PatientTableViewController

#import "PatientsTableTableViewController.h"

//import app delegate to gain access to managed object
#import "LevithAppDelegate.h"
//so we know what information we are communicating with
#import "AddPatientViewController.h"


@interface PatientsTableTableViewController ()

@property (nonatomic, strong) NSManagedObjectContext *managedObjectContext;

//fetch request retursn an array of objects (patients names) from within the data base
@property (nonatomic, strong) NSFetchedResultsController *fetchedResultsController;


@end

@implementation PatientsTableTableViewController

- (id)initWithStyle:(UITableViewStyle)style
{
    self = [super initWithStyle:style];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (NSManagedObjectContext *) managedObjectContext {

    //this code allows us to commuicate with the managed object context throughout the project via
    //"self.managedObjectContext
    return [(LevithAppDelegate*)[[UIApplication sharedApplication]delegate]managedObjectContext];

}

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

    //first check whether the segue is equal to our transition name (modal: addPatient in the storyboard)
    if([[segue identifier]isEqualToString:@"addPatient"])
    {
        //tell the segue where to go
        UINavigationController *navigationController = segue.destinationViewController;

        //create refernce to view controller
        //able to do this because we imported "AddPatientViewController.h"
        AddPatientViewController *addPatientViewController = (AddPatientViewController*) navigationController.topViewController;

        //create the new object
        Patient *addPatient = [NSEntityDescription insertNewObjectForEntityForName:@"Patient" inManagedObjectContext: [self managedObjectContext]];

        addPatientViewController.addPatient = addPatient;
    }
}


- (void)viewDidLoad
{
    [super viewDidLoad];

    //create error object and set value to nil
    NSError *error = nil;
    //check that fetch results are available
    if(![[self fetchedResultsController]performFetch:&error]){
        NSLog(@"Error: %@", error);
        abort();//remove if launching app as this will terminate the app
    }

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    //refer to the fetchresults to find out how many sections
    //sections property then stores the amount as array
    //then counts
    return [[self.fetchedResultsController sections] count];
}

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

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

    return [sectionInfo numberOfObjects];

}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    //declare name and details for cell
    //always confrim the cell identifier is the same as listed in your code
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: CellIdentifier forIndexPath:indexPath];

    //create access to details the cell will display from the core date
    Patient *patient = [self.fetchedResultsController objectAtIndexPath:indexPath];

    //create the title and subtitle (detail text label) information
    cell.textLabel.text = patient.patientLastName;
    cell.detailTextLabel.text = patient.patientFirstName;

    return cell;
}



#pragma mark - Fetched Results Controller Section

// method for fetching results
- (NSFetchedResultsController*) fetchedResultsController{
    //FIRST WE "ASK" IF THERE IS ALREADY A FETCHED RESULTS CONTROLLER
    //IF SO WE RETURN IT
    if (_fetchedResultsController != nil){
        return _fetchedResultsController;
    }
    //if we don't have one we create it
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc]init];

    //we then access the managed object context and create a shortcut name
    NSManagedObjectContext *context = [self managedObjectContext];

    //next we create access to the entity which we have two of: Patient and Perscription
    //this entity is obviously Patient
    //we access the context using the shortcut created above "context"
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Patient" inManagedObjectContext:context];

    //set the fetch request to fetch from out entity
    [fetchRequest setEntity:entity];

    //create a sort descriptor to present sorted results
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"patientLastName" ascending:YES];


    //create temporary array to hold our sorted objects
    NSArray *sortDescriptors = [[NSArray alloc]initWithObjects:sortDescriptor, nil];

    //assign array to sort descriptor property of the fetch request
    fetchRequest.sortDescriptors = sortDescriptors;

    //initialise fetch results with fetch request
    //not fetching in sections so section is nil
    //cache is small and local so also nil
    _fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:context sectionNameKeyPath:nil cacheName:nil];

    //create a delegate for fetch results to allow it to be called by others to fetch results
    _fetchedResultsController.delegate = self;

    return _fetchedResultsController;
}


#pragma mark - Fetched Results Controller Delegates



@end