import UIKit

/// 悬浮窗实现类
/// 使用 UIWindow 创建应用内悬浮窗口
class FloatingWindow: UIWindow {
    
    // MARK: - 属性
    private weak var delegate: FloatingWindowDelegate?
    private var floatingViewController: FloatingViewController?
    private var isMinimized = true
    private var lastPosition = CGPoint(x: 100, y: 100)
    
    // MARK: - 初始化
    init(delegate: FloatingWindowDelegate) {
        self.delegate = delegate
        
        // 创建窗口
        super.init(frame: CGRect(x: 100, y: 100, width: 300, height: 120))
        
        setupWindow()
        setupViewController()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - 私有方法
    
    /// 设置窗口属性
    private func setupWindow() {
        // 设置窗口层级，确保在最顶层显示
        windowLevel = UIWindow.Level.alert + 1
        backgroundColor = UIColor.clear
        
        // 设置窗口为可见但不成为主窗口
        isHidden = true
        
        // 设置圆角
        layer.cornerRadius = 12
        layer.masksToBounds = true
    }
    
    /// 设置视图控制器
    private func setupViewController() {
        floatingViewController = FloatingViewController()
        floatingViewController?.delegate = self
        rootViewController = floatingViewController
    }
    
    // MARK: - 公共方法
    
    /// 显示悬浮窗
    func show() {
        isHidden = false
        makeKeyAndVisible()
        
        // 添加显示动画
        alpha = 0
        UIView.animate(withDuration: 0.3) {
            self.alpha = 1
        }
        
        delegate?.floatingWindowDidChangeState(isMinimized ? "minimized" : "expanded")
    }
    
    /// 隐藏悬浮窗
    func hide() {
        UIView.animate(withDuration: 0.3, animations: {
            self.alpha = 0
        }) { _ in
            self.isHidden = true
            self.resignKey()
        }
        
        delegate?.floatingWindowDidChangeState("hidden")
    }
    
    /// 更新内容
    func updateContent(_ data: FloatingWindowContentData) {
        floatingViewController?.updateContent(data)
    }
    
    /// 设置位置
    func setPosition(x: Double, y: Double) {
        let newPosition = CGPoint(x: x, y: y)
        lastPosition = newPosition
        
        UIView.animate(withDuration: 0.3) {
            self.frame.origin = newPosition
        }
    }
    
    /// 切换最小化/展开状态
    func toggleMinimized() {
        isMinimized.toggle()
        
        let newSize: CGSize
        if isMinimized {
            newSize = CGSize(width: 120, height: 60)
        } else {
            newSize = CGSize(width: 300, height: 120)
        }
        
        UIView.animate(withDuration: 0.3) {
            self.frame.size = newSize
        }
        
        floatingViewController?.setMinimized(isMinimized)
        delegate?.floatingWindowDidChangeState(isMinimized ? "minimized" : "expanded")
    }
}

// MARK: - FloatingViewControllerDelegate
extension FloatingWindow: FloatingViewControllerDelegate {
    
    func floatingViewControllerDidTap() {
        toggleMinimized()
        delegate?.floatingWindowDidClick()
    }
    
    func floatingViewControllerDidPan(translation: CGPoint) {
        let newOrigin = CGPoint(
            x: lastPosition.x + translation.x,
            y: lastPosition.y + translation.y
        )
        
        // 限制在屏幕范围内
        let screenBounds = UIScreen.main.bounds
        let constrainedX = max(0, min(newOrigin.x, screenBounds.width - frame.width))
        let constrainedY = max(0, min(newOrigin.y, screenBounds.height - frame.height))
        
        frame.origin = CGPoint(x: constrainedX, y: constrainedY)
    }
    
    func floatingViewControllerDidEndPan() {
        lastPosition = frame.origin
    }
    
    func floatingViewControllerDidRequestClose() {
        hide()
        delegate?.floatingWindowDidClose()
    }
}

/// 悬浮窗视图控制器
private class FloatingViewController: UIViewController {
    
    // MARK: - 属性
    weak var delegate: FloatingViewControllerDelegate?
    
