import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_animate/flutter_animate.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../core/theme/app_colors.dart';
import '../../../core/theme/app_dimens.dart';
import '../providers/cart_controller.dart';

/// Brief floating confirmation after a scan.
///
/// Deliberately not a dialog: the cashier must never have to dismiss anything
/// between items.
class ScanToast extends ConsumerStatefulWidget {
  const ScanToast({super.key});

  @override
  ConsumerState<ScanToast> createState() => _ScanToastState();
}

class _ScanToastState extends ConsumerState<ScanToast> {
  Timer? _timer;
  ScanFeedback? _visible;

  void _show(ScanFeedback feedback) {
    _timer?.cancel();
    setState(() => _visible = feedback);
    _timer = Timer(
      const Duration(milliseconds: 1600),
      () {
        if (mounted) setState(() => _visible = null);
      },
    );
  }

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    ref.listen<ScanFeedback?>(scanFeedbackProvider, (prev, next) {
      if (next != null) _show(next);
    });

    final feedback = _visible;
    if (feedback == null) return const SizedBox.shrink();

    final success = feedback.isSuccess;
    final color = success ? AppColors.success : AppColors.danger;
    final product = feedback.product;

    final message = feedback.message ??
        switch (feedback.outcome) {
          ScanOutcome.added => 'Added to bill',
          ScanOutcome.incremented => 'Quantity updated',
          ScanOutcome.notFound => 'Product not found',
          ScanOutcome.outOfStock => 'Out of stock',
        };

    return Container(
      margin: const EdgeInsets.symmetric(horizontal: AppSpacing.xxl),
      padding: const EdgeInsets.symmetric(
        horizontal: AppSpacing.xl,
        vertical: AppSpacing.md,
      ),
      decoration: const BoxDecoration(
        color: AppColors.textPrimary,
        borderRadius: AppRadius.brPill,
        boxShadow: AppColors.shadowLg,
      ),
      child: Row(mainAxisSize: MainAxisSize.min, children: [
        Container(
          width: 26,
          height: 26,
          decoration: BoxDecoration(color: color, shape: BoxShape.circle),
          child: Icon(
            success ? Icons.check_rounded : Icons.priority_high_rounded,
            size: 17,
            color: Colors.white,
          ),
        ),
        const SizedBox(width: AppSpacing.md),
        if (product != null) ...[
          Text(product.emoji, style: const TextStyle(fontSize: 17)),
          const SizedBox(width: AppSpacing.sm),
          ConstrainedBox(
            constraints: const BoxConstraints(maxWidth: 220),
            child: Text(
              product.name,
              overflow: TextOverflow.ellipsis,
              style: const TextStyle(
                color: Colors.white,
                fontWeight: FontWeight.w700,
                fontSize: 14.5,
              ),
            ),
          ),
          const SizedBox(width: AppSpacing.sm),
          Container(width: 1, height: 16, color: Colors.white24),
          const SizedBox(width: AppSpacing.sm),
        ],
        Text(
          message,
          style: TextStyle(
            color: Colors.white.withValues(alpha: 0.85),
            fontSize: 13.5,
          ),
        ),
      ],),
    )
        .animate(key: ValueKey(feedback.stamp))
        .fadeIn(duration: 140.ms)
        .slideY(begin: 0.4, end: 0, curve: Curves.easeOutBack)
        .then(delay: 1200.ms)
        .fadeOut(duration: 250.ms);
  }
}