//
//  OrdersView.swift
//  suixinkan
//
//  Created by Codex on 2026/6/22.
//

import SwiftUI

/// 订单 Tab 根视图，展示订单管理和核销订单两个业务入口。
struct OrdersView: View {
    @Environment(AccountContext.self) private var accountContext
    @Environment(PermissionContext.self) private var permissionContext
    @Environment(AppRouter.self) private var appRouter
    @Environment(RouterPath.self) private var router
    @Environment(OrdersAPI.self) private var ordersAPI
    @Environment(ToastCenter.self) private var toastCenter
    @Environment(\.horizontalSizeClass) private var horizontalSizeClass

    @State private var viewModel = OrdersViewModel()
    @State private var manualOrderNumber = ""
    @State private var showDateFilterSheet = false
    @State private var showVerifyConfirmation = false
    @State private var pendingVerifyOrderNumber: String?

    private var currentScenicId: Int? {
        accountContext.currentScenic?.id
    }

    private var currentRoleId: Int? {
        permissionContext.currentRole?.id
    }

    private var contentMaxWidth: CGFloat {
        horizontalSizeClass == .regular ? 900 : .infinity
    }

    private var currentFilterTitle: String {
        OrderFilters.statusFilters.first(where: { $0.id == viewModel.selectedStatus })?.title ?? "全部"
    }

    private var timeFilterTitle: String {
        if let start = viewModel.filterStartDate, let end = viewModel.filterEndDate {
            return "\(Self.dateFormatter.string(from: start)) 至 \(Self.dateFormatter.string(from: end))"
        }
        return "时间筛选"
    }

    var body: some View {
        ScrollView {
            VStack(spacing: AppMetrics.Spacing.small) {
                entrySection

                if currentScenicId == nil {
                    ContentUnavailableView(
                        "缺少经营上下文",
                        systemImage: "mountain.2",
                        description: Text("请先在首页选择景区后查看订单。")
                    )
                    .frame(minHeight: 360)
                } else if viewModel.selectedEntry == .storeOrders {
                    storeOrdersSection
                } else {
                    writeOffSection
                }
            }
            .frame(maxWidth: contentMaxWidth)
            .padding(.horizontal, AppMetrics.Spacing.pageHorizontal)
            .padding(.top, AppMetrics.Spacing.medium)
            .padding(.bottom, AppMetrics.Spacing.pageVertical)
            .frame(maxWidth: .infinity)
        }
        .background(Color(hex: 0xF5F5F5).ignoresSafeArea())
        .navigationTitle("订单")
        .navigationBarTitleDisplayMode(.inline)
        .refreshable { await reload(showLoading: false) }
        .task {
            viewModel.selectedEntry = appRouter.selectedOrdersEntry
            await reload()
        }
        .onChange(of: appRouter.selectedOrdersEntry) { _, entry in
            guard viewModel.selectedEntry != entry else { return }
            viewModel.selectedEntry = entry
            Task { await reload() }
        }
        .onChange(of: accountContext.currentScenic?.id) { _, _ in
            Task { await reload() }
        }
        .confirmationDialog("确认核销该订单？", isPresented: $showVerifyConfirmation, titleVisibility: .visible) {
            Button("确认核销") {
                guard let orderNumber = pendingVerifyOrderNumber else { return }
                Task { await verify(orderNumber: orderNumber) }
            }
            Button("取消", role: .cancel) {
                pendingVerifyOrderNumber = nil
            }
        } message: {
            Text(pendingVerifyOrderNumber.map { "订单号：\($0)" } ?? "")
        }
        .sheet(isPresented: $showDateFilterSheet) {
            OrdersDateFilterSheet(
                startDate: $viewModel.filterStartDate,
                endDate: $viewModel.filterEndDate,
                onApply: { Task { await reload() } }
            )
        }
    }

    private var entrySection: some View {
        VStack(spacing: AppMetrics.Spacing.small) {
            HStack(spacing: 0) {
                entryButton("订单管理", entry: .storeOrders)
                entryButton("核销订单", entry: .verificationOrders)
            }
            .padding(AppMetrics.Spacing.xxxSmall)
            .background(Color(hex: 0xF3F4F6), in: RoundedRectangle(cornerRadius: 8))

