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/theme/app_theme.dart';
import '../../core/widgets/status_badge.dart';
import '../../core/widgets/empty_state.dart';
import '../../core/widgets/error_view.dart';
import '../../shared/models/contract.dart';
import 'contracts_provider.dart';

class ContractListScreen extends ConsumerStatefulWidget {
  const ContractListScreen({super.key});

  @override
  ConsumerState<ContractListScreen> createState() => _ContractListScreenState();
}

class _ContractListScreenState extends ConsumerState<ContractListScreen> {
  String _filter = 'all';
  final _searchCtrl = TextEditingController();

  @override
  void initState() {
    super.initState();
    _searchCtrl.addListener(_reload);
  }

  @override
  void dispose() {
    _searchCtrl.removeListener(_reload);
    _searchCtrl.dispose();
    super.dispose();
  }

  void _reload() {
    ref.read(contractListProvider.notifier).load(filter: _filter, search: _searchCtrl.text);
  }

  void _setFilter(String f) {
    setState(() => _filter = f);
    ref.read(contractListProvider.notifier).load(filter: f, search: _searchCtrl.text);
  }

  @override
  Widget build(BuildContext context) {
    final state = ref.watch(contractListProvider);

    return Scaffold(
      appBar: AppBar(title: const Text('Contracts')),
      body: Column(
        children: [
          Padding(
            padding: const EdgeInsets.fromLTRB(16, 12, 16, 8),
            child: TextField(
              controller: _searchCtrl,
              decoration: const InputDecoration(
                hintText: 'Search contracts...',
                prefixIcon: Icon(Icons.search, color: AppColors.textSub),
              ),
            ),
          ),
          SizedBox(
            height: 40,
            child: ListView(
              scrollDirection: Axis.horizontal,
              padding: const EdgeInsets.symmetric(horizontal: 16),
              children: [
                for (final (val, label) in [('all', 'All'), ('active', 'Active'), ('upcoming', 'Upcoming'), ('expired', 'Expired')])
                  Padding(
                    padding: const EdgeInsets.only(right: 8),
                    child: ChoiceChip(
                      label: Text(label, style: TextStyle(
                        fontSize: 12, fontWeight: FontWeight.w600,
                        color: _filter == val ? Colors.white : AppColors.textSub,
                      )),
                      selected: _filter == val,
                      selectedColor: AppColors.primary,
                      backgroundColor: AppColors.surface,
                      side: BorderSide(color: _filter == val ? AppColors.primary : AppColors.border),
                      onSelected: (_) => _setFilter(val),
                    ),
                  ),
              ],
            ),
          ),
          const SizedBox(height: 8),
          Expanded(
            child: state.when(
              loading: () => const Center(child: CircularProgressIndicator()),
              error: (e, _) => ErrorView(
                message: e.toString(),
                onRetry: () => ref.read(contractListProvider.notifier).load(),
              ),
              data: (paged) {
                final expiring = paged.items.where((c) => c.isExpiringSoon && c.status == 'Active').toList();
                return RefreshIndicator(
                  color: AppColors.primary,
                  onRefresh: () async => ref.read(contractListProvider.notifier).load(
                    filter: _filter, search: _searchCtrl.text),
                  child: CustomScrollView(
                    slivers: [
                      if (expiring.isNotEmpty)
                        SliverToBoxAdapter(
                          child: Container(
                            margin: const EdgeInsets.fromLTRB(16, 4, 16, 8),
                            padding: const EdgeInsets.all(12),
                            decoration: BoxDecoration(
                              color: AppColors.warningLight,
                              borderRadius: BorderRadius.circular(10),
                              border: Border.all(color: AppColors.warning.withOpacity(0.5)),
                            ),
                            child: Row(children: [
                              const Icon(Icons.warning_amber_rounded, color: AppColors.warning, size: 18),
                              const SizedBox(width: 8),
                              Text('${expiring.length} contract(s) expiring soon (≤90 days)',
                                  style: const TextStyle(fontSize: 13, color: Color(0xFFB45309), fontWeight: FontWeight.w600)),
                            ]),
                          ),
                        ),
                      if (paged.items.isEmpty)
                        SliverFillRemaining(child: EmptyState(
                          message: 'No contracts',
                          icon: Icons.description_outlined,
                          actionLabel: 'Upload Contract',
                          onAction: () => context.push('/contracts/upload'),
                        ))
                      else
                        SliverPadding(
                          padding: const EdgeInsets.fromLTRB(16, 0, 16, 100),
                          sliver: SliverList(
                            delegate: SliverChildBuilderDelegate(
                              (_, i) => Padding(
                                padding: const EdgeInsets.only(bottom: 8),
                                child: _ContractCard(contract: paged.items[i]),
                              ),
                              childCount: paged.items.length,
                            ),
                          ),
                        ),
                    ],
                  ),
                );
              },
            ),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () async {
          await context.push('/contracts/upload');
          if (mounted) ref.read(contractListProvider.notifier).load(filter: _filter);
        },
        child: const Icon(Icons.add),
      ),
    );
  }
}

