//
//  SampleManagementUI.swift
//  suixinkan
//

import SnapKit
import UIKit

/// 样片管理模块视觉常量，严格对应 Android Compose 页面中的 dp、颜色与圆角。
enum SampleManagementUITokens {
    static let pageBackground = UIColor(hex: 0xF4F4F4)
    static let inputBackground = UIColor(hex: 0xF4F4F4)
    static let border = UIColor(hex: 0xEEEEEE)
    static let placeholder = UIColor(hex: 0xB6BECA)
    static let text563 = UIColor(hex: 0x4B5563)
    static let statText = UIColor(hex: 0x6B7280)
    static let screenInset: CGFloat = 16
    static let sectionSpacing: CGFloat = 12
    static let cardRadius: CGFloat = 12
    static let fieldRadius: CGFloat = 8
}

/// 样片管理页面基类，复用“空间设置”的原生导航栏外观与返回行为。
class SampleBaseViewController: BaseViewController {
    override func setupNavigationBar() {
        navigationItem.backButtonDisplayMode = .minimal
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        navigationController?.setNavigationBarHidden(false, animated: animated)
        ProfileNavigationStyle.apply(to: navigationController, showsDivider: false)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        ProfileNavigationStyle.restore(navigationController)
    }

    /// 设置与“空间设置”一致的原生导航栏标题。
    func setSampleTitle(_ title: String) {
        self.title = title
    }
}

/// 锚定在输入框下方的 Android 风格下拉菜单，支持滚动加载更多。
final class SampleAnchoredDropdownView: UIControl, UIScrollViewDelegate {
    /// 下拉菜单选项。
    struct Option {
        let title: String
        let isSelected: Bool
        let isLoadMore: Bool

        /// 创建普通或“加载更多”选项。
        init(title: String, isSelected: Bool = false, isLoadMore: Bool = false) {
            self.title = title
            self.isSelected = isSelected
            self.isLoadMore = isLoadMore
        }
    }

    private let cardView = UIView()
    private let scrollView = UIScrollView()
    private let stackView = UIStackView()
    private var onSelect: ((Int) -> Void)?
    private var onReachedBottom: (() -> Void)?
    private var didRequestBottom = false

    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
        cardView.backgroundColor = .white
        cardView.layer.cornerRadius = 4
        cardView.layer.shadowColor = UIColor.black.cgColor
        cardView.layer.shadowOpacity = 0.14
        cardView.layer.shadowRadius = 8
        cardView.layer.shadowOffset = CGSize(width: 0, height: 4)
        scrollView.delegate = self
        stackView.axis = .vertical
        addSubview(cardView)
        cardView.addSubview(scrollView)
        scrollView.addSubview(stackView)
        addTarget(self, action: #selector(dismissMenu), for: .touchUpInside)
        isHidden = true
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    /// 在锚点下方展示菜单。
    func show(
        anchor: UIView,
        options: [Option],
        maximumHeight: CGFloat = 200,
        onReachedBottom: (() -> Void)? = nil,
        onSelect: @escaping (Int) -> Void
    ) {
        guard !options.isEmpty else { return }
        self.onSelect = onSelect
        self.onReachedBottom = onReachedBottom
        didRequestBottom = false
        stackView.arrangedSubviews.forEach { $0.removeFromSuperview() }

        for (index, option) in options.enumerated() {
            let button = UIButton(type: .system)
            button.tag = index
            button.contentHorizontalAlignment = .leading
            button.contentEdgeInsets = UIEdgeInsets(top: 0, left: 12, bottom: 0, right: 12)
            button.setTitle(option.title, for: .normal)
            let color = option.isSelected ? AppColor.primary : (option.isLoadMore ? AppColor.textSecondary : .black)
            button.setTitleColor(color, for: .normal)
            button.titleLabel?.font = .systemFont(ofSize: 14, weight: option.isSelected ? .medium : .regular)
            button.backgroundColor = .white
            button.accessibilityLabel = option.title
            button.addTarget(self, action: #selector(optionTapped(_:)), for: .touchUpInside)
            button.snp.makeConstraints { make in make.height.equalTo(28) }
            stackView.addArrangedSubview(button)
        }

        isHidden = false
        superview?.bringSubviewToFront(self)
        layoutIfNeeded()
        let anchorFrame = anchor.convert(anchor.bounds, to: self)
        let contentHeight = CGFloat(options.count) * 28
        let menuHeight = min(maximumHeight, contentHeight)
        cardView.frame = CGRect(x: anchorFrame.minX, y: anchorFrame.maxY, width: anchorFrame.width, height: menuHeight)
        scrollView.frame = cardView.bounds
        stackView.frame = CGRect(x: 0, y: 0, width: cardView.bounds.width, height: contentHeight)
        scrollView.contentSize = stackView.frame.size
    }

    /// 隐藏菜单。
    func hide() {
        isHidden = true
    }

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        guard !didRequestBottom, scrollView.contentSize.height > scrollView.bounds.height else { return }
        let remaining = scrollView.contentSize.height - scrollView.contentOffset.y - scrollView.bounds.height
        guard remaining <= 10 else { return }
        didRequestBottom = true
        onReachedBottom?()
    }

    @objc private func optionTapped(_ sender: UIButton) {
        isHidden = true
        onSelect?(sender.tag)
    }

    @objc private func dismissMenu() {
        isHidden = true
    }
}