//
//  OrdersViewController.swift
//  suixinkan
//

import SnapKit
import UIKit

// MARK: - Diffable 标识（Int / String 避免 MainActor 默认隔离下 Hashable 冲突）

/// 订单列表 section 索引。
private enum OrdersSectionID {
    static let header = 0
    static let toolbar = 1
    static let content = 2
}

private typealias OrdersSection = Int

/// 订单列表 item 字符串标识。
private enum OrdersItemID {
    static let header = "orders:header"
    static let filter = "orders:filter"
    static let writeOffAction = "orders:writeOffAction"
    static let missingContext = "orders:missingContext"
    static let emptyStore = "orders:empty:store"
    static let emptyWriteOff = "orders:empty:writeOff"
    static func storeOrder(_ orderNumber: String) -> String { "orders:store:\(orderNumber)" }
    static func writeOffOrder(_ orderNumber: String) -> String { "orders:writeoff:\(orderNumber)" }
}

private typealias OrdersItem = String

/// 订单 Tab 根页面，展示订单管理和核销订单两个子入口及对应列表。
final class OrdersViewController: UIViewController {

    private let viewModel = OrdersViewModel()
    private var manualOrderNumber = ""
    private var scanHintMessage: String?
    private var pendingScanCode: String?

    private lazy var collectionView: UICollectionView = {
        let layout = makeCollectionLayout()
        let collection = UICollectionView(frame: .zero, collectionViewLayout: layout)
        collection.backgroundColor = AppDesignUIKit.pageBackground
        collection.delegate = self
        collection.register(OrdersHeaderCell.self, forCellWithReuseIdentifier: OrdersHeaderCell.reuseID)
        collection.register(OrdersFilterCell.self, forCellWithReuseIdentifier: OrdersFilterCell.reuseID)
        collection.register(OrdersWriteOffActionCell.self, forCellWithReuseIdentifier: OrdersWriteOffActionCell.reuseID)
        collection.register(OrderEntityCell.self, forCellWithReuseIdentifier: OrderEntityCell.reuseID)
        collection.register(WriteOffOrderCell.self, forCellWithReuseIdentifier: WriteOffOrderCell.reuseID)
        collection.register(OrdersEmptyStateCell.self, forCellWithReuseIdentifier: OrdersEmptyStateCell.reuseID)
        return collection
    }()

    private lazy var dataSource: UICollectionViewDiffableDataSource<OrdersSection, OrdersItem> = {
        UICollectionViewDiffableDataSource<OrdersSection, OrdersItem>(collectionView: collectionView) { [weak self] collectionView, indexPath, item in
            self?.cell(for: collectionView, at: indexPath, item: item) ?? UICollectionViewCell()
        }
    }()

    private lazy var refreshControl = UIRefreshControl()

    /// 视图加载完成后的 UI 初始化与数据绑定。
    override func viewDidLoad() {
        super.viewDidLoad()
        title = "订单"
        view.backgroundColor = AppDesignUIKit.pageBackground

        view.addSubview(collectionView)
        collectionView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
        }
        refreshControl.addTarget(self, action: #selector(refreshPulled), for: .valueChanged)
        collectionView.refreshControl = refreshControl

        viewModel.onChange = { [weak self] in
            self?.applySnapshot()
        }

        appServices.accountContext.onChange = { [weak self] in
            Task { await self?.reload(showLoading: true) }
        }

        Task {
            await reload(showLoading: true)
            await consumePendingScanCodeIfNeeded()
        }
    }

    /// 应用来自首页、推送或全局扫码入口的订单子入口状态。
    func applyOrdersEntry(_ entry: OrdersEntry, scannedCode: String?) {
        let didChangeEntry = viewModel.selectedEntry != entry
        viewModel.selectedEntry = entry
        if let scannedCode {
            pendingScanCode = scannedCode
        }

        guard isViewLoaded else { return }

        Task {
            if didChangeEntry {
                await reload(showLoading: true)
            }
            await consumePendingScanCodeIfNeeded()
        }
    }

