//
//  gp_textV.swift
//  Hthik
//
//  Created by 忆海16 on 2024/5/31.
//  Copyright © 2024  Hthik. All rights reserved.
//

import Foundation

import UIKit

class TextViewModifier {
    
    // 修改TextView的文本
    static func setText(of textView: UITextView, to text: String) {
        textView.text = text
    }
    
    // 修改TextView的文本颜色
    static func setTextColor(of textView: UITextView, to color: UIColor) {
        textView.textColor = color
    }
    
    // 修改TextView的背景颜色
    static func setBackgroundColor(of textView: UITextView, to color: UIColor) {
        textView.backgroundColor = color
    }
    
    // 修改TextView的字体
    static func setFont(of textView: UITextView, to font: UIFont) {
        textView.font = font
    }
    
    // 设置TextView的占位符
    static func setPlaceholder(of textView: UITextView, to placeholder: String, placeholderColor: UIColor = .lightGray) {
        textView.text = placeholder
        textView.textColor = placeholderColor
        textView.delegate = TextViewPlaceholderDelegate.shared
        TextViewPlaceholderDelegate.shared.setPlaceholder(textView: textView, placeholder: placeholder, placeholderColor: placeholderColor)
    }
}

// 用于处理占位符逻辑的委托类
class TextViewPlaceholderDelegate: NSObject, UITextViewDelegate {
    static let shared = TextViewPlaceholderDelegate()
    private var placeholderMap = [UITextView: (placeholder: String, placeholderColor: UIColor, originalColor: UIColor)]()
    
    func setPlaceholder(textView: UITextView, placeholder: String, placeholderColor: UIColor) {
        let originalColor = textView.textColor ?? .black
        placeholderMap[textView] = (placeholder, placeholderColor, originalColor)
    }
    
    func textViewDidBeginEditing(_ textView: UITextView) {
        guard let placeholderData = placeholderMap[textView], textView.text == placeholderData.placeholder else { return }
        textView.text = nil
        textView.textColor = placeholderData.originalColor
    }
    
    func textViewDidEndEditing(_ textView: UITextView) {
        guard let placeholderData = placeholderMap[textView], textView.text.isEmpty else { return }
        textView.text = placeholderData.placeholder
        textView.textColor = placeholderData.placeholderColor
    }
}