//
//  KBEmojiPanelView.m
//  CustomKeyboard
//

#import "KBEmojiPanelView.h"
#import "KBEmojiDataProvider.h"
#import "KBSkinManager.h"
#import "KBLocalizationManager.h"
#import "Masonry.h"
#import "KBEmojiCollectionCell.h"
#import "KBEmojiBottomBarView.h"


@interface KBEmojiPanelView () <UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>

@property (nonatomic, strong) UILabel *titleLabel;
@property (nonatomic, strong) UIButton *backButton;
@property (nonatomic, strong) UICollectionView *collectionView;
@property (nonatomic, strong) KBEmojiBottomBarView *bottomBar;
//@property (nonatomic, strong) UIButton *searchButton;
@property (nonatomic, strong) NSArray<UIButton *> *tabButtons;
@property (nonatomic, strong) KBEmojiDataProvider *dataProvider;
@property (nonatomic, copy) NSArray<KBEmojiCategory *> *categories;
@property (nonatomic, assign) NSInteger currentIndex;
@property (nonatomic, strong) UIView *magnifierView;
@property (nonatomic, strong) UILabel *magnifierLabel;
@property (nonatomic, strong) UIColor *tabNormalColor;
@property (nonatomic, strong) UIColor *tabSelectedColor;

@end

@implementation KBEmojiPanelView

- (instancetype)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        _dataProvider = [KBEmojiDataProvider shared];
        _currentIndex = 1;
        [self setupUI];
        [self registerNotifications];
        [self reloadData];
    }
    return self;
}

- (void)dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

#pragma mark - Setup

- (void)setupUI {
    self.backgroundColor = [UIColor colorWithWhite:0.08 alpha:1.0];

    UIView *topBar = [[UIView alloc] init];
    topBar.backgroundColor = [UIColor clearColor];
    [self addSubview:topBar];

    self.backButton = [UIButton buttonWithType:UIButtonTypeCustom];
//    self.backButton.titleLabel.font = [UIFont systemFontOfSize:30 weight:UIFontWeightSemibold];
//    [self.backButton setTitle:@"⌨︎" forState:UIControlStateNormal];
    [self.backButton setImage:[UIImage imageNamed:@"back_keybord_icon"] forState:UIControlStateNormal];
    [self.backButton addTarget:self action:@selector(onBack) forControlEvents:UIControlEventTouchUpInside];
    [topBar addSubview:self.backButton];

    self.titleLabel = [[UILabel alloc] init];
    self.titleLabel.font = [UIFont systemFontOfSize:18 weight:UIFontWeightSemibold];
    self.titleLabel.textColor = [UIColor whiteColor];
    [topBar addSubview:self.titleLabel];

    [topBar mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.equalTo(self);
        make.top.equalTo(self.mas_top).offset(4);
        make.height.mas_equalTo(40);
    }];
    [self.backButton mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(topBar.mas_left).offset(12);
        make.centerY.equalTo(topBar);
        make.width.height.mas_equalTo(32);
    }];
    [self.titleLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self);
        make.centerY.equalTo(topBar);
//        make.right.lessThanOrEqualTo(topBar.mas_right).offset(-12);
    }];

    UICollectionViewFlowLayout *layout = [UICollectionViewFlowLayout new];
    layout.scrollDirection = UICollectionViewScrollDirectionVertical;
    layout.minimumInteritemSpacing = 8;
    layout.minimumLineSpacing = 12;
    self.collectionView = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:layout];
    self.collectionView.backgroundColor = [UIColor clearColor];
    self.collectionView.dataSource = self;
    self.collectionView.delegate = self;
    self.collectionView.alwaysBounceVertical = YES;
    [self.collectionView registerClass:KBEmojiCollectionCell.class forCellWithReuseIdentifier:@"KBEmojiCollectionCell"];
    [self addSubview:self.collectionView];

    self.bottomBar = [[KBEmojiBottomBarView alloc] init];
    [self addSubview:self.bottomBar];
    [self.bottomBar.deleteButton addTarget:self action:@selector(onDelete) forControlEvents:UIControlEventTouchUpInside];

//    self.searchButton = [UIButton buttonWithType:UIButtonTypeSystem];
//    self.searchButton.layer.cornerRadius = 20;
//    self.searchButton.titleLabel.font = [UIFont systemFontOfSize:16 weight:UIFontWeightBold];
//    [self.searchButton setTitle:KBLocalized(@"Search") forState:UIControlStateNormal];
//    [self.searchButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
//    [self.searchButton addTarget:self action:@selector(onSearch) forControlEvents:UIControlEventTouchUpInside];
//    [self.bottomBar addSubview:self.searchButton];