    // UI 组件
    private let containerView = UIView()
    private let sourceTextLabel = UILabel()
    private let translatedTextLabel = UILabel()
    private let languageInfoLabel = UILabel()
    private let timestampLabel = UILabel()
    private let closeButton = UIButton(type: .system)
    
    // 手势识别器
    private var panGestureRecognizer: UIPanGestureRecognizer!
    private var tapGestureRecognizer: UITapGestureRecognizer!
    
    private var isMinimized = true
    
    // MARK: - 生命周期
    override func viewDidLoad() {
        super.viewDidLoad()
        setupUI()
        setupGestures()
    }
    
    // MARK: - 私有方法
    
    /// 设置 UI
    private func setupUI() {
        view.backgroundColor = UIColor.clear
        
        // 容器视图
        containerView.backgroundColor = UIColor.black.withAlphaComponent(0.8)
        containerView.layer.cornerRadius = 12
        containerView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(containerView)
        
        // 源文本标签
        sourceTextLabel.textColor = .white
        sourceTextLabel.font = UIFont.systemFont(ofSize: 14)
        sourceTextLabel.numberOfLines = 2
        sourceTextLabel.translatesAutoresizingMaskIntoConstraints = false
        containerView.addSubview(sourceTextLabel)
        
        // 翻译文本标签
        translatedTextLabel.textColor = .systemBlue
        translatedTextLabel.font = UIFont.systemFont(ofSize: 14, weight: .medium)
        translatedTextLabel.numberOfLines = 2
        translatedTextLabel.translatesAutoresizingMaskIntoConstraints = false
        containerView.addSubview(translatedTextLabel)
        
        // 语言信息标签
        languageInfoLabel.textColor = .lightGray
        languageInfoLabel.font = UIFont.systemFont(ofSize: 10)
        languageInfoLabel.translatesAutoresizingMaskIntoConstraints = false
        containerView.addSubview(languageInfoLabel)
        
        // 时间戳标签
        timestampLabel.textColor = .lightGray
        timestampLabel.font = UIFont.systemFont(ofSize: 10)
        timestampLabel.textAlignment = .right
        timestampLabel.translatesAutoresizingMaskIntoConstraints = false
        containerView.addSubview(timestampLabel)
        
        // 关闭按钮
        closeButton.setTitle("×", for: .normal)
        closeButton.setTitleColor(.white, for: .normal)
        closeButton.titleLabel?.font = UIFont.systemFont(ofSize: 18, weight: .bold)
        closeButton.translatesAutoresizingMaskIntoConstraints = false
        closeButton.addTarget(self, action: #selector(closeButtonTapped), for: .touchUpInside)
        containerView.addSubview(closeButton)
        
        setupConstraints()
    }
    
    /// 设置约束
    private func setupConstraints() {
        NSLayoutConstraint.activate([
            // 容器视图
            containerView.topAnchor.constraint(equalTo: view.topAnchor),
            containerView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            containerView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            containerView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            
            // 关闭按钮
            closeButton.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 4),
            closeButton.trailingAnchor.constraint(equalTo: containerView.trailingAnchor, constant: -4),
            closeButton.widthAnchor.constraint(equalToConstant: 20),
            closeButton.heightAnchor.constraint(equalToConstant: 20),
            
            // 源文本标签
            sourceTextLabel.topAnchor.constraint(equalTo: containerView.topAnchor, constant: 8),
            sourceTextLabel.leadingAnchor.constraint(equalTo: containerView.leadingAnchor, constant: 8),
            sourceTextLabel.trailingAnchor.constraint(equalTo: closeButton.leadingAnchor, constant: -4),
            
