//
//  HomeMoreFunctionsViewController.swift
//  suixinkan
//

import SnapKit
import UIKit

/// 首页全部功能页，支持常用应用增删和更多功能网格展示。
final class HomeMoreFunctionsViewController: UIViewController {

    private let viewModel = HomeViewModel()
    private let commonMenuStore = HomeCommonMenuStore()
    private var commonURIs: [String] = []

    private lazy var tableView: UITableView = {
        let table = UITableView(frame: .zero, style: .grouped)
        table.backgroundColor = AppDesignUIKit.pageBackground
        table.separatorStyle = .none
        table.dataSource = self
        table.delegate = self
        table.register(HomeMoreMenuGridCell.self, forCellReuseIdentifier: HomeMoreMenuGridCell.reuseID)
        return table
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        title = "全部功能"
        view.backgroundColor = AppDesignUIKit.pageBackground
        navigationItem.largeTitleDisplayMode = .never

        view.addSubview(tableView)
        tableView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }

        viewModel.onChange = { [weak self] in
            self?.tableView.reloadData()
        }
        rebuildMenus()

        appServices.permissionContext.onChange = { [weak self] in
            self?.rebuildMenus()
        }
    }

    private func rebuildMenus() {
        let services = appServices
        viewModel.buildMenus(
            from: services.permissionContext.rolePermissions,
            currentRoleId: services.permissionContext.currentRole?.id
        )
        commonURIs = commonMenuStore.load(menuItems: viewModel.menuItems)
        tableView.reloadData()
    }

    private var commonItems: [HomeMenuItem] {
        commonURIs.compactMap { menuItem(for: $0) }
    }

    private var moreItems: [HomeMenuItem] {
        viewModel.menuItems.filter { !isCommonURI($0.uri) }
    }

    private func menuItem(for uri: String) -> HomeMenuItem? {
        let availableURIs = Set(viewModel.menuItems.map(\.uri))
        let resolvedUri = HomeMenuRouter.canonicalURI(for: uri, availableURIs: availableURIs)
        guard let existing = viewModel.menuItems.first(where: { $0.uri == resolvedUri }) else { return nil }
        return HomeMenuItem(
            title: HomeMenuRouter.displayTitle(for: resolvedUri, fallback: existing.title),
            uri: resolvedUri,
            iconSrc: existing.iconSrc
        )
    }

    private func isCommonURI(_ uri: String) -> Bool {
        let aliasKey = HomeMenuRouter.menuAliasKey(for: uri)
        return commonURIs.contains { HomeMenuRouter.menuAliasKey(for: $0) == aliasKey }
    }

    private func toggleCommon(_ item: HomeMenuItem, isCommon: Bool) {
        if isCommon {
            commonURIs = commonMenuStore.remove(item.uri, current: commonURIs)
        } else {
            commonURIs = commonMenuStore.add(item.uri, current: commonURIs, menuItems: viewModel.menuItems)
        }
        tableView.reloadData()
    }

    private func openMenu(_ item: HomeMenuItem) {
        let route = HomeMenuRouter.resolve(uri: item.uri, title: item.title)
        if case .destination(let homeRoute) = route, homeRoute == .moreFunctions { return }
        HomeMenuRouting.openRoute(route, from: self)
    }
}

extension HomeMoreFunctionsViewController: UITableViewDataSource, UITableViewDelegate {
    func numberOfSections(in tableView: UITableView) -> Int { 2 }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 1 }

    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        section == 0 ? "常用应用" : "更多功能"
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: HomeMoreMenuGridCell.reuseID, for: indexPath) as! HomeMoreMenuGridCell
        let isCommon = indexPath.section == 0
        let items = isCommon ? commonItems : moreItems
        cell.configure(items: items, isCommon: isCommon) { [weak self] item in
            self?.openMenu(item)
        } onToggle: { [weak self] item in
            self?.toggleCommon(item, isCommon: isCommon)
        }
        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        let count = indexPath.section == 0 ? commonItems.count : moreItems.count
        let rows = max(1, Int(ceil(Double(count) / 3.0)))
        return CGFloat(rows) * 124 + 8
    }
}

private final class HomeMoreMenuGridCell: UITableViewCell {
    static let reuseID = "HomeMoreMenuGridCell"

    private var items: [HomeMenuItem] = []
    private var isCommon = false
    private var onSelect: ((HomeMenuItem) -> Void)?
    private var onToggle: ((HomeMenuItem) -> Void)?

