import 'package:flutter/material.dart';

import '../../../core/theme/app_colors.dart';
import '../../../core/theme/app_dimens.dart';
import '../../../core/theme/app_typography.dart';
import '../../../core/utils/formatters.dart';
import '../../../domain/entities/cart.dart';

/// One row of the bill, with inline quantity stepper.
class CartLineTile extends StatelessWidget {
  const CartLineTile({
    super.key,
    required this.line,
    required this.onIncrement,
    required this.onDecrement,
    required this.onRemove,
  });

  final CartLine line;
  final VoidCallback onIncrement;
  final VoidCallback onDecrement;
  final VoidCallback onRemove;

  @override
  Widget build(BuildContext context) {
    final p = line.product;

    return Dismissible(
      key: ValueKey('dismiss_${p.id}'),
      direction: DismissDirection.endToStart,
      // Confirm rather than dismiss: [onRemove] opens the PIN dialog, and a
      // refused PIN must leave the line exactly where it was. Dismissing first
      // and asking after left the row gone from the screen but still in the
      // cart — and Flutter asserting about a dismissed widget still in the
      // tree. Returning false always is correct: when the PIN is accepted the
      // line disappears because the cart changed, not because of the swipe.
      confirmDismiss: (_) async {
        onRemove();
        return false;
      },
      background: Container(
        alignment: Alignment.centerRight,
        padding: const EdgeInsets.only(right: AppSpacing.xl),
        decoration: const BoxDecoration(
          color: AppColors.dangerSurface,
          borderRadius: AppRadius.brMd,
        ),
        child: const Icon(Icons.delete_outline_rounded,
            color: AppColors.danger,),
      ),
      child: Container(
        padding: const EdgeInsets.all(AppSpacing.md),
        decoration: BoxDecoration(
          color: AppColors.surfaceAlt,
          borderRadius: AppRadius.brMd,
          border: Border.all(
            color: line.exceedsStock ? AppColors.danger : AppColors.border,
          ),
        ),
        child: Column(children: [
          Row(crossAxisAlignment: CrossAxisAlignment.start, children: [
            Container(
              width: 42,
              height: 42,
              decoration: BoxDecoration(
                color: AppColors.surface,
                borderRadius: AppRadius.brSm,
                border: Border.all(color: AppColors.border),
              ),
              alignment: Alignment.center,
              child: Text(p.emoji, style: const TextStyle(fontSize: 21)),
            ),
            const SizedBox(width: AppSpacing.md),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    p.name,
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                    style: const TextStyle(
                      fontSize: 14.5,
                      fontWeight: FontWeight.w600,
                    ),
                  ),
                  const SizedBox(height: 2),
                  Row(children: [
                    Text(
                      Formatters.money(p.price),
                      style: AppTypography.money(13.5,
                          weight: FontWeight.w600,
                          color: AppColors.textSecondary,),
                    ),
                    Text(' / ${p.unit.symbol}',
                        style: const TextStyle(
                          fontSize: 11.5,
                          color: AppColors.textTertiary,
                        ),),
                    if (line.discount.isActive) ...[
                      const SizedBox(width: AppSpacing.sm),
                      Container(
                        padding: const EdgeInsets.symmetric(
                            horizontal: 5, vertical: 1,),
                        decoration: BoxDecoration(
                          color: AppColors.successSurface,
                          borderRadius: BorderRadius.circular(4),
                        ),
                        child: Text(
                          line.discount.label,
                          style: const TextStyle(
                            fontSize: 10,
                            color: AppColors.success,
                            fontWeight: FontWeight.w700,
                          ),
                        ),
                      ),
                    ],
                  ],),
                ],
              ),
            ),
            IconButton(
              onPressed: onRemove,
              icon: const Icon(Icons.close_rounded, size: 18),
              color: AppColors.textTertiary,
              constraints: const BoxConstraints(minWidth: 32, minHeight: 32),
              padding: EdgeInsets.zero,
              tooltip: 'Remove from bill (needs the removal PIN)',
            ),
          ],),

          const SizedBox(height: AppSpacing.sm),

          Row(children: [
            _Stepper(
              quantity: line.quantity,
              unit: p.unit.symbol,
              onIncrement: onIncrement,
              onDecrement: onDecrement,
            ),
            const Spacer(),
            Column(
              crossAxisAlignment: CrossAxisAlignment.end,
              children: [
                if (line.discountAmount > 0)
                  Text(
                    Formatters.money(line.grossAmount),
                    style: const TextStyle(
                      fontSize: 11.5,
                      color: AppColors.textTertiary,
                      decoration: TextDecoration.lineThrough,
                    ),
                  ),
                Text(
                  Formatters.money(line.payable),
                  style: AppTypography.money(16),
                ),
              ],
            ),
          ],),

          if (line.exceedsStock)
            Padding(
              padding: const EdgeInsets.only(top: AppSpacing.sm),
              child: Row(children: [
                const Icon(Icons.error_outline_rounded,
                    size: 14, color: AppColors.danger,),
                const SizedBox(width: AppSpacing.xs),
                Text(
                  'Only ${p.stock.toStringAsFixed(0)} ${p.unit.symbol} '
                  'available',
                  style: const TextStyle(
                    fontSize: 11.5,
                    color: AppColors.danger,
                    fontWeight: FontWeight.w600,
                  ),
                ),
              ],),
            ),
        ],),
      ),
    );
  }
}

class _Stepper extends StatelessWidget {
  const _Stepper({
    required this.quantity,
    required this.unit,
    required this.onIncrement,
    required this.onDecrement,
  });

  final double quantity;
  final String unit;
  final VoidCallback onIncrement;
  final VoidCallback onDecrement;

  @override
  Widget build(BuildContext context) {
    return Container(
      decoration: BoxDecoration(
        color: AppColors.surface,
        borderRadius: AppRadius.brSm,
        border: Border.all(color: AppColors.border),
      ),
      // Minus stops at one rather than emptying the line. Dropping to zero
      // was a silent removal that skipped the PIN the close button asks for —
      // two taps of a stepper should not be a way around the till's only
      // theft control.
      child: Row(mainAxisSize: MainAxisSize.min, children: [
        _btn(Icons.remove_rounded, quantity > 1 ? onDecrement : null),
        Container(
          constraints: const BoxConstraints(minWidth: 42),
          alignment: Alignment.center,
          child: Text(
            quantity % 1 == 0
                ? quantity.toStringAsFixed(0)
                : quantity.toStringAsFixed(2),
            style: AppTypography.money(15.5),
          ),
        ),
        _btn(Icons.add_rounded, onIncrement),
      ],),
    );
  }

  Widget _btn(IconData icon, VoidCallback? onTap) => Material(
        color: Colors.transparent,
        child: InkWell(
          onTap: onTap,
          borderRadius: AppRadius.brSm,
          child: SizedBox(
            width: 34,
            height: 34,
            child: Icon(
              icon,
              size: 17,
              color: onTap == null
                  ? AppColors.textTertiary.withValues(alpha: 0.5)
                  : AppColors.primary,
            ),
          ),
        ),
      );
}