import 'package:flutter/foundation.dart' show kIsWeb;
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../brick/cache_warmer.dart';
import '../providers/connectivity_provider.dart';
import '../providers/sync_queue_provider.dart';
import 'offline_readiness_sheet.dart';

/// Wraps [child] with a polished M3 status banner driven by connectivity + sync state.
///
/// Three states:
/// 1. Online + 0 pending  → no banner (slides away)
/// 2. Online + N pending  → tertiary-toned "Syncing N item(s)…" with spinner + progress bar
/// 3. Offline             → error-toned "Offline — N item(s) queued" (count omitted when 0)
class OfflineBanner extends ConsumerWidget {
  final Widget child;

  const OfflineBanner({super.key, required this.child});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    ref.watch(connectivityMonitorProvider);
    final isOnline = ref.watch(isOnlineProvider);
    final pendingCount = ref.watch(pendingSyncCountProvider);
    final scheme = Theme.of(context).colorScheme;

    return ValueListenableBuilder<bool>(
      valueListenable: CacheWarmer.warmingNotifier,
      builder: (context, isWarming, _) {
        Widget? banner;

        if (!isOnline) {
          final label = pendingCount > 0
              ? 'Offline — $pendingCount item${pendingCount == 1 ? '' : 's'} queued'
              : kIsWeb ? 'No internet connection' : 'No internet — changes saved locally';
          banner = _BannerStrip(
            key: const ValueKey('offline'),
            backgroundColor: scheme.errorContainer,
            foregroundColor: scheme.onErrorContainer,
            icon: Icon(Icons.wifi_off_rounded, color: scheme.onErrorContainer, size: 18),
            label: label,
            showProgress: false,
            onTap: () => showOfflineReadinessSheet(context),
          );
        } else if (isWarming) {
          banner = _BannerStrip(
            key: const ValueKey('warming'),
            backgroundColor: scheme.secondaryContainer,
            foregroundColor: scheme.onSecondaryContainer,
            icon: _SpinningIcon(
              icon: Icons.cloud_sync_rounded,
              color: scheme.onSecondaryContainer,
              size: 18,
            ),
            label: 'Updating offline cache…',
            showProgress: true,
            onTap: () => showOfflineReadinessSheet(context),
          );
        } else if (pendingCount > 0) {
          final label = 'Syncing $pendingCount item${pendingCount == 1 ? '' : 's'}…';
          banner = _BannerStrip(
            key: const ValueKey('syncing'),
            backgroundColor: scheme.tertiaryContainer,
            foregroundColor: scheme.onTertiaryContainer,
            icon: _SpinningIcon(
              icon: Icons.sync_rounded,
              color: scheme.onTertiaryContainer,
              size: 18,
            ),
            label: label,
            showProgress: true,
            onTap: () => showOfflineReadinessSheet(context),
          );
        }

        return Column(
          children: [
            AnimatedSwitcher(
              duration: const Duration(milliseconds: 250),
              transitionBuilder: (child, animation) {
                return SlideTransition(
                  position: Tween<Offset>(
                    begin: const Offset(0, -1),
                    end: Offset.zero,
                  ).animate(CurvedAnimation(
                    parent: animation,
                    curve: Curves.easeOutCubic,
                    reverseCurve: Curves.easeInCubic,
                  )),
                  child: FadeTransition(opacity: animation, child: child),
                );
              },
              child: banner ?? const SizedBox.shrink(key: ValueKey('none')),
            ),
            Expanded(child: child),
          ],
        );
      },
    );
  }
}

class _BannerStrip extends StatelessWidget {
  final Color backgroundColor;
  final Color foregroundColor;
  final Widget icon;
  final String label;
  final bool showProgress;
  final VoidCallback? onTap;

  const _BannerStrip({
    super.key,
    required this.backgroundColor,
    required this.foregroundColor,
    required this.icon,
    required this.label,
    required this.showProgress,
    this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    const radius = BorderRadius.vertical(bottom: Radius.circular(12));
    return Material(
      color: backgroundColor,
      borderRadius: radius,
      child: InkWell(
        borderRadius: radius,
        onTap: onTap,
        child: SafeArea(
          bottom: false,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Padding(
                padding: EdgeInsets.fromLTRB(16, 8, onTap != null ? 12 : 16, showProgress ? 6 : 8),
                child: Row(
                  children: [
                    icon,
                    const SizedBox(width: 10),
                    Expanded(
                      child: Text(
                        label,
                        style: Theme.of(context).textTheme.labelMedium?.copyWith(
                              color: foregroundColor,
                              fontWeight: FontWeight.w500,
                            ),
                      ),
                    ),
                    if (onTap != null)
                      Icon(
                        Icons.chevron_right_rounded,
                        size: 16,
                        color: foregroundColor.withValues(alpha: 0.6),
                      ),
                  ],
                ),
              ),
              if (showProgress)
                ClipRRect(
                  borderRadius: radius,
                  child: LinearProgressIndicator(
                    minHeight: 2,
                    backgroundColor: backgroundColor,
                    valueColor: AlwaysStoppedAnimation(
                      foregroundColor.withValues(alpha: 0.6),
                    ),
                  ),
                ),
            ],
          ),
        ),
      ),
    );
  }
}

class _SpinningIcon extends StatefulWidget {
  final IconData icon;
  final Color color;
  final double size;

  const _SpinningIcon({
    required this.icon,
    required this.color,
    required this.size,
  });

  @override
  State<_SpinningIcon> createState() => _SpinningIconState();
}

class _SpinningIconState extends State<_SpinningIcon>
    with SingleTickerProviderStateMixin {
  late final AnimationController _ctrl;

  @override
  void initState() {
    super.initState();
    _ctrl = AnimationController(
      vsync: this,
      duration: const Duration(seconds: 2),
    )..repeat();
  }

  @override
  void dispose() {
    _ctrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return RotationTransition(
      turns: _ctrl,
      child: Icon(widget.icon, color: widget.color, size: widget.size),
    );
  }
}