ttrpg-tools/src/plotcutter/layout.ts

import { contourToSvgPath } from './contour';
import { getCardShapePoints, calculateCenter } from './contour';
import type { CardPath, SinglePageLayout, LayoutOptions, CardPosition } from './types';

const A4_WIDTH_PORTRAIT = 210;
const A4_HEIGHT_PORTRAIT = 297;
const A4_WIDTH_LANDSCAPE = 297;
const A4_HEIGHT_LANDSCAPE = 210;
const DEFAULT_PRINT_MARGIN = 5;

/**
 * 生成空走路径（抬刀移动路径）
 * @param cardPaths 卡片切割路径
 * @param a4Height A4 纸高度（用于坐标转换）
 */
export function generateTravelPaths(
  cardPaths: CardPath[],
  a4Height: number
): [number, number][][] {
  const travelPaths: [number, number][][] = [];

  // 起点：左上角 (0, a4Height) - 注意 SVG 坐标 Y 向下，plotter 坐标 Y 向上
  const startPoint: [number, number] = [0, a4Height];

  if (cardPaths.length === 0) {
    return travelPaths;
  }

  // 从起点到第一张卡的起点
  travelPaths.push([startPoint, cardPaths[0].startPoint]);

  // 卡片之间的移动
  for (let i = 0; i < cardPaths.length - 1; i++) {
    const currentEnd = cardPaths[i].endPoint;
    const nextStart = cardPaths[i + 1].startPoint;
    travelPaths.push([currentEnd, nextStart]);
  }

  // 从最后一张卡返回起点
  travelPaths.push([cardPaths[cardPaths.length - 1].endPoint, startPoint]);

  return travelPaths;
}

/**
 * 将旅行路径转换为 SVG path 命令
 */
export function travelPathsToSvg(travelPaths: [number, number][][]): string {
  return travelPaths.map(path => contourToSvgPath(path, false)).join(' ');
}

/**
 * 计算所有卡片轮廓的总边界框
 */
export function calculateTotalBounds(cardPaths: CardPath[]): {
  minX: number;
  minY: number;
  maxX: number;
  maxY: number;
  width: number;
  height: number;
} {
  if (cardPaths.length === 0) {
    return { minX: 0, minY: 0, maxX: 0, maxY: 0, width: 0, height: 0 };
  }

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

  for (const cardPath of cardPaths) {
    for (const [x, y] of cardPath.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,
    width: maxX - minX,
    height: maxY - minY
  };
}

/**
 * 计算单页满排时的排版布局和刀路
 * 
 * 此函数只关心单页排满的情况，不考虑实际牌组的张数。
 * 返回的布局信息可以用于：
 * - 预览单页最大容量时的刀路
 * - 计算排版参数
 * - 生成 PLT 文件
 */
export function calculateSinglePageLayout(options: LayoutOptions): SinglePageLayout {
  const {
    cardWidth,
    cardHeight,
    shape,
    bleed,
    cornerRadius,
    orientation,
    printMargin = DEFAULT_PRINT_MARGIN
  } = options;

  // 确定 A4 尺寸
  const a4Width = orientation === 'landscape' ? A4_WIDTH_LANDSCAPE : A4_WIDTH_PORTRAIT;
  const a4Height = orientation === 'landscape' ? A4_HEIGHT_LANDSCAPE : A4_HEIGHT_PORTRAIT;

  // 计算可用区域
  const usableWidth = a4Width - printMargin * 2;
  const usableHeight = a4Height - printMargin * 2;

  // 计算每行/每页的卡片数
  const cardsPerRow = Math.floor(usableWidth / cardWidth);
  const rowsPerPage = Math.floor(usableHeight / cardHeight);
  const cardsPerPage = cardsPerRow * rowsPerPage;

  // 计算网格居中偏移
  const maxGridWidth = cardsPerRow * cardWidth;
  const maxGridHeight = rowsPerPage * cardHeight;
  const offsetX = (a4Width - maxGridWidth) / 2;
  const offsetY = (a4Height - maxGridHeight) / 2;

  // 计算切割尺寸（排版尺寸减去出血）
  const cutWidth = cardWidth - bleed * 2;
  const cutHeight = cardHeight - bleed * 2;

  // 生成卡片位置和刀路
  const cardPositions: CardPosition[] = [];
  const cardPaths: CardPath[] = [];

  for (let i = 0; i < cardsPerPage; i++) {
    const row = Math.floor(i / cardsPerRow);
    const col = i % cardsPerRow;

    // 卡片位置（左下角坐标）
    const x = offsetX + col * cardWidth;
    const y = offsetY + row * cardHeight;

    cardPositions.push({ x, y, cardIndex: i });

    // 生成形状轮廓点（相对于卡片左下角）
    const shapePoints = getCardShapePoints(shape, cutWidth, cutHeight, cornerRadius);

    // 平移到页面坐标并翻转 Y 轴（SVG Y 向下，plotter Y 向上）
    const pagePoints = shapePoints.map(([px, py]) => [
      x + bleed + px,
      a4Height - (y + bleed + py)
    ] as [number, number]);

    const center = calculateCenter(pagePoints);
    const pathD = contourToSvgPath(pagePoints);
    const startPoint = pagePoints[0];
    const endPoint = pagePoints[pagePoints.length - 1];

    cardPaths.push({
      pageIndex: 0,
      cardIndex: i,
      points: pagePoints,
      centerX: center.x,
      centerY: center.y,
      pathD,
      startPoint,
      endPoint
    });
  }

  return {
    cardPositions,
    cardPaths,
    a4Width,
    a4Height,
    cardsPerRow,
    rowsPerPage,
    cardsPerPage
  };
}

/**
 * 根据卡片位置生成刀路（用于自定义布局）
 */
export function generateCardPathsFromPositions(
  positions: CardPosition[],
  options: Omit<LayoutOptions, 'orientation' | 'printMargin'> & { a4Height: number }
): CardPath[] {
  const {
    cardWidth,
    cardHeight,
    shape,
    bleed,
    cornerRadius,
    a4Height
  } = options;

  // 计算切割尺寸
  const cutWidth = cardWidth - bleed * 2;
  const cutHeight = cardHeight - bleed * 2;

  const cardPaths: CardPath[] = [];

  for (const pos of positions) {
    // 生成形状轮廓点（相对于卡片左下角）
    const shapePoints = getCardShapePoints(shape, cutWidth, cutHeight, cornerRadius);

    // 平移到页面坐标并翻转 Y 轴
    const pagePoints = shapePoints.map(([px, py]) => [
      pos.x + bleed + px,
      a4Height - (pos.y + bleed + py)
    ] as [number, number]);

    const center = calculateCenter(pagePoints);
    const pathD = contourToSvgPath(pagePoints);
    const startPoint = pagePoints[0];
    const endPoint = pagePoints[pagePoints.length - 1];

    cardPaths.push({
      pageIndex: 0,
      cardIndex: pos.cardIndex,
      points: pagePoints,
      centerX: center.x,
      centerY: center.y,
      pathD,
      startPoint,
      endPoint
    });
  }

  return cardPaths;
}