    private lazy var collectionView: UICollectionView = {
        let layout = UICollectionViewFlowLayout()
        layout.minimumInteritemSpacing = 14
        layout.minimumLineSpacing = AppMetrics.Spacing.mediumLarge
        let view = UICollectionView(frame: .zero, collectionViewLayout: layout)
        view.backgroundColor = .clear
        view.isScrollEnabled = false
        view.dataSource = self
        view.delegate = self
        view.register(HomeMoreMenuItemCell.self, forCellWithReuseIdentifier: HomeMoreMenuItemCell.reuseID)
        return view
    }()

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        backgroundColor = .clear
        selectionStyle = .none
        contentView.addSubview(collectionView)
        collectionView.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(AppMetrics.Spacing.mediumLarge)
        }
    }

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

    func configure(
        items: [HomeMenuItem],
        isCommon: Bool,
        onSelect: @escaping (HomeMenuItem) -> Void,
        onToggle: @escaping (HomeMenuItem) -> Void
    ) {
        self.items = items
        self.isCommon = isCommon
        self.onSelect = onSelect
        self.onToggle = onToggle
        collectionView.reloadData()
    }
}

extension HomeMoreMenuGridCell: UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        items.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: HomeMoreMenuItemCell.reuseID, for: indexPath) as! HomeMoreMenuItemCell
        let item = items[indexPath.item]
        cell.configure(item: item, isCommon: isCommon) { [weak self] in
            self?.onToggle?(item)
        }
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        onSelect?(items[indexPath.item])
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let width = (collectionView.bounds.width - 28) / 3
        return CGSize(width: width, height: 112)
    }
}

private final class HomeMoreMenuItemCell: UICollectionViewCell {
    static let reuseID = "HomeMoreMenuItemCell"

    private let iconView = UIImageView()
    private let titleLabel = UILabel()
    private let toggleButton = UIButton(type: .system)
    private var onToggle: (() -> Void)?

    override init(frame: CGRect) {
        super.init(frame: frame)
        contentView.backgroundColor = .white
        contentView.layer.cornerRadius = 8

        titleLabel.font = .systemFont(ofSize: AppMetrics.FontSize.callout)
        titleLabel.textColor = UIColor(hex: 0x252525)
        titleLabel.textAlignment = .center
        titleLabel.numberOfLines = 1
        titleLabel.adjustsFontSizeToFitWidth = true

        toggleButton.addTarget(self, action: #selector(toggleTapped), for: .touchUpInside)
        contentView.addSubview(toggleButton)

        let stack = UIStackView(arrangedSubviews: [iconView, titleLabel])
        stack.axis = .vertical
        stack.spacing = AppMetrics.Spacing.mediumLarge + 1
        stack.alignment = .center
        contentView.addSubview(stack)

        stack.snp.makeConstraints { make in
            make.center.equalToSuperview()
            make.leading.trailing.equalToSuperview().inset(4)
        }
        iconView.snp.makeConstraints { make in
            make.width.height.equalTo(34)
        }
        toggleButton.snp.makeConstraints { make in
            make.top.trailing.equalToSuperview().inset(2)
            make.width.height.equalTo(28)
        }
        iconView.contentMode = .scaleAspectFit
    }

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

    func configure(item: HomeMenuItem, isCommon: Bool, onToggle: @escaping () -> Void) {
        self.onToggle = onToggle
        titleLabel.text = item.title
        let symbol = UIImage(systemName: HomeIconCatalog.iconName(for: item.uri))
        iconView.loadRemoteImage(urlString: item.iconSrc, contentMode: .scaleAspectFit, placeholder: symbol)
        iconView.tintColor = AppDesign.primary
        let iconName = isCommon ? "minus.circle.fill" : "plus.circle.fill"
        toggleButton.setImage(UIImage(systemName: iconName), for: .normal)
        toggleButton.tintColor = isCommon ? UIColor(hex: 0xFF1111) : AppDesignUIKit.primary
    }

    @objc private func toggleTapped() {
        onToggle?()
    }
}