////
////  Copyright (c) 2018 Open Whisper Systems. All rights reserved.
////
//
//#import "ThreadViewHelper.h"
//#import <SessionUtilitiesKit/AppContext.h>
//#import <SessionMessagingKit/OWSPrimaryStorage.h>
//#import <SessionMessagingKit/TSDatabaseView.h>
//#import <SessionMessagingKit/TSThread.h>
//#import <SessionMessagingKit/TSContactThread.h>
//#import <SignalUtilitiesKit/SignalUtilitiesKit-Swift.h>
//#import <YapDatabase/YapDatabase.h>
//#import <YapDatabase/YapDatabaseViewChange.h>
//#import <YapDatabase/YapDatabaseViewConnection.h>
//
//NS_ASSUME_NONNULL_BEGIN
//
//@interface ThreadViewHelper ()
//
//@property (nonatomic) YapDatabaseConnection *uiDatabaseConnection;
//@property (nonatomic) YapDatabaseViewMappings *threadMappings;
//@property (nonatomic) BOOL shouldObserveDBModifications;
//
//@end
//
//#pragma mark -
//
//@implementation ThreadViewHelper
//
//- (instancetype)init
//{
//    self = [super init];
//    if (!self) {
//        return self;
//    }
//
//    [self initializeMapping];
//
//    return self;
//}
//
//- (void)dealloc
//{
//    [[NSNotificationCenter defaultCenter] removeObserver:self];
//}
//
//- (void)initializeMapping
//{
//    OWSAssertIsOnMainThread();
//
//    NSString *grouping = TSInboxGroup;
//
//    self.threadMappings =
//        [[YapDatabaseViewMappings alloc] initWithGroups:@[ grouping ] view:TSThreadDatabaseViewExtensionName];
//    [self.threadMappings setIsReversed:YES forGroup:grouping];
//
//    self.uiDatabaseConnection = [OWSPrimaryStorage.sharedManager newDatabaseConnection];
//    [self.uiDatabaseConnection beginLongLivedReadTransaction];
//
//    [[NSNotificationCenter defaultCenter] addObserver:self
//                                             selector:@selector(applicationDidBecomeActive:)
//                                                 name:OWSApplicationDidBecomeActiveNotification
//                                               object:nil];
//    [[NSNotificationCenter defaultCenter] addObserver:self
//                                             selector:@selector(applicationWillResignActive:)
//                                                 name:OWSApplicationWillResignActiveNotification
//                                               object:nil];
//
//    [self updateShouldObserveDBModifications];
//}
//
//- (void)applicationDidBecomeActive:(NSNotification *)notification
//{
//    [self updateShouldObserveDBModifications];
//}
//
//- (void)applicationWillResignActive:(NSNotification *)notification
//{
//    [self updateShouldObserveDBModifications];
//}
//
//- (void)updateShouldObserveDBModifications
//{
//    self.shouldObserveDBModifications = CurrentAppContext().isAppForegroundAndActive;
//}
//
//// Don't observe database change notifications when the app is in the background.
////
//// Instead, rebuild model state when app enters foreground.
