//
//  MTPageView.m
//  MTPage
//
//  Created by ko1o on 2019/5/6.
//  Copyright © 2019年 ko1o. All rights reserved.
//

#import "MTPageView.h"

@interface MTPageParetViewController : UIViewController

@end

@implementation MTPageParetViewController

- (BOOL)shouldAutomaticallyForwardAppearanceMethods
{
    return NO;
}

@end

@interface MTPageItem : NSObject

@property (nonatomic, strong) id itemModel;

@property (nonatomic, strong) UIView *menuItemView;

@property (nonatomic, strong) UIView *menuItemContentView;

@property (nonatomic, strong) UIViewController *viewController;

@end

@implementation MTPageItem

- (void)dealloc
{
    [self.menuItemView removeFromSuperview];
    [self.menuItemContentView removeFromSuperview];
    
    [self.viewController willMoveToParentViewController:nil];
    [self.viewController removeFromParentViewController];
    
    self.viewController = nil;
}

@end

@interface MTPageView () <UIScrollViewDelegate>

@property (nonatomic, strong) MTPageConfig *config;

@property (nonatomic, strong) NSMutableArray <MTPageItem *> *pageItems;

@property (nonatomic, copy) void(^itemDidSelectBlock)(id, NSInteger);

@property (nonatomic, assign) NSInteger currentIndex;

@property (nonatomic, strong) MTPageParetViewController *parentViewController;

@property (nonatomic, strong) UIView *sliderBar;

@property (nonatomic, strong) UIView *bottomLineView;

@property (nonatomic, strong) UIActivityIndicatorView *loadingView;

@property (nonatomic, copy) void (^setupConfigBlock)(MTPageConfig * _Nonnull);

@end

@implementation MTPageView

- (UIViewController *)pageViewController
{
    return _parentViewController;
}

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

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

- (UIScrollView *)menuContentScrollView
{
    if (!_menuContentScrollView) {
        _menuContentScrollView = [[UIScrollView alloc] initWithFrame:CGRectZero];
    }
    return _menuContentScrollView;
}

- (MTPageConfig *)pageConfig
{
    return _config;
}

- (void)startLoading
{
    self.pageContentScrollView.hidden = YES;
    self.menuContentScrollView.hidden = YES;
    self.loadingView.alpha = 1.0;
}

- (BOOL)isLoading
{
    return self.loadingView.alpha >= 0.99;
}

- (void)endLoadingWithItemModels:(NSArray *)itemModels
{
    self.pageContentScrollView.hidden = NO;
    self.menuContentScrollView.hidden = NO;
    self.loadingView.alpha = 0.0;
    if (self.setupConfigBlock) {
        self.setupConfigBlock(self.config);
    }
    [self setupUIWithItemModels:itemModels];
    
    [self relayoutUI];
}

- (void)setupConfig
{
    self.config = [[MTPageConfig alloc] init];
    self.parentViewController = [[MTPageParetViewController alloc] init];
    [self addSubview:self.parentViewController.view];
    
    self.loadingView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
    self.loadingView.alpha = 0.0;
    self.loadingView.centerX = self.width * 0.5;
    self.loadingView.y = 20;
    [self.loadingView startAnimating];
    
    self.menuContentScrollView.frame = CGRectMake(0, 0, self.config.menuContentWidth, 0);
    
    UIView *bottomView = [[UIView alloc] init];
    bottomView.width = SCREEN_WIDTH;
    bottomView.height = 0.7;
    bottomView.backgroundColor = COLOR_WITH_RGB(0xeeeeee);
    [self.menuContentScrollView addSubview:bottomView];
    self.bottomLineView = bottomView;
    self.menuContentScrollView.clipsToBounds = NO;
    
    self.sliderBar = [[UIView alloc] init];
    self.sliderBar.width = 30.0;
    self.sliderBar.height = 2.0;
    self.sliderBar.layer.cornerRadius = 1;
    self.sliderBar.backgroundColor = COLOR_WITH_RGB(0x333333);
    [self.menuContentScrollView addSubview:self.sliderBar];
    [self addSubview:self.loadingView];
}

- (void)setFrame:(CGRect)frame
{
    [super setFrame:frame];
    
    self.parentViewController.view.frame = self.bounds;
    
    self.loadingView.centerX = self.width * 0.5;
    
