#import "RootViewController.h"

#import "Earthquake.h"

@implementation RootViewController

@synthesize managedObjectContext, fetchedResultsController, twoWeeksAgo;

#pragma mark -

- (void)dealloc {

[dateFormatter release];

[fetchedResultsController release];

[managedObjectContext release];

[twoWeeksAgo release];

[super dealloc];

}

- (void)viewDidLoad {

[super viewDidLoad];

// The table row height is not the standard value. Since all the rows have the same height,

// it is more efficient to set this property on the table, rather than using the delegate

// method -tableView:heightForRowAtIndexPath:

//

self.tableView.rowHeight = 64;

NSError *error = nil;

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();

}

// compute the date two weeks ago from today, used later when dumping old earthquakes

NSDate *today = [NSDate date];

NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

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

[offsetComponents setDay:-14]; // 14 days back from today

self.twoWeeksAgo = [gregorian dateByAddingComponents:offsetComponents toDate:today options:0];

[offsetComponents release];

[gregorian release];

}

- (void)viewDidUnload {

[super viewDidUnload];

self.twoWeeksAgo = nil;

}

- (NSDateFormatter *)dateFormatter {

if (dateFormatter == nil) {

dateFormatter = [[NSDateFormatter alloc] init];

[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

[dateFormatter setDateStyle:NSDateFormatterMediumStyle];

[dateFormatter setTimeStyle:NSDateFormatterMediumStyle];

}

return dateFormatter;

}

- (UIImage *)imageForMagnitude:(CGFloat)magnitude {

if (magnitude >= 5.0) {

return [UIImage imageNamed:@"5.0.png"];

}

if (magnitude >= 4.0) {

return [UIImage imageNamed:@"4.0.png"];

}

if (magnitude >= 3.0) {

return [UIImage imageNamed:@"3.0.png"];

}

if (magnitude >= 2.0) {

return [UIImage imageNamed:@"2.0.png"];

}

return nil;

}

#pragma mark -

#pragma mark UITableViewDelegate

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

return [[fetchedResultsController sections] count];

}

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

NSInteger numberOfRows = 0;

if ([[fetchedResultsController sections] count] > 0) {

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

numberOfRows = [sectionInfo numberOfObjects];

}

return numberOfRows;

}

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

// Each subview in the cell will be identified by a unique tag.

static NSUInteger const kLocationLabelTag = 2;

static NSUInteger const kDateLabelTag = 3;

static NSUInteger const kMagnitudeLabelTag = 4;

static NSUInteger const kMagnitudeImageTag = 5;

// Declare references to the subviews which will display the earthquake data.

UILabel *locationLabel = nil;

UILabel *dateLabel = nil;

UILabel *magnitudeLabel = nil;

UIImageView *magnitudeImage = nil;

static NSString *kEarthquakeCellID = @"EarthquakeCellID";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:kEarthquakeCellID];

if (cell == nil) {

// No reusable cell was available, so we create a new cell and configure its subviews.

cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault

reuseIdentifier:kEarthquakeCellID] autorelease];

cell.selectionStyle = UITableViewCellSelectionStyleNone;

locationLabel = [[[UILabel alloc] initWithFrame:CGRectMake(10.0, 0.0, 300.0, 40.0)] autorelease];

locationLabel.tag = kLocationLabelTag;

locationLabel.font = [UIFont boldSystemFontOfSize:16.0];

[cell.contentView addSubview:locationLabel];

dateLabel = [[[UILabel alloc] initWithFrame:CGRectMake(10.0, 42.0, 170.0, 14.0)] autorelease];

dateLabel.tag = kDateLabelTag;

dateLabel.font = [UIFont systemFontOfSize:12.0];

[cell.contentView addSubview:dateLabel];

magnitudeLabel = [[[UILabel alloc] initWithFrame:CGRectMake(277.0, 30.0, 170.0, 29.0)] autorelease];

magnitudeLabel.tag = kMagnitudeLabelTag;

magnitudeLabel.font = [UIFont boldSystemFontOfSize:24.0];

magnitudeLabel.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;

