/*

     File: APLViewController.m

 Abstract: View controller for displaying the earthquake list; initiates the download of the XML data and parses the Earthquake objects at view load time.

  Version: 3.5

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 */

#import "APLViewController.h"

#import "APLParseOperation.h"

#import "APLEarthquake.h"

#import "APLEarthquakeTableViewCell.h"

// this framework is imported so we can use the kCFURLErrorNotConnectedToInternet error code

#import <CFNetwork/CFNetwork.h>

#import <MapKit/MapKit.h>

@interface APLViewController ()

@property (nonatomic) NSMutableArray *earthquakeList;

// queue that manages our NSOperation for parsing earthquake data

@property (nonatomic) NSOperationQueue *parseQueue;

@end

#pragma mark -

@implementation APLViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    self.earthquakeList = [NSMutableArray array];

    /*

     Use NSURLConnection to asynchronously download the data. This means the main thread will not be blocked - the application will remain responsive to the user.

     IMPORTANT! The main thread of the application should never be blocked!

     Also, avoid synchronous network access on any thread.

     */

    static NSString *feedURLString = @"http://earthquake.usgs.gov/eqcenter/catalogs/7day-M2.5.xml";

    NSURLRequest *earthquakeURLRequest =

    [NSURLRequest requestWithURL:[NSURL URLWithString:feedURLString]];

    // send the async request (note that the completion block will be called on the main thread)

    //

    // note: using the block-based "sendAsynchronousRequest" is preferred, and useful for

    // small data transfers that are likely to succeed. If you doing large data transfers,

    // consider using the NSURLConnectionDelegate-based APIs.

    //

    [NSURLConnection sendAsynchronousRequest:earthquakeURLRequest

                                       // the NSOperationQueue upon which the handler block will be dispatched:

                                       queue:[NSOperationQueue mainQueue]

                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {

         // back on the main thread, check for errors, if no errors start the parsing

         //

         [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

         // here we check for any returned NSError from the server, "and" we also check for any http response errors

         if (error != nil) {

             [self handleError:error];

         }

         else {

             // check for any response errors

             NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;

             if ((([httpResponse statusCode]/100) == 2) && [[response MIMEType] isEqual:@"application/atom+xml"]) {

                 // Update the UI and start parsing the data,

                 // Spawn an NSOperation to parse the earthquake data so that the UI is not

                 // blocked while the application parses the XML data.

                 //

                 APLParseOperation *parseOperation = [[APLParseOperation alloc] initWithData:data];

                 [self.parseQueue addOperation:parseOperation];

             }

             else {

                NSString *errorString =

                    NSLocalizedString(@"HTTP Error", @"Error message displayed when receving a connection error.");

                NSDictionary *userInfo = @{NSLocalizedDescriptionKey : errorString};

                NSError *reportError = [NSError errorWithDomain:@"HTTP"

                                                           code:[httpResponse statusCode]

                                                       userInfo:userInfo];

                [self handleError:reportError];

             }

         }

     }];

    // Start the status bar network activity indicator.

    // We'll turn it off when the connection finishes or experiences an error.

    //

    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

    self.parseQueue = [NSOperationQueue new];

    [[NSNotificationCenter defaultCenter] addObserver:self

                                             selector:@selector(addEarthquakes:)

                                                 name:kAddEarthquakesNotificationName object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self

                                             selector:@selector(earthquakesError:)

                                                 name:kEarthquakesErrorNotificationName object:nil];

    // if the locale changes behind our back, we need to be notified so we can update the date

    // format in the table view cells

    [[NSNotificationCenter defaultCenter] addObserver:self

                                             selector:@selector(localeChanged:)

                                                 name:NSCurrentLocaleDidChangeNotification

                                               object:nil];

}

- (void)dealloc {

    // we are no longer interested in these notifications:

    [[NSNotificationCenter defaultCenter] removeObserver:self

                                                    name:kAddEarthquakesNotificationName

                                                  object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self

                                                    name:kEarthquakesErrorNotificationName

                                                  object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self

                                                    name:NSCurrentLocaleDidChangeNotification

                                                  object:nil];

}

/**

 Handle errors in the download by showing an alert to the user. This is a very simple way of handling the error, partly because this application does not have any offline functionality for the user. Most real applications should handle the error in a less obtrusive way and provide offline functionality to the user.

