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Tweaks/FLEX/ExplorerInterface/Tabs/FLEXTabList.m

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+//
+//  FLEXTabList.m
+//  FLEX
+//
+//  Created by Tanner on 2/1/20.
+//  Copyright © 2020 FLEX Team. All rights reserved.
+//
+
+#import "FLEXTabList.h"
+#import "FLEXUtility.h"
+
+@interface FLEXTabList () {
+    NSMutableArray *_openTabs;
+    NSMutableArray *_openTabSnapshots;
+}
+@end
+#pragma mark -
+@implementation FLEXTabList
+
+#pragma mark Initialization
+
++ (FLEXTabList *)sharedList {
+    static FLEXTabList *sharedList = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        sharedList = [self new];
+    });
+    
+    return sharedList;
+}
+
+- (id)init {
+    self = [super init];
+    if (self) {
+        _openTabs = [NSMutableArray new];
+        _openTabSnapshots = [NSMutableArray new];
+        _activeTabIndex = NSNotFound;
+    }
+    
+    return self;
+}
+
+
+#pragma mark Private
+
+- (void)chooseNewActiveTab {
+    if (self.openTabs.count) {
+        self.activeTabIndex = self.openTabs.count - 1;
+    } else {
+        self.activeTabIndex = NSNotFound;
+    }
+}
+
+
+#pragma mark Public
+
+- (void)setActiveTabIndex:(NSInteger)idx {
+    NSParameterAssert(idx < self.openTabs.count || idx == NSNotFound);
+    if (_activeTabIndex == idx) return;
+    
+    _activeTabIndex = idx;
+    _activeTab = (idx == NSNotFound) ? nil : self.openTabs[idx];
+}
+
+- (void)addTab:(UINavigationController *)newTab {
+    NSParameterAssert(newTab);
+    
+    // Update snapshot of the last active tab
+    if (self.activeTab) {
+        [self updateSnapshotForActiveTab];
+    }
+    
+    // Add new tab and snapshot,
+    // update active tab and index
+    [_openTabs addObject:newTab];
+    [_openTabSnapshots addObject:[FLEXUtility previewImageForView:newTab.view]];
+    _activeTab = newTab;
+    _activeTabIndex = self.openTabs.count - 1;
+}
+
+- (void)closeTab:(UINavigationController *)tab {
+    NSParameterAssert(tab);
+    NSInteger idx = [self.openTabs indexOfObject:tab];
+    if (idx != NSNotFound) {
+        [self closeTabAtIndex:idx];
+    }
+}
+
+- (void)closeTabAtIndex:(NSInteger)idx {
+    NSParameterAssert(idx < self.openTabs.count);
+    
+    // Remove old tab and snapshot
+    [_openTabs removeObjectAtIndex:idx];
+    [_openTabSnapshots removeObjectAtIndex:idx];
+    
+    // Update active tab and index if needed
+    if (self.activeTabIndex == idx) {
+        [self chooseNewActiveTab];
+    }
+}
+
+- (void)closeTabsAtIndexes:(NSIndexSet *)indexes {
+    // Remove old tabs and snapshot
+    [_openTabs removeObjectsAtIndexes:indexes];
+    [_openTabSnapshots removeObjectsAtIndexes:indexes];
+    
+    // Update active tab and index if needed
+    if ([indexes containsIndex:self.activeTabIndex]) {
+        [self chooseNewActiveTab];
+    }
+}
+
+- (void)closeActiveTab {
+    [self closeTab:self.activeTab];
+}
+
+- (void)closeAllTabs {
+    // Remove tabs and snapshots
+    [_openTabs removeAllObjects];
+    [_openTabSnapshots removeAllObjects];
+    
+    // Update active tab index
+    self.activeTabIndex = NSNotFound;
+}
+
+- (void)updateSnapshotForActiveTab {
+    if (self.activeTabIndex != NSNotFound) {
+        UIImage *newSnapshot = [FLEXUtility previewImageForView:self.activeTab.view];
+        [_openTabSnapshots replaceObjectAtIndex:self.activeTabIndex withObject:newSnapshot];
+    }
+}
+
+@end