            HStack(spacing: AppMetrics.Spacing.small) {
                contextPill(
                    icon: viewModel.selectedEntry == .storeOrders ? "mountain.2" : "qrcode",
                    title: viewModel.selectedEntry == .storeOrders ? "当前景区" : "核销订单",
                    value: viewModel.selectedEntry == .storeOrders ? (accountContext.currentScenic?.name ?? "--") : "\(viewModel.writeOffTotal)"
                )
                contextPill(
                    icon: "doc.text",
                    title: viewModel.selectedEntry == .storeOrders ? "订单总数" : "当前景区",
                    value: viewModel.selectedEntry == .storeOrders ? "\(viewModel.storeTotal)" : (accountContext.currentScenic?.name ?? "--")
                )
            }
        }
        .padding(AppMetrics.Spacing.medium)
        .background(.white, in: RoundedRectangle(cornerRadius: 8))
    }

    private var storeOrdersSection: some View {
        VStack(spacing: AppMetrics.Spacing.small) {
            storeFilterSection
            storeList
        }
    }

    private var writeOffSection: some View {
        VStack(spacing: AppMetrics.Spacing.small) {
            writeOffActionSection
            writeOffList
        }
    }

    private var storeFilterSection: some View {
        VStack(spacing: AppMetrics.Spacing.small) {
            HStack(spacing: AppMetrics.Spacing.xSmall) {
                Menu {
                    ForEach(OrderFilters.statusFilters) { filter in
                        Button(filter.title) {
                            viewModel.selectedStatus = filter.id
                            Task { await reload() }
                        }
                    }
                } label: {
                    filterLabel(title: currentFilterTitle, icon: "chevron.down")
                }
                Button {
                    showDateFilterSheet = true
                } label: {
                    filterLabel(title: timeFilterTitle, icon: "calendar")
                }
                .buttonStyle(.plain)
            }

            HStack(spacing: AppMetrics.Spacing.xSmall) {
                TextField("输入手机号搜索", text: $viewModel.searchPhone)
                    .keyboardType(.phonePad)
                    .textInputAutocapitalization(.never)
                    .autocorrectionDisabled(true)
                    .font(.system(size: AppMetrics.FontSize.subheadline))
                    .padding(.horizontal, AppMetrics.Spacing.small)
                    .frame(height: 40)
                    .background(Color(hex: 0xF4F4F4), in: RoundedRectangle(cornerRadius: 6))

                Button("搜索") {
                    Task { await reload() }
                }
                .font(.system(size: AppMetrics.FontSize.subheadline, weight: .semibold))
                .foregroundStyle(.white)
                .padding(.horizontal, AppMetrics.Spacing.medium)
                .frame(height: 40)
                .background(AppDesign.primary, in: RoundedRectangle(cornerRadius: 6))
            }
        }
        .padding(AppMetrics.Spacing.medium)
        .background(.white, in: RoundedRectangle(cornerRadius: 8))
    }

    private var storeList: some View {
        LazyVStack(spacing: AppMetrics.Spacing.small) {
            if viewModel.loading {
                ProgressView()
                    .frame(maxWidth: .infinity)
                    .padding(.vertical, AppMetrics.Spacing.xxLarge)
            } else if viewModel.storeOrders.isEmpty {
                ContentUnavailableView("暂无订单", systemImage: "tray", description: Text("可切换筛选条件或下拉刷新。"))
                    .frame(minHeight: 260)
            } else {
                ForEach(viewModel.storeOrders) { item in
                    storeOrderCard(item)
                        .onAppear {
                            guard item.id == viewModel.storeOrders.last?.id else { return }
                            Task { await loadMoreStoreOrders() }
                        }
                }
                if viewModel.loadingMore {
                    ProgressView()
                        .frame(maxWidth: .infinity)
                        .padding(.vertical, AppMetrics.Spacing.small)
                }
            }
        }
    }

    private var writeOffActionSection: some View {
        VStack(spacing: AppMetrics.Spacing.small) {
            Button {
                router.navigate(to: .placeholder(title: "扫码核销"))
            } label: {
                Label("扫码核销", systemImage: "qrcode.viewfinder")
                    .font(.system(size: AppMetrics.FontSize.subheadline, weight: .semibold))
                    .foregroundStyle(.white)
                    .frame(maxWidth: .infinity)
                    .frame(height: 42)
                    .background(Color(hex: 0x9CA3AF), in: RoundedRectangle(cornerRadius: 8))
            }
            .buttonStyle(.plain)
            .accessibilityIdentifier("orders.scan")

