//
//  MentionTextView.m
//  AIIM
//
//  Created by qitewei on 2025/5/30.
//

#import "MentionTextView.h"

@implementation MentionTextView{
    NSMutableArray<NSValue *> *_mentionRanges;
}

- (NSArray<NSValue *> *)mentionRanges {
    return [_mentionRanges copy];
}

- (void)setMentionRanges:(NSArray<NSValue *> *)mentionRanges {
    _mentionRanges = [mentionRanges mutableCopy];
}

- (void)setup {
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(textDidChange:)
                                                 name:UITextViewTextDidChangeNotification
                                               object:self];
    [self detectMentions];
}

- (void)textDidChange:(NSNotification *)notification {
    [self detectMentions];
}

- (void)detectMentions {
    // 支持中文、字母、数字、下划线和连字符
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"@[\\w\\u4e00-\\u9fa5-]+" options:0 error:nil];
    NSArray *matches = [regex matchesInString:self.text options:0 range:NSMakeRange(0, self.text.length)];
    
    NSMutableArray *ranges = [NSMutableArray array];
    for (NSTextCheckingResult *match in matches) {
        [ranges addObject:[NSValue valueWithRange:match.range]];
    }
    self.mentionRanges = ranges;
}

- (BOOL)deleteMentionAtCursorPosition {
    NSRange selectedRange = self.selectedRange;
    if (selectedRange.location == 0) return NO;
    // 找出包含光标前一个位置的所有mention
    NSMutableArray *candidateMentions = [NSMutableArray array];
    for (NSValue *rangeValue in _mentionRanges) {
        NSRange mentionRange = [rangeValue rangeValue];
        if (NSLocationInRange(selectedRange.location - 2, mentionRange)) {
            [candidateMentions addObject:rangeValue];
        }
    }

    if (candidateMentions.count == 0) return NO;

    // 找出最合适的mention（取范围最大的）
    NSValue *bestMatch = candidateMentions.firstObject;
    for (NSValue *rangeValue in candidateMentions) {
        if ([rangeValue rangeValue].length > [bestMatch rangeValue].length) {
            bestMatch = rangeValue;
        }
    }
    
    NSRange deleteRange = [bestMatch rangeValue];
    NSString *deletedMention = [self.text substringWithRange:deleteRange];
    
    // 先保存原始索引
    NSUInteger originalIndex = [_mentionRanges indexOfObject:bestMatch];
    // 执行删除
    NSMutableString *text = [self.text mutableCopy];
    [text deleteCharactersInRange:deleteRange];
    self.text = text;
    
    // 更新selectedRange
    self.selectedRange = NSMakeRange(deleteRange.location, 0);
    
    // 更新其他mention的范围
    [self updateMentionRangesAfterDeletion:deleteRange];
    // 回调
    if (self.mentionDeleteHandler) {
        self.mentionDeleteHandler(deletedMention, originalIndex);
    }
    
    return YES;
}

- (void)updateMentionRangesAfterDeletion:(NSRange)deletedRange {
    NSMutableArray *updatedRanges = [NSMutableArray array];
    for (NSValue *rangeValue in _mentionRanges) {
        NSRange range = [rangeValue rangeValue];
        
        if (NSEqualRanges(range, deletedRange)) {
            continue; // 跳过被删除的
        }
        
        if (range.location > deletedRange.location) {
            range.location -= deletedRange.length;
        }
        [updatedRanges addObject:[NSValue valueWithRange:range]];
    }
    _mentionRanges = updatedRanges;
}

- (void)deleteMentionAtIndex:(NSUInteger)index {
    if (index >= _mentionRanges.count) return;
    
    NSValue *rangeValue = _mentionRanges[index];
    NSRange deleteRange = [rangeValue rangeValue];
    NSString *deletedMention = [self.text substringWithRange:deleteRange];
    
    // 执行删除
    NSMutableString *text = [self.text mutableCopy];
    [text deleteCharactersInRange:deleteRange];
    self.text = text;
    
    // 更新selectedRange
    self.selectedRange = NSMakeRange(deleteRange.location, 0);
    
    // 更新其他mention的范围
    [self updateMentionRangesAfterDeletion:deleteRange];
    
    // 回调
    if (self.mentionDeleteHandler) {
        self.mentionDeleteHandler(deletedMention, index);
    }
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];
    CGPoint location = [touch locationInView:self];
    
    UITextPosition *position = [self closestPositionToPoint:location];
    NSUInteger index = [self offsetFromPosition:self.beginningOfDocument toPosition:position];
    
    for (NSValue *rangeValue in self.mentionRanges) {
        NSRange mentionRange = [rangeValue rangeValue];
        if (NSLocationInRange(index, mentionRange)) {
            if(self.text.length>=(mentionRange.location+mentionRange.length)){
                NSString *mention = [self.text substringWithRange:mentionRange];
                if (self.mentionTapHandler) {
                    self.mentionTapHandler(mention);
                }
            }
            return;
        }
    }
    
    [super touchesEnded:touches withEvent:event];
}

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

@end