    [self.collectionView mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.equalTo(self.mas_left).offset(12);
        make.right.equalTo(self.mas_right).offset(-12);
        make.top.equalTo(topBar.mas_bottom).offset(0);
        make.bottom.equalTo(self.bottomBar.mas_top).offset(0);
    }];

    [self.bottomBar mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.right.bottom.equalTo(self);
        make.height.mas_equalTo(40);
    }];

    UISwipeGestureRecognizer *leftSwipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(onSwipe:)];
    leftSwipe.direction = UISwipeGestureRecognizerDirectionLeft;
    [self addGestureRecognizer:leftSwipe];
    UISwipeGestureRecognizer *rightSwipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(onSwipe:)];
    rightSwipe.direction = UISwipeGestureRecognizerDirectionRight;
    [self addGestureRecognizer:rightSwipe];

    [self applyTheme:[KBSkinManager shared].current];
}

- (void)layoutSubviews {
    [super layoutSubviews];
    [self updateTabButtonCornerRadii];
}

- (void)updateTabButtonCornerRadii {
    for (UIButton *btn in self.tabButtons) {
        CGFloat radius = MIN(CGRectGetHeight(btn.bounds), CGRectGetWidth(btn.bounds)) / 2.0;
        if (radius <= 0) { continue; }
        btn.layer.cornerRadius = radius;
        if (@available(iOS 13.0, *)) {
            btn.layer.cornerCurve = kCACornerCurveContinuous;
        }
    }
    UIButton *deleteButton = self.bottomBar.deleteButton;
    if (deleteButton) {
        CGFloat radius = MIN(CGRectGetHeight(deleteButton.bounds), CGRectGetWidth(deleteButton.bounds)) / 2.0;
        if (radius > 0) {
            deleteButton.layer.cornerRadius = radius;
            if (@available(iOS 13.0, *)) {
                deleteButton.layer.cornerCurve = kCACornerCurveContinuous;
            }
        }
    }
}

- (void)registerNotifications {
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(onEmojiDataChanged)
                                                 name:KBEmojiRecentsDidChangeNotification
                                               object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(onLocalizationChanged)
                                                 name:KBLocalizationDidChangeNotification
                                               object:nil];
}

#pragma mark - Data

- (void)reloadData {
    self.categories = self.dataProvider.categories;
    if (self.categories.count == 0) {
        self.currentIndex = NSNotFound;
        [self.collectionView reloadData];
        self.titleLabel.text = @"";
        return;
    }
    NSInteger preserved = self.currentIndex;
    if (preserved < 0 || preserved >= self.categories.count) {
        preserved = 0;
    }
    [self rebuildTabButtons];
    [self updateSelectionToIndex:preserved];
}

- (void)rebuildTabButtons {
    UIStackView *stackView = self.bottomBar.tabStackView;
    if (!stackView) { return; }
    for (UIView *v in stackView.arrangedSubviews) {
        [stackView removeArrangedSubview:v];
        [v removeFromSuperview];
    }
    NSMutableArray<UIButton *> *buttons = [NSMutableArray arrayWithCapacity:self.categories.count];
    [self.categories enumerateObjectsUsingBlock:^(KBEmojiCategory * _Nonnull cat, NSUInteger idx, BOOL * _Nonnull stop) {
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        btn.tag = idx;
        btn.layer.cornerRadius = 16;
        btn.layer.masksToBounds = YES;
        btn.titleLabel.font = [UIFont systemFontOfSize:18];
        [btn setTitle:cat.iconSymbol ?: @"●" forState:UIControlStateNormal];
        [btn setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
        [btn addTarget:self action:@selector(onTabTapped:) forControlEvents:UIControlEventTouchUpInside];
        btn.contentEdgeInsets = UIEdgeInsetsMake(0, 12, 0, 12);
        btn.translatesAutoresizingMaskIntoConstraints = NO;
//        [btn.heightAnchor constraintEqualTo:self.bottomBar.tabScrollView.heightAnchor].active = YES;
        [stackView addArrangedSubview:btn];
        [buttons addObject:btn];
    }];
    self.tabButtons = buttons.copy;
    [self setNeedsLayout];
}

