertion cell,

    // so configure that cell for insertion; the other cells are configured for deletion.

    //

    if (indexPath.section == INGREDIENTS_SECTION) {

        // If this is the last item, it's the insertion row.

        if (indexPath.row == (NSInteger)self.recipe.ingredients.count) {

            style = UITableViewCellEditingStyleInsert;

        }

        else {

            style = UITableViewCellEditingStyleDelete;

        }

    }

    return style;

}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

    // Only allow deletion, and only in the ingredients section

    if ((editingStyle == UITableViewCellEditingStyleDelete) && (indexPath.section == INGREDIENTS_SECTION)) {

        // Remove the corresponding ingredient object from the recipe's ingredient list and delete the appropriate table view cell.

        Ingredient *ingredient = [self.ingredients objectAtIndex:indexPath.row];

        [self.recipe removeIngredientsObject:ingredient];

        [self.ingredients removeObject:ingredient];

        NSManagedObjectContext *context = ingredient.managedObjectContext;

        [context deleteObject:ingredient];

        [self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationTop];

    }

    else if (editingStyle == UITableViewCellEditingStyleInsert) {

        // User tapped the "+" button to add a new ingredient.

        [self performSegueWithIdentifier:kAddIngredientSegueID sender:self.recipe];

    }

}

#pragma mark - Moving rows

- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {

    BOOL canMove = NO;

    // Moves are only allowed within the ingredients section.  Within the ingredients section, the last row (Add Ingredient) cannot be moved.

    if (indexPath.section == INGREDIENTS_SECTION) {

        canMove = indexPath.row != (NSInteger)self.recipe.ingredients.count;

    }

    return canMove;

}

- (NSIndexPath *)tableView:(UITableView *)tableView targetIndexPathForMoveFromRowAtIndexPath:(NSIndexPath *)sourceIndexPath toProposedIndexPath:(NSIndexPath *)proposedDestinationIndexPath {

    NSIndexPath *target = proposedDestinationIndexPath;

    // Moves are only allowed within the ingredients section, so make sure the destination

    // is in the ingredients section. If the destination is in the ingredients section,

    // make sure that it's not the Add Ingredient row -- if it is, retarget for the penultimate row.

    //

    NSUInteger proposedSection = proposedDestinationIndexPath.section;

    if (proposedSection < INGREDIENTS_SECTION) {

        target = [NSIndexPath indexPathForRow:0 inSection:INGREDIENTS_SECTION];

    } else if (proposedSection > INGREDIENTS_SECTION) {

        target = [NSIndexPath indexPathForRow:(self.recipe.ingredients.count - 1) inSection:INGREDIENTS_SECTION];

    } else {

        NSUInteger ingredientsCount_1 = self.recipe.ingredients.count - 1;

        if (proposedDestinationIndexPath.row > (NSInteger)ingredientsCount_1) {

            target = [NSIndexPath indexPathForRow:ingredientsCount_1 inSection:INGREDIENTS_SECTION];

        }

    }

    return target;

}

- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {

    /*

     Update the ingredients array in response to the move.

     Update the display order indexes within the range of the move.

     */

    Ingredient *ingredient = [self.ingredients objectAtIndex:fromIndexPath.row];

    [self.ingredients removeObjectAtIndex:fromIndexPath.row];

    [self.ingredients insertObject:ingredient atIndex:toIndexPath.row];

    NSInteger start = fromIndexPath.row;

    if (toIndexPath.row < start) {

        start = toIndexPath.row;

    }

    NSInteger end = toIndexPath.row;

    if (fromIndexPath.row > end) {

        end = fromIndexPath.row;

    }

    for (NSInteger i = start; i <= end; i++) {

        ingredient = [self.ingredients objectAtIndex:i];

        ingredient.displayOrder = [NSNumber numberWithInteger:i];

    }

}

#pragma mark - Photo

- (IBAction)photoTapped {

    // If in editing state, then display an image picker; if not, create and push a photo view controller.

    if (self.editing) {

        UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];

        imagePicker.delegate = self;

        [self presentViewController:imagePicker animated:YES completion:nil];

    } else {    

        RecipePhotoViewController *recipePhotoViewController = [[RecipePhotoViewController alloc] init];

        recipePhotoViewController.hidesBottomBarWhenPushed = YES;

        recipePhotoViewController.recipe = self.recipe;

        [self.navigationController pushViewController:recipePhotoViewController animated:YES];

    }

}

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)selectedImage editingInfo:(NSDictionary *)editingInfo {

    // Delete any existing image.

    NSManagedObject *oldImage = self.recipe.image;

    if (oldImage != nil) {

        [self.recipe.managedObjectContext deleteObject:oldImage];

    }

    // Create an image object for the new image.

    NSManagedObject *image =

        [NSEntityDescription insertNewObjectForEntityForName:@"Image"

                                      inManagedObjectContext:self.recipe.managedObjectContext];

    self.recipe.image = image;

    // Set the image for the image managed object.

    [image setValue:selectedImage forKey:@"image"];

    // Create a thumbnail version of the image for the recipe object.

    CGSize size = selectedImage.size;

    CGFloat ratio = 0;

    if (size.width > size.height) {

        ratio = 44.0 / size.width;

    } else {

        ratio = 44.0 / size.height;

    }

    CGRect rect = CGRectMake(0.0, 0.0, ratio * size.width, ratio * size.height);

    UIGraphicsBeginImageContext(rect.size);

    [selectedImage drawInRect:rect];

    self.recipe.thumbnailImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    [self dismissViewControllerAnimated:YES completion:nil];

}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {

    [self dismissViewControllerAnimated:YES completion:nil];

}

- (void)updatePhotoButton {

    /*

     How to present the photo button depends on the editing state and whether the recipe has a thumbnail image.

     * If the recipe has a thumbnail, set the button's highlighted state to the same as the editing state (it's highlighted if editing).

     * If the recipe doesn't have a thumbnail, then: if editing, enable the button and show an image that says "Choose Photo" or similar; if not editing then disable the button and show nothing.  

     */

    BOOL editing = self.editing;

    if (self.recipe.thumbnailImage != nil) {

        self.photoButton.highlighted = editing;

    } else {

        self.photoButton.enabled = editing;

        if (editing) {

            [self.photoButton setImage:[UIImage imageNamed:@"choosePhoto.png"] forState:UIControlStateNormal];

        } else {

            [self.photoButton setImage:nil forState:UIControlStateNormal];

        }

    }

}

@end