// board_painter.dart

import 'dart:typed_data';

import 'package:flutter/material.dart';

import 'package:image_puzzle/play/board.dart';
import 'package:image_puzzle/play/piece.dart';

class BoardPainter extends CustomPainter {
  final Board board;

  // 碎片边框宽度 (可以比背景槽位稍粗，以便突出)
  static const double _pieceStrokeWidth = 1.0;

  // 边框画笔
  final Paint _pieceBorderPaint = Paint()
    ..color = Colors
        .black // 碎片边框颜色
    ..style = PaintingStyle.stroke
    ..strokeWidth = _pieceStrokeWidth
    ..isAntiAlias = true;

  // 边框画笔
  final Paint _innerPieceBorderPaint = Paint()
    ..color = Colors
        .white // 碎片边框颜色
    ..style = PaintingStyle.stroke
    ..strokeWidth = _pieceStrokeWidth
    ..isAntiAlias = true;

  BoardPainter({required this.board}) : super(repaint: Listenable.merge([board.boardNotifier])); // 触发重绘

  @override
  void paint(Canvas canvas, Size size) {
    // 绘制背景
    // _paintBackground(canvas, size);
    if (board.backgroundPicture != null) {
      canvas.drawPicture(board.backgroundPicture!);
    }

    // 绘制pieces
    for (final piece in board.pieces) {
      _drawPiece(canvas, size, piece);
    }
  }

  @override
  bool shouldRepaint(covariant BoardPainter oldDelegate) {
    return true;
  }

  void _drawPiece(Canvas canvas, Size size, Piece piece) {
    final double w = board.pieceLogicalWidth;
    final double h = board.pieceLogicalHeight;

    // 1. 准备变换矩阵和动态 Path
    final Float64List storage64 = Float64List.fromList(piece.transform.storage);
    // 核心：根据 borders 状态动态生成 Path
    final List<Path> paths = _getPiecePath(piece);
    final Path piecePath = paths[0];
    final Path outerBorderPath = paths[1];
    final Path innerBorderPath = paths[2];

    canvas.save();

    canvas.transform(storage64); // 应用平移

    // 裁剪区域：使用动态生成的 Path 来裁剪图片，实现圆角/尖角混合
    canvas.clipPath(piecePath);

    // 绘制图片：只有落在 rrect 内部的部分图片会被绘制
    final Rect dstRect = Rect.fromLTWH(0, 0, w, h);
    canvas.drawImageRect(board.image, piece.sourceRect, dstRect, Paint()..isAntiAlias = true);

    canvas.restore(); // 恢复 Canvas 状态 (移除裁剪和 transform)

    // --- 绘制边框 ---
    // 为了确保边框线宽向外延伸的部分不会被裁剪，我们需要在裁剪区域被移除后重新绘制。
    canvas.save();
    canvas.transform(storage64); // 重新应用平移

    // 绘制碎片边框
    canvas.drawPath(outerBorderPath, _pieceBorderPaint); // 外边框，黑色
    canvas.drawPath(innerBorderPath, _innerPieceBorderPaint); // 内边框，白色

    canvas.restore();
  }

  List<Path> _getPiecePath(Piece piece) {
    if (piece.path == null || piece.outLinePath == null || piece.innerLinePath == null) {
      return piece.generatePaths();
    } else {
      return [piece.path!, piece.outLinePath!, piece.innerLinePath!];
    }
  }

  // 绘制背景(已经被drawPicture取代)
  void _paintBackground(Canvas canvas, Size size) {
    // 绘制整个背景
    canvas.drawRect(
      Rect.fromLTWH(0, 0, size.width, size.height),
      Paint()
        ..color = Colors.lightGreen
        ..style = PaintingStyle.fill,
    );

    for (final piece in board.pieces) {
      canvas.save();

      // 转换 Matrix4 存储格式 (Float32List -> Float64List)
      final Float64List storage64 = Float64List.fromList(piece.transform.storage);

      // 应用碎片的几何变换 (平移/旋转/缩放)
      // 这将 Canvas 原点移动到 piece.transform.storage[12] 和 [13] 处。
      canvas.transform(storage64);

      final Rect rect = Rect.fromLTWH(0, 0, board.pieceLogicalWidth, board.pieceLogicalHeight);

      final RRect rrect = RRect.fromRectAndRadius(rect, Radius.circular(8.0));

      canvas.drawRRect(
        rrect,
        Paint()
          ..color = Colors.green
          ..style = PaintingStyle.fill,
      );

      canvas.drawRRect(
        rrect,
        Paint()
          ..color = Colors.blueGrey
          ..style = PaintingStyle.stroke
          ..strokeWidth = 1.0,
      );

      canvas.restore();
    }
  }
}