// board.dart

import 'dart:async';
import 'dart:math';
import 'dart:typed_data';
import 'dart:ui' as ui;
import 'package:flutter/material.dart';
import 'package:image_puzzle/config/device.dart';
import 'package:image_puzzle/play/piece.dart';
import 'package:logging/logging.dart';
import 'package:vector_math/vector_math.dart' as vmath;

final Logger _log = Logger('board.dart');

enum BoardStatus { loading, playing, success }

class Board {
  // 原图
  final ui.Image image;

  // 所有拼图碎片
  final List<Piece> pieces = [];

  /// 拼图行数（3/4/5，对应9/16/25宫格）
  final int rows;

  /// 拼图列数（3/4/5）
  final int cols;

  /// 整个拼图在屏幕上的目标区域（最终完整显示的位置和大小）
  final Rect targetRect;

  // 碎片的逻辑宽高
  double get pieceLogicalWidth => targetRect.width / cols;
  double get pieceLogicalHeight => targetRect.height / rows;

  // 设备信息
  final Device device;

  // 静态背景绘图 Picture (只绘制一次)
  ui.Picture? _backgroundPicture;
  ui.Picture? get backgroundPicture => _backgroundPicture;

  ValueNotifier boardNotifier = ValueNotifier(1);

  // 用户是否真正可以开始动手开玩（所有加载初始化完成，并且进入的插屏广告播放完成）
  final Completer<bool> startPlayCompleter = Completer();

  BoardStatus _status = BoardStatus.loading;
  BoardStatus get status => _status;

  // 备份的 groups (PieceGroup 对象的列表)
  List<PieceGroup> backupGroups = [];

  void start() {
    _status = BoardStatus.playing;
    invalidate();
  }

  void success() {
    _status = BoardStatus.success;
    invalidate();
  }

  void invalidate() {
    boardNotifier.value++;
  }

  // 是否全部完成
  bool get isAllDone => pieces.every((p) => p.isOK);

  final TickerProviderStateMixin ticker;

  Board(this.ticker, this.image, this.cols, this.rows, this.targetRect, this.device, {Map<String, dynamic>? json}) {
    _recordBackground(); // 录制静态背景，提升性能
    _initPieces();
    rebuildAllGroups();
    backupAllGroups();
  }

  /// 初始化碎片
  _initPieces() {
    final double imagePixelWidth = image.width.toDouble(); // 图片像素宽度
    final double imagePixelHeight = image.height.toDouble(); // 图片像素高度
    final double pieceLogicalWidth = targetRect.width / cols; // 绘图区域逻辑宽度 / 列数 = 每个piece的逻辑宽度
    final double pieceLogicalHeight = targetRect.height / rows; // 绘图区域逻辑高度 / 行数 = 每个piece的逻辑高度
    final double scaleX = imagePixelWidth / targetRect.width; // 像素宽度与逻辑宽度的scale比例
    final double scaleY = imagePixelHeight / targetRect.height; // 像素高度与逻辑高度的scale比例
    final double piecePixelWidth = pieceLogicalWidth * scaleX; // 每个piece的像素宽度
    final double piecePixelHeight = pieceLogicalHeight * scaleY; // 每个piece的像素高度

    final List<({int col, int row})> slotCoords = [];

    for (int r = 0; r < rows; r++) {
      for (int c = 0; c < cols; c++) {
        slotCoords.add((col: c, row: r));
      }
    }

    slotCoords.shuffle(Random());

    int index = 0;

    for (int r = 0; r < rows; r++) {
      for (int c = 0; c < cols; c++) {
        final correctX = targetRect.left + c * pieceLogicalWidth; // piece的正确位置坐标 x
        final correctY = targetRect.top + r * pieceLogicalHeight; // piece的正确位置坐标 y
        final correctOffset = Offset(correctX, correctY);

        final initialSlot = slotCoords[index];
        final initialX = targetRect.left + initialSlot.col * pieceLogicalWidth; // 初始位置坐标
        final initialY = targetRect.top + initialSlot.row * pieceLogicalHeight;

        final initialTransform = vmath.Matrix4.translationValues(initialX, initialY, 0.0); // 记录初始位置坐标transform matrix

        final sourceRect = Rect.fromLTWH(c * piecePixelWidth, r * piecePixelHeight, piecePixelWidth, piecePixelHeight); // 对应图片的像素矩形

        pieces.add(
          Piece(
            board: this,
            index: index,
            row: r,
            col: c,
            rows: rows,
            cols: cols,
            correctOffset: correctOffset,
            curCol: initialSlot.col,
            curRow: initialSlot.row,
            sourceRect: sourceRect,
            transform: initialTransform,
            borders: [true, true, true, true],
          ),
        );
        index++;
      }
    }
  }