class _ContractCard extends StatelessWidget {
  final Contract contract;
  const _ContractCard({required this.contract});

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () => context.push('/contracts/${contract.id}'),
      child: Container(
        padding: const EdgeInsets.all(14),
        decoration: BoxDecoration(
          color: AppColors.surface,
          borderRadius: BorderRadius.circular(12),
          border: Border.all(color: contract.isExpiringSoon ? AppColors.warningLight : AppColors.border),
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(children: [
              Expanded(child: Text(contract.title,
                  style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 14, color: AppColors.text),
                  maxLines: 2, overflow: TextOverflow.ellipsis)),
              const SizedBox(width: 8),
              StatusBadge(contract.status, small: true),
            ]),
            const SizedBox(height: 8),
            if (contract.periodStart != null && contract.periodEnd != null)
              Text(
                '${DateFormat('d MMM yyyy', 'id').format(contract.periodStart!)} — ${DateFormat('d MMM yyyy', 'id').format(contract.periodEnd!)}',
                style: const TextStyle(fontSize: 12, color: AppColors.textSub),
              ),
            if (contract.companyName != null || contract.vendorName != null) ...[
              const SizedBox(height: 4),
              Row(children: [
                if (contract.companyName != null) ...[
                  const Icon(Icons.business_outlined, size: 11, color: AppColors.textSub),
                  const SizedBox(width: 3),
                  Text(contract.companyName!, style: const TextStyle(fontSize: 11, color: AppColors.textSub)),
                ],
                if (contract.companyName != null && contract.vendorName != null)
                  const Text('  ·  ', style: TextStyle(fontSize: 11, color: AppColors.textSub)),
                if (contract.vendorName != null) ...[
                  const Icon(Icons.local_shipping_outlined, size: 11, color: AppColors.textSub),
                  const SizedBox(width: 3),
                  Text(contract.vendorName!, style: const TextStyle(fontSize: 11, color: AppColors.textSub)),
                ],
              ]),
            ],
            if (contract.isExpiringSoon && contract.status == 'Active') ...[
              const SizedBox(height: 6),
              Row(children: [
                const Icon(Icons.warning_amber_rounded, size: 13, color: AppColors.warning),
                const SizedBox(width: 4),
                Text('Expires in ${contract.daysUntilExpiry} days',
                    style: const TextStyle(fontSize: 11, color: AppColors.warning, fontWeight: FontWeight.w600)),
              ]),
            ],
            if (contract.status == 'Expired' && contract.successors.isNotEmpty) ...[
              const SizedBox(height: 6),
              Row(children: [
                const Icon(Icons.check_circle_outline, size: 13, color: AppColors.primary),
                const SizedBox(width: 4),
                const Text('Digantikan', style: TextStyle(fontSize: 11, color: AppColors.primary, fontWeight: FontWeight.w600)),
              ]),
            ],
          ],
        ),
      ),
    );
  }
}