//
//  TaskManagementView.swift
//  suixinkan
//
//  Created by Codex on 2026/6/23.
//

import SwiftUI

/// 任务管理页面，展示任务列表、筛选条件和发布任务入口。
struct TaskManagementView: View {
    @EnvironmentObject private var accountContext: AccountContext
    @EnvironmentObject private var router: RouterPath
    @Environment(\.taskAPI) private var taskAPI
    @EnvironmentObject private var toastCenter: ToastCenter
    @Environment(\.globalLoading) private var globalLoading

    @StateObject private var viewModel = TaskManagementViewModel()

    var body: some View {
        ScrollView {
            LazyVStack(spacing: AppMetrics.Spacing.medium) {
                filterSection
                contentSection
            }
            .padding(.horizontal, AppMetrics.Spacing.pageHorizontal)
            .padding(.vertical, AppMetrics.Spacing.medium)
        }
        .background(Color(hex: 0xF5F7FA))
        .navigationTitle("任务管理")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .topBarTrailing) {
                Button {
                    router.navigate(to: .home(.taskCreate))
                } label: {
                    Image(systemName: "plus")
                }
                .accessibilityLabel("发布任务")
            }
        }
        .refreshable { await reload(showLoading: false) }
        .task {
            guard viewModel.tasks.isEmpty else { return }
            await reload(showLoading: true)
        }
    }

    /// 筛选区域，包含状态、搜索和日期筛选。
    private var filterSection: some View {
        VStack(spacing: AppMetrics.Spacing.small) {
            Picker("任务状态", selection: $viewModel.selectedStatus) {
                ForEach(TaskStatusFilter.allCases) { status in
                    Text(status.title).tag(status)
                }
            }
            .pickerStyle(.segmented)
            .onChange(of: viewModel.selectedStatus) { _ in
                Task { await reload(showLoading: true) }
            }

            HStack(spacing: AppMetrics.Spacing.small) {
                Image(systemName: "magnifyingglass")
                    .foregroundStyle(AppDesign.placeholder)
                TextField("搜索任务名称", text: $viewModel.searchText)
                    .textInputAutocapitalization(.never)
                    .submitLabel(.search)
                    .onSubmit { Task { await reload(showLoading: true) } }
                Button("搜索") {
                    Task { await reload(showLoading: true) }
                }
                .font(.system(size: AppMetrics.FontSize.subheadline, weight: .semibold))
                .foregroundStyle(AppDesign.primary)
            }
            .appInputFieldStyle(cornerRadius: AppMetrics.CornerRadius.input, minHeight: AppMetrics.ControlSize.inputHeight)

            VStack(spacing: AppMetrics.Spacing.xSmall) {
                TaskDatePickerRow(title: "开始日期", date: $viewModel.startDate)
                TaskDatePickerRow(title: "结束日期", date: $viewModel.endDate)
                HStack {
                    Button("清除日期") {
                        viewModel.startDate = nil
                        viewModel.endDate = nil
                        Task { await reload(showLoading: true) }
                    }
                    .foregroundStyle(AppDesign.textSecondary)

                    Spacer()

                    Button("应用日期") {
                        Task { await reload(showLoading: true) }
                    }
                    .font(.system(size: AppMetrics.FontSize.subheadline, weight: .semibold))
                    .foregroundStyle(AppDesign.primary)
                }
                .font(.system(size: AppMetrics.FontSize.subheadline))
            }
            .padding(AppMetrics.Spacing.medium)
            .background(.white, in: RoundedRectangle(cornerRadius: AppMetrics.CornerRadius.card))
        }
    }

    /// 列表内容区域，展示空状态、任务卡片和加载更多。
    @ViewBuilder
    private var contentSection: some View {
        if accountContext.currentScenic?.id == nil {
            TaskEmptyState(title: "缺少景区上下文", message: "请先在首页选择景区后再查看任务。")
        } else if viewModel.tasks.isEmpty {
            TaskEmptyState(title: "暂无任务", message: viewModel.errorMessage ?? "当前筛选条件下没有任务。")
        } else {
            ForEach(viewModel.tasks) { task in
                Button {
                    router.navigate(to: .home(.taskDetail(id: task.id, summary: task)))
                } label: {
                    TaskCardView(task: task)
                }
                .buttonStyle(.plain)
                .onAppear {
                    guard task.id == viewModel.tasks.last?.id else { return }
                    Task { await loadMore() }
                }
            }

            if viewModel.isLoadingMore {
                Text("加载更多...")
                    .font(.system(size: AppMetrics.FontSize.footnote))
                    .foregroundStyle(AppDesign.textSecondary)
                    .padding(.vertical, AppMetrics.Spacing.small)
            } else if viewModel.hasMore {
                Button("加载更多") {
                    Task { await loadMore() }
                }
                .font(.system(size: AppMetrics.FontSize.subheadline, weight: .semibold))
                .foregroundStyle(AppDesign.primary)
                .padding(.vertical, AppMetrics.Spacing.small)
            }
        }
    }