- (void)updateSelectionToIndex:(NSInteger)index {
    if (self.categories.count == 0) {
        self.currentIndex = NSNotFound;
        [self.collectionView reloadData];
        self.titleLabel.text = @"";
        return;
    }
    if (index < 0) { index = 0; }
    if (index >= self.categories.count) { index = self.categories.count - 1; }
    self.currentIndex = index;
    KBEmojiCategory *cat = self.categories[index];
    self.titleLabel.text = cat.displayTitle;
    [self.collectionView reloadData];
    [self updateTabHighlightStates];
    [self scrollTabToVisible:index];
}

- (void)selectCategoryAtIndex:(NSInteger)index {
    [self updateSelectionToIndex:index];
}

- (void)updateTabHighlightStates {
    [self.tabButtons enumerateObjectsUsingBlock:^(UIButton * _Nonnull btn, NSUInteger idx, BOOL * _Nonnull stop) {
        BOOL selected = (idx == self.currentIndex);
        btn.backgroundColor = selected ? self.tabSelectedColor : self.tabNormalColor;
        btn.alpha = selected ? 1.0 : 0.6;
    }];
}

- (void)scrollTabToVisible:(NSInteger)index {
    if (index < 0 || index >= self.tabButtons.count) return;
    UIScrollView *scrollView = self.bottomBar.tabScrollView;
    UIStackView *stackView = self.bottomBar.tabStackView;
    if (!scrollView || !stackView) { return; }
    UIButton *btn = self.tabButtons[index];
    CGRect rect = [scrollView convertRect:btn.frame fromView:stackView];
    rect = CGRectInset(rect, -12, 0);
    [scrollView scrollRectToVisible:rect animated:YES];
}

#pragma mark - Actions

- (void)onBack {
    if ([self.delegate respondsToSelector:@selector(emojiPanelViewDidRequestClose:)]) {
        [self.delegate emojiPanelViewDidRequestClose:self];
    }
}

- (void)onSearch {
    if ([self.delegate respondsToSelector:@selector(emojiPanelViewDidTapSearch:)]) {
        [self.delegate emojiPanelViewDidTapSearch:self];
    }
}

- (void)onDelete {
    if ([self.delegate respondsToSelector:@selector(emojiPanelViewDidTapDelete:)]) {
        [self.delegate emojiPanelViewDidTapDelete:self];
    }
}

- (void)onTabTapped:(UIButton *)sender {
    [self updateSelectionToIndex:sender.tag];
}

- (void)onSwipe:(UISwipeGestureRecognizer *)gesture {
    if (self.categories.count == 0) return;
    if (gesture.direction == UISwipeGestureRecognizerDirectionLeft) {
        if (self.currentIndex + 1 < self.categories.count) {
            [self updateSelectionToIndex:self.currentIndex + 1];
        }
    } else if (gesture.direction == UISwipeGestureRecognizerDirectionRight) {
        if (self.currentIndex - 1 >= 0) {
            [self updateSelectionToIndex:self.currentIndex - 1];
        }
    }
}

- (void)onEmojiDataChanged {
    [self reloadData];
}

- (void)onLocalizationChanged {
//    [self.searchButton setTitle:KBLocalized(@"Search") forState:UIControlStateNormal];
    [self reloadData];
}

#pragma mark - Theme

- (void)applyTheme:(KBSkinTheme *)theme {
    UIColor *bg = theme.keyboardBackground ?: [UIColor colorWithWhite:0.08 alpha:1.0];
    self.backgroundColor = bg;
    self.collectionView.backgroundColor = [UIColor clearColor];
    self.titleLabel.textColor = theme.keyTextColor ?: [UIColor whiteColor];
    UIColor *searchColor = theme.accentColor ?: [UIColor colorWithRed:0.35 green:0.35 blue:0.95 alpha:1];
//    self.searchButton.backgroundColor = searchColor;
    self.tabNormalColor = [UIColor colorWithWhite:1 alpha:0.08];
    self.tabSelectedColor = theme.accentColor ?: [UIColor colorWithWhite:1 alpha:0.25];
    [self updateTabHighlightStates];
    if (self.bottomBar.deleteButton) {
        self.bottomBar.deleteButton.backgroundColor = self.tabNormalColor;
        UIColor *deleteTitleColor = theme.keyTextColor ?: [UIColor whiteColor];
        [self.bottomBar.deleteButton setTitleColor:deleteTitleColor forState:UIControlStateNormal];
    }
    if (self.magnifierView) {
        self.magnifierView.backgroundColor = theme.keyBackground ?: [UIColor colorWithWhite:1 alpha:0.9];
    }
    if (self.magnifierLabel) {
        self.magnifierLabel.textColor = theme.keyTextColor ?: [UIColor blackColor];
    }
}

