//
//  AppRestrictVC.swift
//  QuickLocation
//

import FamilyControls
import UIKit
import RxSwift
import RxCocoa
import ManagedSettings

@available(iOS 16.0, *)
final class AppRestrictVC: BaseViewController {
    private var rootView: AppRestrictView!
    private var tokens: [ApplicationToken] = []
    private var linkingToken: ApplicationToken?

    override func loadView() {
        rootView = AppRestrictView(frame: UIScreen.main.bounds)
        view = rootView
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        rootView.tableView.dataSource = self
        rootView.tableView.delegate = self
        rootView.tableView.register(AppRestrictCell.self, forCellReuseIdentifier: AppRestrictCell.reuseId)
        bind()
        reload()
    }

    private func bind() {
        rootView.navView.onBackTapped = { [weak self] in
            self?.navigationController?.popViewController(animated: true)
        }
        rootView.addBtn.rx.tap.subscribe(onNext: { [weak self] in
            self?.addApps()
        }).disposed(by: disposeBag)
    }

    private func reload() {
        tokens = AppRestrictManager.shared.applicationTokens
        rootView.setListVisible(!tokens.isEmpty, rowCount: tokens.count)
        rootView.tableView.reloadData()
    }

    private func addApps() {
        Task { @MainActor in
            do {
                if !AppRestrictManager.shared.isAuthorized {
                    try await AppRestrictManager.shared.requestAuthorization()
                }
                guard AppRestrictManager.shared.isAuthorized else {
                    DLToast.show(text: "需要屏幕使用时间权限")
                    return
                }
                let initialSelection = AppRestrictManager.shared.selection
                let presenter = FamilyActivityPickerPresenter(selection: initialSelection)
                presenter.onComplete = { [weak self] selection in
                    let addedApplications = selection.applicationTokens
                        .subtracting(initialSelection.applicationTokens)
                    AppRestrictManager.shared.mergeSelection(selection)
                    self?.reload()
                    if addedApplications.isEmpty, !selection.categoryTokens.isEmpty {
                        self?.showCategorySelectionNotice()
                    } else if !addedApplications.isEmpty {
                        self?.showApplicationTokens(addedApplications)
                    }
                }
                present(presenter, animated: false)
            } catch {
                DLToast.show(text: "授权失败，请在设置中开启屏幕使用时间权限")
            }
        }
    }

    private func showCategorySelectionNotice() {
        let alert = UIAlertController(
            title: "请选择具体应用",
            message: "系统不会返回分类“全部”中的具体应用。请展开分类，取消“全部”，再逐个勾选需要配对的应用。",
            preferredStyle: .alert
        )
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        alert.addAction(UIAlertAction(title: "重新选择", style: .default) { [weak self] _ in
            self?.addApps()
        })
        present(alert, animated: true)
    }

    private func showApplicationTokens(_ tokens: Set<ApplicationToken>) {
        let values = tokens.compactMap { token in
            AppRestrictTokenCodec.encode(token)?.base64EncodedString()
        }.sorted()
        guard !values.isEmpty else {
            DLToast.show(text: "ApplicationToken 编码失败")
            return
        }

        let message = values.enumerated().map { index, value in
            values.count == 1 ? value : "应用 \(index + 1)：\n\(value)"
        }.joined(separator: "\n\n")
        let alert = UIAlertController(
            title: "ApplicationToken",
            message: message,
            preferredStyle: .alert
        )
        alert.addAction(UIAlertAction(title: "复制", style: .default) { _ in
            UIPasteboard.general.string = values.joined(separator: "\n")
            DLToast.show(text: "Token 已复制")
        })
        alert.addAction(UIAlertAction(title: "关闭", style: .cancel))
        present(alert, animated: true)
    }

    private func openLink(for token: ApplicationToken) {
        linkingToken = token
        let vc = SelectActivityVC()
        vc.onSelect = { [weak self] item in
            guard let self, let token = self.linkingToken else { return }
            AppRestrictManager.shared.link(
                catalogId: item.id,
                token: token,
                displayName: item.name,
                iconURL: item.iconURL
            )
            self.linkingToken = nil
            self.reload()
        }
        let nav = UINavigationController(rootViewController: vc)
        present(nav, animated: true)
    }

    private func deleteApp(_ token: ApplicationToken) {
        AppRestrictManager.shared.removeApplication(token)
        reload()
    }
}

@available(iOS 16.0, *)
extension AppRestrictVC: UITableViewDataSource, UITableViewDelegate {
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        tokens.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: AppRestrictCell.reuseId, for: indexPath) as! AppRestrictCell
        let token = tokens[indexPath.row]
        let catalog = AppRestrictManager.shared.catalogItem(for: token)
        cell.configure(token: token, catalog: catalog)
        cell.onPair = { [weak self] in
            self?.openLink(for: token)
        }
        cell.onDelete = { [weak self] in
            self?.deleteApp(token)
        }
        return cell
    }
}

/// Fallback when system is below iOS 16.
final class AppRestrictUnsupportedVC: BaseViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        let nav = BaseNavigationView(title: "应用配对库")
        view.addSubview(nav)
        nav.layoutChain.top().edgesHorzontal().height(kNaviHeight)
        nav.onBackTapped = { [weak self] in
            self?.navigationController?.popViewController(animated: true)
        }
        let lab = UILabel()
        lab.text = "该功能需要 iOS 16 及以上系统"
        lab.textAlignment = .center
        lab.textColor = UIColor(hexStr: "#767676")
        view.addSubview(lab)
        lab.layoutChain.center()
    }
}

enum AppRestrictFactory {
    static func make() -> UIViewController {
        if #available(iOS 16.0, *) {
            return AppRestrictVC()
        }
        return AppRestrictUnsupportedVC()
    }
}