//
//  EPLoginButton.swift
//  YuMi
//
//  Created by AI on 2025-01-27.
//  登录按钮组件 - 使用 StackView 实现 icon 左侧固定 + title 居中
//

import UIKit
import SnapKit

/// 登录按钮点击代理
protocol EPLoginButtonDelegate: AnyObject {
    func loginButtonDidTap(_ button: EPLoginButton)
}

/// 登录按钮组件
class EPLoginButton: UIControl {
    
    // MARK: - Properties
    
    weak var delegate: EPLoginButtonDelegate?
    
    private let stackView = UIStackView()
    private let iconImageView = UIImageView()
    private let titleLabel = UILabel()
    private let leftSpacer = UIView()
    private let rightSpacer = UIView()
    
    // MARK: - Initialization
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setupUI()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - Setup
    
    private func setupUI() {
        backgroundColor = EPLoginConfig.Colors.background
        layer.cornerRadius = EPLoginConfig.Layout.cornerRadius
        
        // StackView 配置
        stackView.axis = .horizontal
        stackView.alignment = .center
        stackView.distribution = .fill
        stackView.spacing = 0
        stackView.isUserInteractionEnabled = false
        addSubview(stackView)
        
        // Icon
        iconImageView.contentMode = .scaleAspectFit
        
        // Title
        titleLabel.font = .systemFont(ofSize: EPLoginConfig.Layout.inputFontSize, weight: .semibold)
        titleLabel.textColor = EPLoginConfig.Colors.text
        titleLabel.textAlignment = .center
        
        // Spacers - 让 title 居中
        leftSpacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
        rightSpacer.setContentHuggingPriority(.defaultLow, for: .horizontal)
        
        // 布局顺序: [Leading 33] + [Icon] + [Flexible Spacer] + [Title] + [Flexible Spacer] + [Trailing 33]
        let leadingPadding = UIView()
        let trailingPadding = UIView()
        
        stackView.addArrangedSubview(leadingPadding)
        stackView.addArrangedSubview(iconImageView)
        stackView.addArrangedSubview(leftSpacer)
        stackView.addArrangedSubview(titleLabel)
        stackView.addArrangedSubview(rightSpacer)
        stackView.addArrangedSubview(trailingPadding)
        
        // 约束
        stackView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
        
        leadingPadding.snp.makeConstraints { make in
            make.width.equalTo(EPLoginConfig.Layout.loginButtonIconLeading)
        }
        
        iconImageView.snp.makeConstraints { make in
            make.size.equalTo(EPLoginConfig.Layout.loginButtonIconSize)
        }
        
        trailingPadding.snp.makeConstraints { make in
            make.width.equalTo(EPLoginConfig.Layout.loginButtonIconLeading)
        }
        
        // 设置 leftSpacer 和 rightSpacer 宽度相等，实现 title 居中
        leftSpacer.snp.makeConstraints { make in
            make.width.equalTo(rightSpacer)
        }
        
        // 添加点击事件
        addTarget(self, action: #selector(handleTap), for: .touchUpInside)
    }
    
    // MARK: - Configuration
    
    /// 配置按钮
    /// - Parameters:
    ///   - icon: 图标名称
    ///   - title: 标题文字
    func configure(icon: String, title: String) {
        iconImageView.image = kImage(icon)
        titleLabel.text = title
    }
    
    // MARK: - Actions
    
    @objc private func handleTap() {
        delegate?.loginButtonDidTap(self)
    }
    
    // MARK: - Touch Feedback
    
    override var isHighlighted: Bool {
        didSet {
            UIView.animate(withDuration: 0.1) {
                self.alpha = self.isHighlighted ? 0.7 : 1.0
            }
        }
    }
}