            // 翻译文本标签
            translatedTextLabel.topAnchor.constraint(equalTo: sourceTextLabel.bottomAnchor, constant: 4),
            translatedTextLabel.leadingAnchor.constraint(equalTo: containerView.leadingAnchor, constant: 8),
            translatedTextLabel.trailingAnchor.constraint(equalTo: containerView.trailingAnchor, constant: -8),
            
            // 语言信息标签
            languageInfoLabel.topAnchor.constraint(equalTo: translatedTextLabel.bottomAnchor, constant: 4),
            languageInfoLabel.leadingAnchor.constraint(equalTo: containerView.leadingAnchor, constant: 8),
            languageInfoLabel.bottomAnchor.constraint(equalTo: containerView.bottomAnchor, constant: -4),
            
            // 时间戳标签
            timestampLabel.topAnchor.constraint(equalTo: translatedTextLabel.bottomAnchor, constant: 4),
            timestampLabel.trailingAnchor.constraint(equalTo: containerView.trailingAnchor, constant: -8),
            timestampLabel.bottomAnchor.constraint(equalTo: containerView.bottomAnchor, constant: -4)
        ])
    }
    
    /// 设置手势识别器
    private func setupGestures() {
        // 拖拽手势
        panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
        view.addGestureRecognizer(panGestureRecognizer)
        
        // 点击手势
        tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
        view.addGestureRecognizer(tapGestureRecognizer)
    }
    
    // MARK: - 手势处理
    
    @objc private func handlePan(_ gesture: UIPanGestureRecognizer) {
        let translation = gesture.translation(in: view.superview)
        
        switch gesture.state {
        case .changed:
            delegate?.floatingViewControllerDidPan(translation: translation)
        case .ended, .cancelled:
            delegate?.floatingViewControllerDidEndPan()
        default:
            break
        }
    }
    
    @objc private func handleTap(_ gesture: UITapGestureRecognizer) {
        delegate?.floatingViewControllerDidTap()
    }
    
    @objc private func closeButtonTapped() {
        delegate?.floatingViewControllerDidRequestClose()
    }
    
    // MARK: - 公共方法
    
    /// 更新内容
    func updateContent(_ data: FloatingWindowContentData) {
        sourceTextLabel.text = data.sourceText.isEmpty ? "正在识别..." : data.sourceText
        translatedTextLabel.text = data.translatedText.isEmpty ? "翻译中..." : data.translatedText
        languageInfoLabel.text = "\(data.sourceLanguage) → \(data.targetLanguage)"
        
        // 格式化时间戳
        if data.timestamp > 0 {
            let date = Date(timeIntervalSince1970: TimeInterval(data.timestamp / 1000))
            let formatter = DateFormatter()
            formatter.dateFormat = "HH:mm:ss"
            timestampLabel.text = formatter.string(from: date)
        }
        
        // 中间结果的视觉提示
        translatedTextLabel.alpha = data.isIntermediate ? 0.7 : 1.0
    }
    
    /// 设置最小化状态
    func setMinimized(_ minimized: Bool) {
        isMinimized = minimized
        
        // 在最小化状态下隐藏部分元素
        sourceTextLabel.isHidden = minimized
        languageInfoLabel.isHidden = minimized
        timestampLabel.isHidden = minimized
        closeButton.isHidden = minimized
        
        // 调整翻译文本标签的约束
        if minimized {
            translatedTextLabel.numberOfLines = 1
            translatedTextLabel.font = UIFont.systemFont(ofSize: 12, weight: .medium)
        } else {
            translatedTextLabel.numberOfLines = 2
            translatedTextLabel.font = UIFont.systemFont(ofSize: 14, weight: .medium)
        }
    }
}

/// 悬浮窗视图控制器代理协议
private protocol FloatingViewControllerDelegate: AnyObject {
    func floatingViewControllerDidTap()
    func floatingViewControllerDidPan(translation: CGPoint)
    func floatingViewControllerDidEndPan()
    func floatingViewControllerDidRequestClose()
}