/*

     File: AppDelegate.m 

 Abstract: Application delegate for the TopPaid sample.

 It also downloads in the background the "Top Paid iPhone Apps" RSS feed using NSURLConnection. 

  Version: 1.1 

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 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION 

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 */

#import "AppDelegate.h"

#import "ParseOperation.h"

#import "AppRecord.h"

#import "ContentController.h"

// This framework was imported so we could use the kCFURLErrorNotConnectedToInternet error code.

#import <CFNetwork/CFNetwork.h>

static NSString *const TopPaidAppsFeed =

    @"http://phobos.apple.com/WebObjects/MZStoreServices.woa/ws/RSS/toppaidapplications/limit=75/xml";

NSString *AppDataDownloadCompleted = @"AppDataDownloadCompleted";

@implementation AppDelegate

@synthesize window, appRecords, queue, appListFeedConnection, appListData, contentController;

#pragma mark -

// -------------------------------------------------------------------------------

//  applicationDidFinishLaunching:application

// -------------------------------------------------------------------------------

- (void)applicationDidFinishLaunching:(UIApplication *)application

{

    [[NSBundle mainBundle] loadNibNamed:@"Content" owner:self options:nil];

    [self.window addSubview:self.contentController.view];

    [window makeKeyAndVisible];

    // Initialize the array of app records and pass a reference to that list to our root view controller

    self.appRecords = [NSMutableArray array];

    NSURLRequest *urlRequest = [NSURLRequest requestWithURL:[NSURL URLWithString:TopPaidAppsFeed]];

    self.appListFeedConnection = [[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self] autorelease];

    // Test the validity of the connection object. The most likely reason for the connection object

    // to be nil is a malformed URL, which is a programmatic error easily detected during development

    // If the URL is more dynamic, then you should implement a more flexible validation technique, and

    // be able to both recover from errors and communicate problems to the user in an unobtrusive manner.

    //

    NSAssert(self.appListFeedConnection != nil, @"Failure to create URL connection.");

    // show in the status bar that network activity is starting

    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

}

// -------------------------------------------------------------------------------

//  handleLoadedApps:loadedApps

// -------------------------------------------------------------------------------

- (void)handleLoadedApps:(NSArray *)loadedApps

{

    [self.appRecords addObjectsFromArray:loadedApps];

    // tell our interested view controller reload its data, now that parsing has completed

    [[NSNotificationCenter defaultCenter] postNotificationName:AppDataDownloadCompleted object:loadedApps];

}

// -------------------------------------------------------------------------------

//  didFinishParsing:appList

// -------------------------------------------------------------------------------

- (void)didFinishParsing:(NSArray *)appList

{

    [self performSelectorOnMainThread:@selector(handleLoadedApps:) withObject:appList waitUntilDone:NO];

    self.queue = nil;   // we are finished with the queue and our ParseOperation

}

- (void)parseErrorOccurred:(NSError *)error

{

    [self performSelectorOnMainThread:@selector(handleError:) withObject:error waitUntilDone:NO];

}

#pragma mark -

#pragma mark NSURLConnection delegate methods

// -------------------------------------------------------------------------------

//  handleError:error

// -------------------------------------------------------------------------------

- (void)handleError:(NSError *)error

{

    NSString *errorMessage = [error localizedDescription];

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Cannot Show Top Paid Apps"

                                                        message:errorMessage

                                                       delegate:nil

                                              cancelButtonTitle:@"OK"

                                              otherButtonTitles:nil];

    [alertView show];

    [alertView release];

}

// The following are delegate methods for NSURLConnection. Similar to callback functions, this is how

// the connection object,  which is working in the background, can asynchronously communicate back to

// its delegate on the thread from which it was started - in this case, the main thread.

//

// -------------------------------------------------------------------------------

//  connection:didReceiveResponse:response

// -------------------------------------------------------------------------------

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response

{

    self.appListData = [NSMutableData data];    // start off with new data

}

// -------------------------------------------------------------------------------

//  connection:didReceiveData:data

// -------------------------------------------------------------------------------

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

{

    [appListData appendData:data];  // append incoming data

}

// -------------------------------------------------------------------------------

//  connection:didFailWithError:error

// -------------------------------------------------------------------------------

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error

{

    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;

    if ([error code] == kCFURLErrorNotConnectedToInternet)

    {

        // if we can identify the error, we can present a more precise message to the user.

        NSDictionary *userInfo = [NSDictionary dictionaryWithObject:@"No Connection Error"

                                                             forKey:NSLocalizedDescriptionKey];

        NSError *noConnectionError = [NSError errorWithDomain:NSCocoaErrorDomain

                                                         code:kCFURLErrorNotConnectedToInternet

                                                     userInfo:userInfo];

        [self handleError:noConnectionError];

    }

    else

    {

        // otherwise handle the error generically

        [self handleError:error];

    }

    self.appListFeedConnection = nil;   // release our connection

}

// -------------------------------------------------------------------------------

//  connectionDidFinishLoading:connection

// -------------------------------------------------------------------------------

- (void)connectionDidFinishLoading:(NSURLConnection *)connection

{

    self.appListFeedConnection = nil;   // release our connection

    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;   

    // create the queue to run our ParseOperation

    self.queue = [[NSOperationQueue alloc] init];

    // create an ParseOperation (NSOperation subclass) to parse the RSS feed data so that the UI is not blocked

    // "ownership of appListData has been transferred to the parse operation and should no longer be

    // referenced in this thread.

    //

    ParseOperation *parser = [[ParseOperation alloc] initWithData:appListData delegate:self];

    [queue addOperation:parser]; // this will start the "ParseOperation"

    [parser release];

    // ownership of appListData has been transferred to the parse operation

    // and should no longer be referenced in this thread

    self.appListData = nil;

}

// -------------------------------------------------------------------------------

//  dealloc

// -------------------------------------------------------------------------------

- (void)dealloc

{

    [appRecords release];

    [appListFeedConnection release];

    [appListData release];

    [contentController release];

    [window release];

    [super dealloc];

}

@end