import Kingfisher
import SnapKit
import UIKit

/// 当前账号的 AI 修图任务中心，提供筛选、游标分页、刷新与状态轮询。
final class TravelAlbumAIJobListViewController: BaseViewController {
    private enum Section { case main }

    private let viewModel = TravelAlbumAIJobListViewModel()
    private let api: any TravelAlbumServing
    private let filterContainer = UIView()
    private let filterStack = UIStackView()
    private var filterButtons: [TravelAlbumAIJobFilter: UIButton] = [:]
    private lazy var collectionView = UICollectionView(frame: .zero, collectionViewLayout: makeLayout())
    private let refreshControl = UIRefreshControl()
    private let emptyView = AIJobEmptyView()
    private var dataSource: UICollectionViewDiffableDataSource<Section, TravelAlbumAIJobSummary>!
    private var pollingTask: Task<Void, Never>?
    private var isVisible = false
    private var isPresentingLoading = false

    /// 创建任务中心，可注入 API 以支持测试。
    init(api: (any TravelAlbumServing)? = nil) {
        self.api = api ?? NetworkServices.shared.travelAlbumAPI
        super.init(nibName: nil, bundle: nil)
    }

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

    override func setupNavigationBar() {
        let titleLabel = UILabel()
        titleLabel.text = "AI修图任务"
        titleLabel.textColor = UIColor(hex: 0x0F1F3D)
        titleLabel.font = .systemFont(ofSize: 20, weight: .semibold)
        navigationItem.titleView = titleLabel
        navigationItem.backButtonDisplayMode = .minimal
        let appearance = UINavigationBarAppearance()
        appearance.configureWithOpaqueBackground()
        appearance.backgroundColor = .white
        appearance.shadowColor = .clear
        navigationItem.standardAppearance = appearance
        navigationItem.scrollEdgeAppearance = appearance
        navigationItem.compactAppearance = appearance
        navigationController?.setNavigationBarHidden(false, animated: false)
    }

    override func setupUI() {
        view.backgroundColor = AppColor.pageBackgroundSoft
        configureFilters()
        collectionView.backgroundColor = .clear
        collectionView.alwaysBounceVertical = true
        collectionView.delegate = self
        collectionView.refreshControl = refreshControl
        collectionView.register(AIJobSummaryCell.self, forCellWithReuseIdentifier: AIJobSummaryCell.reuseIdentifier)
        dataSource = UICollectionViewDiffableDataSource<Section, TravelAlbumAIJobSummary>(collectionView: collectionView) {
            collectionView, indexPath, item in
            let cell = collectionView.dequeueReusableCell(
                withReuseIdentifier: AIJobSummaryCell.reuseIdentifier,
                for: indexPath
            ) as! AIJobSummaryCell
            cell.apply(item)
            return cell
        }
        emptyView.onRetry = { [weak self] in self?.reload() }
        view.addSubview(filterContainer)
        filterContainer.addSubview(filterStack)
        view.addSubview(collectionView)
        view.addSubview(emptyView)
    }

    override func setupConstraints() {
        filterContainer.snp.makeConstraints { make in
            make.top.equalTo(view.safeAreaLayoutGuide).offset(12)
            make.leading.trailing.equalToSuperview().inset(20)
            make.height.equalTo(46)
        }
        filterStack.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(2)
        }
        collectionView.snp.makeConstraints { make in
            make.top.equalTo(filterContainer.snp.bottom).offset(14)
            make.leading.trailing.bottom.equalToSuperview()
        }
        emptyView.snp.makeConstraints { make in
            make.top.equalTo(filterContainer.snp.bottom)
            make.leading.trailing.bottom.equalToSuperview()
        }
    }