    _pageContentScrollView.frame = CGRectMake(0, CGRectGetMaxY(_menuContentScrollView.frame), self.frame.size.width, self.frame.size.height - CGRectGetMaxY(_menuContentScrollView.frame));
    _pageContentScrollView.bounces = NO;
    
    for (MTPageItem *item in [self.pageItems mutableCopy]) {
        CGRect pageViewFrame = item.viewController.view.frame;
        pageViewFrame.size = _pageContentScrollView.bounds.size;
        item.viewController.view.frame = pageViewFrame;
    }
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    [self.menuContentScrollView addSubview:self.sliderBar];
    self.sliderBar.bottom = self.menuContentScrollView.height - self.menuContentScrollView.contentInset.bottom - 10;
  
    self.sliderBar.hidden = self.pageItems.count == 0;
    
    if (self.config.didLayoutSubviewsBlock) {
        self.config.didLayoutSubviewsBlock(self, self.pageContentScrollView, self.menuContentScrollView, self.sliderBar);
    }
    if (self.pageItems.count > self.currentIndex) {
        
        MTPageItem *pageItem = self.pageItems[self.currentIndex];
        self.sliderBar.centerX = pageItem.menuItemView.superview.centerX;
        self.sliderBar.bottom = self.menuContentScrollView.height - self.menuContentScrollView.contentInset.top - self.menuContentScrollView.contentInset.bottom + 1;
        
        [self.menuContentScrollView.superview insertSubview:self.bottomLineView belowSubview:self.menuContentScrollView];
        self.bottomLineView.y = self.menuContentScrollView.height;
        self.bottomLineView.hidden = !self.config.showBottomLine;
        self.menuContentScrollView.clipsToBounds = YES;
        self.pageContentScrollView.height = self.height - self.pageContentScrollView.y;
    }
    
}

- (void)setupUIWithItemModels:(NSArray *)itemModels
{
    MTPageConfig *config = self.config;
    self.currentIndex = -1;
    
    _pageItems = [NSMutableArray array];
    
    _menuContentScrollView.contentInset = config.menuContentInset;
    _menuContentScrollView.showsHorizontalScrollIndicator = NO;
    
    [self addSubview:_menuContentScrollView];
    
    _pageContentScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, CGRectGetMaxY(_menuContentScrollView.frame), self.frame.size.width, self.frame.size.height - CGRectGetMaxY(_menuContentScrollView.frame))];
    _pageContentScrollView.pagingEnabled = YES;
    _pageContentScrollView.showsHorizontalScrollIndicator = NO;
    _pageContentScrollView.scrollEnabled = self.config.pageScrollEnable;
    _pageContentScrollView.delegate = self;
    
    [self.parentViewController.view addSubview:_pageContentScrollView];
    
    [_menuContentScrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
    [_pageContentScrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
    
    for (id itemModel in itemModels) {
        [self addItemWithModel:itemModel needRelayout:NO];
    }
    
    UIView *lastMenuItemContentView = self.pageItems.lastObject.menuItemContentView;
    UIView *lastPageView = self.pageItems.lastObject.viewController.view;
    _menuContentScrollView.contentSize = CGSizeMake(CGRectGetMaxX(lastMenuItemContentView.frame), 0);
    _pageContentScrollView.contentSize = CGSizeMake(CGRectGetMaxX(lastPageView.frame), 0);
    
    [self selectItemAtIndex:config.defaultPageIndex animated:NO];
}

- (void)viewWillAppear:(BOOL)animated
{
    UIViewController *currentVc = self.pageItems[self.currentIndex].viewController;
    [currentVc viewWillAppear:animated];
}

- (void)relayoutUI
{
    UIView *lastMenuItemContentView = nil;
    UIView *lastPageView = nil;
    for (int i = 0; i < self.pageItems.count; i++) {
        MTPageItem *pageItem = self.pageItems[i];
        CGRect menuItemContentViewFrame = pageItem.menuItemContentView.frame;
        menuItemContentViewFrame.origin = CGPointMake(CGRectGetMaxX(lastMenuItemContentView.frame) + (lastMenuItemContentView ? self.config.menuItemSpacing : 0 ), menuItemContentViewFrame.origin.y);
        pageItem.menuItemContentView.frame = menuItemContentViewFrame;
        pageItem.menuItemContentView.tag = i;
        lastMenuItemContentView = pageItem.menuItemContentView;
        
        UIView *pageSubview = pageItem.viewController.view;
        CGRect pageSubviewFrame = pageSubview.frame;
        pageSubviewFrame.origin = CGPointMake(CGRectGetMaxX(lastPageView.frame), pageSubviewFrame.origin.y);
        pageSubview.frame = pageSubviewFrame;
        
        lastPageView = pageSubview;
    }
    _menuContentScrollView.contentSize = CGSizeMake(CGRectGetMaxX(lastMenuItemContentView.frame), 0);
    _pageContentScrollView.contentSize = CGSizeMake(CGRectGetMaxX(lastPageView.frame), 0);
    
    if (self.currentIndex >= self.pageItems.count && self.pageItems.count > 0) {
        self.currentIndex = self.pageItems.count - 1;
    }
    [self selectItemAtIndex:self.currentIndex];
}

