//
//  MTGridSelectView.m
//  MTGridSelectDemo
//
//  Created by mambaxie on 2019/1/19.
//  Copyright © 2019年 tencent. All rights reserved.
//

#import "MTGridSelectView.h"
#import "MTGridSelectConfig.h"

#define kItemContentViewCellReuseIdentifier @"kItemContentViewCellReuseIdentifier"

@interface MTGridSelectModel : NSObject

@property (nonatomic, strong) id model;

@property (nonatomic, assign) MTGridItemState state;

@property (nonatomic, strong) UIView *itemView;

@end

@implementation MTGridSelectModel

@end

@interface MTGridSelectView () <UICollectionViewDelegate, UICollectionViewDataSource>

@property (nonatomic, strong) MTGridSelectConfig *config;

@property (nonatomic, copy) void (^setupConfigBlock)(MTGridSelectConfig * _Nonnull);
@property (nonatomic, copy) MTGridDidSetupItemContentViewBlock didSetupItemContentViewBlock;
@property (nonatomic, copy) MTGridItemStateChangedBlock itemStateChangedBlock;
@property (nonatomic, copy) void (^selectValueChangedBlock)(NSArray *selectedModels);

@property (nonatomic, copy) NSArray<MTGridSelectModel *> *itemModels;

@property (nonatomic, strong) MTGridSelectModel *previousSelectItemModel;
@property (nonatomic, strong) NSMutableIndexSet *seletedIndexSet;

@end

@implementation MTGridSelectView

- (instancetype)init
{
    if (self = [super init]) {
        [self setupConfig];
    }
    return self;
}

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        [self setupConfig];
    }
    return self;
}

- (void)setupConfig
{
    MTGridSelectConfig *config = [[MTGridSelectConfig alloc] init];
    config.contentWidth = [UIScreen mainScreen].bounds.size.width;
    config.contentInset = UIEdgeInsetsMake(15, 15, 15, 15);
    config.rowSpacing = 10.0;
    config.columnSpacing = 10.0;
    config.maxColumn = 3;
    config.itemRatio = 0.3;
    config.itemHeight = 0.0;
    config.itemSize = CGSizeZero;
    config.multiple = NO;
    config.maxSelecteCount = 3;
    
    self.config = config;
}

+ (instancetype)gridSelectViewWithItemModels:(NSArray *)itemModels
                                 setupConfig:(void(^)(MTGridSelectConfig *config))setupConfigBlock
                     didSetupItemContentView:(MTGridDidSetupItemContentViewBlock)didSetupItemContentViewBlock
                            itemStateChanged:(MTGridItemStateChangedBlock)itemStateChangedBlock
                          selectValueChanged:(void(^)(NSArray *selectedModels))selectValueChangedBlock
{
    MTGridSelectView *grideSeletView = [[self alloc] init];
    
    grideSeletView.seletedIndexSet = [[NSMutableIndexSet alloc] init];
    grideSeletView.originalModels = itemModels;
    NSMutableArray *itemModelsM = [NSMutableArray array];
    for (id model in itemModels) {
        MTGridSelectModel *itemModel = [[MTGridSelectModel alloc] init];
        itemModel.state = MTGridItemStateNormal;
        itemModel.model = model;
        [itemModelsM addObject:itemModel];
    }
    grideSeletView.itemModels = [itemModelsM copy];
    grideSeletView.setupConfigBlock = setupConfigBlock;
    grideSeletView.didSetupItemContentViewBlock = didSetupItemContentViewBlock;
    grideSeletView.itemStateChangedBlock = itemStateChangedBlock;
    grideSeletView.selectValueChangedBlock = selectValueChangedBlock;
    grideSeletView.clipsToBounds = NO;
    [grideSeletView createAndLayoutItemContentViews];
    
    return grideSeletView;
}

- (void)setFrame:(CGRect)frame
{
    [super setFrame:frame];
    
    _collectionView.frame = self.bounds;
}

- (NSArray<id> *)selectedItems
{
    return [self.originalModels objectsAtIndexes:self.seletedIndexSet];
}

- (NSInteger)itemTotalCount
{
    return self.originalModels.count;
}

- (void)reloadDataWithItemModels:(NSArray *)itemModels
{
    NSMutableArray *itemModelsM = [NSMutableArray array];
    for (id model in itemModels) {
        MTGridSelectModel *itemModel = [[MTGridSelectModel alloc] init];
        itemModel.state = MTGridItemStateNormal;
        itemModel.model = model;
        [itemModelsM addObject:itemModel];
    }
    self.originalModels = itemModels;
    self.itemModels = [itemModelsM copy];
    [self.collectionView reloadData];
}

/// collectionViewCell 点击改变状态
- (void)changeItemViewStateAtIndex:(NSInteger)index
{
    MTGridSelectModel *itemModel = self.itemModels[index];
    MTGridItemState newState = MTGridItemStateNormal;
    if (self.config.multiple) { // 多选
        if (itemModel.state == MTGridItemStateNormal) {
            // 超过上限
            if (self.selectedItems.count >= self.config.maxSelecteCount) {
                if (self.limitBlock) {
                    self.limitBlock();
                }
                return;
            }
            
            newState = MTGridItemStateSelected;
        } else if (itemModel.state == MTGridItemStateSelected) {
            newState = MTGridItemStateNormal;
        }
    } else { // 单选
        self.previousSelectItemModel.state = MTGridItemStateNormal;
        NSInteger previousIndex = [self.itemModels indexOfObject:self.previousSelectItemModel];
        [self.seletedIndexSet removeIndex:previousIndex];
        if (self.previousSelectItemModel) {
            self.itemStateChangedBlock(self.previousSelectItemModel.itemView, self.previousSelectItemModel.model, self.previousSelectItemModel.state, YES);
        }
        newState = MTGridItemStateSelected;
        self.previousSelectItemModel = itemModel;
    }
    