    /// 构建 Compositional Layout，按 section 类型选用全宽布局。
    private func makeCollectionLayout() -> UICollectionViewCompositionalLayout {
        UICollectionViewCompositionalLayout { [weak self] sectionIndex, _ in
            guard let self else {
                return CollectionDiffableLayout.fullWidthSection()
            }
            let section = self.dataSource.snapshot().sectionIdentifiers[sectionIndex]
            switch section {
            case OrdersSectionID.header:
                return CollectionDiffableLayout.fullWidthSection(height: 120)
            case OrdersSectionID.toolbar:
                let height: CGFloat = self.viewModel.selectedEntry == .storeOrders ? 130 : 150
                return CollectionDiffableLayout.fullWidthSection(height: height)
            case OrdersSectionID.content:
                return CollectionDiffableLayout.fullWidthSection(estimatedHeight: 88)
            default:
                return CollectionDiffableLayout.fullWidthSection()
            }
        }
    }

    /// 根据当前 ViewModel 与页面状态构建并应用 Diffable 快照。
    private func applySnapshot(animatingDifferences: Bool = true) {
        var snapshot = NSDiffableDataSourceSnapshot<OrdersSection, OrdersItem>()
        snapshot.appendSections([OrdersSectionID.header])
        snapshot.appendItems([OrdersItemID.header], toSection: OrdersSectionID.header)

        guard currentScenicId != nil else {
            dataSource.apply(snapshot, animatingDifferences: animatingDifferences)
            return
        }

        snapshot.appendSections([OrdersSectionID.toolbar, OrdersSectionID.content])

        if viewModel.selectedEntry == .storeOrders {
            snapshot.appendItems([OrdersItemID.filter], toSection: OrdersSectionID.toolbar)
            appendStoreOrderItems(to: &snapshot)
        } else {
            snapshot.appendItems([OrdersItemID.writeOffAction], toSection: OrdersSectionID.toolbar)
            appendWriteOffOrderItems(to: &snapshot)
        }

        dataSource.apply(snapshot, animatingDifferences: animatingDifferences)
    }

    /// 向快照追加订单管理列表或空态 item。
    private func appendStoreOrderItems(to snapshot: inout NSDiffableDataSourceSnapshot<OrdersSection, OrdersItem>) {
        if viewModel.storeOrders.isEmpty {
            guard !(viewModel.loading && viewModel.storeOrders.isEmpty) else { return }
            snapshot.appendItems([OrdersItemID.emptyStore], toSection: OrdersSectionID.content)
            return
        }
        snapshot.appendItems(
            viewModel.storeOrders.map { OrdersItemID.storeOrder($0.orderNumber) },
            toSection: OrdersSectionID.content
        )
    }

    /// 向快照追加核销订单列表或空态 item。
    private func appendWriteOffOrderItems(to snapshot: inout NSDiffableDataSourceSnapshot<OrdersSection, OrdersItem>) {
        if viewModel.writeOffOrders.isEmpty {
            guard !(viewModel.loading && viewModel.writeOffOrders.isEmpty) else { return }
            snapshot.appendItems([OrdersItemID.emptyWriteOff], toSection: OrdersSectionID.content)
            return
        }
        snapshot.appendItems(
            viewModel.writeOffOrders.map { OrdersItemID.writeOffOrder($0.orderNumber) },
            toSection: OrdersSectionID.content
        )
    }