  // 根据坐标查找指定位置的碎片
  Piece? findPieceAt(Offset localPos) {
    for (var piece in pieces.reversed) {
      // 从上层开始找
      // 计算碎片在画布上的绝对位置board
      final transform = piece.transform;
      final posX = transform.storage[12];
      final posY = transform.storage[13];
      final pieceRect = Rect.fromLTWH(posX, posY, pieceLogicalWidth, pieceLogicalHeight);

      if (pieceRect.contains(localPos)) {
        return piece;
      }
    }
    return null;
  }

  // 查找某个坐标上的碎片，排除某个piece
  Piece? findPieceAtExclude(Offset localPos, Piece excludePiece) {
    for (var piece in pieces.reversed) {
      // 从上层开始找
      if (piece == excludePiece) continue;
      // 计算碎片在画布上的绝对位置
      final transform = piece.transform;
      final posX = transform.storage[12];
      final posY = transform.storage[13];
      final pieceRect = Rect.fromLTWH(posX, posY, pieceLogicalWidth, pieceLogicalHeight);

      if (pieceRect.contains(localPos)) {
        return piece;
      }
    }
    return null;
  }

  vmath.Matrix4 getTransformByCoordinate(int row, int col) {
    final x = targetRect.left + col * pieceLogicalWidth;
    final y = targetRect.top + row * pieceLogicalHeight;

    final transform = vmath.Matrix4.translationValues(x, y, 0.0);
    return transform;
  }

  // 根据坐标获取该位置上的piece
  Piece? getPieceByCoordinate(int row, int col) {
    return pieces.firstWhereOrNull((p) => p.curRow == row && p.curCol == col);
  }

  // 根据坐标获取该位置上的piece
  Piece? getPieceByIndex(int index) {
    return pieces.firstWhereOrNull((p) => p.index == index);
  }

  // 初始化检查合并分组 (改进版：固定点迭代合并)
  void rebuildAllGroups() {
    _log.info('rebuildAllGroups');
    // 1. 清除所有旧组 和 原path
    for (var p in pieces) {
      p.group = null;
      p.path = null;
      p.outLinePath = null;
      p.innerLinePath = null;
    }

    bool mergedInPass;

    // 2. 迭代合并，直到一轮循环中没有发生任何合并
    do {
      mergedInPass = false;

      // 3. 遍历所有碎片对 (i, j)
      for (int i = 0; i < pieces.length; i++) {
        for (int j = i + 1; j < pieces.length; j++) {
          final piece = pieces[i];
          final otherPiece = pieces[j];

          // 4. 检查是否可以合并，并且它们不属于同一个组
          if (piece.canMerge(otherPiece)) {
            if (!piece.isSameGroup(otherPiece)) {
              // 5. 合并组
              // piece.groupWith(otherPiece) 会创建一个新的 PieceGroup，
              // 并将 piece 和 otherPiece (以及它们可能已有的组员) 的 group 引用全部指向新组。
              piece.groupWith(otherPiece);
              mergedInPass = true;
            }
          }
        }
      }
      // 如果 mergedInPass 为 true，说明本轮循环发生了合并，需要重新开始下一轮遍历
      // 因为新的合并可能促使其他碎片或碎片组也得以连接
    } while (mergedInPass);
  }

  // 备份所有group， 方便进行比较， 发现新合成的group，以便呈现动画特效
  void backupAllGroups() {
    backupGroups.clear();
    for (var p in pieces) {
      if (p.group != null && !backupGroups.contains(p.group)) {
        backupGroups.add(p.group!);
      }
    }
    _log.info('backupAllGroups: ${backupGroups.length}');
  }

