import 'package:sysfarma_mobile/src/app/widgets/app_panel.dart';
import 'package:sysfarma_mobile/src/app/widgets/empty_state_panel.dart';
import 'package:sysfarma_mobile/src/core/network/api_client.dart';
import 'package:sysfarma_mobile/src/core/theme/app_tokens.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

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

  @override
  ConsumerState<LotsOverviewReportScreen> createState() =>
      _LotsOverviewReportScreenState();
}

class _LotsOverviewReportScreenState
    extends ConsumerState<LotsOverviewReportScreen> {
  String _kind = 'all';
  bool _isLoading = true;
  Map<String, dynamic> _data = const {};

  @override
  void initState() {
    super.initState();
    _refresh();
  }

  Future<void> _refresh() async {
    if (mounted) setState(() => _isLoading = true);
    final response =
        await ref.read(apiClientProvider).lotsOverviewReport(kind: _kind);
    if (!mounted) return;
    setState(() {
      _data = response.data ?? const {};
      _isLoading = false;
    });
  }

  void _setKind(String kind) {
    if (kind == _kind) return;
    setState(() => _kind = kind);
    _refresh();
  }

  @override
  Widget build(BuildContext context) {
    final totals = Map<String, dynamic>.from(_data['totals'] as Map? ?? const {});
    final items = List<Map<String, dynamic>>.from(_data['items'] as List? ?? const []);
    final withLots = totals['with_lots'] ?? 0;
    final withoutLots = totals['without_lots'] ?? 0;
    final totalGroups = totals['total_lots_groups'] ?? 0;

    return SafeArea(
      child: RefreshIndicator(
        onRefresh: _refresh,
        child: ListView(
          padding: AppTokens.pagePadding,
          children: [
            Row(
              children: [
                Expanded(
                  child: _SegmentChip(
                    label: 'Todos',
                    selected: _kind == 'all',
                    onTap: () => _setKind('all'),
                  ),
                ),
                const SizedBox(width: 8),
                Expanded(
                  child: _SegmentChip(
                    label: 'Con lote',
                    selected: _kind == 'with',
                    onTap: () => _setKind('with'),
                  ),
                ),
                const SizedBox(width: 8),
                Expanded(
                  child: _SegmentChip(
                    label: 'Sin lote',
                    selected: _kind == 'without',
                    onTap: () => _setKind('without'),
                  ),
                ),
              ],
            ),
            const SizedBox(height: 14),
            Row(
              children: [
                Expanded(
                  child: _StatCard(
                    label: 'Con lote',
                    value: '$withLots',
                    color: AppTokens.primary,
                    icon: Icons.label_important_rounded,
                  ),
                ),
                const SizedBox(width: 12),
                Expanded(
                  child: _StatCard(
                    label: 'Sin lote',
                    value: '$withoutLots',
                    color: AppTokens.secondary,
                    icon: Icons.label_off_rounded,
                  ),
                ),
                const SizedBox(width: 12),
                Expanded(
                  child: _StatCard(
                    label: 'Lotes',
                    value: '$totalGroups',
                    color: AppTokens.cta,
                    icon: Icons.inventory_rounded,
                  ),
                ),
              ],
            ),
            const SizedBox(height: 14),
            if (_isLoading)
              const Padding(
                padding: EdgeInsets.symmetric(vertical: 32),
                child: Center(child: CircularProgressIndicator()),
              )
            else if (items.isEmpty)
              const EmptyStatePanel(
                icon: Icons.label_outline_rounded,
                title: 'Sin productos',
                subtitle: 'No hay productos para este filtro.',
              )
            else
              AppPanel(
                title: 'Productos',
                trailing: Text('${items.length}',
                    style: Theme.of(context).textTheme.titleMedium?.copyWith(
                          color: AppTokens.primary,
                          fontWeight: FontWeight.w700,
                        )),
                child: Column(
                  children: [
                    for (final item in items) ...[
                      _ItemRow(item: item),
                      if (item != items.last) const Divider(height: 16),
                    ],
                  ],
                ),
              ),
          ],
        ),
      ),
    );
  }
}

class _SegmentChip extends StatelessWidget {
  const _SegmentChip(
      {required this.label, required this.selected, required this.onTap});
  final String label;
  final bool selected;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Colors.transparent,
      child: InkWell(
        borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
        onTap: onTap,
        child: Container(
          padding: const EdgeInsets.symmetric(vertical: 10),
          decoration: BoxDecoration(
            color: selected
                ? AppTokens.primary.withValues(alpha: 0.10)
                : AppTokens.surface,
            borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
            border: Border.all(
              color: selected ? AppTokens.primary : AppTokens.border,
            ),
          ),
          child: Center(
            child: Text(
              label,
              style: Theme.of(context).textTheme.labelLarge?.copyWith(
                    color: selected ? AppTokens.primary : AppTokens.secondary,
                    fontWeight: selected ? FontWeight.w700 : FontWeight.w500,
                  ),
            ),
          ),
        ),
      ),
    );
  }
}

class _StatCard extends StatelessWidget {
  const _StatCard({
    required this.label,
    required this.value,
    required this.color,
    required this.icon,
  });
  final String label;
  final String value;
  final Color color;
  final IconData icon;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(12),
      decoration: BoxDecoration(
        color: color.withValues(alpha: 0.10),
        borderRadius: BorderRadius.circular(AppTokens.radiusMedium),
        border: Border.all(color: color.withValues(alpha: 0.20)),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Icon(icon, color: color, size: 18),
          const SizedBox(height: 4),
          Text(
            value,
            style: Theme.of(context).textTheme.headlineSmall?.copyWith(
                  color: color,
                  fontWeight: FontWeight.w800,
                ),
          ),
          Text(
            label,
            style: Theme.of(context).textTheme.bodySmall?.copyWith(
                  color: AppTokens.secondary,
                ),
          ),
        ],
      ),
    );
  }
}

class _ItemRow extends StatefulWidget {
  const _ItemRow({required this.item});
  final Map<String, dynamic> item;

