//
//  UITextField+Extensions.swift
//  SHECommunity
//
//  Created by psj on 2023/11/6.
//

import Foundation
import UIKit

extension UITextInput {
    var isComposingText: Bool {
        markedTextRange != nil
    }
}

extension UITextField {
    func placeholderColor(placeholder: String, color: UIColor, font: UIFont = UIFont.systemFont(ofSize:15) ) {
        // 字体大小
        self.attributedPlaceholder = NSAttributedString.init(string:placeholder, attributes: [NSAttributedString.Key.font:font])
        // 字体颜色
        self.attributedPlaceholder = NSAttributedString.init(string:placeholder, attributes: [NSAttributedString.Key.foregroundColor:color])
    }
    
    /// EZSE: Add left padding to the text in textfield
    public func addLeftTextPadding(_ blankSize: CGFloat) {
        let leftView = UIView()
        leftView.frame = CGRect(x: 0, y: 0, width: blankSize, height: frame.height)
        self.leftView = leftView
        self.leftViewMode = UITextField.ViewMode.always
    }

    @discardableResult
    func limitCommittedText(to maximumLength: Int) -> String? {
        guard !isComposingText else { return nil }
        let currentText = text ?? ""
        guard maximumLength > 0, currentText.count > maximumLength else {
            return currentText
        }

        let cursorOffset = selectedTextRange.map {
            offset(from: beginningOfDocument, to: $0.start)
        } ?? (currentText as NSString).length
        let limitedText = String(currentText.prefix(maximumLength))
        text = limitedText
        restoreCursor(to: cursorOffset, text: limitedText)
        return limitedText
    }

    private func restoreCursor(to offset: Int, text: String) {
        let validOffset = min(max(0, offset), (text as NSString).length)
        guard let cursorPosition = position(from: beginningOfDocument, offset: validOffset) else { return }
        selectedTextRange = textRange(from: cursorPosition, to: cursorPosition)
    }
}

extension UITextView {
    @discardableResult
    func limitCommittedText(to maximumLength: Int) -> String? {
        guard !isComposingText else { return nil }
        let currentText = text ?? ""
        guard maximumLength > 0, currentText.count > maximumLength else {
            return currentText
        }

        let cursorOffset = selectedTextRange.map {
            offset(from: beginningOfDocument, to: $0.start)
        } ?? (currentText as NSString).length
        let limitedText = String(currentText.prefix(maximumLength))
        text = limitedText
        restoreCursor(to: cursorOffset, text: limitedText)
        return limitedText
    }

    private func restoreCursor(to offset: Int, text: String) {
        let validOffset = min(max(0, offset), (text as NSString).length)
        guard let cursorPosition = position(from: beginningOfDocument, offset: validOffset) else { return }
        selectedTextRange = textRange(from: cursorPosition, to: cursorPosition)
    }
}