notifications-for-youtube/Notifications for YouTube/NYTRulesWindowController.m

//
//  NYTRulesWindowController.m
//  Notifications for YouTube
//
//  Created by Kim Wittenburg on 21.07.13.
//  Copyright (c) 2013 Kim Wittenburg. All rights reserved.
//

#import "NYTRulesWindowController.h"

// Core Imports
#import "NYTUser.h"
#import "NYTUtil.h"
#import "NYTAuthentication.h"

// Other Imports
#import "NYTChannelRestriction.h"

@interface NYTRulesWindowController ()

@property (readwrite) BOOL loading;
@property (readwrite) NSArray *subscriptions;

/* The restrictions previously stored in the user defaults
 */
@property NSDictionary *savedRestrictions;

@end

@implementation NYTRulesWindowController

/* Convenient init
 */
- (id)init
{
    return [self initWithWindowNibName:@"NYTRulesWindowController" owner:self];
}

- (void)windowDidLoad
{
    [super windowDidLoad];

    // Load the subscriptions
    [self loadSubscriptions];
}

#pragma mark *** Loading ***

- (void)loadSubscriptions
{
    self.loading = YES;

    // Load in background to not block the main thread
    dispatch_queue_t prevQueue = dispatch_get_current_queue();
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        
        // Prepare for multiple pages
        NSError *error;
        NSMutableArray *loadedSubscriptions;
        NSUInteger processedResults = 0;
        NSUInteger totalResults = 0;

        do {
            // We are creating a couple of objects so setup a separate autoreleasepool
            @autoreleasepool {
                // Load the document
                NSString *url = [NSString stringWithFormat:@"https://gdata.youtube.com/feeds/api/users/default/subscriptions?max-results=50&start-index=%li&v=2", processedResults+1];
                NSXMLDocument *document = LoadXMLDocumentSynchronous(url, [NYTAuthentication sharedAuthentication].authentication, &error);

                // Store the entries as app-friendly video objects
                if (document) {

                    // Set up the collection for collecting the videos
                    if (processedResults == 0) {
                        static NSString *const totalResultsPath = @"./feed/openSearch:totalResults";
                        NSXMLElement *totalResultsElement = [document nodesForXPath:totalResultsPath error:nil][0];
                        totalResults = (NSUInteger) totalResultsElement.stringValue.integerValue;
                        loadedSubscriptions = [NSMutableArray arrayWithCapacity:totalResults];
                    }

                    // For each page parse its results and add them to the collection
                    static NSString *const resultsPerPagePath = @"./feed/openSearch:itemsPerPage";
                    NSXMLElement *resultsPerPageElement = [document nodesForXPath:resultsPerPagePath error:nil][0];
                    int resultsPerPage = resultsPerPageElement.stringValue.intValue;

                    processedResults += resultsPerPage;
                    NSArray *pageSubscriptions = [self subscriptionsOnPage:document error:&error];
                    if (pageSubscriptions) {
                        [loadedSubscriptions addObjectsFromArray:pageSubscriptions];
                    } else {
                        // Abort on error
                        [self abortLoadingOnQueue:prevQueue withError:error];
                        return;
                    }
                } else {
                    // Abort on error
                    [self abortLoadingOnQueue:prevQueue withError:error];
                    return;
                }
            }
        } while (processedResults < totalResults);

        // Finish the loading process on the main thread
        dispatch_async(prevQueue, ^{
            self.subscriptions = loadedSubscriptions;
            self.loading = NO;
        });
    });
}

- (NSArray *)subscriptionsOnPage:(NSXMLDocument *)document error:(NSError **)error
{
    // Set up the stored restrictions (but just once)
    if (!self.savedRestrictions) {
        self.savedRestrictions = [[[NSUserDefaults standardUserDefaults] objectForKey:@"Rules"] mutableCopy];
        if (!self.savedRestrictions) {
            self.savedRestrictions = [NSMutableDictionary new];
        }
    }

    // For every entry parse a subscription
    NSArray *entries = [document nodesForXPath:@"./feed/entry" error:nil];
    NSMutableArray *subscriptions = [NSMutableArray arrayWithCapacity:entries.count];
    for (NSXMLNode *entry in entries) {
        NYTUser *user = [[NYTUser alloc] initWithSubscriptionEntry:entry];

        // Have a restriction object available for each subscription. If there is none stored create a default one.
        NSData *restrictionData = self.savedRestrictions[user.channelID];
        NYTChannelRestriction *restriction;
        if (restrictionData) {
            restriction = [NSKeyedUnarchiver unarchiveObjectWithData:restrictionData];
        } else {
            restriction = [[NYTChannelRestriction alloc] init];
        }
        restriction.user = user;
        [subscriptions addObject:restriction];
    }
    return subscriptions;
}

- (void)abortLoadingOnQueue:(dispatch_queue_t)queue withError:(NSError *)error
{
    dispatch_async(queue, ^{
        [NSApp presentError:error modalForWindow:self.window delegate:self didPresentSelector:@selector(didPresentErrorWithRecovery:contextInfo:) contextInfo:NULL];
    });
}

- (void)didPresentErrorWithRecovery:(BOOL)didRecover contextInfo:(void *)contextInfo
{
    if (!didRecover) {
        [self cancel:nil];
    }
}

- (IBAction)enableAllNotifications:(id)sender {
    // Really enable all (also clearing the predicate)
    for (NYTChannelRestriction *restriction in self.subscriptions) {
        restriction.disableAllNotifications = NO;
        restriction.predicate = nil;
    }
}

- (IBAction)disableAllNotifications:(id)sender {
    for (NYTChannelRestriction *restriction in self.subscriptions) {
        restriction.disableAllNotifications = YES;
    }
}

- (IBAction)save:(id)sender {
    // Encode and save the restrictions that are not default values.
    NSMutableDictionary *restrictsToSave = [NSMutableDictionary new];
    for (NYTChannelRestriction *restrictions in self.subscriptions) {
        if (restrictions.differsFromDefaultValues) {
            restrictsToSave[restrictions.user.channelID] = [NSKeyedArchiver archivedDataWithRootObject:restrictions];
        }
    }
    [[NSUserDefaults standardUserDefaults] setObject:restrictsToSave forKey:@"Rules"];
    [[NSUserDefaults standardUserDefaults] synchronize];
    // Hide this window
    [self cancel:sender];
}

- (IBAction)cancel:(id)sender {
    // Just hide the window without saving
    [self.window orderOut:sender];
    [NSApp endSheet:self.window];
}
@end