import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:intl/intl.dart';
import '../../core/auth/auth_notifier.dart';
import '../../core/auth/auth_state.dart';
import '../../core/theme/app_theme.dart';
import '../../core/api/api_client.dart';
import '../../shared/models/task.dart';
import '../../shared/models/contract.dart';
import '../../shared/providers/lookup_providers.dart';

// Dashboard stats provider
final dashboardProvider = FutureProvider.autoDispose<_DashboardData>((ref) async {
  final futures = await Future.wait([
    apiDio.get('/tasks/admin', queryParameters: {'page': 1, 'limit': 500}),
    apiDio.get('/surat', queryParameters: {'page': 1, 'limit': 500}),
    apiDio.get('/contracts', queryParameters: {'page': 1, 'limit': 500}),
  ]);
  final tasks = PagedTasks.fromJson(futures[0].data);
  final pendingCount = (futures[1].data['total'] as int? ?? 0);
  final contracts = PagedContracts.fromJson(futures[2].data);
  return _DashboardData(
    tasks: tasks,
    suratPendingCount: pendingCount,
    contracts: contracts,
  );
});

class _DashboardData {
  final PagedTasks tasks;
  final int suratPendingCount;
  final PagedContracts contracts;
  _DashboardData({required this.tasks, required this.suratPendingCount, required this.contracts});
}

class DashboardScreen extends ConsumerWidget {
  const DashboardScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final authState = ref.watch(authProvider);
    final user = authState is AuthAuthenticated ? authState.user : null;
    final dashAsync = ref.watch(dashboardProvider);
    final unreadAsync = ref.watch(notifUnreadCountProvider);

    return Scaffold(
      appBar: AppBar(
        title: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text('Dashboard', style: TextStyle(fontSize: 17, fontWeight: FontWeight.w700)),
            if (user != null)
              Text('Hi, ${user.username}',
                  style: const TextStyle(fontSize: 12, color: AppColors.textSub, fontWeight: FontWeight.w400)),
          ],
        ),
        actions: [
          Stack(
            children: [
              IconButton(
                icon: const Icon(Icons.notifications_outlined),
                onPressed: () => context.push('/notifications'),
              ),
              unreadAsync.whenData((count) => count > 0
                  ? Positioned(
                      top: 8, right: 8,
                      child: Container(
                        width: 14, height: 14,
                        decoration: const BoxDecoration(color: AppColors.danger, shape: BoxShape.circle),
                        child: Center(child: Text('${count > 9 ? 9 : count}',
                            style: const TextStyle(color: Colors.white, fontSize: 8, fontWeight: FontWeight.w700))),
                      ),
                    )
                  : const SizedBox()).value ?? const SizedBox(),
            ],
          ),
          IconButton(icon: const Icon(Icons.person_outline), onPressed: () => context.push('/profile')),
        ],
      ),
      body: RefreshIndicator(
        color: AppColors.primary,
        onRefresh: () async {
          ref.invalidate(dashboardProvider);
          ref.invalidate(notifUnreadCountProvider);
        },
        child: dashAsync.when(
          loading: () => const Center(child: CircularProgressIndicator()),
          error: (e, _) => Center(child: Text(e.toString())),
          data: (data) {
            final todoCount = data.tasks.items.where((t) => t.status == 'todo').length;
            final inProgressCount = data.tasks.items.where((t) => t.status == 'in_progress').length;
            final doneCount = data.tasks.items.where((t) => t.status == 'done').length;
            final activeTasks = data.tasks.items
                .where((t) => t.status != 'done')
                .toList()
              ..sort((a, b) {
                const order = {'in_progress': 0, 'todo': 1};
                return (order[a.status] ?? 2).compareTo(order[b.status] ?? 2);
              });