[cell.contentView addSubview:magnitudeLabel];

magnitudeImage = [[[UIImageView alloc] initWithImage:[UIImage imageNamed:@"5.0.png"]] autorelease];

CGRect imageFrame = magnitudeImage.frame;

imageFrame.origin = CGPointMake(180.0, 27.0);

imageFrame.size = CGSizeMake(imageFrame.size.width - 8.0, imageFrame.size.height - 8.0); // skring the image a little to fit

magnitudeImage.frame = imageFrame;

magnitudeImage.tag = kMagnitudeImageTag;

magnitudeImage.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;

[cell.contentView addSubview:magnitudeImage];

} else {

// A reusable cell was available, so we just need to get a reference to the subviews

// using their tags.

//

locationLabel = (UILabel *)[cell.contentView viewWithTag:kLocationLabelTag];

dateLabel = (UILabel *)[cell.contentView viewWithTag:kDateLabelTag];

magnitudeLabel = (UILabel *)[cell.contentView viewWithTag:kMagnitudeLabelTag];

magnitudeImage = (UIImageView *)[cell.contentView viewWithTag:kMagnitudeImageTag];

}

// get the specific earthquake for this row

Earthquake *earthquake = (Earthquake *)[fetchedResultsController objectAtIndexPath:indexPath];

// set the relevant data for each subview in the cell

locationLabel.text = earthquake.location;

dateLabel.text = [NSString stringWithFormat:@"%@", [self.dateFormatter stringFromDate:earthquake.date]];

magnitudeLabel.text = [NSString stringWithFormat:@"%.1f", [earthquake.magnitude floatValue]];

magnitudeImage.image = [self imageForMagnitude:[earthquake.magnitude floatValue]];

return cell;

}

#pragma mark -

#pragma mark Core Data

- (NSFetchedResultsController *)fetchedResultsController {

// Set up the fetched results controller if needed.

if (fetchedResultsController == nil) {

// Create the fetch request for the entity.

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

// Edit the entity name as appropriate.

NSEntityDescription *entity = [NSEntityDescription entityForName:@"Earthquake"

inManagedObjectContext:managedObjectContext];

[fetchRequest setEntity:entity];

// Edit the sort key as appropriate.

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"date" ascending:NO];

NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];

[fetchRequest setSortDescriptors:sortDescriptors];

// Edit the section name key path and cache name if appropriate.

// nil for section name key path means "no sections".

NSFetchedResultsController *aFetchedResultsController =

[[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest

managedObjectContext:managedObjectContext

sectionNameKeyPath:nil

cacheName:nil];

self.fetchedResultsController = aFetchedResultsController;

[aFetchedResultsController release];

[fetchRequest release];

[sortDescriptor release];

[sortDescriptors release];

}

return fetchedResultsController;

}

- (void)updateContext:(NSNotification *)notification

{

NSManagedObjectContext *mainContext = [self managedObjectContext];

[mainContext mergeChangesFromContextDidSaveNotification:notification];

// keep our number of earthquakes to a manageable level, remove earthquakes older than 2 weeks

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

NSEntityDescription *entity = [NSEntityDescription entityForName:@"Earthquake"

inManagedObjectContext:managedObjectContext];

[fetchRequest setEntity:entity];

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"date < %@", self.twoWeeksAgo];

[fetchRequest setPredicate:predicate];

NSError *error = nil;

NSArray *olderEarthquakes = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];

Earthquake *earthquake;

for (earthquake in olderEarthquakes) {

[self.managedObjectContext deleteObject:earthquake];

}

// update our fetched results after the merge

//

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();

}

[fetchRequest release];

[self.tableView reloadData];

}

- (void)mergeChanges:(NSNotification *)notification {

NSManagedObjectContext *mainContext = [self managedObjectContext];

if ([notification object] == mainContext) {

// main context save, no need to perform the merge

return;

}

[self performSelectorOnMainThread:@selector(updateContext:) withObject:notification waitUntilDone:YES];

}