import 'dart:async';

import 'package:flutter/material.dart';

import '../guid/guid_glyph_shape.dart';
import '../theme/app_theme.dart';

/// Swipeable question card: right submits, left defers (does not resolve).
///
/// The center band supports vertical drag as a slider from -10 (down) to 10 (up).
class SwipeQuestionTile extends StatefulWidget {
  const SwipeQuestionTile({
    super.key,
    required this.questionId,
    required this.onSwipeRight,
    required this.onSwipeLeft,
    this.busy = false,
  });

  final String questionId;
  final Future<void> Function(num answer) onSwipeRight;
  final Future<void> Function() onSwipeLeft;
  final bool busy;

  @override
  State<SwipeQuestionTile> createState() => _SwipeQuestionTileState();
}

class _SwipeQuestionTileState extends State<SwipeQuestionTile> {
  double _dragOffset = 0;
  double _verticalOffset = 0;
  bool _acting = false;

  static const double _swipeThreshold = 96;
  static const double _maxVerticalDrag = 120;
  static const double _sliderMin = -10;
  static const double _sliderMax = 10;

  /// Swipe up → +10, swipe down → -10 (linear between).
  double get _sliderValue =>
      (_verticalOffset / _maxVerticalDrag * _sliderMax).clamp(_sliderMin, _sliderMax);

  Future<void> _releaseDrag() async {
    if (_acting || widget.busy) {
      setState(() => _dragOffset = 0);
      return;
    }

    if (_dragOffset > _swipeThreshold) {
      setState(() {
        _acting = true;
        _dragOffset = MediaQuery.sizeOf(context).width;
      });
      await widget.onSwipeRight(_sliderValue);
    } else if (_dragOffset < -_swipeThreshold) {
      setState(() {
        _acting = true;
        _dragOffset = -MediaQuery.sizeOf(context).width;
      });
      await widget.onSwipeLeft();
    } else if (mounted) {
      setState(() => _dragOffset = 0);
    }
    if (mounted) {
      setState(() {
        _acting = false;
        _dragOffset = 0;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    final double width = MediaQuery.sizeOf(context).width;
    final double progress = (_dragOffset / _swipeThreshold).clamp(-1.0, 1.0);

    return LayoutBuilder(
      builder: (BuildContext context, BoxConstraints constraints) {
        return Stack(
          alignment: Alignment.center,
          children: <Widget>[
            Positioned.fill(
              child: DecoratedBox(
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(16),
                  gradient: LinearGradient(
                    begin: Alignment.centerLeft,
                    end: Alignment.centerRight,
                    colors: <Color>[
                      Colors.redAccent.withValues(
                        alpha: 0.15 + 0.35 * (-progress).clamp(0.0, 1.0),
                      ),
                      AppColors.surfaceElevated,
                      AppColors.success.withValues(
                        alpha: 0.15 + 0.35 * progress.clamp(0.0, 1.0),
                      ),
                    ],
                  ),
                ),
              ),
            ),
            Transform.translate(
              offset: Offset(_dragOffset, 0),
              child: GestureDetector(
                onHorizontalDragUpdate: widget.busy || _acting
                    ? null
                    : (DragUpdateDetails details) {
                        setState(() {
                          _dragOffset += details.delta.dx;
                          _dragOffset = _dragOffset.clamp(-width * 0.55, width * 0.55);
                        });
                      },
                onHorizontalDragEnd: widget.busy || _acting
                    ? null
                    : (_) => unawaited(_releaseDrag()),
                child: Material(
                  color: AppColors.surfaceElevated,
                  elevation: 4,
                  shadowColor: Colors.black45,
                  borderRadius: BorderRadius.circular(16),
                  child: Container(
                    width: constraints.maxWidth,
                    constraints: const BoxConstraints(minHeight: 220),
                    padding: const EdgeInsets.symmetric(
                      horizontal: 16,
                      vertical: 24,
                    ),
                    decoration: BoxDecoration(
                      borderRadius: BorderRadius.circular(16),
                    ),
                    child: Stack(
                      alignment: Alignment.center,
                      children: <Widget>[
                        Positioned(
                          top: 20,
                          bottom: 20,
                          left: constraints.maxWidth * 0.22,
                          right: constraints.maxWidth * 0.22,
                          child: DecoratedBox(
                            decoration: BoxDecoration(
                              borderRadius: BorderRadius.circular(14),
                              color: Color.lerp(
                                AppColors.surfaceElevated,
                                AppColors.surface,
                                0.45,
                              ),
                            ),
                          ),
                        ),
                        Positioned(
                          top: 24,
                          bottom: 24,
                          left: constraints.maxWidth * 0.22,
                          right: constraints.maxWidth * 0.22,
                          child: GestureDetector(
                            behavior: HitTestBehavior.opaque,
                            onVerticalDragUpdate: widget.busy || _acting
                                ? null
                                : (DragUpdateDetails details) {
                                    setState(() {
                                      _verticalOffset -= details.delta.dy;
                                      _verticalOffset = _verticalOffset.clamp(
                                        -_maxVerticalDrag,
                                        _maxVerticalDrag,
                                      );
                                    });
                                  },
                            child: Center(
                              child: Transform.translate(
                                offset: Offset(0, -_verticalOffset),
                                child: QuestionGuidGlyph(
                                  guid: widget.questionId,
                                  displayValue: _sliderValue,
                                ),
                              ),
                            ),
                          ),
                        ),
                      ],
                    ),
                  ),
                ),
              ),
            ),
            if (widget.busy)
              const Positioned.fill(
                child: ColoredBox(
                  color: Color(0x66000000),
                  child: Center(child: CircularProgressIndicator()),
                ),
              ),
          ],
        );
      },
    );
  }
}