import 'package:flutter/material.dart';

import '../../l10n/app_localizations.dart';
import '../../models/bar_tab.dart';
import '../../models/tab_item.dart';
import '../../utils/money.dart';
import '../../utils/tab_orders.dart';
import '../widgets/order_divider.dart';

/// Changes how many of [item] are on the tab: [delta] > 0 rings up more,
/// [delta] < 0 takes drinks of order [orderId] off.
typedef ItemQuantityChanged =
    Future<void> Function(TabItem item, int delta, String? orderId);

class SelectedTabDetails extends StatelessWidget {
  final BarTab tab;
  final ItemQuantityChanged onItemQuantityChanged;
  final VoidCallback onCloseTabPressed;

  const SelectedTabDetails({
    super.key,
    required this.tab,
    required this.onItemQuantityChanged,
    required this.onCloseTabPressed,
  });

  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    final l10n = AppLocalizations.of(context);

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Expanded(
          child: tab.items.isEmpty
              ? Center(
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Icon(
                        Icons.local_bar_outlined,
                        size: 32,
                        color: scheme.onSurface.withValues(alpha: 0.25),
                      ),
                      const SizedBox(height: 8),
                      Text(
                        l10n.tapProductsToAdd,
                        style: Theme.of(context).textTheme.bodyMedium,
                      ),
                    ],
                  ),
                )
              : _OrderList(
                  // Another tab starts with its own orders folded
                  key: ValueKey(tab.id),
                  orders: ordersOfTab(tab),
                  onItemQuantityChanged: onItemQuantityChanged,
                ),
        ),
        const SizedBox(height: 8),
        Container(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
          decoration: BoxDecoration(
            color: Theme.of(
              context,
            ).colorScheme.primary.withValues(alpha: 0.12),
            borderRadius: BorderRadius.circular(16),
            border: Border.all(
              color: Theme.of(
                context,
              ).colorScheme.primary.withValues(alpha: 0.3),
            ),
          ),
          child: Row(
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      l10n.total,
                      style: Theme.of(context).textTheme.bodySmall,
                    ),
                    Text(
                      tab.totalInCents.asEuro,
                      style: Theme.of(
                        context,
                      ).textTheme.headlineMedium?.copyWith(fontSize: 24),
                    ),
                  ],
                ),
              ),
              FilledButton(
                onPressed: tab.items.isEmpty ? null : onCloseTabPressed,
                child: Text(l10n.closeTab),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

/// The tab's orders, oldest first, each under the time it started.
class _OrderList extends StatefulWidget {
  final List<TabOrder<TabItem>> orders;
  final ItemQuantityChanged onItemQuantityChanged;

  const _OrderList({
    super.key,
    required this.orders,
    required this.onItemQuantityChanged,
  });

  @override
  State<_OrderList> createState() => _OrderListState();
}

/// The current (latest) order is open, earlier ones are folded away under
/// their time and total; tapping a header flips it.
class _OrderListState extends State<_OrderList> {
  /// Orders opened or closed by hand, by [_key].
  final _toggled = <String, bool>{};

  String _key(TabOrder<TabItem> order) =>
      order.orderId ?? order.startedAt.toIso8601String();

  @override
  Widget build(BuildContext context) {
    final orders = widget.orders;
    final children = <Widget>[];
    for (final (orderIndex, order) in orders.indexed) {
      final key = _key(order);
      final expanded = _toggled[key] ?? orderIndex == orders.length - 1;
      children.add(
        OrderDivider(
          key: ValueKey('order-$key'),
          startedAt: order.startedAt,
          totalInCents: order.rows.fold<int>(
            0,
            (total, row) => total + row.quantity * row.line.unitPriceInCents,
          ),
          expanded: expanded,
          onTap: () => setState(() => _toggled[key] = !expanded),
        ),
      );
      if (!expanded) continue;

      for (final (index, row) in order.rows.indexed) {
        if (index > 0) children.add(const Divider(height: 1));
        children.add(
          TabItemRow(
            key: ValueKey('${order.orderId ?? order.startedAt}-${row.line.id}'),
            item: row.line,
            quantity: row.quantity,
            orderId: order.orderId,
            onQuantityChanged: widget.onItemQuantityChanged,
          ),
        );
      }
    }

    return ListView(children: children);
  }
}

class TabItemRow extends StatelessWidget {
  final TabItem item;

  /// How many of [item] are in this order.
  final int quantity;
  final String? orderId;
  final ItemQuantityChanged onQuantityChanged;

  const TabItemRow({
    super.key,
    required this.item,
    required this.quantity,
    required this.orderId,
    required this.onQuantityChanged,
  });

  Future<void> _changeQuantity(BuildContext context, int delta) async {
    final l10n = AppLocalizations.of(context);

    try {
      await onQuantityChanged(item, delta, orderId);
    } catch (e) {
      if (!context.mounted) return;
      ScaffoldMessenger.of(
        context,
      ).showSnackBar(SnackBar(content: Text(l10n.couldNotUpdateQuantity)));
    }
  }

  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;

    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 10),
      child: Row(
        children: [
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  item.productName,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: const TextStyle(fontWeight: FontWeight.w600),
                ),
                const SizedBox(height: 2),
                Text(
                  '$quantity × ${item.unitPriceInCents.asEuro}',
                  style: Theme.of(context).textTheme.bodySmall,
                ),
              ],
            ),
          ),
          Container(
            decoration: BoxDecoration(
              color: scheme.onSurface.withValues(alpha: 0.05),
              borderRadius: BorderRadius.circular(999),
            ),
            child: Row(
              mainAxisSize: MainAxisSize.min,
              children: [
                IconButton(
                  visualDensity: VisualDensity.compact,
                  onPressed: () => _changeQuantity(context, -1),
                  icon: const Icon(Icons.remove_rounded, size: 18),
                ),
                SizedBox(
                  width: 22,
                  child: Text(
                    '$quantity',
                    textAlign: TextAlign.center,
                    style: const TextStyle(fontWeight: FontWeight.w700),
                  ),
                ),
                IconButton(
                  visualDensity: VisualDensity.compact,
                  onPressed: () => _changeQuantity(context, 1),
                  icon: const Icon(Icons.add_rounded, size: 18),
                ),
              ],
            ),
          ),
          SizedBox(
            width: 72,
            child: Text(
              (quantity * item.unitPriceInCents).asEuro,
              textAlign: TextAlign.end,
              style: const TextStyle(fontWeight: FontWeight.w700),
            ),
          ),
        ],
      ),
    );
  }
}