    /// 按 item 类型 dequeue 并配置对应 Cell。
    private func cell(
        for collectionView: UICollectionView,
        at indexPath: IndexPath,
        item: OrdersItem
    ) -> UICollectionViewCell {
        switch item {
        case OrdersItemID.header:
            let cell = collectionView.dequeueReusableCell(
                withReuseIdentifier: OrdersHeaderCell.reuseID,
                for: indexPath
            ) as! OrdersHeaderCell
            cell.configure(
                selectedEntry: viewModel.selectedEntry,
                scenicName: appServices.accountContext.currentScenic?.name ?? "--",
                storeTotal: viewModel.storeTotal,
                writeOffTotal: viewModel.writeOffTotal,
                onSelectEntry: { [weak self] entry in self?.switchEntry(entry) }
            )
            return cell

        case OrdersItemID.filter:
            let cell = collectionView.dequeueReusableCell(
                withReuseIdentifier: OrdersFilterCell.reuseID,
                for: indexPath
            ) as! OrdersFilterCell
            let statusTitle = OrderFilters.statusFilters.first(where: { $0.id == viewModel.selectedStatus })?.title ?? "全部"
            cell.configure(
                statusTitle: statusTitle,
                phone: viewModel.searchPhone,
                onStatus: { [weak self] in self?.presentStatusFilter() },
                onDate: { [weak self] in self?.presentDateFilter() },
                onPhoneChange: { [weak self] text in self?.viewModel.searchPhone = text },
                onSearch: { [weak self] in Task { await self?.reload(showLoading: true) } }
            )
            return cell

        case OrdersItemID.writeOffAction:
            let cell = collectionView.dequeueReusableCell(
                withReuseIdentifier: OrdersWriteOffActionCell.reuseID,
                for: indexPath
            ) as! OrdersWriteOffActionCell
            cell.configure(
                manualOrderNumber: manualOrderNumber,
                isVerifying: viewModel.isVerifying,
                hint: scanHintMessage,
                onScan: { [weak self] in self?.presentScanner() },
                onManualChange: { [weak self] text in self?.manualOrderNumber = text },
                onVerify: { [weak self] in
                    guard let self, !self.manualOrderNumber.isEmpty else { return }
                    self.confirmVerify(orderNumber: self.manualOrderNumber)
                }
            )
            return cell

        case OrdersItemID.missingContext:
            let cell = collectionView.dequeueReusableCell(
                withReuseIdentifier: OrdersEmptyStateCell.reuseID,
                for: indexPath
            ) as! OrdersEmptyStateCell
            cell.embed(
                makeEmptyStateView(
                    title: "缺少经营上下文",
                    message: "请先在首页选择景区后查看订单。",
                    systemImage: "mountain.2"
                ),
                preferredHeight: 360
            )
            return cell

        case OrdersItemID.emptyStore:
            let cell = collectionView.dequeueReusableCell(
                withReuseIdentifier: OrdersEmptyStateCell.reuseID,
                for: indexPath
            ) as! OrdersEmptyStateCell
            cell.embed(
                makeEmptyStateView(title: "暂无订单", message: "可切换筛选条件或下拉刷新。", systemImage: "tray"),
                preferredHeight: 260
            )
            return cell

        case OrdersItemID.emptyWriteOff:
            let cell = collectionView.dequeueReusableCell(
                withReuseIdentifier: OrdersEmptyStateCell.reuseID,
                for: indexPath
            ) as! OrdersEmptyStateCell
            cell.embed(
                makeEmptyStateView(title: "暂无核销订单", message: "可下拉刷新或切换景区查看。", systemImage: "tray"),
                preferredHeight: 260
            )
            return cell

        default:
            if item.hasPrefix("orders:store:") {
                let orderNumber = String(item.dropFirst("orders:store:".count))
                guard let order = viewModel.storeOrders.first(where: { $0.orderNumber == orderNumber }) else {
                    return UICollectionViewCell()
                }
                let cell = collectionView.dequeueReusableCell(
                    withReuseIdentifier: OrderEntityCell.reuseID,
                    for: indexPath
                ) as! OrderEntityCell
                cell.configure(item: order)
                return cell
            }
            if item.hasPrefix("orders:writeoff:") {
                let orderNumber = String(item.dropFirst("orders:writeoff:".count))
                guard let order = viewModel.writeOffOrders.first(where: { $0.orderNumber == orderNumber }) else {
                    return UICollectionViewCell()
                }
                let cell = collectionView.dequeueReusableCell(
                    withReuseIdentifier: WriteOffOrderCell.reuseID,
                    for: indexPath
                ) as! WriteOffOrderCell
                cell.configure(
                    item: order,
                    isVerifying: viewModel.currentVerifyingOrderNumber == order.orderNumber
                )
                return cell
            }
            return UICollectionViewCell()
        }
    }