 */

- (void)handleError:(NSError *)error {

    NSString *errorMessage = [error localizedDescription];

    NSString *alertTitle = NSLocalizedString(@"Error", @"Title for alert displayed when download or parse error occurs.");

    NSString *okTitle = NSLocalizedString(@"OK ", @"OK Title for alert displayed when download or parse error occurs.");

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:alertTitle message:errorMessage delegate:nil cancelButtonTitle:okTitle otherButtonTitles:nil];

    [alertView show];

}

/**

 Our NSNotification callback from the running NSOperation to add the earthquakes

 */

- (void)addEarthquakes:(NSNotification *)notif {

    assert([NSThread isMainThread]);

    [self addEarthquakesToList:[[notif userInfo] valueForKey:kEarthquakeResultsKey]];

}

/**

 Our NSNotification callback from the running NSOperation when a parsing error has occurred

 */

- (void)earthquakesError:(NSNotification *)notif {

    assert([NSThread isMainThread]);

    [self handleError:[[notif userInfo] valueForKey:kEarthquakesMessageErrorKey]];

}

/**

 The NSOperation "ParseOperation" calls addEarthquakes: via NSNotification, on the main thread which in turn calls this method, with batches of parsed objects. The batch size is set via the kSizeOfEarthquakeBatch constant.

 */

- (void)addEarthquakesToList:(NSArray *)earthquakes {

    NSInteger startingRow = [self.earthquakeList count];

    NSInteger earthquakeCount = [earthquakes count];

    NSMutableArray *indexPaths = [[NSMutableArray alloc] initWithCapacity:earthquakeCount];

    for (NSInteger row = startingRow; row < (startingRow + earthquakeCount); row++) {

        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:0];

        [indexPaths addObject:indexPath];

    }

    [self.earthquakeList addObjectsFromArray:earthquakes];

    [self.tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationAutomatic];

}

#pragma mark - UITableViewDelegate

// The number of rows is equal to the number of earthquakes in the array.

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

    return [self.earthquakeList count];

}

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

    static NSString *kEarthquakeCellID = @"EarthquakeCellID";

    APLEarthquakeTableViewCell *cell = (APLEarthquakeTableViewCell *)[tableView dequeueReusableCellWithIdentifier:kEarthquakeCellID];

    // Get the specific earthquake for this row.

    APLEarthquake *earthquake = (self.earthquakeList)[indexPath.row];

    [cell configureWithEarthquake:earthquake];

    return cell;

}

/**

 * When the user taps a row in the table, display the USGS web page that displays details of the earthquake they selected.

 */

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

    NSString *buttonTitle = NSLocalizedString(@"Cancel", @"Cancel");

    NSString *buttonTitle1 = NSLocalizedString(@"Show USGS Site in Safari", @"Show USGS Site in Safari");

    NSString *buttonTitle2 = NSLocalizedString(@"Show Location in Maps", @"Show Location in Maps");

    UIActionSheet *sheet = [[UIActionSheet alloc] initWithTitle:nil

                                                       delegate:self

                                              cancelButtonTitle:buttonTitle destructiveButtonTitle:nil

                                              otherButtonTitles:buttonTitle1, buttonTitle2, nil];

    [sheet showInView:self.view];

}

#pragma mark -

/**

 * Called when the user selects an option in the sheet. The sheet will automatically be dismissed.

 */

- (void)actionSheet:(UIActionSheet *)actionSheet willDismissWithButtonIndex:(NSInteger)buttonIndex {

    NSIndexPath *selectedIndexPath = [self.tableView indexPathForSelectedRow];

    APLEarthquake *earthquake = (APLEarthquake *)(self.earthquakeList)[selectedIndexPath.row];

    switch (buttonIndex) {

        case 0: {

            // open the earthquake info in Safari

            //

            [[UIApplication sharedApplication] openURL:earthquake.USGSWebLink];

        }

            break;

        case 1: {

            // open the earthquake info in Maps

            // create a map region pointing to the earthquake location

            CLLocationCoordinate2D location = (CLLocationCoordinate2D) { earthquake.latitude, earthquake.longitude };

            NSValue *locationValue = [NSValue valueWithMKCoordinate:location];

            MKCoordinateSpan span = (MKCoordinateSpan) { 2.0, 2.0 };

            NSValue *spanValue = [NSValue valueWithMKCoordinateSpan:span];

            NSDictionary *launchOptions = @{ MKLaunchOptionsMapTypeKey : @(MKMapTypeStandard),

                                            MKLaunchOptionsMapCenterKey : locationValue,

                                            MKLaunchOptionsMapSpanKey : spanValue,

                                            MKLaunchOptionsShowsTrafficKey : @(NO),

                                             MKLaunchOptionsDirectionsModeDriving : @(NO) };

            // make sure the map item has a pin placed on it with the title as the earthquake location

            MKPlacemark *placemark = [[MKPlacemark alloc] initWithCoordinate:location

                                                           addressDictionary:nil];

            MKMapItem *mapItem = [[MKMapItem alloc] initWithPlacemark:placemark];

            [mapItem setName:earthquake.location];

            [mapItem openInMapsWithLaunchOptions:launchOptions];

            break;

        }

    }

    [self.tableView deselectRowAtIndexPath:selectedIndexPath animated:YES];

}

#pragma mark - Locale changes

- (void)localeChanged:(NSNotification *)notif

{

    // the user changed the locale (region format) in Settings, so we are notified here to

    // update the date format in the table view cells

    //

    [self.tableView reloadData];

}

@end