//- (void)setShouldObserveDBModifications:(BOOL)shouldObserveDBModifications
//{
//    if (_shouldObserveDBModifications == shouldObserveDBModifications) {
//        return;
//    }
//
//    _shouldObserveDBModifications = shouldObserveDBModifications;
//
//    if (shouldObserveDBModifications) {
//        [self.uiDatabaseConnection beginLongLivedReadTransaction];
//        [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
//            [self.threadMappings updateWithTransaction:transaction];
//        }];
//        [self updateThreads];
//        [self.delegate threadListDidChange];
//
//        [[NSNotificationCenter defaultCenter] addObserver:self
//                                                 selector:@selector(yapDatabaseModified:)
//                                                     name:YapDatabaseModifiedNotification
//                                                   object:OWSPrimaryStorage.sharedManager.dbNotificationObject];
//        [[NSNotificationCenter defaultCenter] addObserver:self
//                                                 selector:@selector(yapDatabaseModifiedExternally:)
//                                                     name:YapDatabaseModifiedExternallyNotification
//                                                   object:nil];
//    } else {
//        [[NSNotificationCenter defaultCenter] removeObserver:self
//                                                        name:YapDatabaseModifiedNotification
//                                                      object:OWSPrimaryStorage.sharedManager.dbNotificationObject];
//        [[NSNotificationCenter defaultCenter] removeObserver:self
//                                                        name:YapDatabaseModifiedExternallyNotification
//                                                      object:nil];
//    }
//}
//
//#pragma mark - Database
//
//- (YapDatabaseConnection *)uiDatabaseConnection
//{
//    OWSAssertIsOnMainThread();
//
//    return _uiDatabaseConnection;
//}
//
//- (void)yapDatabaseModifiedExternally:(NSNotification *)notification
//{
//    OWSAssertIsOnMainThread();
//
//    OWSLogVerbose(@"");
//
//    if (self.shouldObserveDBModifications) {
//        // External database modifications can't be converted into incremental updates,
//        // so rebuild everything.  This is expensive and usually isn't necessary, but
//        // there's no alternative.
//        //
//        // We don't need to do this if we're not observing db modifications since we'll
//        // do it when we resume.
//        [self.uiDatabaseConnection beginLongLivedReadTransaction];
//        [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
//            [self.threadMappings updateWithTransaction:transaction];
//        }];
//        
//        [self updateThreads];
//        [self.delegate threadListDidChange];
//    }
//}
//
//- (void)yapDatabaseModified:(NSNotification *)notification
//{
//    OWSAssertIsOnMainThread();
//
//    OWSLogVerbose(@"");
//
//    NSArray *notifications = [self.uiDatabaseConnection beginLongLivedReadTransaction];
//
//    if (!
//        [[self.uiDatabaseConnection ext:TSMessageDatabaseViewExtensionName] hasChangesForNotifications:notifications]) {
//        [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
//            [self.threadMappings updateWithTransaction:transaction];
//        }];
//        return;
//    }
//
//    NSArray *sectionChanges = nil;
//    NSArray *rowChanges = nil;
//    [[self.uiDatabaseConnection ext:TSThreadDatabaseViewExtensionName] getSectionChanges:&sectionChanges
//                                                                              rowChanges:&rowChanges
//                                                                        forNotifications:notifications
//                                                                            withMappings:self.threadMappings];
//
//    if (sectionChanges.count == 0 && rowChanges.count == 0) {
//        // Ignore irrelevant modifications.
//        return;
//    }
//
//    [self updateThreads];
//
//    [self.delegate threadListDidChange];
//}
//
//- (void)updateThreads
//{
//    OWSAssertIsOnMainThread();
//
//    NSMutableArray<TSThread *> *threads = [NSMutableArray new];
//    [self.uiDatabaseConnection readWithBlock:^(YapDatabaseReadTransaction *transaction) {
//        NSUInteger numberOfSections = [self.threadMappings numberOfSections];
//        OWSAssertDebug(numberOfSections == 1);
//        for (NSUInteger section = 0; section < numberOfSections; section++) {
//            NSUInteger numberOfItems = [self.threadMappings numberOfItemsInSection:section];
//            for (NSUInteger item = 0; item < numberOfItems; item++) {
//                TSThread *thread = [[transaction extension:TSThreadDatabaseViewExtensionName]
//                    objectAtIndexPath:[NSIndexPath indexPathForItem:(NSInteger)item inSection:(NSInteger)section]
//                         withMappings:self.threadMappings];
//                if (!thread.shouldBeVisible) { continue; }
//                if ([thread isKindOfClass:TSContactThread.class]) {
//                    NSString *publicKey = ((TSContactThread *)thread).contactSessionID;
//                    if ([[LKStorage.shared getContactWithSessionID:publicKey] name] == nil) { continue; }
//                    [threads addObject:thread];
//                } else {
//                    [threads addObject:thread];
//                }
//            }
//        }
//    }];
//
//    _threads = [threads copy];
//}
//
//@end
//
//NS_ASSUME_NONNULL_END