//
//  KBKeyboardInteractionHandler.m
//  CustomKeyboard
//

#import "KBKeyboardInteractionHandler.h"
#import "KBKeyButton.h"
#import "KBKey.h"
#import "KBKeyPreviewView.h"

static const NSTimeInterval kKBPreviewShowDuration = 0.08;
static const NSTimeInterval kKBPreviewHideDuration = 0.06;

@interface KBKeyboardInteractionHandler ()
@property (nonatomic, strong) KBKeyPreviewView *previewView;
@end

@implementation KBKeyboardInteractionHandler

- (UIView *)resolveHitView:(UIView *)hitView
                     point:(CGPoint)point
                 container:(UIView *)container
                  rowViews:(NSArray<UIView *> *)rowViews {
    if ([hitView isKindOfClass:[KBKeyButton class]]) {
        return hitView;
    }
    if ([self isHitInsideKeyRows:hitView rowViews:rowViews]) {
        KBKeyButton *btn = [self nearestKeyButtonForPoint:point
                                                container:container
                                                 rowViews:rowViews];
        if (btn) { return btn; }
    }
    return hitView;
}

- (NSArray<KBKeyButton *> *)collectKeyButtonsInView:(UIView *)view {
    if (!view) { return @[]; }
    NSMutableArray<KBKeyButton *> *buttons = [NSMutableArray array];
    [self collectKeyButtonsInView:view into:buttons];
    return buttons.copy;
}

- (void)showPreviewForButton:(KBKeyButton *)button inContainer:(UIView *)container {
    if (!button || !container) { return; }
    KBKey *key = button.key;
    if (key.type != KBKeyTypeCharacter) return;

    if (!self.previewView) {
        self.previewView = [[KBKeyPreviewView alloc] initWithFrame:CGRectZero];
        self.previewView.hidden = YES;
        [container addSubview:self.previewView];
    } else if (self.previewView.superview != container) {
        [container addSubview:self.previewView];
    }

    [self.previewView configureWithKey:key icon:button.iconView.image];

    // 计算预览视图位置：在按钮上方稍微偏上
    CGRect btnFrameInSelf = [button convertRect:button.bounds toView:container];
    CGFloat previewWidth = 42;
    CGFloat previewHeight = CGRectGetHeight(btnFrameInSelf) * 1.2;
    CGFloat centerX = CGRectGetMidX(btnFrameInSelf);
    CGFloat centerY = CGRectGetMinY(btnFrameInSelf) - previewHeight * 0.6;

    self.previewView.frame = CGRectMake(0, 0, previewWidth, previewHeight);
    self.previewView.center = CGPointMake(centerX, centerY);
    self.previewView.alpha = 0.0;
    self.previewView.hidden = NO;

    [UIView animateWithDuration:kKBPreviewShowDuration
                          delay:0
                        options:UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveEaseOut
                     animations:^{
                         self.previewView.alpha = 1.0;
                     }
                     completion:nil];
}

- (void)hidePreview {
    if (!self.previewView || self.previewView.isHidden) return;
    [UIView animateWithDuration:kKBPreviewHideDuration
                          delay:0
                        options:UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveEaseIn
                     animations:^{
                         self.previewView.alpha = 0.0;
                     }
                     completion:^(BOOL finished) {
                         self.previewView.hidden = YES;
                     }];
}

- (void)bringPreviewToFrontIfNeededInContainer:(UIView *)container {
    if (!container) { return; }
    if (self.previewView && self.previewView.superview == container) {
        [container bringSubviewToFront:self.previewView];
    }
}

#pragma mark - Private

- (BOOL)isHitInsideKeyRows:(UIView *)hitView rowViews:(NSArray<UIView *> *)rowViews {
    if (!hitView) { return NO; }
    if ([rowViews containsObject:hitView]) { return YES; }
    for (UIView *row in rowViews) {
        if ([hitView isDescendantOfView:row]) { return YES; }
    }
    return NO;
}

- (KBKeyButton *)nearestKeyButtonForPoint:(CGPoint)point
                                container:(UIView *)container
                                 rowViews:(NSArray<UIView *> *)rowViews {
    if (!container) { return nil; }
    KBKeyButton *best = nil;
    CGFloat bestDistance = CGFLOAT_MAX;

    UIView *targetRow = nil;
    for (UIView *row in rowViews) {
        CGRect rowFrame = [container convertRect:row.bounds fromView:row];
        if (CGRectContainsPoint(rowFrame, point)) {
            targetRow = row;
            break;
        }
    }

    NSArray<UIView *> *candidateRows = targetRow ? @[targetRow] : rowViews;
    for (UIView *row in candidateRows) {
        NSArray<KBKeyButton *> *buttons = [self collectKeyButtonsInView:row];
        for (KBKeyButton *btn in buttons) {
            CGRect frame = [container convertRect:btn.frame fromView:btn.superview];
            CGFloat dx = point.x - CGRectGetMidX(frame);
            CGFloat dy = point.y - CGRectGetMidY(frame);
            CGFloat dist = (dx * dx) + (dy * dy);
            if (dist < bestDistance) {
                bestDistance = dist;
                best = btn;
            }
        }
    }
    return best;
}

- (void)collectKeyButtonsInView:(UIView *)view
                           into:(NSMutableArray<KBKeyButton *> *)buttons {
    for (UIView *sub in view.subviews) {
        if ([sub isKindOfClass:[KBKeyButton class]]) {
            [buttons addObject:(KBKeyButton *)sub];
            continue;
        }
        if (sub.subviews.count > 0) {
            [self collectKeyButtonsInView:sub into:buttons];
        }
    }
}

@end