#pragma mark - Magnifier

- (void)showMagnifierForEmoji:(NSString *)emoji fromRect:(CGRect)rect {
    if (!self.magnifierView) {
        self.magnifierView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 68, 68)];
        self.magnifierView.layer.cornerRadius = 12;
        self.magnifierView.layer.masksToBounds = YES;
        self.magnifierView.layer.shadowColor = [UIColor colorWithWhite:0 alpha:0.3].CGColor;
        self.magnifierView.layer.shadowOpacity = 0.6;
        self.magnifierView.layer.shadowOffset = CGSizeMake(0, 2);
        self.magnifierView.layer.shadowRadius = 3;
        self.magnifierLabel = [[UILabel alloc] initWithFrame:self.magnifierView.bounds];
        self.magnifierLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
        self.magnifierLabel.textAlignment = NSTextAlignmentCenter;
        self.magnifierLabel.font = [UIFont systemFontOfSize:40];
        [self.magnifierView addSubview:self.magnifierLabel];
        self.magnifierView.alpha = 0;
        [self addSubview:self.magnifierView];
    }
    self.magnifierLabel.text = emoji;
    CGRect converted = [self convertRect:rect fromView:self.collectionView];
    CGFloat targetX = CGRectGetMidX(converted);
    CGFloat targetY = CGRectGetMinY(converted) - CGRectGetHeight(self.magnifierView.bounds)/2 - 8;
    targetX = MAX(CGRectGetWidth(self.magnifierView.bounds)/2 + 8, targetX);
    targetX = MIN(CGRectGetWidth(self.bounds) - CGRectGetWidth(self.magnifierView.bounds)/2 - 8, targetX);
    if (targetY < CGRectGetHeight(self.magnifierView.bounds)/2 + 10) {
        targetY = CGRectGetHeight(self.magnifierView.bounds)/2 + 10;
    }
    self.magnifierView.center = CGPointMake(targetX, targetY);
    self.magnifierView.hidden = NO;
    [UIView animateWithDuration:0.08 animations:^{
        self.magnifierView.alpha = 1.0;
    }];
}

- (void)hideMagnifier {
    if (!self.magnifierView) return;
    [UIView animateWithDuration:0.08 animations:^{
        self.magnifierView.alpha = 0.0;
    } completion:^(BOOL finished) {
        self.magnifierView.hidden = YES;
    }];
}

#pragma mark - UICollectionViewDataSource

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
    if (self.currentIndex == NSNotFound || self.currentIndex >= self.categories.count) {
        return 0;
    }
    KBEmojiCategory *cat = self.categories[self.currentIndex];
    return cat.items.count;
}

- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    KBEmojiCollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"KBEmojiCollectionCell" forIndexPath:indexPath];
    KBEmojiCategory *cat = self.categories[self.currentIndex];
    if (indexPath.item < cat.items.count) {
        KBEmojiItem *item = cat.items[indexPath.item];
        [cell configureWithEmoji:item.value];
    } else {
        [cell configureWithEmoji:@""];
    }
    return cell;
}

#pragma mark - UICollectionViewDelegate

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    if (self.currentIndex == NSNotFound || self.currentIndex >= self.categories.count) return;
    KBEmojiCategory *cat = self.categories[self.currentIndex];
    if (indexPath.item >= cat.items.count) return;
    KBEmojiItem *item = cat.items[indexPath.item];
    if (item.value.length == 0) return;
    [self.dataProvider recordEmojiSelection:item.value];
    if ([self.delegate respondsToSelector:@selector(emojiPanelView:didSelectEmoji:)]) {
        [self.delegate emojiPanelView:self didSelectEmoji:item.value];
    }
}

- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath {
    KBEmojiCategory *cat = (self.currentIndex < self.categories.count) ? self.categories[self.currentIndex] : nil;
    if (indexPath.item >= cat.items.count) return;
    KBEmojiItem *item = cat.items[indexPath.item];
    UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
    if (!cell) return;
    [self showMagnifierForEmoji:item.value fromRect:cell.frame];
}

- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath {
    [self hideMagnifier];
}

#pragma mark - UICollectionViewDelegateFlowLayout

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    CGFloat availableWidth = collectionView.bounds.size.width;
    NSInteger columns = 8;
    CGFloat spacing = 8;
    CGFloat totalSpacing = spacing * (columns - 1);
    CGFloat width = floor((availableWidth - totalSpacing) / columns);
    if (width < 32) { width = 32; }
    return CGSizeMake(width, width);
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
    return 12;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
    return 8;
}

@end