#import "TGMediaPickerGallerySelectedItemsModel.h"

@interface TGMediaPickerGallerySelectedItemsModel ()
{
    TGMediaSelectionContext *_selectionContext;
    SMetaDisposable *_selectionChangedDisposable;
    
    NSMutableArray *_items;
    bool _keepItems;
}
@end

@implementation TGMediaPickerGallerySelectedItemsModel

- (instancetype)initWithSelectionContext:(TGMediaSelectionContext *)selectionContext
{
    return [self initWithSelectionContext:selectionContext items:nil];
}

- (instancetype)initWithSelectionContext:(TGMediaSelectionContext *)selectionContext items:(NSArray *)items
{
    self = [super init];
    if (self != nil)
    {
        if (items == nil)
        {
            _items = [selectionContext.selectedItems mutableCopy];
        }
        else
        {
            _items = [items mutableCopy];
            _keepItems = true;
        }
        _selectionContext = selectionContext;
        
        if (_selectionContext != nil)
        {
            __weak TGMediaPickerGallerySelectedItemsModel *weakSelf = self;
            _selectionChangedDisposable = [[SMetaDisposable alloc] init];
            [_selectionChangedDisposable setDisposable:[[selectionContext selectionChangedSignal] startStrictWithNext:^(TGMediaSelectionChange *next)
            {
                __strong TGMediaPickerGallerySelectedItemsModel *strongSelf = weakSelf;
                if (strongSelf == nil)
                    return;
                
                if (strongSelf.selectionUpdated != nil)
                    strongSelf.selectionUpdated(false, false, false, strongSelf.selectedCount);
                
                if (next.sender == strongSelf)
                    return;
                
                if (next.selected)
                    [strongSelf addSelectedItem:next.item];
                else if (!strongSelf->_keepItems)
                    [strongSelf removeSelectedItem:next.item];
            } file:__FILE_NAME__ line:__LINE__]];
        }
    }
    return self;
}

- (void)dealloc
{
    [_selectionChangedDisposable dispose];
}

- (void)addSelectedItem:(id<TGMediaSelectableItem>)selectedItem
{
    for (id<TGMediaSelectableItem> item in _items)
    {
        if ([item.uniqueIdentifier isEqualToString:selectedItem.uniqueIdentifier])
        {
            if (self.selectionUpdated != nil)
                self.selectionUpdated(false, false, false, 0);
            
            return;
        }
    }
    
    [_items addObject:selectedItem];
    
    if (self.selectionUpdated != nil)
        self.selectionUpdated(true, true, true, _items.count - 1);
}

- (void)removeSelectedItem:(id<TGMediaSelectableItem>)selectedItem
{
    NSInteger index = [_items indexOfObject:selectedItem];
    if (index != NSNotFound)
    {
        [_items removeObject:selectedItem];
        
        if (self.selectionUpdated != nil)
            self.selectionUpdated(true, true, false, index);
    }
}

- (void)clear
{
    [_items enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(id<TGMediaSelectableItem> item, NSUInteger index, __unused BOOL *stop)
    {
        if (self.selectionUpdated != nil)
            self.selectionUpdated(true, false, false, index);
    }];
    
    [_items removeAllObjects];
}

- (NSInteger)selectedCount
{
    NSInteger count = 0;
    for (id<TGMediaSelectableItem> item in _items)
    {
        if ([_selectionContext isItemSelected:item])
            count++;
    }
    return count;
}

- (NSInteger)totalCount
{
    return _items.count;
}

- (NSArray *)items
{
    return _items;
}

- (NSArray *)selectedItems
{
    NSMutableArray *items = [[NSMutableArray alloc] init];
    for (id<TGMediaSelectableItem> item in _items)
    {
        if ([_selectionContext isItemSelected:item])
            [items addObject:item];
    }
    return items;
}

@end