    /// 重新加载任务列表。
    private func reload(showLoading: Bool) async {
        do {
            try await globalLoading.withOptionalLoading(showLoading && accountContext.currentScenic?.id != nil) {
                try await viewModel.reload(api: taskAPI, scenicId: accountContext.currentScenic?.id)
            }
        } catch {
            toastCenter.show(error.localizedDescription)
        }
    }

    /// 加载下一页任务列表。
    private func loadMore() async {
        do {
            try await viewModel.loadMore(api: taskAPI, scenicId: accountContext.currentScenic?.id)
        } catch {
            toastCenter.show(error.localizedDescription)
        }
    }
}

/// 任务卡片视图，展示任务名称、状态、订单和时间信息。
private struct TaskCardView: View {
    let task: PhotographerTaskItem

    var body: some View {
        VStack(alignment: .leading, spacing: AppMetrics.Spacing.small) {
            HStack(alignment: .top, spacing: AppMetrics.Spacing.small) {
                VStack(alignment: .leading, spacing: AppMetrics.Spacing.xSmall) {
                    Text(task.name.isEmpty ? "未命名任务" : task.name)
                        .font(.system(size: AppMetrics.FontSize.body, weight: .semibold))
                        .foregroundStyle(AppDesign.textPrimary)
                        .lineLimit(2)

                    if !task.orderNumber.isEmpty {
                        Text("订单号：\(task.orderNumber)")
                            .font(.system(size: AppMetrics.FontSize.footnote))
                            .foregroundStyle(AppDesign.textSecondary)
                    }
                }

                Spacer(minLength: AppMetrics.Spacing.small)

                Text(task.statusName.isEmpty ? "\(task.taskStatus)" : task.statusName)
                    .font(.system(size: AppMetrics.FontSize.caption, weight: .semibold))
                    .foregroundStyle(statusColor)
                    .padding(.horizontal, AppMetrics.Spacing.small)
                    .padding(.vertical, AppMetrics.Spacing.xxSmall)
                    .background(statusColor.opacity(0.12), in: Capsule())
            }

            if !task.photogRemark.isEmpty {
                Text(task.photogRemark)
                    .font(.system(size: AppMetrics.FontSize.subheadline))
                    .foregroundStyle(AppDesign.textSecondary)
                    .lineLimit(2)
            }

            HStack(spacing: AppMetrics.Spacing.small) {
                Label(task.editorName.isEmpty ? "暂无编辑" : task.editorName, systemImage: "person.crop.circle")
                Spacer()
                Text(task.createdAt.isEmpty ? task.updatedAt : task.createdAt)
            }
            .font(.system(size: AppMetrics.FontSize.caption))
            .foregroundStyle(AppDesign.placeholder)
        }
        .padding(AppMetrics.Spacing.medium)
        .background(.white, in: RoundedRectangle(cornerRadius: AppMetrics.CornerRadius.card))
    }

    /// 返回任务状态对应的强调色。
    private var statusColor: Color {
        switch task.taskStatus {
        case 3:
            AppDesign.success
        case 4:
            Color(hex: 0xEF4444)
        case 1, 2:
            AppDesign.warning
        default:
            AppDesign.primary
        }
    }
}

/// 任务日期筛选行，封装可选日期选择控件。
private struct TaskDatePickerRow: View {
    let title: String
    @Binding var date: Date?

    var body: some View {
        HStack {
            Text(title)
                .font(.system(size: AppMetrics.FontSize.subheadline))
                .foregroundStyle(AppDesign.textSecondary)
            Spacer()
            DatePicker(
                title,
                selection: Binding(
                    get: { date ?? Date() },
                    set: { date = $0 }
                ),
                displayedComponents: .date
            )
            .labelsHidden()
        }
    }
}

/// 任务空状态视图，用于缺少景区或无数据时展示。
private struct TaskEmptyState: View {
    let title: String
    let message: String

    var body: some View {
        VStack(spacing: AppMetrics.Spacing.small) {
            Image(systemName: "tray")
                .font(.system(size: 36, weight: .semibold))
                .foregroundStyle(AppDesign.placeholder)
            Text(title)
                .font(.system(size: AppMetrics.FontSize.body, weight: .semibold))
                .foregroundStyle(AppDesign.textPrimary)
            Text(message)
                .font(.system(size: AppMetrics.FontSize.subheadline))
                .foregroundStyle(AppDesign.textSecondary)
                .multilineTextAlignment(.center)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, AppMetrics.Spacing.xxLarge)
        .padding(.horizontal, AppMetrics.Spacing.large)
        .background(.white, in: RoundedRectangle(cornerRadius: AppMetrics.CornerRadius.card))
    }
}