import 'package:flutter/material.dart';
import 'package:widgets/my_load_image.dart';

class RatingWidget extends StatefulWidget {
  /// 星星数量
  final int count;

  /// 最大评分值
  final double maxRating;

  /// 当前选中的评分值
  final double value;

  /// 没一颗星的大小
  final double size;

  /// 每个星之间的间距
  final double padding;

  /// 空星的图片资源
  final String nomalImage;

  /// 满星的图片资源
  final String selectImage;

  /// 是否可以操作选择
  final bool selectAble;

  /// 选中评分的回调
  final ValueChanged<String> onRatingUpdate;

  /// 是否只显示整数的分数
  final bool integerOnly;

  RatingWidget({
    required this.nomalImage,
    required this.selectImage,
    required this.onRatingUpdate,
    this.count = 5,
    this.value = 5.0,
    this.maxRating = 5.0,
    this.size = 20,
    this.padding = 0,
    this.selectAble = false,
    this.integerOnly = false,
  });

  @override
  _RatingWidgetState createState() => _RatingWidgetState();
}

class _RatingWidgetState extends State<RatingWidget> {
  late double value;

  @override
  Widget build(BuildContext context) {
    return Listener(
      child: buildRowRating(),
      onPointerDown: (PointerDownEvent event) {
        double x = event.localPosition.dx;
        if (x < 0) x = 0;
        pointValue(x);
      },
      onPointerMove: (PointerMoveEvent event) {
        double x = event.localPosition.dx;
        if (x < 0) x = 0;
        pointValue(x);
      },
      onPointerUp: (_) {},
      behavior: HitTestBehavior.deferToChild,
    );
  }

  pointValue(double dx) {
    if (!widget.selectAble) {
      return;
    }
    if (dx >= widget.size * widget.count + widget.padding * (widget.count - 1)) {
      value = widget.maxRating;
    } else {
      for (double i = 1; i < widget.count + 1; i++) {
        if (dx > widget.size * i + widget.padding * (i - 1) && dx < widget.size * i + widget.padding * i) {
          value = i * (widget.maxRating / widget.count);
          break;
        } else if (dx > widget.size * (i - 1) + widget.padding * (i - 1) && dx < widget.size * i + widget.padding * i) {
          value = (dx - widget.padding * (i - 1)) / (widget.size * widget.count) * widget.maxRating;
          break;
        }
      }
    }

    if (widget.integerOnly) {
      value = value.ceilToDouble(); // 直接向上取整
    }

    setState(() {
      widget.onRatingUpdate(value.toStringAsFixed(1));
    });
  }

  int fullStars() {
    if (value != null) {
      return (value / (widget.maxRating / widget.count)).ceil(); // 使用向上取整
    }
    return 0;
  }

  double star() {
    if (widget.integerOnly) {
      return 0;
    }
    if (value != null) {
      if (widget.count / fullStars() == widget.maxRating / value) {
        return 0;
      }
      return (value % (widget.maxRating / widget.count)) / (widget.maxRating / widget.count);
    }
    return 0;
  }

  List<Widget> buildRow() {
    int full = fullStars();
    List<Widget> children = [];
    for (int i = 0; i < full; i++) {
      children.add(MyAssetImage(
        widget.selectImage,
        width: widget.size,
        height: widget.size,
      ));

      if (i < widget.count - 1) {
        children.add(
          SizedBox(
            width: widget.padding,
          ),
        );
      }
    }
    if (full < widget.count) {
      children.add(ClipRect(
        clipper: SMClipper(rating: star() * widget.size),
        child: MyAssetImage(
          widget.selectImage,
          width: widget.size,
          height: widget.size,
        ),
      ));
    }

    return children;
  }

  List<Widget> buildNomalRow() {
    List<Widget> children = [];
    for (int i = 0; i < widget.count; i++) {
      children.add(MyAssetImage(
        widget.nomalImage,
        width: widget.size,
        height: widget.size,
      ));
      if (i < widget.count - 1) {
        children.add(SizedBox(
          width: widget.padding,
        ));
      }
    }
    return children;
  }

  Widget buildRowRating() {
    return Container(
      child: Stack(
        children: <Widget>[
          Row(
            children: buildNomalRow(),
          ),
          Row(
            children: buildRow(),
          )
        ],
      ),
    );
  }

  @override
  void initState() {
    super.initState();
    value = widget.value;
  }
}

class SMClipper extends CustomClipper<Rect> {
  final double rating;

  SMClipper({required this.rating});

  @override
  Rect getClip(Size size) {
    return Rect.fromLTRB(0.0, 0.0, rating, size.height);
  }

  @override
  bool shouldReclip(SMClipper oldClipper) {
    return rating != oldClipper.rating;
  }
}