    override func bindActions() {
        refreshControl.addTarget(self, action: #selector(refreshTriggered), for: .valueChanged)
        viewModel.onStateChange = { [weak self] in Task { @MainActor in self?.applyState() } }
        viewModel.onShowMessage = { [weak self] message in Task { @MainActor in self?.showToast(message) } }
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(applicationBecameActive),
            name: UIApplication.didBecomeActiveNotification,
            object: nil
        )
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(applicationEnteredBackground),
            name: UIApplication.didEnterBackgroundNotification,
            object: nil
        )
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        Task { await viewModel.loadFirstPage(api: api) }
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        isVisible = true
        updateLoadingPresentation()
        updatePolling()
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        isVisible = false
        setLoadingPresented(false)
        stopPolling()
    }

    deinit {
        pollingTask?.cancel()
        NotificationCenter.default.removeObserver(self)
    }

    private func configureFilters() {
        filterContainer.accessibilityIdentifier = "aiRetouchJob.filterContainer"
        filterContainer.backgroundColor = .white
        filterContainer.layer.cornerRadius = 12
        filterContainer.layer.borderWidth = 1
        filterContainer.layer.borderColor = UIColor(hex: 0xE8EEF7).cgColor
        filterContainer.layer.shadowColor = UIColor(hex: 0x315B94).withAlphaComponent(0.12).cgColor
        filterContainer.layer.shadowOpacity = 1
        filterContainer.layer.shadowRadius = 7
        filterContainer.layer.shadowOffset = CGSize(width: 0, height: 3)
        filterStack.axis = .horizontal
        filterStack.spacing = 0
        filterStack.distribution = .fillEqually
        TravelAlbumAIJobFilter.allCases.forEach { filter in
            var configuration = UIButton.Configuration.plain()
            configuration.title = filter.title
            configuration.contentInsets = .zero
            let button = UIButton(configuration: configuration)
            button.tag = TravelAlbumAIJobFilter.allCases.firstIndex(of: filter) ?? 0
            button.titleLabel?.font = .systemFont(ofSize: 15, weight: .medium)
            button.layer.cornerRadius = 10
            button.addTarget(self, action: #selector(filterTapped(_:)), for: .touchUpInside)
            button.accessibilityLabel = "筛选：\(filter.title)"
            filterButtons[filter] = button
            filterStack.addArrangedSubview(button)
        }
    }

    private func makeLayout() -> UICollectionViewLayout {
        UICollectionViewCompositionalLayout { _, environment in
            let item = NSCollectionLayoutItem(layoutSize: .init(
                widthDimension: .fractionalWidth(1),
                heightDimension: .estimated(250)
            ))
            let group = NSCollectionLayoutGroup.vertical(
                layoutSize: .init(widthDimension: .fractionalWidth(1), heightDimension: .estimated(250)),
                subitems: [item]
            )
            let section = NSCollectionLayoutSection(group: group)
            section.interGroupSpacing = 14
            section.contentInsets = NSDirectionalEdgeInsets(top: 0, leading: 20, bottom: 24, trailing: 20)
            return section
        }
    }

    @MainActor
    private func applyState() {
        filterButtons.forEach { filter, button in
            let selected = filter == viewModel.selectedFilter
            button.configuration?.baseForegroundColor = selected ? .white : AppColor.textSecondary
            button.configuration?.background.backgroundColor = .clear
            button.backgroundColor = selected ? AppColor.primary : .clear
            button.accessibilityTraits = selected ? [.button, .selected] : .button
        }
        refreshControl.endRefreshing()
        var snapshot = NSDiffableDataSourceSnapshot<Section, TravelAlbumAIJobSummary>()
        snapshot.appendSections([.main])
        snapshot.appendItems(viewModel.items)
        dataSource.apply(snapshot, animatingDifferences: true)
        let empty = viewModel.items.isEmpty && !viewModel.isLoading
        emptyView.isHidden = !empty
        emptyView.apply(
            title: viewModel.errorMessage == nil ? "暂无AI修图任务" : "任务加载失败",
            message: viewModel.errorMessage ?? "提交AI修图后，可以在这里查看进度和结果。",
            showsRetry: viewModel.errorMessage != nil
        )
        updateLoadingPresentation()
        updatePolling()
    }