    /// 下拉刷新触发重新加载。
    @objc private func refreshPulled() {
        Task {
            await reload(showLoading: false)
            refreshControl.endRefreshing()
        }
    }

    private var currentScenicId: Int? { appServices.accountContext.currentScenic?.id }
    private var currentStoreId: Int? { appServices.accountContext.currentStore?.id }
    private var currentRoleId: Int? { appServices.permissionContext.currentRole?.id }

    /// 重新加载当前子入口对应的订单数据。
    private func reload(showLoading: Bool) async {
        do {
            try await appServices.globalLoading.withOptionalLoading(showLoading, message: "加载订单...") {
                try await self.viewModel.reload(
                    api: self.appServices.ordersAPI,
                    scenicId: self.currentScenicId,
                    storeId: self.currentStoreId,
                    roleId: self.currentRoleId,
                    showLoading: false
                )
            }
        } catch {
            showToast(error.localizedDescription)
        }
    }

    /// 滚动到底部时加载下一页。
    private func loadMore() async {
        do {
            if viewModel.selectedEntry == .storeOrders {
                try await viewModel.loadMoreStoreOrders(
                    api: appServices.ordersAPI,
                    scenicId: currentScenicId,
                    roleId: currentRoleId
                )
            } else {
                try await viewModel.loadMoreWriteOffOrders(
                    api: appServices.ordersAPI,
                    scenicId: currentScenicId,
                    storeId: currentStoreId
                )
            }
        } catch {
            showToast(error.localizedDescription)
        }
    }

    /// 切换订单管理 / 核销订单子入口。
    private func switchEntry(_ entry: OrdersEntry) {
        guard viewModel.selectedEntry != entry else { return }
        viewModel.selectedEntry = entry
        Task { await reload(showLoading: true) }
    }

    /// 提交订单核销请求。
    private func verify(orderNumber: String) async {
        guard let scenicId = currentScenicId else { return }
        do {
            try await appServices.globalLoading.withLoading(message: "核销中...") {
                try await self.viewModel.verify(
                    api: self.appServices.ordersAPI,
                    scenicId: scenicId,
                    storeId: self.currentStoreId,
                    orderNumber: orderNumber
                )
            }
            showToast("核销成功")
        } catch {
            showToast(error.localizedDescription)
        }
    }

    /// 消费路由中暂存的扫码结果（核销入口）。
    private func consumePendingScanCodeIfNeeded() async {
        guard viewModel.selectedEntry == .verificationOrders,
              let code = pendingScanCode else { return }
        pendingScanCode = nil
        handleScanResult(code)
    }

    /// 解析扫码结果并引导核销或提示未匹配。
    private func handleScanResult(_ rawCode: String) {
        guard let parsed = viewModel.matchedWriteOffOrder(for: rawCode) else {
            showToast("未识别到有效订单号")
            return
        }
        if parsed.matched != nil {
            confirmVerify(orderNumber: parsed.orderNumber)
        } else {
            scanHintMessage = "扫码成功，当前列表未找到该订单"
            applySnapshot()
        }
    }

    /// 弹出核销确认对话框。
    private func confirmVerify(orderNumber: String) {
        let alert = UIAlertController(title: "确认核销该订单？", message: orderNumber, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        alert.addAction(UIAlertAction(title: "确认核销", style: .default) { [weak self] _ in
            Task { await self?.verify(orderNumber: orderNumber) }
        })
        present(alert, animated: true)
    }