    [self changeItemStateAtIndexs:@[@(index)] state:newState changeByInner:YES];
}

/// 选中指定下标
- (void)selectItemAtIndex:(NSInteger)index
{
    [self selectItemAtIndexs:@[@(index)]];
}

/// 选中多个指定下标
- (void)selectItemAtIndexs:(NSArray <NSNumber *>*)indexs
{
    [self changeItemStateAtIndexs:indexs state:MTGridItemStateSelected changeByInner:NO];
}

/// 全选
- (void)selectAllItem
{
    [self changeAllItemViewState:MTGridItemStateSelected];
}

/// 全不选
- (void)deselectAllItem
{
    [self changeAllItemViewState:MTGridItemStateNormal];
}

/// 改变指定下标状态
- (void)changeItemStateAtIndex:(NSInteger)index state:(MTGridItemState)state
{
    [self changeItemStateAtIndexs:@[@(index)] state:state changeByInner:NO];
}

/// 改变多个下标状态
- (void)changeItemStateAtIndexs:(NSArray <NSNumber *>*)indexs state:(MTGridItemState)state changeByInner:(BOOL)changeByInner
{
    BOOL isChanged = NO;
    for (NSNumber *indexNumber in indexs) {
        MTGridSelectModel *itemModel = self.itemModels[[indexNumber integerValue]];
        if (itemModel.state != state) {
            itemModel.state = state;
            if (MTGridItemStateSelected == state) {
                [self.seletedIndexSet addIndex:indexNumber.integerValue];
            } else {
                [self.seletedIndexSet removeIndex:indexNumber.integerValue];
            }
            if (self.itemStateChangedBlock) {
                self.itemStateChangedBlock(itemModel.itemView, itemModel.model, itemModel.state, changeByInner);
            }
            isChanged = YES;
        }
        if (!self.config.multiple) { // 单选
            self.previousSelectItemModel = itemModel;
        }
    }
    if (self.selectValueChangedBlock && isChanged) {
        self.selectValueChangedBlock([self.originalModels objectsAtIndexes:self.seletedIndexSet]);
    }
}

- (void)changeAllItemViewState:(MTGridItemState)state
{
    NSMutableArray * array = [NSMutableArray array];
    [self.itemModels enumerateObjectsUsingBlock:^(MTGridSelectModel * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        [array addObject:@(idx)];
    }];
    [self changeItemStateAtIndexs:array state:state changeByInner:NO];
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    
    CGRect frame = self.frame;
    frame.size = self.collectionView.frame.size;
    self.frame = frame;
}

- (void)createAndLayoutItemContentViews
{
    MTGridSelectConfig *config = self.config;
    if (self.setupConfigBlock) {
        self.setupConfigBlock(config);
    }
    
    UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
    flowLayout.minimumLineSpacing = config.rowSpacing;
    flowLayout.minimumInteritemSpacing = config.columnSpacing;
    
    CGSize itemSize = config.itemSize;
    
    if (CGSizeEqualToSize(itemSize, CGSizeZero)) {
        itemSize.width = (config.contentWidth - config.contentInset.left - config.contentInset.right - config.columnSpacing * (config.maxColumn - 1)) / config.maxColumn;
        itemSize.height = config.itemHeight > 0 ? config.itemHeight : itemSize.width * config.itemRatio;
    }
    flowLayout.itemSize = itemSize;
    
    CGFloat contentHeight = config.contentInset.top + config.contentInset.bottom + (itemSize.height + config.rowSpacing) * (self.itemModels.count / config.maxColumn + 1) - config.rowSpacing;
    CGFloat contentWidth = config.contentInset.left + config.contentInset.right + (itemSize.width + config.columnSpacing) * config.maxColumn - config.columnSpacing;
    
    self.collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, config.contentWidth, contentHeight) collectionViewLayout:flowLayout];
    [self layoutSubviews];
    self.collectionView.showsVerticalScrollIndicator = YES;
    self.collectionView.showsHorizontalScrollIndicator = YES;
    self.collectionView.contentSize = CGSizeMake(contentWidth, contentHeight);
    self.collectionView.backgroundColor = [UIColor clearColor];
    self.collectionView.contentInset = config.contentInset;
    self.collectionView.dataSource = self;
    self.collectionView.delegate = self;
    [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:kItemContentViewCellReuseIdentifier];
    [self addSubview:self.collectionView];
    
    [self.collectionView reloadData];
    
    dispatch_async(dispatch_get_main_queue(), ^{
        // 默认选中
        [self selectItemAtIndexs:self.config.defaultSelectIndexs];
    });
}

#pragma mark - UICollectionViewDelegate
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
    [collectionView deselectItemAtIndexPath:indexPath animated:NO];
    
    [self changeItemViewStateAtIndex:indexPath.item];
}

#pragma mark - UICollectionViewDataSource
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return self.itemModels.count;
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    UICollectionViewCell *itemContentViewCell = [collectionView dequeueReusableCellWithReuseIdentifier:kItemContentViewCellReuseIdentifier forIndexPath:indexPath];
    
    MTGridSelectModel *itemModel = self.itemModels[indexPath.item];
    if (self.didSetupItemContentViewBlock) {
        [itemContentViewCell.contentView removeSubviews];
        UIView *itemView = self.didSetupItemContentViewBlock(itemContentViewCell.contentView, itemModel.model);
        itemModel.itemView = itemView;
        // 默认禁掉交互
        itemView.userInteractionEnabled = NO;
        [itemContentViewCell.contentView addSubview:itemView];
    }
    
    return itemContentViewCell;
}


@end