    @MainActor
    private func updateLoadingPresentation() {
        setLoadingPresented(isVisible && viewModel.isLoading && viewModel.items.isEmpty)
    }

    @MainActor
    private func setLoadingPresented(_ presented: Bool) {
        guard isPresentingLoading != presented else { return }
        isPresentingLoading = presented
        if presented {
            showLoading()
        } else {
            hideLoading()
        }
    }

    private func reload() { Task { await viewModel.loadFirstPage(api: api) } }

    @objc private func refreshTriggered() {
        Task { await viewModel.loadFirstPage(api: api, refreshing: true) }
    }

    @objc private func filterTapped(_ sender: UIButton) {
        guard TravelAlbumAIJobFilter.allCases.indices.contains(sender.tag) else { return }
        Task { await viewModel.selectFilter(TravelAlbumAIJobFilter.allCases[sender.tag], api: api) }
    }

    @objc private func applicationBecameActive() { updatePolling() }
    @objc private func applicationEnteredBackground() { stopPolling() }

    private func updatePolling() {
        guard isVisible,
              UIApplication.shared.applicationState == .active,
              viewModel.containsInProgressJobs,
              pollingTask == nil
        else {
            if !viewModel.containsInProgressJobs { stopPolling() }
            return
        }
        pollingTask = Task { [weak self] in
            while !Task.isCancelled {
                try? await Task.sleep(for: .seconds(15))
                guard !Task.isCancelled, let self else { break }
                await self.viewModel.loadFirstPage(api: self.api, silent: true)
            }
        }
    }

    private func stopPolling() {
        pollingTask?.cancel()
        pollingTask = nil
    }
}

extension TravelAlbumAIJobListViewController: UICollectionViewDelegate {
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        guard let item = dataSource.itemIdentifier(for: indexPath) else { return }
        navigationController?.pushViewController(
            TravelAlbumAIJobDetailViewController(batchId: item.aiRetouchBatchId, api: api),
            animated: true
        )
    }

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        guard scrollView.contentSize.height > 0,
              scrollView.contentOffset.y + scrollView.bounds.height > scrollView.contentSize.height - 240
        else { return }
        Task { await viewModel.loadMore(api: api) }
    }
}

/// AI 修图任务列表卡片。
private final class AIJobSummaryCell: UICollectionViewCell {
    static let reuseIdentifier = "AIJobSummaryCell"
    private let topInfoView = UIView()
    private let albumCoverImageView = UIImageView()
    private let albumLabel = UILabel()
    private let phoneLabel = UILabel()
    private let taskLabel = UILabel()
    private let timeIconView = UIImageView(image: UIImage(systemName: "clock"))
    private let timeLabel = UILabel()
    private let timeStack = UIStackView()
    private let statusBadge = AIJobStatusBadgeView()
    private let previewStack = UIStackView()
    private var previewImageViews: [UIImageView] = []
    private let progressRow = UIStackView()
    private let completedLabel = UILabel()
    private let outputLabel = UILabel()
    private let progressView = UIProgressView(progressViewStyle: .default)
    private let percentLabel = UILabel()
    private let etaLabel = UILabel()
    private let bottomRow = UIView()
    private let outputPill = UIView()
    private let outputIconView = UIImageView(image: UIImage(systemName: "wand.and.stars"))
    private let detailsLabel = UILabel()
    private let chevronView = UIImageView(image: UIImage(systemName: "chevron.right"))
    private let contentStack = UIStackView()

    override init(frame: CGRect) {
        super.init(frame: frame)
        contentView.backgroundColor = .white
        contentView.layer.cornerRadius = 16
        contentView.layer.borderWidth = 1
        contentView.layer.borderColor = UIColor(hex: 0xE6EDF8).cgColor
        contentView.layer.shadowColor = UIColor(hex: 0x315B94).withAlphaComponent(0.1).cgColor
        contentView.layer.shadowOpacity = 1
        contentView.layer.shadowRadius = 9
        contentView.layer.shadowOffset = CGSize(width: 0, height: 4)