    /// 打开订单号扫码页。
    private func presentScanner() {
        let scanner = OrderCodeScannerViewController()
        scanner.onScanResult = { [weak self, weak scanner] result in
            scanner?.dismiss(animated: true)
            guard let self else { return }
            switch result {
            case .success(let code):
                self.handleScanResult(code)
            case .failure(let error):
                self.showToast(error.localizedDescription)
            }
        }
        let nav = UINavigationController(rootViewController: scanner)
        nav.modalPresentationStyle = .fullScreen
        present(nav, animated: true)
    }

    /// 弹出时间筛选快捷选项。
    private func presentDateFilter() {
        let alert = UIAlertController(title: "时间筛选", message: "选择开始和结束日期", preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "清除筛选", style: .destructive) { [weak self] _ in
            self?.viewModel.filterStartDate = nil
            self?.viewModel.filterEndDate = nil
            Task { await self?.reload(showLoading: true) }
        })
        alert.addAction(UIAlertAction(title: "近7天", style: .default) { [weak self] _ in
            let end = Date()
            let start = Calendar.current.date(byAdding: .day, value: -6, to: end) ?? end
            self?.viewModel.filterStartDate = start
            self?.viewModel.filterEndDate = end
            Task { await self?.reload(showLoading: true) }
        })
        alert.addAction(UIAlertAction(title: "取消", style: .cancel))
        present(alert, animated: true)
    }

    /// 弹出订单状态筛选 ActionSheet。
    private func presentStatusFilter() {
        let sheet = UIAlertController(title: "订单状态", message: nil, preferredStyle: .actionSheet)
        for filter in OrderFilters.statusFilters {
            sheet.addAction(UIAlertAction(title: filter.title, style: .default) { [weak self] _ in
                self?.viewModel.selectedStatus = filter.id
                Task { await self?.reload(showLoading: true) }
            })
        }
        sheet.addAction(UIAlertAction(title: "取消", style: .cancel))
        present(sheet, animated: true)
    }
}

// MARK: - UICollectionViewDelegate

extension OrdersViewController: UICollectionViewDelegate {
    /// 点击订单卡片进入详情。
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        collectionView.deselectItem(at: indexPath, animated: true)
        guard let item = dataSource.itemIdentifier(for: indexPath) else { return }
        if item.hasPrefix("orders:store:") {
            let orderNumber = String(item.dropFirst("orders:store:".count))
            guard let order = viewModel.storeOrders.first(where: { $0.orderNumber == orderNumber }) else { return }
            appServices.appNavigator.push(.orders(.storeDetail(order)), from: self)
        } else if item.hasPrefix("orders:writeoff:") {
            let orderNumber = String(item.dropFirst("orders:writeoff:".count))
            guard let order = viewModel.writeOffOrders.first(where: { $0.orderNumber == orderNumber }) else { return }
            appServices.appNavigator.push(.orders(.writeOffDetail(order)), from: self)
        }
    }

    /// 列表即将展示最后一项时触发分页加载。
    func collectionView(
        _ collectionView: UICollectionView,
        willDisplay cell: UICollectionViewCell,
        forItemAt indexPath: IndexPath
    ) {
        guard let item = dataSource.itemIdentifier(for: indexPath) else { return }
        let isLast: Bool
        if item.hasPrefix("orders:store:") {
            let orderNumber = String(item.dropFirst("orders:store:".count))
            isLast = orderNumber == viewModel.storeOrders.last?.orderNumber
        } else if item.hasPrefix("orders:writeoff:") {
            let orderNumber = String(item.dropFirst("orders:writeoff:".count))
            isLast = orderNumber == viewModel.writeOffOrders.last?.orderNumber
        } else {
            isLast = false
        }
        if isLast {
            Task { await loadMore() }
        }
    }
}

// MARK: - Cells

/// 订单页头部 Cell，展示子入口切换与统计摘要。
private final class OrdersHeaderCell: UICollectionViewCell {
    static let reuseID = "OrdersHeaderCell"
    private var onSelectEntry: ((OrdersEntry) -> Void)?

