/*

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

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 Table view controller to display Events by section.

 */

#import "APLMasterViewController.h"

#import "APLEvent.h"

@interface APLMasterViewController ()

@property (nonatomic) NSFetchedResultsController *fetchedResultsController;

@end

#pragma mark -

@implementation APLMasterViewController

- (void)viewDidLoad

{

    [super viewDidLoad];

    NSError *error;

    if (![self.fetchedResultsController performFetch:&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();

    }

}

#pragma mark - Table view methods

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

{

    NSInteger count = [[self.fetchedResultsController sections] count];

    return count;

}

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

{

    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];

    NSInteger count = [sectionInfo numberOfObjects];

    return count;

}

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

{

    static NSString *CellIdentifier = @"Cell";

    /*

     Use a default table view cell to display the event's title.

     */

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    APLEvent *event = [self.fetchedResultsController objectAtIndexPath:indexPath];

    cell.textLabel.text = event.title;

    return cell;

}

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

{

    id <NSFetchedResultsSectionInfo> theSection = [[self.fetchedResultsController sections] objectAtIndex:section];

    /*

     Section information derives from an event's sectionIdentifier, which is a string representing the number (year * 1000) + month.

     To display the section title, convert the year and month components to a string representation.

     */

    static NSDateFormatter *formatter = nil;

    if (!formatter)

    {

        formatter = [[NSDateFormatter alloc] init];

        [formatter setCalendar:[NSCalendar currentCalendar]];

        NSString *formatTemplate = [NSDateFormatter dateFormatFromTemplate:@"MMMM YYYY" options:0 locale:[NSLocale currentLocale]];

        [formatter setDateFormat:formatTemplate];

    }

    NSInteger numericSection = [[theSection name] integerValue];

    NSInteger year = numericSection / 1000;

    NSInteger month = numericSection - (year * 1000);

    NSDateComponents *dateComponents = [[NSDateComponents alloc] init];

    dateComponents.year = year;

    dateComponents.month = month;

    NSDate *date = [[NSCalendar currentCalendar] dateFromComponents:dateComponents];

    NSString *titleString = [formatter stringFromDate:date];

    return titleString;

}

#pragma mark - Fetched results controller

- (NSFetchedResultsController *)fetchedResultsController

{

    if (_fetchedResultsController != nil)

    {

        return _fetchedResultsController;

    }

    /*

     Set up the fetched results controller.

     */

    // Create the fetch request for the entity.

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

    // Edit the entity name as appropriate.

    NSEntityDescription *entity = [NSEntityDescription entityForName:@"APLEvent" inManagedObjectContext:self.managedObjectContext];

    [fetchRequest setEntity:entity];

    // Set the batch size to a suitable number.

    [fetchRequest setFetchBatchSize:20];

    // Sort using the timeStamp property.

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

    [fetchRequest setSortDescriptors:@[sortDescriptor ]];

    // Use the sectionIdentifier property to group into sections.

    _fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:@"sectionIdentifier" cacheName:@"Root"];

    _fetchedResultsController.delegate = self;

    return _fetchedResultsController;

}    

@end