            return ListView(
              padding: const EdgeInsets.all(16),
              children: [
                // Stat cards
                GridView.count(
                  crossAxisCount: 2,
                  shrinkWrap: true,
                  physics: const NeverScrollableScrollPhysics(),
                  mainAxisSpacing: 10, crossAxisSpacing: 10,
                  childAspectRatio: 1.6,
                  children: [
                    _StatCard(
                      icon: Icons.assignment_outlined,
                      label: 'Active Tasks',
                      value: '${data.tasks.items.where((t) => t.status != 'done').length}',
                      color: AppColors.blue,
                      bgColor: AppColors.blueLight,
                      onTap: () => context.go('/tasks'),
                    ),
                    _StatCard(
                      icon: Icons.mail_outline,
                      label: 'Pending Letters',
                      value: '${data.suratPendingCount}',
                      color: AppColors.warning,
                      bgColor: AppColors.warningLight,
                      onTap: () => context.go('/surat'),
                    ),
                    _StatCard(
                      icon: Icons.description_outlined,
                      label: 'Active Contracts',
                      value: '${data.contracts.items.where((c) => c.status == 'Active').length}',
                      color: AppColors.primary,
                      bgColor: AppColors.primaryLight,
                      onTap: () => context.go('/contracts'),
                    ),
                    _StatCard(
                      icon: Icons.warning_amber_outlined,
                      label: 'Expiring Contracts',
                      value: '${data.contracts.items.where((c) => c.isExpiringSoon && c.status == 'Active').length}',
                      color: AppColors.danger,
                      bgColor: AppColors.dangerLight,
                      onTap: () => context.go('/contracts'),
                    ),
                  ],
                ),
                const SizedBox(height: 20),

                // Quick actions
                const Text('Quick Actions',
                    style: TextStyle(fontSize: 14, fontWeight: FontWeight.w700, color: AppColors.text)),
                const SizedBox(height: 10),
                Row(children: [
                  _QuickAction(icon: Icons.add_task, label: 'New Task', onTap: () => context.push('/tasks/create')),
                  const SizedBox(width: 10),
                  _QuickAction(icon: Icons.mail_outlined, label: 'New Letter', onTap: () => context.push('/surat/create')),
                  const SizedBox(width: 10),
                  _QuickAction(icon: Icons.upload_file_outlined, label: 'Upload Contract', onTap: () => context.push('/contracts/upload')),
                ]),
                const SizedBox(height: 20),

                // Task Overview header
                Row(children: [
                  const Expanded(child: Text('Task Overview',
                      style: TextStyle(fontSize: 14, fontWeight: FontWeight.w700, color: AppColors.text))),
                  TextButton(
                    onPressed: () => context.go('/tasks'),
                    child: const Text('View All →', style: TextStyle(fontSize: 13)),
                  ),
                ]),
                const SizedBox(height: 8),

                // Status summary pills
                Row(children: [
                  _StatusPill(label: 'To Do', count: todoCount, color: AppColors.blue, bgColor: AppColors.blueLight),
                  const SizedBox(width: 8),
                  _StatusPill(label: 'In Progress', count: inProgressCount, color: AppColors.warning, bgColor: AppColors.warningLight),
                  const SizedBox(width: 8),
                  _StatusPill(label: 'Done', count: doneCount, color: AppColors.primary, bgColor: AppColors.primaryLight),
                ]),
                const SizedBox(height: 12),