- (void)menuItemDidTap:(UITapGestureRecognizer *)gr
{
    UIView *menuItemContentView = gr.view;
    
    [self selectItemAtIndex:menuItemContentView.tag];
}

+ (instancetype)pageViewWithItemModels:(NSArray *)itemModels
                           setupConfig:(void (^)(MTPageConfig * _Nonnull))setupConfigBlock
                         itemDidSelect:(void (^)(id _Nonnull, NSInteger))itemDidSelectBlock
{
    MTPageView *pageView = [[self alloc] init];
    
    pageView.itemDidSelectBlock = itemDidSelectBlock;
    pageView.setupConfigBlock = setupConfigBlock;
    
    if (setupConfigBlock) {
        setupConfigBlock(pageView.config);
    }
    
    pageView.frame = CGRectMake(0, 0, pageView.config.pageWidth, pageView.config.pageHeight);
    if (itemModels.count > 0) {
        [pageView setupUIWithItemModels:itemModels];
    }
    
    return pageView;
}

- (void)selectItemAtIndex:(NSInteger)index animated:(BOOL)animated
{
    if (index == self.currentIndex || index < 0 || index >= self.pageItems.count) return;
    /// 选择菜单
    [self selectedMenuItemAtIndex:index animated:animated];
    
    /// 滚动到指定pageview
    [self scrollToPageViewAtIndex:index animated:animated];
}

/// 选中指定下标
- (void)selectItemAtIndex:(NSInteger)index
{
    BOOL animated = self.config.switchAnimated;
    
    [self selectItemAtIndex:index animated:animated];
}

- (UIViewController *)currentPageViewController
{
    return self.currentIndex < self.parentViewController.childViewControllers.count ? self.parentViewController.childViewControllers[self.currentIndex] : nil;
}

- (void)selectedMenuItemAtIndex:(NSInteger)index animated:(BOOL)animated
{
    NSTimeInterval animatedDuration = animated * self.config.animatedDuration;
    MTPageItem *lastSelectPageItem = nil;
    if (self.currentIndex >= 0 && self.currentIndex < self.pageItems.count) {
        lastSelectPageItem = self.pageItems[self.currentIndex];
    }
    
    void(^changeMenuItemStateBlock)(void) = ^ {
        MTPageItem *pageItem = self.pageItems[index];
        [UIView animateWithDuration:animatedDuration animations:^{
            if (self.config.itemStateChangedBlock) {
                self.config.itemStateChangedBlock(lastSelectPageItem.menuItemView, lastSelectPageItem.itemModel, MTPageMenuStateNormal);
                self.config.itemStateChangedBlock(pageItem.menuItemView, pageItem.itemModel, MTPageMenuStateSelected);
            }
            self.sliderBar.centerX = pageItem.menuItemView.superview.centerX;
        }];
        
        if (self.itemDidSelectBlock) {
            self.itemDidSelectBlock(pageItem.itemModel, index);
        }
        
        
        CGFloat maxX = CGRectGetMaxX(pageItem.menuItemView.superview.frame) + self.menuContentScrollView.contentInset.right;
        CGFloat minX = CGRectGetMinX(pageItem.menuItemView.superview.frame) - self.menuContentScrollView.contentInset.left;
        if (minX < self.menuContentScrollView.contentOffset.x) {
            [self.menuContentScrollView setContentOffset:CGPointMake(minX, self.menuContentScrollView.contentOffset.y) animated:YES];
            
        }
        if (maxX > self.menuContentScrollView.contentOffset.x + self.menuContentScrollView.frame.size.width) {
            [self.menuContentScrollView setContentOffset:CGPointMake(maxX - self.menuContentScrollView.frame.size.width, self.menuContentScrollView.contentOffset.y) animated:YES];
        }
    };
    
    [UIView animateWithDuration:animatedDuration animations:^{
        changeMenuItemStateBlock();
    }];
    
    self.currentIndex = index;
}

- (void)scrollToPageViewAtIndex:(NSInteger)index animated:(BOOL)animated
{
    [UIView animateWithDuration:self.config.animatedDuration * animated animations:^{
        [self.pageContentScrollView setContentOffset:CGPointMake(self.pageContentScrollView.frame.size.width * index, 0) animated:animated];
    }];
    
    [self handlePageViewDiappearOrAppearWhenSelectIndex:index animated:animated];
}

- (void)handlePageViewDiappearOrAppearWhenSelectIndex:(NSInteger)index animated:(BOOL)animated
{
    UIViewController *willDisappearVc = self.pageItems[self.currentIndex].viewController;
    UIViewController *willAppearVc = self.pageItems[index].viewController;
    
