ttrpg-tools/src/plotcutter/contour.ts

import type { CardShape, ContourPoint, ContourBounds } from './types';

// 重新导出类型以兼容旧导入路径
export type { CardShape, ContourPoint, ContourBounds };


/**
 * 生成内接正三角形的轮廓点（无圆角版本）
 * @param width 外框宽度
 * @param height 外框高度
 * @returns 正三角形轮廓点（相对于外框左下角，顺时针）
 */
export function getInscribedTrianglePoints(
  width: number,
  height: number
): [number, number][] {
  // 以短边为基准计算内接正三角形的边长
  const minDim = Math.min(width, height);
  // 正三角形的高 = 边长 * sqrt(3) / 2
  const triangleHeight = minDim * Math.sqrt(3) / 2;
  const sideLength = minDim;

  // 计算居中偏移
  const offsetX = (width - sideLength) / 2;
  const offsetY = (height - triangleHeight) / 2;

  // 正三角形三个顶点（底边在下，顶点在上，顺时针：左上→右上→下）
  const points: [number, number][] = [
    [offsetX, offsetY + triangleHeight],                     // 左下顶点
    [offsetX + sideLength, offsetY + triangleHeight],        // 右下顶点
    [offsetX + sideLength / 2, offsetY]                      // 顶部顶点
  ];

  return points;
}

/**
 * 生成内接正六边形的轮廓点（无圆角版本）
 * @param width 外框宽度
 * @param height 外框高度
 * @returns 正六边形轮廓点（相对于外框左下角，顺时针）
 */
export function getInscribedHexagonPoints(
  width: number,
  height: number
): [number, number][] {
  // 以短边为基准计算内接正六边形的半径
  const minDim = Math.min(width, height);
  const radius = minDim / 2;

  // 中心点
  const centerX = width / 2;
  const centerY = height / 2;

  // 正六边形六个顶点（平顶，从右上角开始顺时针）
  // 角度：-60°, 0°, 60°, 120°, 180°, 240° (顺时针)
  const points: [number, number][] = [];
  for (let i = 0; i < 6; i++) {
    const angle = (-Math.PI / 3) + (i * Math.PI / 3); // 从 -60° 开始，顺时针
    points.push([
      centerX + radius * Math.cos(angle),
      centerY - radius * Math.sin(angle)  // Y 向下为正，所以减去 sin
    ]);
  }

  return points;
}

/**
 * 为正多边形添加圆角
 * @param vertices 多边形顶点数组（顺时针或逆时针）
 * @param cornerRadius 圆角半径
 * @param segmentsPerCorner 每个圆角的分段数
 * @returns 带圆角的多边形轮廓点
 */
export function getRoundedPolygonPoints(
  vertices: [number, number][],
  cornerRadius: number,
  segmentsPerCorner: number = 4
): [number, number][] {
  if (vertices.length < 3) return vertices;

  const n = vertices.length;

  // 计算最大允许的圆角半径（不超过边长的一半）
  let maxRadius = Infinity;
  for (let i = 0; i < n; i++) {
    const [x1, y1] = vertices[i];
    const [x2, y2] = vertices[(i + 1) % n];
    const edgeLength = Math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2);
    maxRadius = Math.min(maxRadius, edgeLength / 2);
  }

  const r = Math.min(cornerRadius, maxRadius);

  if (r <= 0) {
    return vertices;
  }

  const points: [number, number][] = [];

  for (let i = 0; i < n; i++) {
    const currVertex = vertices[i];
    const nextVertex = vertices[(i + 1) % n];

    // 计算当前边的向量
    const edgeDx = nextVertex[0] - currVertex[0];
    const edgeDy = nextVertex[1] - currVertex[1];
    const edgeLen = Math.sqrt(edgeDx ** 2 + edgeDy ** 2);
    const edgeUx = edgeDx / edgeLen;
    const edgeUy = edgeDy / edgeLen;