                // Active tasks: in_progress first, then todo
                if (activeTasks.isEmpty)
                  Container(
                    padding: const EdgeInsets.all(20),
                    decoration: BoxDecoration(
                      color: AppColors.surface,
                      borderRadius: BorderRadius.circular(10),
                      border: Border.all(color: AppColors.border),
                    ),
                    child: const Center(
                      child: Text('All tasks completed! 🎉',
                          style: TextStyle(fontSize: 13, color: AppColors.textSub)),
                    ),
                  )
                else
                  ...activeTasks.take(6).map((t) => Padding(
                    padding: const EdgeInsets.only(bottom: 8),
                    child: GestureDetector(
                      onTap: () => context.push('/tasks/${t.id}'),
                      child: Container(
                        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
                        decoration: BoxDecoration(
                          color: AppColors.surface,
                          borderRadius: BorderRadius.circular(10),
                          border: Border.all(
                            color: t.isOverdue ? AppColors.dangerLight : AppColors.border,
                          ),
                        ),
                        child: Row(children: [
                          Container(
                            width: 8, height: 8,
                            decoration: BoxDecoration(
                              color: t.status == 'in_progress' ? AppColors.warning : AppColors.blue,
                              shape: BoxShape.circle,
                            ),
                          ),
                          const SizedBox(width: 10),
                          Expanded(child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Text(t.title,
                                  style: const TextStyle(fontSize: 13, fontWeight: FontWeight.w500),
                                  maxLines: 1, overflow: TextOverflow.ellipsis),
                              if (t.assignedUsername != null)
                                Text(t.assignedUsername!,
                                    style: const TextStyle(fontSize: 11, color: AppColors.textSub)),
                            ],
                          )),
                          const SizedBox(width: 8),
                          Column(
                            crossAxisAlignment: CrossAxisAlignment.end,
                            children: [
                              Container(
                                padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
                                decoration: BoxDecoration(
                                  color: t.status == 'in_progress'
                                      ? AppColors.warningLight
                                      : AppColors.blueLight,
                                  borderRadius: BorderRadius.circular(4),
                                ),
                                child: Text(
                                  t.status == 'in_progress' ? 'In Progress' : 'To Do',
                                  style: TextStyle(
                                    fontSize: 10, fontWeight: FontWeight.w600,
                                    color: t.status == 'in_progress' ? AppColors.warning : AppColors.blue,
                                  ),
                                ),
                              ),
                              if (t.dueDate != null) ...[
                                const SizedBox(height: 2),
                                Text(
                                  DateFormat('d MMM').format(t.dueDate!),
                                  style: TextStyle(
                                    fontSize: 10,
                                    color: t.isOverdue ? AppColors.danger : AppColors.textSub,
                                  ),
                                ),
                              ],
                            ],
                          ),
                        ]),
                      ),
                    ),
                  )),
              ],
            );
          },
        ),
      ),
    );
  }
}

// ── Status pill ───────────────────────────────────────────────────────────────

class _StatusPill extends StatelessWidget {
  final String label;
  final int count;
  final Color color;
  final Color bgColor;

  const _StatusPill({
    required this.label, required this.count,
    required this.color, required this.bgColor,
  });

  @override
  Widget build(BuildContext context) => Expanded(
    child: Container(
      padding: const EdgeInsets.symmetric(vertical: 8, horizontal: 10),
      decoration: BoxDecoration(color: bgColor, borderRadius: BorderRadius.circular(8)),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('$count',
              style: TextStyle(fontSize: 18, fontWeight: FontWeight.w800, color: color)),
          Text(label,
              style: TextStyle(fontSize: 10, fontWeight: FontWeight.w500, color: color)),
        ],
      ),
    ),
  );
}

// ── Stat card ─────────────────────────────────────────────────────────────────

class _StatCard extends StatelessWidget {
  final IconData icon;
  final String label;
  final String value;
  final Color color;
  final Color bgColor;
  final VoidCallback onTap;

  const _StatCard({
    required this.icon, required this.label, required this.value,
    required this.color, required this.bgColor, required this.onTap,
  });

  @override
  Widget build(BuildContext context) => GestureDetector(
    onTap: onTap,
    child: Container(
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: BorderRadius.circular(12),
        border: Border.all(color: AppColors.border),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Container(
            padding: const EdgeInsets.all(6),
            decoration: BoxDecoration(color: bgColor, borderRadius: BorderRadius.circular(8)),
            child: Icon(icon, size: 18, color: color),
          ),
          const Spacer(),
          Text(value, style: TextStyle(fontSize: 22, fontWeight: FontWeight.w800, color: color)),
          Text(label, style: const TextStyle(fontSize: 11, color: AppColors.textSub)),
        ],
      ),
    ),
  );
}

// ── Quick action ──────────────────────────────────────────────────────────────

class _QuickAction extends StatelessWidget {
  final IconData icon;
  final String label;
  final VoidCallback onTap;

  const _QuickAction({required this.icon, required this.label, required this.onTap});

  @override
  Widget build(BuildContext context) => Expanded(
    child: GestureDetector(
      onTap: onTap,
      child: Container(
        padding: const EdgeInsets.symmetric(vertical: 14),
        decoration: BoxDecoration(
          color: AppColors.surface,
          borderRadius: BorderRadius.circular(12),
          border: Border.all(color: AppColors.border),
        ),
        child: Column(
          children: [
            Icon(icon, color: AppColors.primary, size: 24),
            const SizedBox(height: 6),
            Text(label,
                style: const TextStyle(fontSize: 11, fontWeight: FontWeight.w600, color: AppColors.text),
                textAlign: TextAlign.center),
          ],
        ),
      ),
    ),
  );
}