import 'dart:async';

import 'package:flutter/material.dart';
import 'package:get_it/get_it.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart' as lucide;
import 'package:shadcn_ui/shadcn_ui.dart';

import 'package:superport_v2/widgets/app_layout.dart';
import 'package:superport_v2/widgets/components/empty_state.dart';

import '../../domain/entities/dashboard_kpi.dart';
import '../../domain/entities/dashboard_pending_approval.dart';
import '../../domain/entities/dashboard_transaction_summary.dart';
import '../../domain/repositories/dashboard_repository.dart';
import '../controllers/dashboard_controller.dart';

/// Superport 메인 대시보드 화면.
class DashboardPage extends StatefulWidget {
  const DashboardPage({super.key});

  @override
  State<DashboardPage> createState() => _DashboardPageState();
}

class _DashboardPageState extends State<DashboardPage> {
  late final DashboardController _controller;
  Timer? _autoRefreshTimer;
  final DateFormat _timestampFormat = DateFormat('yyyy-MM-dd HH:mm');

  static const _kpiPresets = [
    _KpiPreset(
      key: 'inbound',
      label: '오늘 입고',
      icon: lucide.LucideIcons.packagePlus,
    ),
    _KpiPreset(
      key: 'outbound',
      label: '오늘 출고',
      icon: lucide.LucideIcons.packageMinus,
    ),
    _KpiPreset(
      key: 'pending_approvals',
      label: '결재 대기',
      icon: lucide.LucideIcons.messageSquareWarning,
    ),
    _KpiPreset(
      key: 'customer_inquiries',
      label: '고객사 문의',
      icon: lucide.LucideIcons.users,
    ),
  ];

  @override
  void initState() {
    super.initState();
    _controller = DashboardController(
      repository: GetIt.I<DashboardRepository>(),
    );
    _controller.ensureLoaded();
    _autoRefreshTimer = Timer.periodic(
      const Duration(minutes: 5),
      (_) => _controller.refresh(),
    );
  }

  @override
  void dispose() {
    _autoRefreshTimer?.cancel();
    _controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: _controller,
      builder: (context, _) {
        return AppLayout(
          title: '대시보드',
          subtitle: '입·출·대여 현황과 결재 대기를 한 눈에 확인합니다.',
          breadcrumbs: const [AppBreadcrumbItem(label: '대시보드')],
          actions: [
            ShadButton.ghost(
              onPressed: _controller.isLoading ? null : _controller.refresh,
              leading: _controller.isRefreshing
                  ? const SizedBox(
                      width: 16,
                      height: 16,
                      child: CircularProgressIndicator(strokeWidth: 2),
                    )
                  : const Icon(lucide.LucideIcons.refreshCw, size: 16),
              child: const Text('새로고침'),
            ),
          ],
          child: _buildBody(context),
        );
      },
    );
  }

  Widget _buildBody(BuildContext context) {
    final summary = _controller.summary;
    final theme = ShadTheme.of(context);

    if (_controller.isLoading && summary == null) {
      return const Center(child: CircularProgressIndicator());
    }

    if (summary == null) {
      return Center(
        child: ConstrainedBox(
          constraints: const BoxConstraints(maxWidth: 480),
          child: ShadCard(
            title: Text('대시보드 데이터를 불러오지 못했습니다.', style: theme.textTheme.h3),
            description: Text(
              _controller.errorMessage ?? '네트워크 연결을 확인한 뒤 다시 시도해 주세요.',
              style: theme.textTheme.muted,
            ),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                const SuperportEmptyState(
                  title: '데이터가 없습니다',
                  description: '권한 또는 네트워크 상태를 확인한 뒤 다시 시도해 주세요.',
                ),
                const SizedBox(height: 16),
                Align(
                  alignment: Alignment.centerRight,
                  child: ShadButton(
                    onPressed: _controller.isLoading
                        ? null
                        : _controller.refresh,
                    child: const Text('다시 시도'),
                  ),
                ),
              ],
            ),
          ),
        ),
      );
    }

    final kpiMap = summary.kpis.fold<Map<String, DashboardKpi>>({}, (map, kpi) {
      map[kpi.key] = kpi;
      return map;
    });

