import 'dart:io';
import 'dart:math' as math;
import 'dart:ui' show ImageFilter;

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

import '../../providers/appearance_provider.dart';
import '../theme/app_theme.dart';
import 'window_chrome.dart';


class ScrollFadeHeader extends ConsumerWidget {
  final ValueNotifier<double> scrollProgress;


  final List<Widget> actions;

  const ScrollFadeHeader({
    super.key,
    required this.scrollProgress,
    this.actions = const [],
  });

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final tokens = context.appTokens;
    final isDesktop = Platform.isMacOS || Platform.isWindows;
    final topPadding = isDesktop
        ? tokens.titleBarHeight
        : math.max(MediaQuery.paddingOf(context).top, tokens.titleBarHeight);
    final overlayHeight = topPadding + 12;

    final headerMode =
        ref.watch(appearanceProvider).value?.headerMode ?? HeaderMode.frosted;
    final isFrosted = headerMode == HeaderMode.frosted;
    final theme = Theme.of(context);

    final background = ValueListenableBuilder<double>(
      valueListenable: scrollProgress,
      builder: (_, raw, _) {
        final p = raw.clamp(0.0, 1.0);
        if (isFrosted) {
          final entryProgress = (p / 0.25).clamp(0.0, 1.0);
          final glassProgress =
              Curves.easeOutCubic.transform(entryProgress) * 0.42;
          return ClipRect(
            child: BackdropFilter(
              filter: ImageFilter.blur(
                sigmaX: glassProgress * 10,
                sigmaY: glassProgress * 10,
              ),
              child: DecoratedBox(
                decoration: BoxDecoration(
                  color: theme.colorScheme.surface.withValues(
                    alpha: glassProgress * 0.88,
                  ),
                  border: Border(
                    bottom: BorderSide(
                      color: theme.colorScheme.onSurface.withValues(
                        alpha: glassProgress * 0.08,
                      ),
                      width: 1,
                    ),
                  ),
                ),
              ),
            ),
          );
        }
        return ColoredBox(
          color: theme.colorScheme.surface.withValues(alpha: p),
        );
      },
    );

    return SizedBox(
      height: overlayHeight,
      width: double.infinity,
      child: Stack(
        children: [
          Positioned.fill(child: IgnorePointer(child: background)),
          if (actions.isNotEmpty)
            Positioned(
              right: 0,
              top: tokens.chromeInset,
              height: WindowChrome.controlsHeight,
              child: Row(
                mainAxisSize: MainAxisSize.min,
                crossAxisAlignment: CrossAxisAlignment.center,
                children: [
                  ...actions,
                  SizedBox(width: WindowChrome.reservedTrailingWidth(tokens)),
                ],
              ),
            ),
        ],
      ),
    );
  }
}