    // 计算当前边上的圆角终点（距离顶点 r 的位置）
    const endPx = currVertex[0] + edgeUx * r;
    const endPy = currVertex[1] + edgeUy * r;

    // 计算上一条边的向量
    const prevVertex = vertices[(i - 1 + n) % n];
    const prevEdgeDx = currVertex[0] - prevVertex[0];
    const prevEdgeDy = currVertex[1] - prevVertex[1];
    const prevEdgeLen = Math.sqrt(prevEdgeDx ** 2 + prevEdgeDy ** 2);
    const prevEdgeUx = prevEdgeDx / prevEdgeLen;
    const prevEdgeUy = prevEdgeDy / prevEdgeLen;

    // 计算上一条边上的圆角起点（距离顶点 r 的位置）
    const startPx = currVertex[0] - prevEdgeUx * r;
    const startPy = currVertex[1] - prevEdgeUy * r;

    // 计算角平分线方向
    const bisectorX = prevEdgeUx + edgeUx;
    const bisectorY = prevEdgeUy + edgeUy;
    const bisectorLen = Math.sqrt(bisectorX ** 2 + bisectorY ** 2);

    // 如果 bisectorLen 接近 0，说明是 180 度角（直线），跳过圆角
    if (bisectorLen < 1e-6) {
      points.push([endPx, endPy]);
      continue;
    }

    const normalX = bisectorX / bisectorLen;
    const normalY = bisectorY / bisectorLen;

    // 计算叉积判断方向（顺时针/逆时针）
    const crossProduct = prevEdgeUx * edgeUy - prevEdgeUy * edgeUx;
    const direction = crossProduct >= 0 ? -1 : 1; // -1 表示内角，1 表示外角

    // 计算圆角中心
    const angle = Math.acos(Math.max(-1, Math.min(1, prevEdgeUx * edgeUx + prevEdgeUy * edgeUy)));
    const tangentDistance = r / Math.tan(angle / 2);
    const centerX = currVertex[0] + direction * normalX * tangentDistance;
    const centerY = currVertex[1] + direction * normalY * tangentDistance;

    // 计算起始角度和结束角度
    const startAngle = Math.atan2(startPy - centerY, startPx - centerX);
    const endAngle = Math.atan2(endPy - centerY, endPx - centerX);

    // 添加圆角起点
    points.push([startPx, startPy]);

    // 生成圆角弧线点
    let angleDiff = endAngle - startAngle;
    // 根据方向调整角度差
    if (direction === -1) {
      // 顺时针（内角）
      if (angleDiff < 0) angleDiff += 2 * Math.PI;
    } else {
      // 逆时针（外角）
      if (angleDiff > 0) angleDiff -= 2 * Math.PI;
    }

    // 生成弧线点（不包括起点，因为已经添加了）
    for (let j = 1; j <= segmentsPerCorner; j++) {
      const t = j / segmentsPerCorner;
      const arcAngle = startAngle + angleDiff * t;
      points.push([
        centerX + r * Math.cos(arcAngle),
        centerY + r * Math.sin(arcAngle)
      ]);
    }
  }

  return points;
}

/**
 * 根据形状生成卡片轮廓点（单位：mm，相对于卡片左下角）
 */
export function getCardShapePoints(
  shape: CardShape,
  width: number,
  height: number,
  cornerRadius: number = 0,
  segmentsPerCorner: number = 4
): [number, number][] {
  // 处理带圆角的情况 - 统一使用 getRoundedPolygonPoints
  if (cornerRadius > 0) {
    if (shape === 'rectangle') {
      const vertices: [number, number][] = [
        [0, 0],
        [width, 0],
        [width, height],
        [0, height]
      ];
      return getRoundedPolygonPoints(vertices, cornerRadius, segmentsPerCorner);
    }
    if (shape === 'triangle') {
      const vertices = getInscribedTrianglePoints(width, height);
      return getRoundedPolygonPoints(vertices, cornerRadius, segmentsPerCorner);
    }
    if (shape === 'hexagon') {
      const vertices = getInscribedHexagonPoints(width, height);
      return getRoundedPolygonPoints(vertices, cornerRadius, segmentsPerCorner);
    }
  }

