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/error_view.dart';
import 'contracts_provider.dart';

class ContractDetailScreen extends ConsumerWidget {
  final int id;
  const ContractDetailScreen({super.key, required this.id});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final async = ref.watch(contractDetailProvider(id));

    return async.when(
      loading: () => const Scaffold(body: Center(child: CircularProgressIndicator())),
      error: (e, _) => Scaffold(appBar: AppBar(),
          body: ErrorView(message: e.toString(), onRetry: () => ref.invalidate(contractDetailProvider(id)))),
      data: (contract) => Scaffold(
        appBar: AppBar(
          title: const Text('Contract Detail'),
          flexibleSpace: Container(
            decoration: const BoxDecoration(
              gradient: LinearGradient(
                colors: [AppColors.primary, AppColors.primaryDark],
                begin: Alignment.topLeft, end: Alignment.bottomRight,
              ),
            ),
          ),
          foregroundColor: Colors.white,
          actions: [
            IconButton(
              icon: const Icon(Icons.edit_outlined),
              onPressed: () async {
                await context.push('/contracts/$id/edit');
                ref.invalidate(contractDetailProvider(id));
              },
            ),
          ],
        ),
        body: ListView(
          padding: const EdgeInsets.all(16),
          children: [
            // Header card
            _card(Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(children: [
                  Expanded(child: Text(contract.title,
                      style: const TextStyle(fontSize: 16, fontWeight: FontWeight.w700, color: AppColors.text))),
                  const SizedBox(width: 8),
                  StatusBadge(contract.status),
                ]),
                const SizedBox(height: 12),
                if (contract.companyName != null)
                  _info('Company', contract.companyName!),
                if (contract.vendorName != null)
                  _info('Vendor', contract.vendorName!),
                if (contract.predecessors.isNotEmpty)
                  _info('Menggantikan', contract.predecessors.map((p) => p.title).join(', '), color: AppColors.textSub),
                if (contract.successors.isNotEmpty)
                  _info('Digantikan oleh', contract.successors.map((s) => s.title).join(', '), color: AppColors.primary),
                if (contract.periodStart != null)
                  _info('Start', DateFormat('d MMMM yyyy').format(contract.periodStart!)),
                if (contract.periodEnd != null)
                  _info('End', DateFormat('d MMMM yyyy').format(contract.periodEnd!),
                      color: contract.isExpiringSoon ? AppColors.warning : null),
                if (contract.isExpiringSoon && contract.status == 'Active')
                  Container(
                    margin: const EdgeInsets.only(top: 8),
                    padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 6),
                    decoration: BoxDecoration(
                      color: AppColors.warningLight,
                      borderRadius: BorderRadius.circular(8),
                    ),
                    child: Row(children: [
                      const Icon(Icons.warning_amber_rounded, size: 14, color: AppColors.warning),
                      const SizedBox(width: 6),
                      Text('Expires in ${contract.daysUntilExpiry} days',
                          style: const TextStyle(fontSize: 12, color: Color(0xFFB45309), fontWeight: FontWeight.w600)),
                    ]),
                  ),
              ],
            )),
            const SizedBox(height: 12),

            // AI Analysis (body HTML parsed to sections)
            if (contract.body != null && contract.body!.isNotEmpty) ...[
              const Text('AI Analysis', style: TextStyle(fontSize: 14, fontWeight: FontWeight.w700, color: AppColors.text)),
              const SizedBox(height: 8),
              ..._parseAccordionSections(contract.body!).map((s) => _AccordionCard(title: s.$1, body: s.$2)),
            ],
            const SizedBox(height: 24),
          ],
        ),
      ),
    );
  }

  List<(String, String)> _parseAccordionSections(String html) {
    // Extract h2/h3 sections from HTML
    final sections = <(String, String)>[];
    final sectionTitles = [
      'Ringkasan', 'Harga', 'Jangka Waktu', 'Sanksi', 'Pasal Kritis',
    ];
    // Simple: split by <h2> or <h3> tags
    final regex = RegExp(r'<h[23][^>]*>(.*?)</h[23]>(.*?)(?=<h[23]|$)', dotAll: true);
    final matches = regex.allMatches(html);
    if (matches.isEmpty) {
      // Fallback: show as plain text
      return [('Contract Analysis', html.replaceAll(RegExp(r'<[^>]*>'), '').trim())];
    }
    for (final m in matches) {
      final title = m.group(1)?.replaceAll(RegExp(r'<[^>]*>'), '').trim() ?? '';
      final body = m.group(2)?.replaceAll(RegExp(r'<[^>]*>'), '').trim() ?? '';
      if (title.isNotEmpty) sections.add((title, body));
    }
    if (sections.isEmpty) {
      for (int i = 0; i < sectionTitles.length; i++) {
        sections.add((sectionTitles[i], ''));
      }
    }
    return sections;
  }

  Widget _card(Widget child) => Container(
    padding: const EdgeInsets.all(14),
    decoration: BoxDecoration(
      color: AppColors.surface,
      borderRadius: BorderRadius.circular(12),
      border: Border.all(color: AppColors.border),
    ),
    child: child,
  );

  Widget _info(String label, String value, {Color? color}) => Padding(
    padding: const EdgeInsets.only(bottom: 8),
    child: Row(children: [
      SizedBox(width: 90, child: Text(label,
          style: const TextStyle(fontSize: 13, color: AppColors.textSub))),
      Expanded(child: Text(value,
          style: TextStyle(fontSize: 13, fontWeight: FontWeight.w600, color: color ?? AppColors.text))),
    ]),
  );
}

class _AccordionCard extends StatefulWidget {
  final String title;
  final String body;
  const _AccordionCard({required this.title, required this.body});

  @override
  State<_AccordionCard> createState() => _AccordionCardState();
}

class _AccordionCardState extends State<_AccordionCard> {
  bool _expanded = false;

  @override
  Widget build(BuildContext context) => Container(
    margin: const EdgeInsets.only(bottom: 8),
    decoration: BoxDecoration(
      color: AppColors.surface,
      borderRadius: BorderRadius.circular(12),
      border: Border.all(color: AppColors.border),
    ),
    child: Column(
      children: [
        InkWell(
          onTap: () => setState(() => _expanded = !_expanded),
          borderRadius: BorderRadius.circular(12),
          child: Padding(
            padding: const EdgeInsets.all(14),
            child: Row(children: [
              Expanded(child: Text(widget.title,
                  style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 14))),
              Icon(_expanded ? Icons.expand_less : Icons.expand_more, color: AppColors.textSub),
            ]),
          ),
        ),
        if (_expanded && widget.body.isNotEmpty)
          Padding(
            padding: const EdgeInsets.fromLTRB(14, 0, 14, 14),
            child: Text(widget.body,
                style: const TextStyle(fontSize: 13, color: AppColors.text, height: 1.5)),
          ),
      ],
    ),
  );
}