            HStack(spacing: AppMetrics.Spacing.xSmall) {
                TextField("手动输入订单号", text: $manualOrderNumber)
                    .textInputAutocapitalization(.never)
                    .autocorrectionDisabled(true)
                    .font(.system(size: AppMetrics.FontSize.subheadline))
                    .padding(.horizontal, AppMetrics.Spacing.small)
                    .frame(height: 42)
                    .background(Color(hex: 0xF4F4F4), in: RoundedRectangle(cornerRadius: 8))
                    .accessibilityIdentifier("orders.manualOrderNumber")

                Button(viewModel.isVerifying ? "核销中" : "核销") {
                    triggerManualVerify()
                }
                .font(.system(size: AppMetrics.FontSize.subheadline, weight: .semibold))
                .foregroundStyle(.white)
                .padding(.horizontal, AppMetrics.Spacing.medium)
                .frame(height: 42)
                .background(AppDesign.primary, in: RoundedRectangle(cornerRadius: 8))
                .disabled(viewModel.isVerifying)
            }
        }
        .padding(AppMetrics.Spacing.medium)
        .background(.white, in: RoundedRectangle(cornerRadius: 8))
    }

    private var writeOffList: some View {
        LazyVStack(spacing: AppMetrics.Spacing.small) {
            if viewModel.loading {
                ProgressView()
                    .frame(maxWidth: .infinity)
                    .padding(.vertical, AppMetrics.Spacing.xxLarge)
            } else if viewModel.writeOffOrders.isEmpty {
                ContentUnavailableView("暂无核销订单", systemImage: "tray", description: Text("可下拉刷新或切换景区查看。"))
                    .frame(minHeight: 260)
            } else {
                ForEach(viewModel.writeOffOrders) { item in
                    writeOffOrderCard(item)
                        .onAppear {
                            guard item.id == viewModel.writeOffOrders.last?.id else { return }
                            Task { await loadMoreWriteOffOrders() }
                        }
                }
                if viewModel.loadingMore {
                    ProgressView()
                        .frame(maxWidth: .infinity)
                        .padding(.vertical, AppMetrics.Spacing.small)
                }
            }
        }
    }

    private func entryButton(_ title: String, entry: OrdersEntry) -> some View {
        let selected = viewModel.selectedEntry == entry
        return Button {
            switchEntry(entry)
        } label: {
            Text(title)
                .font(.system(size: AppMetrics.FontSize.subheadline, weight: selected ? .semibold : .medium))
                .foregroundStyle(selected ? AppDesign.primary : AppDesign.textSecondary)
                .frame(maxWidth: .infinity)
                .frame(height: 36)
                .background(selected ? .white : .clear, in: RoundedRectangle(cornerRadius: 6))
        }
        .buttonStyle(.plain)
    }

    private func contextPill(icon: String, title: String, value: String) -> some View {
        HStack(spacing: AppMetrics.Spacing.xSmall) {
            Image(systemName: icon)
                .font(.system(size: AppMetrics.FontSize.footnote, weight: .semibold))
                .foregroundStyle(AppDesign.primary)
                .frame(width: 28, height: 28)
                .background(AppDesign.primarySoft, in: RoundedRectangle(cornerRadius: 8))
            VStack(alignment: .leading, spacing: AppMetrics.Spacing.xxxSmall) {
                Text(title)
                    .font(.system(size: AppMetrics.FontSize.caption))
                    .foregroundStyle(AppDesign.textSecondary)
                Text(value)
                    .font(.system(size: AppMetrics.FontSize.footnote, weight: .semibold))
                    .foregroundStyle(AppDesign.textPrimary)
                    .lineLimit(1)
                    .minimumScaleFactor(0.75)
            }
            Spacer(minLength: 0)
        }
        .padding(AppMetrics.Spacing.xSmall)
        .frame(maxWidth: .infinity)
        .background(Color(hex: 0xF8FAFC), in: RoundedRectangle(cornerRadius: 8))
    }