        configureTopInfo()
        configurePreviewGrid()

        completedLabel.font = .systemFont(ofSize: 14, weight: .medium)
        completedLabel.textColor = UIColor(hex: 0x263754)
        progressView.tintColor = AppColor.primary
        progressView.trackTintColor = UIColor(hex: 0xE5EAF2)
        progressView.layer.cornerRadius = 3
        progressView.clipsToBounds = true
        percentLabel.font = .systemFont(ofSize: 14, weight: .medium)
        percentLabel.textColor = UIColor(hex: 0x263754)
        percentLabel.textAlignment = .right
        progressRow.axis = .horizontal
        progressRow.alignment = .center
        progressRow.spacing = 10
        progressRow.addArrangedSubview(completedLabel)
        progressRow.addArrangedSubview(progressView)
        progressRow.addArrangedSubview(percentLabel)
        progressView.snp.makeConstraints { $0.height.equalTo(6) }
        completedLabel.setContentHuggingPriority(.required, for: .horizontal)
        percentLabel.setContentHuggingPriority(.required, for: .horizontal)

        etaLabel.font = .systemFont(ofSize: 13)
        etaLabel.textColor = UIColor(hex: 0x7F8CA3)
        configureBottomRow()

        contentStack.axis = .vertical
        contentStack.spacing = 12
        [topInfoView, previewStack, progressRow, etaLabel, bottomRow].forEach {
            contentStack.addArrangedSubview($0)
        }
        contentView.addSubview(contentStack)
        contentStack.snp.makeConstraints { $0.edges.equalToSuperview().inset(14) }
        topInfoView.snp.makeConstraints { $0.height.equalTo(72) }
        previewStack.snp.makeConstraints { $0.height.equalTo(104) }
        bottomRow.snp.makeConstraints { $0.height.equalTo(34) }
        accessibilityIdentifier = "aiRetouchJob.summaryCell"
    }

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

    override func prepareForReuse() {
        super.prepareForReuse()
        albumCoverImageView.kf.cancelDownloadTask()
        albumCoverImageView.image = nil
        previewImageViews.forEach {
            $0.kf.cancelDownloadTask()
            $0.image = nil
            $0.isHidden = true
        }
    }

    func apply(_ item: TravelAlbumAIJobSummary) {
        albumLabel.text = item.album.name.isEmpty ? "未命名相册" : item.album.name
        let phone = TravelAlbumDisplayFormatter.maskPhone(item.album.userPhone)
        phoneLabel.text = phone.isEmpty ? "未提供手机号" : phone
        taskLabel.text = "任务 #\(item.aiRetouchBatchId)"
        timeLabel.text = relativeTime(item.createdAt)
        statusBadge.apply(item.status)
        albumCoverImageView.kf.setImage(
            with: URL(string: item.album.coverURL),
            placeholder: UIImage(systemName: "photo")
        )
        previewImageViews.enumerated().forEach { index, imageView in
            guard item.previewImages.indices.contains(index) else {
                imageView.isHidden = true
                return
            }
            imageView.isHidden = false
            imageView.kf.setImage(
                with: URL(string: item.previewImages[index].thumbnailURL),
                placeholder: UIImage(systemName: "photo")
            )
        }
        previewStack.isHidden = item.previewImages.isEmpty