  @override
  State<_ItemRow> createState() => _ItemRowState();
}

class _ItemRowState extends State<_ItemRow> {
  bool _expanded = false;

  @override
  Widget build(BuildContext context) {
    final item = widget.item;
    final hasLots = item['lots_enabled'] == true;
    final lotsCount = item['lots_count'] ?? 0;
    final totalQty = item['total_quantity'] ?? 0;
    final lots = List<Map<String, dynamic>>.from(
        item['lots'] as List? ?? const []);
    final canExpand = hasLots && lots.isNotEmpty;

    return Material(
      color: Colors.transparent,
      child: InkWell(
        onTap: canExpand
            ? () => setState(() => _expanded = !_expanded)
            : null,
        borderRadius: BorderRadius.circular(AppTokens.radiusSmall),
        child: Padding(
          padding: const EdgeInsets.symmetric(vertical: 6),
          child: Column(
            children: [
              Row(
                children: [
                  Container(
                    width: 8,
                    height: 36,
                    decoration: BoxDecoration(
                      color: hasLots
                          ? AppTokens.primary
                          : AppTokens.secondary,
                      borderRadius: BorderRadius.circular(4),
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          item['description']?.toString() ?? '-',
                          maxLines: 1,
                          overflow: TextOverflow.ellipsis,
                          style: Theme.of(context).textTheme.titleSmall,
                        ),
                        const SizedBox(height: 2),
                        Text(
                          hasLots
                              ? '$lotsCount lote(s) · $totalQty u'
                              : 'Sin control de lotes',
                          style: Theme.of(context)
                              .textTheme
                              .labelSmall
                              ?.copyWith(
                                color: AppTokens.secondary,
                              ),
                        ),
                      ],
                    ),
                  ),
                  if (canExpand)
                    Icon(
                      _expanded
                          ? Icons.expand_less_rounded
                          : Icons.expand_more_rounded,
                      color: AppTokens.secondary,
                    )
                  else if (hasLots)
                    Container(
                      padding: const EdgeInsets.symmetric(
                          horizontal: 8, vertical: 3),
                      decoration: BoxDecoration(
                        color: AppTokens.primary.withValues(alpha: 0.12),
                        borderRadius: BorderRadius.circular(999),
                      ),
                      child: const Text(
                        'Con lote',
                        style: TextStyle(
                          color: AppTokens.primary,
                          fontSize: 10,
                          fontWeight: FontWeight.w700,
                        ),
                      ),
                    ),
                ],
              ),
              if (canExpand && _expanded) ...[
                const SizedBox(height: 8),
                Container(
                  margin: const EdgeInsets.only(left: 20),
                  padding: const EdgeInsets.symmetric(
                      horizontal: 10, vertical: 8),
                  decoration: BoxDecoration(
                    color: AppTokens.primary.withValues(alpha: 0.05),
                    borderRadius: BorderRadius.circular(8),
                    border: Border.all(
                      color: AppTokens.primary.withValues(alpha: 0.20),
                    ),
                  ),
                  child: Column(
                    children: [
                      for (var i = 0; i < lots.length; i++) ...[
                        _LotDetailRow(lot: lots[i]),
                        if (i < lots.length - 1)
                          Divider(
                            height: 14,
                            color: AppTokens.primary.withValues(alpha: 0.15),
                          ),
                      ],
                    ],
                  ),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }
}

class _LotDetailRow extends StatelessWidget {
  const _LotDetailRow({required this.lot});
  final Map<String, dynamic> lot;

  @override
  Widget build(BuildContext context) {
    final code = lot['code']?.toString() ?? '-';
    final dueDate = lot['date_of_due']?.toString() ?? '-';
    final qty = lot['quantity']?.toString() ?? '0';

    Color dueColor = AppTokens.secondary;
    String dueLabel = dueDate;
    if (dueDate != '-') {
      try {
        final due = DateTime.parse(dueDate);
        final daysLeft = due.difference(DateTime.now()).inDays;
        if (daysLeft < 0) {
          dueColor = AppTokens.danger;
          dueLabel = '$dueDate (vencido)';
        } else if (daysLeft <= 30) {
          dueColor = AppTokens.danger;
          dueLabel = '$dueDate (${daysLeft}d)';
        } else if (daysLeft <= 90) {
          dueColor = AppTokens.warning;
          dueLabel = '$dueDate (${daysLeft}d)';
        }
      } catch (_) {}
    }

    return Row(
      children: [
        const Icon(Icons.label_outline_rounded,
            size: 14, color: AppTokens.primary),
        const SizedBox(width: 6),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisSize: MainAxisSize.min,
            children: [
              Text(
                code,
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
                style: Theme.of(context).textTheme.labelSmall?.copyWith(
                      fontWeight: FontWeight.w700,
                    ),
              ),
              Text(
                dueLabel,
                style: Theme.of(context).textTheme.labelSmall?.copyWith(
                      color: dueColor,
                    ),
              ),
            ],
          ),
        ),
        const SizedBox(width: 8),
        Text(
          '$qty u',
          style: Theme.of(context).textTheme.labelSmall?.copyWith(
                color: AppTokens.primary,
                fontWeight: FontWeight.w800,
              ),
        ),
      ],
    );
  }
}