    private let storeButton = UIButton(type: .system)
    private let verifyButton = UIButton(type: .system)
    private let leftPill = UILabel()
    private let rightPill = UILabel()

    /// 初始化 Cell 与子视图布局。
    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
        let card = UIView()
        card.backgroundColor = .white
        card.layer.cornerRadius = 8
        contentView.addSubview(card)
        card.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(UIEdgeInsets(top: 4, left: 0, bottom: 4, right: 0))
        }

        let segmentBackground = UIView()
        segmentBackground.backgroundColor = UIColor(hex: 0xF3F4F6)
        segmentBackground.layer.cornerRadius = 8
        card.addSubview(segmentBackground)
        storeButton.addTarget(self, action: #selector(storeTapped), for: .touchUpInside)
        verifyButton.addTarget(self, action: #selector(verifyTapped), for: .touchUpInside)
        segmentBackground.addSubview(storeButton)
        segmentBackground.addSubview(verifyButton)

        [leftPill, rightPill].forEach {
            $0.font = .systemFont(ofSize: AppMetrics.FontSize.caption)
            $0.numberOfLines = 2
            card.addSubview($0)
        }

        segmentBackground.snp.makeConstraints { make in
            make.top.leading.trailing.equalToSuperview().inset(12)
            make.height.equalTo(40)
        }
        storeButton.snp.makeConstraints { make in
            make.leading.top.bottom.equalToSuperview().inset(2)
            make.width.equalToSuperview().multipliedBy(0.5)
        }
        verifyButton.snp.makeConstraints { make in
            make.trailing.top.bottom.equalToSuperview().inset(2)
            make.width.equalToSuperview().multipliedBy(0.5)
        }
        leftPill.snp.makeConstraints { make in
            make.leading.bottom.equalToSuperview().inset(12)
            make.top.equalTo(segmentBackground.snp.bottom).offset(10)
            make.width.equalToSuperview().multipliedBy(0.45)
        }
        rightPill.snp.makeConstraints { make in
            make.trailing.bottom.equalToSuperview().inset(12)
            make.top.equalTo(leftPill)
            make.width.equalToSuperview().multipliedBy(0.45)
        }
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 配置头部展示内容与入口切换回调。
    func configure(
        selectedEntry: OrdersEntry,
        scenicName: String,
        storeTotal: Int,
        writeOffTotal: Int,
        onSelectEntry: @escaping (OrdersEntry) -> Void
    ) {
        self.onSelectEntry = onSelectEntry
        updateSegment(storeButton, title: "订单管理", selected: selectedEntry == .storeOrders)
        updateSegment(verifyButton, title: "核销订单", selected: selectedEntry == .verificationOrders)
        if selectedEntry == .storeOrders {
            leftPill.text = "当前景区\n\(scenicName)"
            rightPill.text = "订单总数\n\(storeTotal)"
        } else {
            leftPill.text = "核销订单\n\(writeOffTotal)"
            rightPill.text = "当前景区\n\(scenicName)"
        }
    }

    /// 更新分段按钮选中样式。
    private func updateSegment(_ button: UIButton, title: String, selected: Bool) {
        button.setTitle(title, for: .normal)
        button.titleLabel?.font = .systemFont(ofSize: AppMetrics.FontSize.subheadline, weight: selected ? .semibold : .medium)
        button.setTitleColor(selected ? AppDesignUIKit.primary : AppDesignUIKit.textSecondary, for: .normal)
        button.backgroundColor = selected ? .white : .clear
        button.layer.cornerRadius = 6
    }

    /// 切换到订单管理入口。
    @objc private func storeTapped() { onSelectEntry?(.storeOrders) }
    /// 切换到核销订单入口。
    @objc private func verifyTapped() { onSelectEntry?(.verificationOrders) }
}

/// 订单筛选栏 Cell，承载状态 / 时间与手机号搜索。
private final class OrdersFilterCell: UICollectionViewCell, UITextFieldDelegate {
    static let reuseID = "OrdersFilterCell"
    private let phoneField = UITextField()
    private var onPhoneChange: ((String) -> Void)?
    private var onSearch: (() -> Void)?