    [willDisappearVc viewWillDisappear:YES];
    [willAppearVc viewWillAppear:YES];
    
    [UIView animateWithDuration:self.config.animatedDuration * animated animations:^{
    } completion:^(BOOL finished) {
        [willDisappearVc viewDidDisappear:YES];
        [willAppearVc viewDidAppear:YES];
    }];
    
}

/// 对换下标
- (void)exchangeItemAtIndex:(NSInteger)index1 withItemAtIndex:(NSInteger)index2
{
    [self.pageItems exchangeObjectAtIndex:index1 withObjectAtIndex:index2];
    
    [self relayoutUI];
}

/// 移除下标
- (void)removeItemAtIndex:(NSInteger)index
{
    [self.pageItems removeObjectAtIndex:index];
    
    [self relayoutUI];
}

- (void)addItemWithModel:(id)itemModel
{
    [self addItemWithModel:itemModel needRelayout:YES];
}

- (void)addItemWithModel:(id)itemModel needRelayout:(BOOL)needRelayout
{
    MTPageConfig *config = self.config;
    
    UIView *lastMenuItemContentView = self.pageItems.lastObject.menuItemContentView;
    UIView *lastPageView = self.pageItems.lastObject.viewController.view;
    
    MTPageItem *pageItem = [[MTPageItem alloc] init];
    pageItem.itemModel = itemModel;
    if (config.setupMenuItemContentViewBlock) {
        UIView *menuItemContentView = [[UIView alloc] initWithFrame:CGRectMake(CGRectGetMaxX(lastMenuItemContentView.frame) + (lastMenuItemContentView ? config.menuItemSpacing : 0), 0, config.menuItemSize.width, config.menuItemSize.height)];
        UIView *menuItemView = config.setupMenuItemContentViewBlock(menuItemContentView, itemModel);
        if (!CGSizeEqualToSize(config.menuItemSize, CGSizeZero)) { // 设置item大小
            CGRect frame = menuItemView.frame;
            frame.size = config.menuItemSize;
            menuItemView.frame = frame;
        } else {
            CGRect frame = menuItemContentView.frame;
            frame.size = menuItemView.frame.size;
            menuItemContentView.frame = frame;
        }
        CGRect menuContentScrollViewFrame = _menuContentScrollView.frame;
        menuContentScrollViewFrame.size = CGSizeMake(config.menuContentWidth, menuItemContentView.height + config.menuContentInset.top + config.menuContentInset.bottom);
        _menuContentScrollView.frame = menuContentScrollViewFrame;
        
        [menuItemContentView addSubview:menuItemView];
        [_menuContentScrollView addSubview:menuItemContentView];
        
        pageItem.menuItemView = menuItemView;
        pageItem.menuItemContentView = menuItemContentView;
        
        menuItemContentView.tag = self.pageItems.count;
        [menuItemContentView addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(menuItemDidTap:)]];
        
        menuItemView.centerY = menuItemContentView.height * 0.5;
        lastMenuItemContentView = menuItemContentView;
    }
    
    if (config.setupPageContentViewBlock) {
        UIViewController *vc = config.setupPageContentViewBlock(_pageContentScrollView, itemModel);
        pageItem.viewController = vc;
        [self.parentViewController addChildViewController:vc];
        UIView *view = vc.view;
        view.frame = CGRectMake(CGRectGetMaxX(lastPageView.frame), 0, _pageContentScrollView.frame.size.width, _pageContentScrollView.frame.size.height);
        [_pageContentScrollView addSubview:view];
        [vc didMoveToParentViewController:self.parentViewController];
        
        lastPageView = view;
    }
    
    if (self.config.itemStateChangedBlock) {
        self.config.itemStateChangedBlock(pageItem.menuItemView, itemModel, MTPageMenuStateNormal);
    }
    [self.pageItems addObject:pageItem];
    
    _menuContentScrollView.contentSize = CGSizeMake(CGRectGetMaxX(lastMenuItemContentView.frame), 0);
    _pageContentScrollView.contentSize = CGSizeMake(CGRectGetMaxX(lastPageView.frame), 0);
    
    if (needRelayout) {
        [self relayoutUI];
    }
}

#pragma mark - UIScrollViewDelegate
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
    NSInteger index = (*targetContentOffset).x / scrollView.frame.size.width;
    
    if (index != self.currentIndex) {
        [self selectedMenuItemAtIndex:index animated:self.config.switchAnimated];
        [self handlePageViewDiappearOrAppearWhenSelectIndex:index animated:self.config.switchAnimated];
    }
}

@end