        progressView.progress = Float(item.progress.fraction)
        if item.status.isInProgress {
            completedLabel.text = "已完成 \(item.progress.completed) / \(item.progress.total)"
            percentLabel.text = "\(Int((item.progress.fraction * 100).rounded()))%"
            etaLabel.text = item.estimatedFinishAt.map {
                "预计 \(TravelAlbumAIJobDateFormatter.time($0)) 前完成"
            } ?? "完成后将通过消息通知"
            progressRow.isHidden = false
            etaLabel.isHidden = false
            outputIconView.image = UIImage(systemName: "wand.and.stars")
            outputIconView.tintColor = AppColor.primary
            outputPill.backgroundColor = AppColor.primaryLight
            outputLabel.textColor = AppColor.primary
            outputLabel.text = item.outputs.map { "\(shortTitle($0.type)) \($0.count)张" }.joined(separator: " · ")
        } else if item.status == .partiallySucceeded {
            progressRow.isHidden = true
            etaLabel.isHidden = true
            outputIconView.image = UIImage(systemName: "exclamationmark.circle.fill")
            outputIconView.tintColor = AppColor.warning
            outputPill.backgroundColor = .clear
            outputLabel.textColor = UIColor(hex: 0xB56A00)
            outputLabel.text = "\(item.progress.succeeded)张成功 · \(item.progress.failed)张失败"
        } else {
            progressRow.isHidden = true
            etaLabel.isHidden = true
            let succeeded = item.status == .succeeded
            outputIconView.image = UIImage(systemName: succeeded ? "checkmark.circle.fill" : "xmark.circle.fill")
            outputIconView.tintColor = succeeded ? AppColor.success : AppColor.danger
            outputPill.backgroundColor = .clear
            outputLabel.textColor = succeeded ? UIColor(hex: 0x178A55) : AppColor.danger
            outputLabel.text = succeeded ? "\(item.progress.succeeded)张结果已生成" : item.status.title
        }
        accessibilityLabel = [albumLabel.text, statusBadge.accessibilityLabel, timeLabel.text, phoneLabel.text, taskLabel.text,
                              outputLabel.text, completedLabel.text, etaLabel.text]
            .compactMap { $0 }.joined(separator: "，")
        accessibilityTraits = .button
    }

    private func configureTopInfo() {
        albumCoverImageView.accessibilityIdentifier = "aiRetouchJob.albumCover"
        albumCoverImageView.contentMode = .scaleAspectFill
        albumCoverImageView.clipsToBounds = true
        albumCoverImageView.layer.cornerRadius = 10
        albumCoverImageView.backgroundColor = AppColor.pageBackground
        albumCoverImageView.tintColor = AppColor.textTertiary
        albumLabel.font = .systemFont(ofSize: 17, weight: .semibold)
        albumLabel.textColor = UIColor(hex: 0x0F1F3D)
        albumLabel.lineBreakMode = .byTruncatingTail
        phoneLabel.font = .systemFont(ofSize: 14)
        phoneLabel.textColor = UIColor(hex: 0x72809A)
        taskLabel.font = .systemFont(ofSize: 14)
        taskLabel.textColor = UIColor(hex: 0x72809A)
        timeIconView.tintColor = UIColor(hex: 0x7F8CA3)
        timeIconView.contentMode = .scaleAspectFit
        timeLabel.font = .systemFont(ofSize: 13)
        timeLabel.textColor = UIColor(hex: 0x7F8CA3)
        timeStack.axis = .horizontal
        timeStack.spacing = 5
        timeStack.alignment = .center
        timeStack.addArrangedSubview(timeIconView)
        timeStack.addArrangedSubview(timeLabel)

        [albumCoverImageView, albumLabel, phoneLabel, taskLabel, timeStack, statusBadge].forEach {
            topInfoView.addSubview($0)
        }
        albumCoverImageView.snp.makeConstraints { make in
            make.leading.top.equalToSuperview()
            make.size.equalTo(68)
        }
        timeIconView.snp.makeConstraints { $0.size.equalTo(15) }
        timeStack.snp.makeConstraints { make in
            make.top.trailing.equalToSuperview()
        }
        statusBadge.snp.makeConstraints { make in
            make.trailing.bottom.equalToSuperview()
            make.height.equalTo(30)
        }
        albumLabel.snp.makeConstraints { make in
            make.top.equalToSuperview().offset(1)
            make.leading.equalTo(albumCoverImageView.snp.trailing).offset(12)
            make.trailing.lessThanOrEqualTo(timeStack.snp.leading).offset(-8)
        }
        phoneLabel.snp.makeConstraints { make in
            make.leading.equalTo(albumLabel)
            make.top.equalTo(albumLabel.snp.bottom).offset(6)
            make.trailing.lessThanOrEqualTo(statusBadge.snp.leading).offset(-8)
        }
        taskLabel.snp.makeConstraints { make in
            make.leading.equalTo(albumLabel)
            make.top.equalTo(phoneLabel.snp.bottom).offset(5)
            make.trailing.lessThanOrEqualTo(statusBadge.snp.leading).offset(-8)
        }
    }

