//
//  ClipInboxViewController.swift
//  Note
//
//  Created by Kimi Code CLI on 2026/7/15.
//

import UIKit

class ClipInboxViewController: UIViewController {

    private var tableView: UITableView!
    private var emptyLabel: UILabel!
    private var archiveButton: UIButton!
    private var clips: [Clip] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        title = "收集箱"
        navigationItem.largeTitleDisplayMode = .never
        view.backgroundColor = .systemGroupedBackground

        setupNavigationBar()
        setupArchiveButton()
        setupTableView()
        setupEmptyLabel()
    }

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

    private func setupNavigationBar() {
        let clearButton = UIBarButtonItem(
            title: "清空",
            style: .plain,
            target: self,
            action: #selector(didTapClearButton)
        )
        clearButton.tintColor = .systemRed
        navigationItem.rightBarButtonItem = clearButton
    }

    private func setupTableView() {
        tableView = UITableView(frame: .zero, style: .insetGrouped)
        tableView.translatesAutoresizingMaskIntoConstraints = false
        tableView.delegate = self
        tableView.dataSource = self
        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "clipCell")
        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: archiveButton.topAnchor, constant: -16)
        ])
    }

    private func setupArchiveButton() {
        var config = UIButton.Configuration.filled()
        config.title = "归档"
        config.baseBackgroundColor = .systemBlue
        config.baseForegroundColor = .white
        config.cornerStyle = .medium
        config.contentInsets = NSDirectionalEdgeInsets(top: 0, leading: 16, bottom: 0, trailing: 16)

        archiveButton = UIButton(configuration: config)
        archiveButton.translatesAutoresizingMaskIntoConstraints = false
        archiveButton.addTarget(self, action: #selector(didTapArchiveButton), for: .touchUpInside)
        view.addSubview(archiveButton)

        NSLayoutConstraint.activate([
            archiveButton.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 16),
            archiveButton.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -16),
            archiveButton.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -16),
            archiveButton.heightAnchor.constraint(equalToConstant: 52)
        ])
    }

    @objc private func didTapArchiveButton() {
        guard clips.count >= 2 else {
            let alert = UIAlertController(title: "提示", message: "至少需要两条文案才能归档。", preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: "确定", style: .default))
            present(alert, animated: true)
            return
        }

        let title = self.archiveTitle()
        let itemsText = clips.map { "\($0.text)\n\n---" }.joined(separator: "\n\n")
        let archivedText = "\(title)\n\n\(itemsText)"
        let viewController = FormatNoteViewController()
        viewController.initialText = archivedText
        navigationController?.pushViewController(viewController, animated: true)
    }

    private func archiveTitle() -> String {
        let dateFormatter = DateFormatter()
        dateFormatter.locale = Locale(identifier: "zh_CN")
        dateFormatter.dateFormat = "yyyy年MM月dd日"
        let dateString = dateFormatter.string(from: Date())
        let weekdays = ["星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"]
        let weekdayIndex = Calendar.current.component(.weekday, from: Date()) - 1
        let weekday = (weekdayIndex >= 0 && weekdayIndex < weekdays.count) ? weekdays[weekdayIndex] : ""
        return "【读书摘抄】\(dateString) \(weekday)"
    }

    private func setupEmptyLabel() {
        emptyLabel = UILabel()
        emptyLabel.translatesAutoresizingMaskIntoConstraints = false
        emptyLabel.text = "还没有保存的文案\n复制内容后运行快捷指令即可收藏"
        emptyLabel.numberOfLines = 0
        emptyLabel.textAlignment = .center
        emptyLabel.textColor = .secondaryLabel
        emptyLabel.font = UIFont.preferredFont(forTextStyle: .body)
        emptyLabel.isHidden = true
        view.addSubview(emptyLabel)