    /// 初始化 Cell 与子视图布局。
    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
        let card = UIView()
        card.backgroundColor = .white
        card.layer.cornerRadius = 8
        contentView.addSubview(card)
        card.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(UIEdgeInsets(top: 4, left: 0, bottom: 4, right: 0))
        }
        phoneField.delegate = self
        phoneField.keyboardType = .phonePad
        phoneField.font = .systemFont(ofSize: AppMetrics.FontSize.subheadline)
        phoneField.backgroundColor = UIColor(hex: 0xF4F4F4)
        phoneField.layer.cornerRadius = 6
        phoneField.leftView = UIView(frame: CGRect(x: 0, y: 0, width: 12, height: 1))
        phoneField.leftViewMode = .always
        card.addSubview(phoneField)
        phoneField.snp.makeConstraints { make in
            make.leading.bottom.equalToSuperview().inset(12)
            make.height.equalTo(40)
            make.trailing.equalToSuperview().inset(100)
        }
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 配置筛选栏展示内容与交互回调。
    func configure(
        statusTitle: String,
        phone: String,
        onStatus: @escaping () -> Void,
        onDate: @escaping () -> Void,
        onPhoneChange: @escaping (String) -> Void,
        onSearch: @escaping () -> Void
    ) {
        phoneField.text = phone
        self.onPhoneChange = onPhoneChange
        self.onSearch = onSearch
    }

    /// 手机号输入变化时同步到 ViewModel。
    func textFieldDidChangeSelection(_ textField: UITextField) {
        onPhoneChange?(textField.text ?? "")
    }
}

/// 核销操作栏 Cell，承载扫码与手动输入核销。
private final class OrdersWriteOffActionCell: UICollectionViewCell, UITextFieldDelegate {
    static let reuseID = "OrdersWriteOffActionCell"
    private let manualField = UITextField()
    private var onManualChange: ((String) -> Void)?
    private var onVerify: (() -> Void)?

    /// 初始化 Cell 与子视图布局。
    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
        let card = UIView()
        card.backgroundColor = .white
        card.layer.cornerRadius = 8
        contentView.addSubview(card)
        card.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(UIEdgeInsets(top: 4, left: 0, bottom: 4, right: 0))
        }

        manualField.delegate = self
        manualField.placeholder = "手动输入订单号"
        manualField.autocorrectionType = .no
        manualField.autocapitalizationType = .none
        manualField.backgroundColor = UIColor(hex: 0xF4F4F4)
        manualField.layer.cornerRadius = 8
        manualField.leftView = UIView(frame: CGRect(x: 0, y: 0, width: 12, height: 1))
        manualField.leftViewMode = .always
        card.addSubview(manualField)
        manualField.snp.makeConstraints { make in
            make.leading.bottom.equalToSuperview().inset(12)
            make.height.equalTo(42)
            make.trailing.equalToSuperview().inset(90)
        }
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 配置核销操作栏展示内容与交互回调。
    func configure(
        manualOrderNumber: String,
        isVerifying: Bool,
        hint: String?,
        onScan: @escaping () -> Void,
        onManualChange: @escaping (String) -> Void,
        onVerify: @escaping () -> Void
    ) {
        manualField.text = manualOrderNumber
        self.onManualChange = onManualChange
        self.onVerify = onVerify
    }

    /// 手动订单号输入变化时同步到页面状态。
    func textFieldDidChangeSelection(_ textField: UITextField) {
        onManualChange?(textField.text ?? "")
    }
}

/// 订单管理列表 Cell，展示单笔订单摘要。
private final class OrderEntityCell: UICollectionViewCell {
    static let reuseID = "OrderEntityCell"
    private let titleLabel = UILabel()
    private let statusLabel = UILabel()
    private let amountLabel = UILabel()
    private let phoneLabel = UILabel()

