import 'dart:async';
import 'dart:math';

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';

import '../../l10n/app_localizations.dart';
import '../../models/product.dart';
import '../widgets/product_tile.dart';

class ProductGrid extends StatelessWidget {
  final List<Product> products;
  final int rows;
  final bool hasSelectedTab;
  final ValueChanged<Product> onProductTap;

  const ProductGrid({
    super.key,
    required this.products,
    required this.rows,
    required this.hasSelectedTab,
    required this.onProductTap,
  });

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

    if (products.isEmpty) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Container(
              padding: const EdgeInsets.all(20),
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                color: scheme.onSurface.withValues(alpha: 0.05),
              ),
              child: Icon(
                Icons.inventory_2_outlined,
                size: 40,
                color: scheme.onSurface.withValues(alpha: 0.3),
              ),
            ),
            const SizedBox(height: 16),
            Text(
              l10n.noProductsYet,
              style: Theme.of(context).textTheme.titleMedium,
            ),
            const SizedBox(height: 4),
            Text(
              l10n.addFirstProduct,
              style: Theme.of(context).textTheme.bodyMedium,
            ),
            const SizedBox(height: 20),
            FilledButton.icon(
              onPressed: () => context.push('/admin'),
              icon: const Icon(Icons.admin_panel_settings_outlined),
              label: Text(l10n.admin),
            ),
          ],
        ),
      );
    }

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Padding(
          padding: const EdgeInsets.fromLTRB(20, 18, 20, 4),
          child: Row(
            children: [
              Text(
                l10n.products,
                style: Theme.of(context).textTheme.titleLarge,
              ),
              const SizedBox(width: 10),
              if (!hasSelectedTab)
                Flexible(
                  child: Container(
                    padding: const EdgeInsets.symmetric(
                      horizontal: 10,
                      vertical: 4,
                    ),
                    decoration: BoxDecoration(
                      color: scheme.onSurface.withValues(alpha: 0.06),
                      borderRadius: BorderRadius.circular(999),
                    ),
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Icon(
                          Icons.info_outline_rounded,
                          size: 14,
                          color: scheme.onSurface.withValues(alpha: 0.5),
                        ),
                        const SizedBox(width: 4),
                        Flexible(
                          child: Text(
                            l10n.selectTabToAddItems,
                            overflow: TextOverflow.ellipsis,
                            style: Theme.of(context).textTheme.bodySmall,
                          ),
                        ),
                      ],
                    ),
                  ),
                ),
            ],
          ),
        ),
        Expanded(
          child: LayoutBuilder(
            builder: (context, constraints) {
              const padding = EdgeInsets.fromLTRB(16, 12, 16, 16);
              const spacing = 12.0;
              const minTileHeight = 72.0;

              // Exactly [rows] rows fill the height; the column count keeps
              // the tiles as close to square as the width allows
              final rowCount = rows.clamp(2, 6).toInt();
              final tileHeight = max(
                minTileHeight,
                (constraints.maxHeight -
                        padding.vertical -
                        (rowCount - 1) * spacing) /
                    rowCount,
              );
              final columns = max(
                1,
                ((constraints.maxWidth - padding.horizontal + spacing) /
                        (tileHeight + spacing))
                    .round(),
              );

              return GridView.builder(
                key: ValueKey('product-grid-$rowCount'),
                padding: padding,
                itemCount: products.length,
                gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                  crossAxisCount: columns,
                  crossAxisSpacing: spacing,
                  mainAxisSpacing: spacing,
                  mainAxisExtent: tileHeight,
                ),
                itemBuilder: (context, index) {
                  final product = products[index];

                  return _FireTile(
                    key: ValueKey(product.id),
                    enabled: hasSelectedTab,
                    onTap: () => onProductTap(product),
                    builder: (onTap) => ProductTile(
                      product: product,
                      enabled: hasSelectedTab,
                      onTap: onTap,
                    ),
                  );
                },
              );
            },
          ),
        ),
      ],
    );
  }
}

/// Five quick taps on the same product set its tile on fire for a moment.
class _FireTile extends StatefulWidget {
  final bool enabled;
  final VoidCallback onTap;
  final Widget Function(VoidCallback onTap) builder;

  const _FireTile({
    super.key,
    required this.enabled,
    required this.onTap,
    required this.builder,
  });

  @override
  State<_FireTile> createState() => _FireTileState();
}

class _FireTileState extends State<_FireTile>
    with SingleTickerProviderStateMixin {
  static const _tapsNeeded = 5;
  static const _tapWindow = Duration(milliseconds: 700);
  static const _burnTime = Duration(milliseconds: 2500);

  late final AnimationController _flicker = AnimationController(
    vsync: this,
    duration: const Duration(milliseconds: 180),
  );

  int _tapCount = 0;
  DateTime? _lastTap;
  Timer? _burnTimer;

  bool get _isOnFire => _burnTimer != null;

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

  void _onTap() {
    widget.onTap();

    final now = DateTime.now();
    final last = _lastTap;
    _tapCount = last != null && now.difference(last) < _tapWindow
        ? _tapCount + 1
        : 1;
    _lastTap = now;
    if (_tapCount < _tapsNeeded && !_isOnFire) return;

    // Each extra quick tap keeps it burning.
    _burnTimer?.cancel();
    _burnTimer = Timer(_burnTime, () {
      if (!mounted) return;
      _flicker.stop();
      setState(() => _burnTimer = null);
    });
    if (!_flicker.isAnimating) _flicker.repeat(reverse: true);
    setState(() {});
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      fit: StackFit.expand,
      clipBehavior: Clip.none,
      children: [
        widget.builder(_onTap),
        IgnorePointer(
          child: AnimatedOpacity(
            opacity: _isOnFire ? 1 : 0,
            duration: const Duration(milliseconds: 300),
            child: AnimatedBuilder(
              animation: _flicker,
              builder: (context, _) {
                final heat = _flicker.value;

                return Stack(
                  fit: StackFit.expand,
                  clipBehavior: Clip.none,
                  children: [
                    DecoratedBox(
                      decoration: BoxDecoration(
                        borderRadius: BorderRadius.circular(16),
                        border: Border.all(
                          color: Color.lerp(
                            Colors.deepOrange,
                            Colors.amber,
                            heat,
                          )!,
                          width: 2.5,
                        ),
                        boxShadow: [
                          BoxShadow(
                            color: Colors.deepOrange.withValues(
                              alpha: 0.45 + 0.3 * heat,
                            ),
                            blurRadius: 14 + 10 * heat,
                            spreadRadius: 1 + 2 * heat,
                          ),
                        ],
                      ),
                    ),
                    Positioned(
                      left: 8,
                      bottom: 6,
                      child: Transform.scale(
                        scale: 1 + 0.15 * heat,
                        alignment: Alignment.bottomCenter,
                        child: const Text('🔥', style: TextStyle(fontSize: 26)),
                      ),
                    ),
                  ],
                );
              },
            ),
          ),
        ),
      ],
    );
  }
}