  // 当前group与之前备份的group进行比较，返回新合并的group列表，这些group需要展示动画特效
  List<PieceGroup> compareAllGroups() {
    _log.info('compareAllGroups');
    List<PieceGroup> newGroups = [];

    List<PieceGroup> currentGroups = [];
    for (var p in pieces) {
      if (p.group != null && !currentGroups.contains(p.group)) {
        currentGroups.add(p.group!);
      }
    }

    if (backupGroups.isEmpty) {
      // 之前都不存在群组，那么当前新合成的所有group都是新group
      newGroups.addAll(currentGroups);
    } else {
      for (var g in currentGroups) {
        bool alreadyExists = false;
        for (var bakgroup in backupGroups) {
          if (bakgroup.containsGroup(g)) {
            alreadyExists = true;
            break;
          }
        }
        if (!alreadyExists) {
          newGroups.add(g);
        }
      }
    }

    if (newGroups.isNotEmpty) {
      for (var g in newGroups) {
        _log.info('发现新群组：');
        g.print();
      }
    }

    return newGroups;
  }

  // 检查游戏是否全部完成
  bool checkWinCondition() {
    return pieces.every((p) => p.isOK);
  }

  /// 退出释放资源
  dispose() {
    _backgroundPicture?.dispose();
    _backgroundPicture = null;
    image.dispose();
    boardNotifier.dispose();
  }

  // 录制背景，避免每次都重复绘制，提升性能
  void _recordBackground() {
    // 确保在录制前释放旧的 Picture 资源
    _backgroundPicture?.dispose();
    _backgroundPicture = null;

    final recorder = ui.PictureRecorder();

    // 录制器的边界设置为整个屏幕尺寸，因为我们在这里绘制的是 full screen background。
    final recordBounds = Rect.fromLTWH(0, 0, device.screenSize.width, device.screenSize.height);

    final canvas = Canvas(recorder, recordBounds);

    // --- 静态绘制配置 ---
    const double cornerRadius = 8.0;
    const double strokeWidth = 1.0; // 拼图槽位的线宽
    final double halfStroke = strokeWidth / 2.0;

    // 1. 绘制整个屏幕背景
    canvas.drawRect(
      recordBounds,
      Paint()
        ..color = Colors
            .lightGreen // 主背景色
        ..style = PaintingStyle.fill,
    );

    // 2. 绘制每个拼图槽位（圆角矩形）作为背景的一部分 (静态内容)
    final slotFillPaint = Paint()
      ..color = Colors.green
      // .shade100 // 槽位填充色
      ..style = PaintingStyle.fill;

    final slotStrokePaint = Paint()
      ..color =
          Color(0xff26600c) // 槽位边框色
      ..style = PaintingStyle.stroke
      ..strokeWidth = strokeWidth;

    for (int r = 0; r < rows; r++) {
      for (int c = 0; c < cols; c++) {
        // 计算当前槽位的边界 (Canvas坐标系)
        final left = targetRect.left + c * pieceLogicalWidth;
        final top = targetRect.top + r * pieceLogicalHeight;
        final right = left + pieceLogicalWidth;
        final bottom = top + pieceLogicalHeight;

        // 为了避免描边溢出到相邻槽位，将矩形向内收缩 halfStroke
        final slotRect = Rect.fromLTRB(left + halfStroke, top + halfStroke, right - halfStroke, bottom - halfStroke);

        final slotRRect = RRect.fromRectAndRadius(slotRect, const Radius.circular(cornerRadius));

        // 绘制填充
        canvas.drawRRect(slotRRect, slotFillPaint);

        // 绘制描边
        canvas.drawRRect(slotRRect, slotStrokePaint);
      }
    }

    // --- 结束录制并存储 ---
    _backgroundPicture = recorder.endRecording();
    _log.info('Static background picture recorded. Size: ${recordBounds.size}');
  }
}

// 辅助扩展：解决 Dart 缺少 firstWhereOrNull 的问题
extension IterableExtension<T> on Iterable<T> {
  T? firstWhereOrNull(bool Function(T element) test) {
    for (final element in this) {
      if (test(element)) {
        return element;
      }
    }
    return null;
  }
}