  const points: [number, number][] = [];

  switch (shape) {
    case 'circle': {
      const radius = Math.min(width, height) / 2;
      const centerX = width / 2;
      const centerY = height / 2;
      for (let i = 0; i < 36; i++) {
        const angle = (i / 36) * Math.PI * 2;
        points.push([
          centerX + radius * Math.cos(angle),
          centerY + radius * Math.sin(angle)
        ]);
      }
      break;
    }
    case 'triangle': {
      return getInscribedTrianglePoints(width, height);
    }
    case 'hexagon': {
      return getInscribedHexagonPoints(width, height);
    }
    case 'rectangle':
    default: {
      points.push([0, 0]);
      points.push([width, 0]);
      points.push([width, height]);
      points.push([0, height]);
      break;
    }
  }

  return points;
}

/**
 * 计算多边形的中心点
 */
export function calculateCenter(points: [number, number][]): { x: number; y: number } {
  let sumX = 0;
  let sumY = 0;
  for (const [x, y] of points) {
    sumX += x;
    sumY += y;
  }
  return {
    x: sumX / points.length,
    y: sumY / points.length
  };
}

/**
 * 计算轮廓的边界框
 */
export function calculateBounds(points: [number, number][]): ContourBounds {
  if (points.length === 0) {
    return { minX: 0, minY: 0, maxX: 0, maxY: 0 };
  }

  let minX = Infinity;
  let minY = Infinity;
  let maxX = -Infinity;
  let maxY = -Infinity;

  for (const [x, y] of points) {
    minX = Math.min(minX, x);
    minY = Math.min(minY, y);
    maxX = Math.max(maxX, x);
    maxY = Math.max(maxY, y);
  }

  return { minX, minY, maxX, maxY };
}

/**
 * 根据进度计算点在路径上的位置
 */
export function getPointOnPath(points: [number, number][], progress: number): [number, number] {
  if (points.length === 0) return [0, 0];
  if (points.length === 1) return points[0];

  const totalSegments = points.length;
  const scaledProgress = progress * totalSegments;
  const segmentIndex = Math.floor(scaledProgress);
  const segmentProgress = scaledProgress - segmentIndex;

  const currentIndex = Math.min(segmentIndex, points.length - 1);
  const nextIndex = (currentIndex + 1) % points.length;

  const [x1, y1] = points[currentIndex];
  const [x2, y2] = points[nextIndex];

  return [
    x1 + (x2 - x1) * segmentProgress,
    y1 + (y2 - y1) * segmentProgress
  ];
}

/**
 * 将轮廓点转换为 SVG path 命令
 * @param points 轮廓点数组
 * @param closed 是否闭合路径
 */
export function contourToSvgPath(points: [number, number][], closed = true): string {
  if (points.length === 0) return '';

  const [startX, startY] = points[0];
  let d = `M ${startX} ${startY}`;

  for (let i = 1; i < points.length; i++) {
    const [x, y] = points[i];
    d += ` L ${x} ${y}`;
  }

  if (closed) {
    d += ' Z';
  }

  return d;
}

/**
 * 平移轮廓点（添加偏移量）
 */
export function translateContour(
  points: [number, number][],
  offsetX: number,
  offsetY: number
): [number, number][] {
  return points.map(([x, y]) => [x + offsetX, y + offsetY] as [number, number]);
}

/**
 * 翻转轮廓（用于 SVG 坐标转换，Y 轴翻转）
 * @param points 轮廓点
 * @param height 画布高度
 */
export function flipContourY(
  points: [number, number][],
  height: number
): [number, number][] {
  return points.map(([x, y]) => [x, height - y] as [number, number]);
}