    private func configurePreviewGrid() {
        previewStack.axis = .horizontal
        previewStack.spacing = 8
        previewStack.distribution = .fillEqually
        for index in 0..<3 {
            let slot = UIView()
            let imageView = UIImageView()
            imageView.contentMode = .scaleAspectFill
            imageView.clipsToBounds = true
            imageView.layer.cornerRadius = 10
            imageView.backgroundColor = AppColor.pageBackground
            imageView.tintColor = AppColor.textTertiary
            imageView.accessibilityIdentifier = "aiRetouchJob.preview.\(index)"
            slot.addSubview(imageView)
            imageView.snp.makeConstraints { $0.edges.equalToSuperview() }
            previewStack.addArrangedSubview(slot)
            previewImageViews.append(imageView)
        }
    }

    private func configureBottomRow() {
        outputPill.layer.cornerRadius = 9
        outputPill.clipsToBounds = true
        outputIconView.contentMode = .scaleAspectFit
        outputLabel.font = .systemFont(ofSize: 13, weight: .medium)
        outputLabel.numberOfLines = 1
        outputLabel.adjustsFontSizeToFitWidth = true
        outputLabel.minimumScaleFactor = 0.8
        outputPill.addSubview(outputIconView)
        outputPill.addSubview(outputLabel)
        outputIconView.snp.makeConstraints { make in
            make.leading.equalToSuperview().offset(10)
            make.centerY.equalToSuperview()
            make.size.equalTo(17)
        }
        outputLabel.snp.makeConstraints { make in
            make.leading.equalTo(outputIconView.snp.trailing).offset(6)
            make.trailing.equalToSuperview().inset(10)
            make.centerY.equalToSuperview()
        }
        detailsLabel.text = "查看详情"
        detailsLabel.font = .systemFont(ofSize: 13)
        detailsLabel.textColor = UIColor(hex: 0x7F8CA3)
        chevronView.tintColor = UIColor(hex: 0x7F8CA3)
        chevronView.contentMode = .scaleAspectFit
        [outputPill, detailsLabel, chevronView].forEach { bottomRow.addSubview($0) }
        outputPill.snp.makeConstraints { make in
            make.leading.top.bottom.equalToSuperview()
            make.trailing.lessThanOrEqualTo(detailsLabel.snp.leading).offset(-8)
        }
        chevronView.snp.makeConstraints { make in
            make.trailing.centerY.equalToSuperview()
            make.size.equalTo(14)
        }
        detailsLabel.snp.makeConstraints { make in
            make.trailing.equalTo(chevronView.snp.leading).offset(-6)
            make.centerY.equalToSuperview()
        }
    }

    private func shortTitle(_ type: TravelAlbumAIJobOutputType) -> String {
        switch type {
        case .refined: "精修"
        case .atmosphere: "氛围感"
        case .cover: "封面"
        case .unknown: "其他"
        }
    }

    private func relativeTime(_ value: String) -> String {
        guard let date = TravelAlbumAIJobDateFormatter.date(value) else { return "--" }
        let calendar = Calendar.current
        let prefix: String
        if calendar.isDateInToday(date) {
            prefix = "今天"
        } else if calendar.isDateInYesterday(date) {
            prefix = "昨天"
        } else {
            prefix = date.formatted(.dateTime.month().day())
        }
        return "\(prefix) \(date.formatted(.dateTime.hour().minute()))"
    }
}