    return SingleChildScrollView(
      padding: const EdgeInsets.only(bottom: 48),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          if (_controller.errorMessage != null)
            Padding(
              padding: const EdgeInsets.only(bottom: 16),
              child: DecoratedBox(
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(12),
                  color: theme.colorScheme.destructive.withValues(alpha: 0.12),
                ),
                child: ListTile(
                  leading: Icon(
                    lucide.LucideIcons.info,
                    color: theme.colorScheme.destructive,
                  ),
                  title: Text(
                    '대시보드 데이터를 최신 상태로 동기화하지 못했습니다.',
                    style: theme.textTheme.small,
                  ),
                  subtitle: Text(
                    _controller.errorMessage!,
                    style: theme.textTheme.small,
                  ),
                  trailing: TextButton(
                    onPressed: _controller.refresh,
                    child: const Text('다시 시도'),
                  ),
                ),
              ),
            ),
          Wrap(
            spacing: 16,
            runSpacing: 16,
            children: [
              for (final preset in _kpiPresets)
                _KpiCard(
                  icon: preset.icon,
                  label: preset.label,
                  kpi: kpiMap[preset.key],
                ),
            ],
          ),
          const SizedBox(height: 12),
          if (summary.generatedAt != null)
            Text(
              '최근 갱신: ${_timestampFormat.format(summary.generatedAt!.toLocal())}',
              style: theme.textTheme.small,
            ),
          const SizedBox(height: 24),
          LayoutBuilder(
            builder: (context, constraints) {
              final showSidePanel = constraints.maxWidth > 920;
              return Flex(
                direction: showSidePanel ? Axis.horizontal : Axis.vertical,
                crossAxisAlignment: CrossAxisAlignment.start,
                mainAxisSize: showSidePanel ? MainAxisSize.max : MainAxisSize.min,
                children: [
                  Flexible(
                    flex: 3,
                    fit: showSidePanel ? FlexFit.tight : FlexFit.loose,
                    child: _RecentTransactionsCard(
                      transactions: summary.recentTransactions,
                    ),
                  ),
                  if (showSidePanel)
                    const SizedBox(width: 16)
                  else
                    const SizedBox(height: 16),
                  Flexible(
                    flex: 2,
                    fit: showSidePanel ? FlexFit.tight : FlexFit.loose,
                    child: _PendingApprovalCard(
                      approvals: summary.pendingApprovals,
                    ),
                  ),
                ],
              );
            },
          ),
          const SizedBox(height: 24),
          const _ReminderPanel(),
        ],
      ),
    );
  }
}

class _KpiCard extends StatelessWidget {
  const _KpiCard({required this.icon, required this.label, this.kpi});

  final IconData icon;
  final String label;
  final DashboardKpi? kpi;

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    return ConstrainedBox(
      constraints: const BoxConstraints(minWidth: 220, maxWidth: 260),
      child: ShadCard(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Icon(icon, size: 20, color: theme.colorScheme.primary),
            const SizedBox(height: 12),
            Text(label, style: theme.textTheme.small),
            const SizedBox(height: 6),
            Text(kpi?.displayValue ?? '--', style: theme.textTheme.h3),
            const SizedBox(height: 8),
            _DeltaTrendRow(kpi: kpi),
          ],
        ),
      ),
    );
  }
}

class _DeltaTrendRow extends StatelessWidget {
  const _DeltaTrendRow({this.kpi});

  final DashboardKpi? kpi;

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    final delta = kpi?.delta;

    if (delta == null) {
      return Text(kpi?.trendLabel ?? '데이터 동기화 중', style: theme.textTheme.muted);
    }

    final absDelta = delta.abs();
    final percent = (absDelta * 100).toStringAsFixed(1);
    final trimmedPercent = percent.endsWith('.0')
        ? percent.substring(0, percent.length - 2)
        : percent;
    final percentText = delta > 0
        ? '+$trimmedPercent%'
        : delta < 0
            ? '-$trimmedPercent%'
            : '0%';

    final icon = delta > 0
        ? lucide.LucideIcons.arrowUpRight
        : delta < 0
            ? lucide.LucideIcons.arrowDownRight
            : lucide.LucideIcons.minus;

    final Color color;
    if (delta > 0) {
      color = theme.colorScheme.primary;
    } else if (delta < 0) {
      color = theme.colorScheme.destructive;
    } else {
      color = theme.textTheme.muted.color ?? theme.colorScheme.mutedForeground;
    }

    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        Icon(icon, size: 16, color: color),
        const SizedBox(width: 4),
        Text(
          percentText,
          style: theme.textTheme.small.copyWith(color: color),
        ),
        const SizedBox(width: 8),
        Flexible(
          child: Text(
            kpi?.trendLabel ?? '전일 대비',
            overflow: TextOverflow.ellipsis,
            style: theme.textTheme.muted,
          ),
        ),
      ],
    );
  }
}

class _RecentTransactionsCard extends StatelessWidget {
  const _RecentTransactionsCard({required this.transactions});

  final List<DashboardTransactionSummary> transactions;

