//
//  ViewController.swift
//  Note
//
//  Created by fish on 2026/7/12.
//

import UIKit

class ViewController: UIViewController {

    private var tableView: UITableView!
    private var editButton: UIBarButtonItem!

    private let menuOrderKey = "homeMenuOrder"

    private struct MenuItem {
        let icon: String
        let iconColor: UIColor
        let title: String
        let identifier: String
    }

    private let defaultMenuItems: [MenuItem] = [
        MenuItem(icon: "tray.full", iconColor: .systemIndigo, title: "收集箱", identifier: "inbox"),
        MenuItem(icon: "note.text", iconColor: .systemYellow, title: "打开备忘录", identifier: "notes"),
        MenuItem(icon: "doc.text", iconColor: .systemBlue, title: "格式化日志", identifier: "formatLog"),
        MenuItem(icon: "text.alignleft", iconColor: .systemGreen, title: "格式化笔记", identifier: "formatNote"),
        MenuItem(icon: "folder", iconColor: .systemOrange, title: "打开文件", identifier: "files")
    ]

    private var menuItems: [[MenuItem]] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        menuItems = [loadMenuOrder()]
        setupUI()
        setupAppStateObserver()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        updateInboxBadge()
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    private func setupAppStateObserver() {
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(appDidBecomeActive),
            name: UIApplication.didBecomeActiveNotification,
            object: nil
        )
    }

    @objc private func appDidBecomeActive() {
        updateInboxBadge()
    }

    private func setupUI() {
        title = "首页"
        navigationController?.navigationBar.prefersLargeTitles = true
        navigationItem.largeTitleDisplayMode = .always
        view.backgroundColor = .systemGroupedBackground

        editButton = UIBarButtonItem(title: "编辑", style: .plain, target: self, action: #selector(didTapEditButton))
        navigationItem.rightBarButtonItem = editButton

        tableView = UITableView(frame: .zero, style: .insetGrouped)
        tableView.translatesAutoresizingMaskIntoConstraints = false
        tableView.delegate = self
        tableView.dataSource = self
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "menuCell")
        tableView.backgroundColor = .systemGroupedBackground
        view.addSubview(tableView)

        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: view.topAnchor),
            tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
    }

    @objc private func didTapEditButton() {
        tableView.setEditing(!tableView.isEditing, animated: true)
        editButton.title = tableView.isEditing ? "完成" : "编辑"
    }

    private func loadMenuOrder() -> [MenuItem] {
        guard let savedOrder = UserDefaults.standard.array(forKey: menuOrderKey) as? [String] else {
            return defaultMenuItems
        }

        var orderedItems: [MenuItem] = []
        for identifier in savedOrder {
            if let item = defaultMenuItems.first(where: { $0.identifier == identifier }) {
                orderedItems.append(item)
            }
        }

        let remaining = defaultMenuItems.filter { item in
            !orderedItems.contains { $0.identifier == item.identifier }
        }
        return orderedItems + remaining
    }

    private func saveMenuOrder() {
        let identifiers = menuItems.flatMap { $0.map(\.identifier) }
        UserDefaults.standard.set(identifiers, forKey: menuOrderKey)
    }
}

extension ViewController: UITableViewDataSource {

    func numberOfSections(in tableView: UITableView) -> Int {
        return menuItems.count
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return menuItems[section].count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "menuCell", for: indexPath)
        let item = menuItems[indexPath.section][indexPath.row]

        var config = cell.defaultContentConfiguration()
        config.text = item.title
        config.image = UIImage(systemName: item.icon)
        config.imageProperties.tintColor = item.iconColor
        config.imageToTextPadding = 12
        cell.contentConfiguration = config
        cell.accessoryType = tableView.isEditing ? .none : .disclosureIndicator
        cell.selectionStyle = tableView.isEditing ? .none : .default

        return cell
    }

    func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
        return true
    }

    func tableView(_ tableView: UITableView, moveRowAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
        guard sourceIndexPath != destinationIndexPath else { return }

        let item = menuItems[sourceIndexPath.section].remove(at: sourceIndexPath.row)
        menuItems[destinationIndexPath.section].insert(item, at: destinationIndexPath.row)
        saveMenuOrder()
    }
}

extension ViewController: UITableViewDelegate {

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
        guard !tableView.isEditing else { return }

        let item = menuItems[indexPath.section][indexPath.row]
        switch item.identifier {
        case "inbox":
            let viewController = ClipInboxViewController()
            navigationController?.pushViewController(viewController, animated: true)
        case "notes":
            openSystemNotesApp()
        case "formatLog":
            let viewController = FormatLogViewController()
            navigationController?.pushViewController(viewController, animated: true)
        case "formatNote":
            let viewController = FormatNoteViewController()
            navigationController?.pushViewController(viewController, animated: true)
        case "files":
            openFilesApp()
        default:
            break
        }
    }

    func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {
        return .none
    }

    func tableView(_ tableView: UITableView, shouldIndentWhileEditingRowAt indexPath: IndexPath) -> Bool {
        return false
    }

    private func updateInboxBadge() {
        Task {
            guard let count = try? await ClipStore.shared.count(), count > 0 else {
                await MainActor.run {
                    self.updateInboxTitle("收集箱")
                }
                return
            }
            await MainActor.run {
                self.updateInboxTitle("收集箱（\(count)）")
            }
        }
    }

    private func updateInboxTitle(_ title: String) {
        for (sectionIndex, section) in menuItems.enumerated() {
            for (rowIndex, item) in section.enumerated() {
                if item.identifier == "inbox" {
                    menuItems[sectionIndex][rowIndex] = MenuItem(
                        icon: item.icon,
                        iconColor: item.iconColor,
                        title: title,
                        identifier: item.identifier
                    )
                    let indexPath = IndexPath(row: rowIndex, section: sectionIndex)
                    tableView.reloadRows(at: [indexPath], with: .none)
                    return
                }
            }
        }
    }

    private func openSystemNotesApp() {
        openURLIfPossible("mobilenotes://")
    }

    private func openFilesApp() {
        openURLIfPossible("shareddocuments://")
    }

    private func openURLIfPossible(_ string: String) {
        guard let url = URL(string: string) else { return }
        guard UIApplication.shared.canOpenURL(url) else { return }
        UIApplication.shared.open(url, options: [:], completionHandler: nil)
    }
}