    private func filterLabel(title: String, icon: String) -> some View {
        HStack(spacing: AppMetrics.Spacing.xSmall) {
            Text(title)
                .font(.system(size: AppMetrics.FontSize.subheadline))
                .foregroundStyle(Color(hex: 0x4B5563))
                .lineLimit(1)
                .minimumScaleFactor(0.75)
            Spacer(minLength: AppMetrics.Spacing.xSmall)
            Image(systemName: icon)
                .font(.system(size: AppMetrics.FontSize.caption, weight: .semibold))
                .foregroundStyle(Color(hex: 0x4B5563))
        }
        .padding(.horizontal, AppMetrics.Spacing.small)
        .frame(maxWidth: .infinity)
        .frame(height: 38)
        .background(Color(hex: 0xF4F4F4), in: RoundedRectangle(cornerRadius: 6))
    }

    private func storeOrderCard(_ item: OrderEntity) -> some View {
        VStack(alignment: .leading, spacing: AppMetrics.Spacing.xSmall) {
            HStack(alignment: .top, spacing: AppMetrics.Spacing.xSmall) {
                Text("订单号：\(item.orderNumber)")
                    .font(.system(size: AppMetrics.FontSize.title3))
                    .foregroundStyle(.black)
                    .lineLimit(1)
                    .minimumScaleFactor(0.72)
                Spacer()
                statusBadge(item.orderStatusName, color: statusColor(for: item.orderStatus))
            }

            Text(item.createdAt.isEmpty ? "--" : item.createdAt)
                .font(.system(size: AppMetrics.FontSize.subheadline))
                .foregroundStyle(AppDesign.textSecondary)

            if !item.orderTypeLabel.isEmpty {
                Text(item.orderTypeLabel)
                    .font(.system(size: AppMetrics.FontSize.caption, weight: .medium))
                    .foregroundStyle(AppDesign.primary)
                    .padding(.horizontal, AppMetrics.Spacing.xSmall)
                    .padding(.vertical, AppMetrics.Spacing.xxSmall)
                    .background(AppDesign.primarySoft, in: RoundedRectangle(cornerRadius: 4))
            }

            orderInfoRow("付款金额", "¥\(item.actualPayAmount)", valueColor: AppDesign.primary)
            orderInfoRow("付款时间", item.payTime.isEmpty ? "--" : item.payTime)
            orderInfoRow("完成时间", item.completeTime.isEmpty ? "--" : item.completeTime)
            orderInfoRow("付款方式", item.payTypeName.isEmpty ? "--" : item.payTypeName)
            orderInfoRow("手机号", maskPhoneNumber(item.phone))
            orderInfoRow("关联项目", item.projectName.isEmpty ? "--" : item.projectName)
        }
        .padding(AppMetrics.Spacing.medium)
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(.white, in: RoundedRectangle(cornerRadius: 8))
        .contentShape(Rectangle())
        .onTapGesture {
            router.navigate(to: .placeholder(title: "订单详情"))
        }
        .accessibilityIdentifier("orders.store.card.\(item.orderNumber)")
    }

    private func writeOffOrderCard(_ item: WriteOffOrderItem) -> some View {
        VStack(alignment: .leading, spacing: AppMetrics.Spacing.xSmall) {
            HStack(alignment: .top, spacing: AppMetrics.Spacing.xSmall) {
                Text("订单号：\(item.orderNumber)")
                    .font(.system(size: AppMetrics.FontSize.subheadline, weight: .semibold))
                    .foregroundStyle(.black)
                    .lineLimit(1)
                Spacer()
                statusBadge(displayVerificationStatus(for: item), color: writeOffStatusColor(for: item))
            }