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    return ShadCard(
      title: Text('최근 트랜잭션', style: theme.textTheme.h3),
      description: Text(
        '최근 7일간의 입·출고 및 대여/결재 흐름입니다.',
        style: theme.textTheme.muted,
      ),
      child: SizedBox(
        height: 320,
        child: transactions.isEmpty
            ? const Center(
                child: SuperportEmptyState(
                  title: '최근 트랜잭션이 없습니다',
                  description: '최근 7일간 생성된 입·출·대여 트랜잭션이 없습니다.',
                ),
              )
            : ShadTable.list(
                header: const [
                  ShadTableCell.header(child: Text('번호')),
                  ShadTableCell.header(child: Text('일자')),
                  ShadTableCell.header(child: Text('유형')),
                  ShadTableCell.header(child: Text('상태')),
                  ShadTableCell.header(child: Text('작성자')),
                ],
                children: [
                  for (final row in transactions)
                    [
                      ShadTableCell(child: Text(row.transactionNo)),
                      ShadTableCell(child: Text(row.transactionDate)),
                      ShadTableCell(child: Text(row.transactionType)),
                      ShadTableCell(child: Text(row.statusName)),
                      ShadTableCell(child: Text(row.createdBy)),
                    ],
                ],
                columnSpanExtent: (index) => const FixedTableSpanExtent(140),
                rowSpanExtent: (index) => const FixedTableSpanExtent(52),
              ),
      ),
    );
  }
}

class _PendingApprovalCard extends StatelessWidget {
  const _PendingApprovalCard({required this.approvals});

  final List<DashboardPendingApproval> approvals;

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    if (approvals.isEmpty) {
      return ShadCard(
        title: Text('내 결재 대기', style: theme.textTheme.h3),
        description: Text(
          '현재 승인 대기 중인 결재 요청입니다.',
          style: theme.textTheme.muted,
        ),
        child: const SuperportEmptyState(
          title: '대기 중인 결재가 없습니다',
          description: '새로운 결재 요청이 등록되면 이곳에서 바로 확인할 수 있습니다.',
        ),
      );
    }

    return ShadCard(
      title: Text('내 결재 대기', style: theme.textTheme.h3),
      description: Text('현재 승인 대기 중인 결재 요청입니다.', style: theme.textTheme.muted),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          for (final approval in approvals) ...[
            ListTile(
              leading: const Icon(lucide.LucideIcons.fileCheck, size: 20),
              title: Text(approval.approvalNo, style: theme.textTheme.small),
              subtitle: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(approval.title, style: theme.textTheme.p),
                  const SizedBox(height: 4),
                  Text(approval.stepSummary, style: theme.textTheme.muted),
                  if (approval.requestedAt != null &&
                      approval.requestedAt!.trim().isNotEmpty)
                    Padding(
                      padding: const EdgeInsets.only(top: 4),
                      child: Text(
                        '상신: ${approval.requestedAt}',
                        style: theme.textTheme.small,
                      ),
                    ),
                ],
              ),
              trailing: ShadButton.ghost(
                size: ShadButtonSize.sm,
                child: const Text('상세'),
                onPressed: () {},
              ),
            ),
            const Divider(),
          ],
        ],
      ),
    );
  }
}

class _KpiPreset {
  const _KpiPreset({
    required this.key,
    required this.label,
    required this.icon,
  });

  final String key;
  final String label;
  final IconData icon;
}

class _ReminderPanel extends StatelessWidget {
  const _ReminderPanel();

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    return ShadCard(
      title: Text('주의/알림', style: theme.textTheme.h3),
      description: Text(
        '지연된 결재나 시스템 점검 일정을 확인하세요.',
        style: theme.textTheme.muted,
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: const [
          _ReminderItem(
            icon: lucide.LucideIcons.clock,
            label: '결재 지연',
            message: '영업부 장비 구매 결재가 2일째 대기 중입니다.',
          ),
          SizedBox(height: 12),
          _ReminderItem(
            icon: lucide.LucideIcons.triangleAlert,
            label: '시스템 점검',
            message: '2024-03-15 22:00 ~ 23:00 서버 점검이 예정되어 있습니다.',
          ),
          SizedBox(height: 12),
          _ReminderItem(
            icon: lucide.LucideIcons.mail,
            label: '고객 문의',
            message: '3건의 신규 고객 문의가 접수되었습니다.',
          ),
        ],
      ),
    );
  }
}

class _ReminderItem extends StatelessWidget {
  const _ReminderItem({
    required this.icon,
    required this.label,
    required this.message,
  });

  final IconData icon;
  final String label;
  final String message;

  @override
  Widget build(BuildContext context) {
    final theme = ShadTheme.of(context);
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Icon(icon, size: 18, color: theme.colorScheme.primary),
        const SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(label, style: theme.textTheme.small),
              const SizedBox(height: 4),
              Text(message, style: theme.textTheme.p),
            ],
          ),
        ),
      ],
    );
  }
}