/// 带图标与底色的任务状态徽标，保证状态不只依赖颜色表达。
private final class AIJobStatusBadgeView: UIView {
    private let iconView = UIImageView()
    private let titleLabel = UILabel()

    override init(frame: CGRect) {
        super.init(frame: frame)
        layer.cornerRadius = 9
        iconView.contentMode = .scaleAspectFit
        titleLabel.font = .systemFont(ofSize: 14, weight: .medium)
        addSubview(iconView)
        addSubview(titleLabel)
        iconView.snp.makeConstraints { make in
            make.leading.equalToSuperview().offset(9)
            make.centerY.equalToSuperview()
            make.size.equalTo(17)
        }
        titleLabel.snp.makeConstraints { make in
            make.leading.equalTo(iconView.snp.trailing).offset(5)
            make.trailing.equalToSuperview().inset(10)
            make.centerY.equalToSuperview()
        }
    }

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

    func apply(_ status: TravelAlbumAIJobStatus) {
        titleLabel.text = status.title
        let color: UIColor
        let background: UIColor
        let symbol: String
        switch status {
        case .queued:
            color = AppColor.primary
            background = AppColor.infoBackground
            symbol = "clock.arrow.circlepath"
        case .processing:
            color = AppColor.primary
            background = AppColor.infoBackground
            symbol = "arrow.triangle.2.circlepath"
        case .succeeded:
            color = AppColor.success
            background = AppColor.successBackground
            symbol = "checkmark.circle.fill"
        case .partiallySucceeded:
            color = AppColor.warning
            background = AppColor.warningBackground
            symbol = "exclamationmark.circle.fill"
        case .failed:
            color = AppColor.danger
            background = AppColor.dangerBackground
            symbol = "xmark.circle.fill"
        case .canceled, .unknown:
            color = AppColor.textSecondary
            background = AppColor.pageBackground
            symbol = "minus.circle.fill"
        }
        titleLabel.textColor = color
        iconView.tintColor = color
        iconView.image = UIImage(systemName: symbol)
        backgroundColor = background
        accessibilityLabel = status.title
    }
}

/// 任务列表空态和错误态。
private final class AIJobEmptyView: UIView {
    private let imageView = UIImageView(image: UIImage(systemName: "photo.on.rectangle.angled"))
    private let titleLabel = UILabel()
    private let messageLabel = UILabel()
    private let retryButton = UIButton(type: .system)
    var onRetry: (() -> Void)?

    override init(frame: CGRect) {
        super.init(frame: frame)
        imageView.tintColor = AppColor.primary
        imageView.contentMode = .scaleAspectFit
        titleLabel.font = .systemFont(ofSize: 17, weight: .semibold)
        titleLabel.textAlignment = .center
        messageLabel.font = .systemFont(ofSize: 14)
        messageLabel.textColor = AppColor.textSecondary
        messageLabel.textAlignment = .center
        messageLabel.numberOfLines = 0
        retryButton.setTitle("重新加载", for: .normal)
        retryButton.addTarget(self, action: #selector(retry), for: .touchUpInside)
        let stack = UIStackView(arrangedSubviews: [imageView, titleLabel, messageLabel, retryButton])
        stack.axis = .vertical
        stack.alignment = .center
        stack.spacing = 12
        addSubview(stack)
        stack.snp.makeConstraints { make in
            make.centerY.equalToSuperview().offset(-40)
            make.leading.trailing.equalToSuperview().inset(40)
        }
        imageView.snp.makeConstraints { $0.size.equalTo(52) }
    }

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

    func apply(title: String, message: String, showsRetry: Bool) {
        titleLabel.text = title
        messageLabel.text = message
        retryButton.isHidden = !showsRetry
    }

    @objc private func retry() { onRetry?() }
}