//
//  MTTextFieldLimitManager.m
//  Meet
//
//  Created by ko1o on 2018/10/22.
//  Copyright © 2018年 ko1o. All rights reserved.
//

#import "MTTextFieldLimitManager.h"
#import "UITextField+MTLimit.h"
@interface MTTextFieldLimitManager()
@property (nonatomic, assign) NSInteger maxNumberOfDescriptionChars;    //最大限制字符个数

@end

@implementation MTTextFieldLimitManager

- (void)setupLimitTextField:(UITextField *)textField bytesLength:(NSInteger)maxLength {
    
    [textField addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
    
    self.maxNumberOfDescriptionChars = maxLength;
}

- (void)removeLimitTextField:(UITextField *)textField
{
    [textField removeTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
}

- (void)cutTextField:(UITextField *)textField  bytesLength:(NSInteger)maxLength
{
    UITextRange *selectedRange = [textField markedTextRange];
    // 获取高亮部分 中文联想
    UITextPosition *posi = [textField positionFromPosition:selectedRange.start offset:0];
    
    // 如果在变化中是高亮部分在变，就不要计算字符
    if (selectedRange && posi) {
        return;
    }
    
    if (textField.text.mt_customByteLength > maxLength) {
        textField.text = [textField.text mt_safeSubStringWithByteLength:maxLength];
    }
}

// 监听文本改变
- (void)textFieldDidChange:(UITextField*)textField
{
    [self cutTextField:textField bytesLength: self.maxNumberOfDescriptionChars];
    
    //设置代理 (扩展)
    if (self.limitDelegate && [self.limitDelegate respondsToSelector:@selector(limitTextFieldDidChange:)]) {
        [self.limitDelegate limitTextFieldDidChange:textField];
    }
}

@end