            Text(item.payTime.isEmpty ? "--" : item.payTime)
                .font(.system(size: AppMetrics.FontSize.caption))
                .foregroundStyle(AppDesign.textSecondary)
            orderInfoRow("项目名称", item.projectName.isEmpty ? "--" : item.projectName)
            orderInfoRow("手机号", item.userPhone.isEmpty ? "--" : item.userPhone)
            orderInfoRow("订单状态", item.orderStatusName.isEmpty ? "--" : item.orderStatusName)

            HStack {
                Text("¥\(item.orderAmount)")
                    .font(.system(size: AppMetrics.FontSize.title3, weight: .bold))
                    .foregroundStyle(AppDesign.primary)
                Spacer()
                Button("详情") {
                    router.navigate(to: .placeholder(title: "核销订单详情"))
                }
                .font(.system(size: AppMetrics.FontSize.caption, weight: .medium))
                .foregroundStyle(AppDesign.primary)
                .padding(.horizontal, AppMetrics.Spacing.small)
                .frame(height: 32)
                .background(AppDesign.primarySoft, in: RoundedRectangle(cornerRadius: 8))
                .buttonStyle(.plain)
                .accessibilityIdentifier("orders.writeoff.detail.\(item.orderNumber)")

                Button(verifyButtonTitle(for: item)) {
                    pendingVerifyOrderNumber = item.orderNumber
                    showVerifyConfirmation = true
                }
                .font(.system(size: AppMetrics.FontSize.footnote, weight: .semibold))
                .foregroundStyle(.white)
                .padding(.horizontal, AppMetrics.Spacing.small)
                .frame(height: 32)
                .background(canVerify(item) ? AppDesign.primary : Color(hex: 0x9CA3AF), in: RoundedRectangle(cornerRadius: 8))
                .buttonStyle(.plain)
                .disabled(!canVerify(item) || viewModel.isVerifying)
                .accessibilityIdentifier("orders.writeoff.verify.\(item.orderNumber)")
            }
        }
        .padding(AppMetrics.Spacing.medium)
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(.white, in: RoundedRectangle(cornerRadius: 8))
    }

    private func orderInfoRow(_ title: String, _ value: String, valueColor: Color = .black) -> some View {
        HStack(alignment: .top, spacing: AppMetrics.Spacing.xSmall) {
            Text(title)
                .font(.system(size: AppMetrics.FontSize.subheadline))
                .foregroundStyle(Color(hex: 0x4B5563))
                .frame(width: 72, alignment: .leading)
            Spacer(minLength: AppMetrics.Spacing.xSmall)
            Text(value)
                .font(.system(size: AppMetrics.FontSize.subheadline, weight: .medium))
                .foregroundStyle(valueColor)
                .multilineTextAlignment(.trailing)
                .lineLimit(2)
                .minimumScaleFactor(0.75)
        }
    }

    private func statusBadge(_ text: String, color: Color) -> some View {
        Text(text.isEmpty ? "--" : text)
            .font(.system(size: AppMetrics.FontSize.caption, weight: .medium))
            .foregroundStyle(color)
            .padding(.horizontal, AppMetrics.Spacing.xSmall)
            .padding(.vertical, AppMetrics.Spacing.xxSmall)
            .background(color.opacity(0.12), in: RoundedRectangle(cornerRadius: 4))
    }

    private func switchEntry(_ entry: OrdersEntry) {
        guard viewModel.selectedEntry != entry else { return }
        viewModel.selectedEntry = entry
        appRouter.selectOrders(entry: entry)
        Task { await reload() }
    }

    private func reload(showLoading: Bool = true) async {
        do {
            try await viewModel.reload(
                api: ordersAPI,
                scenicId: currentScenicId,
                roleId: currentRoleId,
                showLoading: showLoading
            )
        } catch {
            toastCenter.show(error.localizedDescription)
        }
    }

    private func loadMoreStoreOrders() async {
        do {
            try await viewModel.loadMoreStoreOrders(api: ordersAPI, scenicId: currentScenicId, roleId: currentRoleId)
        } catch {
            toastCenter.show(error.localizedDescription)
        }
    }