        NSLayoutConstraint.activate([
            emptyLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            emptyLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            emptyLabel.leadingAnchor.constraint(equalTo: view.readableContentGuide.leadingAnchor),
            emptyLabel.trailingAnchor.constraint(equalTo: view.readableContentGuide.trailingAnchor)
        ])
    }

    private func loadClips() {
        Task {
            do {
                clips = try await ClipStore.shared.loadAll()
                await MainActor.run {
                    tableView.reloadData()
                    updateEmptyState()
                }
            } catch {
                await MainActor.run {
                    showError(message: "加载失败: \(error.localizedDescription)")
                }
            }
        }
    }

    private func updateEmptyState() {
        let isEmpty = clips.isEmpty
        emptyLabel.isHidden = !isEmpty
        tableView.isHidden = isEmpty
        archiveButton.isHidden = isEmpty
    }

    @objc private func didTapClearButton() {
        guard !clips.isEmpty else {
            let alert = UIAlertController(title: "提示", message: "收集箱为空，没有可清空的内容。", preferredStyle: .alert)
            alert.addAction(UIAlertAction(title: "确定", style: .default))
            present(alert, animated: true)
            return
        }

        let alert = UIAlertController(
            title: "清空收集箱",
            message: "确定要删除所有保存的文案吗？此操作不可撤销。",
            preferredStyle: .alert
        )
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        alert.addAction(UIAlertAction(title: "清空", style: .destructive) { [weak self] _ in
            self?.clearAllClips()
        })
        present(alert, animated: true)
    }

    private func clearAllClips() {
        Task {
            do {
                try await ClipStore.shared.clearAll()
                clips = []
                await MainActor.run {
                    tableView.reloadData()
                    updateEmptyState()
                }
            } catch {
                await MainActor.run {
                    showError(message: "清空失败: \(error.localizedDescription)")
                }
            }
        }
    }

    private func deleteClip(at indexPath: IndexPath) {
        let clip = clips[indexPath.row]
        Task {
            do {
                try await ClipStore.shared.delete(id: clip.id)
                clips.remove(at: indexPath.row)
                await MainActor.run {
                    tableView.deleteRows(at: [indexPath], with: .automatic)
                    updateEmptyState()
                }
            } catch {
                await MainActor.run {
                    showError(message: "删除失败: \(error.localizedDescription)")
                }
            }
        }
    }

    private func openClip(_ clip: Clip) {
        let viewController = ClipEditViewController(clip: clip)
        navigationController?.pushViewController(viewController, animated: true)
    }

    private func showError(message: String) {
        let alert = UIAlertController(title: "提示", message: message, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "确定", style: .default))
        present(alert, animated: true)
    }
}

extension ClipInboxViewController: UITableViewDataSource {

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

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "clipCell", for: indexPath)
        let clip = clips[indexPath.row]

        var config = cell.defaultContentConfiguration()
        config.text = previewText(for: clip.text)
        config.secondaryText = formattedDate(clip.createdAt)
        config.secondaryTextProperties.color = .secondaryLabel
        cell.contentConfiguration = config
        cell.accessoryType = .disclosureIndicator

        return cell
    }

    private func previewText(for text: String) -> String {
        let lines = text.components(separatedBy: .newlines)
        let firstTwoLines = Array(lines.prefix(2))
        let preview = firstTwoLines.joined(separator: " ").trimmingCharacters(in: .whitespaces)
        if preview.isEmpty {
            return "（无内容）"
        }
        return preview
    }

    private func formattedDate(_ date: Date) -> String {
        let formatter = RelativeDateTimeFormatter()
        formatter.unitsStyle = .short
        return formatter.localizedString(for: date, relativeTo: Date())
    }
}

extension ClipInboxViewController: UITableViewDelegate {

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
        let clip = clips[indexPath.row]
        openClip(clip)
    }

    func tableView(_ tableView: UITableView,
                   trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
        let deleteAction = UIContextualAction(style: .destructive, title: "删除") { [weak self] _, _, completion in
            self?.deleteClip(at: indexPath)
            completion(true)
        }
        return UISwipeActionsConfiguration(actions: [deleteAction])
    }
}