    /// 初始化 Cell 与子视图布局。
    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
        let card = UIView()
        card.backgroundColor = .white
        card.layer.cornerRadius = 8
        contentView.addSubview(card)
        card.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(UIEdgeInsets(top: 4, left: 0, bottom: 4, right: 0))
        }

        titleLabel.font = .systemFont(ofSize: AppMetrics.FontSize.subheadline, weight: .semibold)
        statusLabel.font = .systemFont(ofSize: AppMetrics.FontSize.caption, weight: .medium)
        amountLabel.font = .systemFont(ofSize: AppMetrics.FontSize.body, weight: .semibold)
        amountLabel.textColor = AppDesignUIKit.primary
        phoneLabel.font = .systemFont(ofSize: AppMetrics.FontSize.caption)
        phoneLabel.textColor = AppDesignUIKit.textSecondary

        let stack = UIStackView(arrangedSubviews: [titleLabel, phoneLabel, amountLabel])
        stack.axis = .vertical
        stack.spacing = 4
        card.addSubview(stack)
        card.addSubview(statusLabel)
        stack.snp.makeConstraints { make in make.leading.top.bottom.equalToSuperview().inset(12) }
        statusLabel.snp.makeConstraints { make in make.trailing.top.equalToSuperview().inset(12) }
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 配置订单卡片展示内容。
    func configure(item: OrderEntity) {
        titleLabel.text = item.orderNumber
        statusLabel.text = item.orderStatusName
        amountLabel.text = "¥\(item.actualPayAmount.isEmpty ? item.orderAmount : item.actualPayAmount)"
        phoneLabel.text = item.phone
    }
}

/// 核销订单列表 Cell，展示单笔核销订单摘要。
private final class WriteOffOrderCell: UICollectionViewCell {
    static let reuseID = "WriteOffOrderCell"
    private let titleLabel = UILabel()
    private let subtitleLabel = UILabel()

    /// 初始化 Cell 与子视图布局。
    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
        let card = UIView()
        card.backgroundColor = .white
        card.layer.cornerRadius = 8
        contentView.addSubview(card)
        card.snp.makeConstraints { make in
            make.edges.equalToSuperview().inset(UIEdgeInsets(top: 4, left: 0, bottom: 4, right: 0))
        }
        titleLabel.font = .systemFont(ofSize: AppMetrics.FontSize.subheadline, weight: .semibold)
        subtitleLabel.font = .systemFont(ofSize: AppMetrics.FontSize.caption)
        subtitleLabel.textColor = AppDesignUIKit.textSecondary
        let stack = UIStackView(arrangedSubviews: [titleLabel, subtitleLabel])
        stack.axis = .vertical
        stack.spacing = 4
        card.addSubview(stack)
        stack.snp.makeConstraints { make in make.edges.equalToSuperview().inset(12) }
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 配置核销订单卡片展示内容。
    func configure(item: WriteOffOrderItem, isVerifying: Bool) {
        titleLabel.text = item.orderNumber
        subtitleLabel.text = isVerifying ? "核销中..." : (item.projectName.isEmpty ? item.userPhone : item.projectName)
    }
}

/// 订单列表空态 Cell，复用通用空态视图。
private final class OrdersEmptyStateCell: UICollectionViewCell {
    static let reuseID = "OrdersEmptyStateCell"
    private var heightConstraint: Constraint?

    /// 初始化 Cell。
    override init(frame: CGRect) {
        super.init(frame: frame)
        backgroundColor = .clear
    }

    @available(*, unavailable)
    required init?(coder: NSCoder) { fatalError() }

    /// 嵌入空态视图并设置占位高度。
    func embed(_ emptyView: UIView, preferredHeight: CGFloat) {
        contentView.subviews.forEach { $0.removeFromSuperview() }
        contentView.addSubview(emptyView)
        emptyView.snp.makeConstraints { make in
            make.edges.equalToSuperview()
            heightConstraint = make.height.equalTo(preferredHeight).constraint
        }
    }
}