    private func loadMoreWriteOffOrders() async {
        do {
            try await viewModel.loadMoreWriteOffOrders(api: ordersAPI, scenicId: currentScenicId)
        } catch {
            toastCenter.show(error.localizedDescription)
        }
    }

    private func triggerManualVerify() {
        let orderNumber = manualOrderNumber.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !orderNumber.isEmpty else {
            toastCenter.show("请输入订单号")
            return
        }
        pendingVerifyOrderNumber = orderNumber
        showVerifyConfirmation = true
    }

    private func verify(orderNumber: String) async {
        guard let scenicId = currentScenicId else { return }
        do {
            try await viewModel.verify(api: ordersAPI, scenicId: scenicId, orderNumber: orderNumber)
            manualOrderNumber = ""
            pendingVerifyOrderNumber = nil
            toastCenter.show("核销成功")
        } catch {
            toastCenter.show(error.localizedDescription)
        }
    }

    private func canVerify(_ item: WriteOffOrderItem) -> Bool {
        let status = displayVerificationStatus(for: item)
        return !status.contains("已核销") && !status.contains("已退款") && !status.contains("已完成")
    }

    private func displayVerificationStatus(for item: WriteOffOrderItem) -> String {
        let text = item.orderVerificationStatus.trimmingCharacters(in: .whitespacesAndNewlines)
        return text.isEmpty ? "待核销" : text
    }

    private func verifyButtonTitle(for item: WriteOffOrderItem) -> String {
        canVerify(item) ? "核销" : "已处理"
    }

    private func writeOffStatusColor(for item: WriteOffOrderItem) -> Color {
        canVerify(item) ? AppDesign.primary : Color(hex: 0x22C55E)
    }

    private func statusColor(for status: Int) -> Color {
        switch status {
        case 18:
            return AppDesign.primary
        case 30:
            return Color(hex: 0x22C55E)
        case 50:
            return Color(hex: 0xEF4444)
        default:
            return Color(hex: 0x6B7280)
        }
    }

    private func maskPhoneNumber(_ phone: String) -> String {
        let trimmed = phone.trimmingCharacters(in: .whitespacesAndNewlines)
        guard trimmed.count >= 7 else { return trimmed.isEmpty ? "--" : trimmed }
        let prefix = trimmed.prefix(3)
        let suffix = trimmed.suffix(4)
        return "\(prefix)****\(suffix)"
    }

    private static let dateFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.locale = Locale(identifier: "en_US_POSIX")
        formatter.dateFormat = "yyyy-MM-dd"
        return formatter
    }()
}

/// 订单日期筛选 Sheet，负责选择开始和结束日期。
private struct OrdersDateFilterSheet: View {
    @Environment(\.dismiss) private var dismiss
    @Binding var startDate: Date?
    @Binding var endDate: Date?
    let onApply: () -> Void

    @State private var draftStartDate = Date()
    @State private var draftEndDate = Date()

    var body: some View {
        NavigationStack {
            Form {
                DatePicker("开始日期", selection: $draftStartDate, displayedComponents: .date)
                DatePicker("结束日期", selection: $draftEndDate, displayedComponents: .date)
            }
            .navigationTitle("时间筛选")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .cancellationAction) {
                    Button("清空") {
                        startDate = nil
                        endDate = nil
                        onApply()
                        dismiss()
                    }
                }
                ToolbarItem(placement: .confirmationAction) {
                    Button("确定") {
                        startDate = min(draftStartDate, draftEndDate)
                        endDate = max(draftStartDate, draftEndDate)
                        onApply()
                        dismiss()
                    }
                }
            }
            .onAppear {
                draftStartDate = startDate ?? Date()
                draftEndDate = endDate ?? Date()
            }
        }
    }
}

#Preview {
    NavigationStack {
        OrdersView()
            .environment(AccountContext())
            .environment(PermissionContext())
            .environment(AppRouter())
            .environment(RouterPath())
            .environment(OrdersAPI(client: APIClient()))
            .environment(ToastCenter())
    }
}