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

class FadedScrollView extends StatefulWidget {
  final Widget child;
  final double fadeHeight;
  final double easingDistance;
  final double maxBlur;
  final ScrollController? controller;
  final EdgeInsetsGeometry? padding;

  const FadedScrollView({
    super.key,
    required this.child,
    this.fadeHeight = 20.0,
    this.easingDistance = 10.0,
    this.maxBlur = 3.0,
    this.controller,
    this.padding,
  });

  @override
  State<FadedScrollView> createState() => _FadedScrollViewState();
}

class _FadedScrollViewState extends State<FadedScrollView> {
  late ScrollController _scrollController;

  @override
  void initState() {
    super.initState();
    _scrollController = widget.controller ?? ScrollController();
  }

  @override
  void dispose() {
    if (widget.controller == null) {
      _scrollController.dispose();
    }
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: _scrollController,
      builder: (context, child) {
        final double offset = _scrollController.hasClients ? _scrollController.offset : 0.0;
        final double fadeProgress = (offset / widget.easingDistance).clamp(0.0, 1.0);
        final double currentBlur = widget.maxBlur * fadeProgress;
        
        return Stack(
          children: [
            // Main content
            ShaderMask(
              shaderCallback: (Rect bounds) {
                final double fadeStop = widget.fadeHeight / bounds.height;
                final Color transparentColor = Colors.white.withOpacity(1.0 - fadeProgress);
                
                return LinearGradient(
                  begin: Alignment.topCenter,
                  end: Alignment.bottomCenter,
                  colors: [
                    transparentColor,
                    Colors.white,
                    Colors.white,
                  ],
                  stops: [0.0, fadeStop, 1.0],
                ).createShader(bounds);
              },
              blendMode: BlendMode.dstIn,
              child: SingleChildScrollView(
                controller: _scrollController,
                padding: widget.padding,
                child: widget.child,
              ),
            ),
            
            // Single blur with extended fade area for smoother transition
            if (currentBlur > 0)
              Positioned(
                top: 0,
                left: 0,
                right: 0,
                height: widget.fadeHeight * 1.5, // Extend beyond fade area
                child: ClipRect(
                  child: BackdropFilter(
                    filter: ImageFilter.blur(
                      sigmaX: currentBlur * 0.7, // Reduce intensity slightly
                      sigmaY: currentBlur * 0.7,
                    ),
                    child: Container(
                      decoration: BoxDecoration(
                        gradient: LinearGradient(
                          begin: Alignment.topCenter,
                          end: Alignment.bottomCenter,
                          colors: [
                            Colors.transparent,
                            Colors.transparent,
                            Colors.transparent,
                            Colors.black.withOpacity(0.0),
                          ],
                          stops: [0.0, 0.6, 0.9, 1.0],
                        ),
                      ),
                    ),
                  ),
                ),
              ),
          ],
        );
      },
    );
  }
}