ttrpg-tools/src/components/md-deck/hooks/usePageLayout.ts

import { createMemo } from 'solid-js';
import type { DeckStore } from './deckStore';
import type { PageData, CropMarkData } from './usePDFExport';

export interface A4Size {
  width: number;
  height: number;
}

export interface UsePageLayoutReturn {
  getA4Size: () => A4Size;
  pages: ReturnType<typeof createMemo<PageData[]>>;
  cropMarks: ReturnType<typeof createMemo<CropMarkData[]>>;
}

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

/**
 * 页面布局计算 hook
 */
export function usePageLayout(store: DeckStore): UsePageLayoutReturn {
  const orientation = () => store.state.printOrientation;
  const doubleSided = () => store.state.printDoubleSided;
  const frontOddPageOffsetX = () => store.state.printFrontOddPageOffsetX;
  const frontOddPageOffsetY = () => store.state.printFrontOddPageOffsetY;

  const getA4Size = () => {
    if (orientation() === 'landscape') {
      return { width: A4_WIDTH_LANDSCAPE, height: A4_HEIGHT_LANDSCAPE };
    }
    return { width: A4_WIDTH_PORTRAIT, height: A4_HEIGHT_PORTRAIT };
  };

  const pages = createMemo<PageData[]>(() => {
    const cards = store.state.cards;
    const cardWidth = store.state.dimensions?.cardWidth || 56;
    const cardHeight = store.state.dimensions?.cardHeight || 88;
    const { width: a4Width, height: a4Height } = getA4Size();

    const usableWidth = a4Width - PRINT_MARGIN * 2;
    const cardsPerRow = Math.floor(usableWidth / cardWidth);
    const usableHeight = a4Height - PRINT_MARGIN * 2;
    const rowsPerPage = Math.floor(usableHeight / cardHeight);
    const cardsPerPage = cardsPerRow * rowsPerPage;

    const maxGridWidth = cardsPerRow * cardWidth;
    const maxGridHeight = rowsPerPage * cardHeight;
    const baseOffsetX = (a4Width - maxGridWidth) / 2;
    const baseOffsetY = (a4Height - maxGridHeight) / 2;

    const result: PageData[] = [];

    if (doubleSided()) {
      // 双面打印模式：每页多张卡牌，正面和背面分别在相邻的两页
      const totalCards = cards.length;
      const totalPages = Math.ceil(totalCards / cardsPerPage);

      for (let pageIndex = 0; pageIndex < totalPages; pageIndex++) {
        const frontPageIndex = pageIndex * 2;
        const backPageIndex = pageIndex * 2 + 1;

        // 确保页面数组有足够长度
        while (result.length <= backPageIndex) {
          result.push({
            pageIndex: result.length,
            cards: [],
            bounds: { minX: Infinity, minY: Infinity, maxX: -Infinity, maxY: -Infinity },
            frameBounds: { minX: Infinity, minY: Infinity, maxX: -Infinity, maxY: -Infinity }
          });
        }

        const frontPage = result[frontPageIndex];
        const backPage = result[backPageIndex];

        // 计算当前正面页的卡牌范围
        const startCardIndex = pageIndex * cardsPerPage;
        const endCardIndex = Math.min(startCardIndex + cardsPerPage, totalCards);

        for (let i = startCardIndex; i < endCardIndex; i++) {
          // 正面：正常顺序排列
          const indexInPage = i - startCardIndex;
          const row = Math.floor(indexInPage / cardsPerRow);
          const col = indexInPage % cardsPerRow;
          // 双面打印时，所有正面页都在奇数物理页上，所以都应用偏移
          const pageOffsetX = frontOddPageOffsetX();
          const pageOffsetY = frontOddPageOffsetY();

          const frontX = baseOffsetX + col * cardWidth + pageOffsetX;
          const frontY = baseOffsetY + row * cardHeight + pageOffsetY;

          frontPage.cards.push({ data: cards[i], x: frontX, y: frontY, side: 'front' as const });
          frontPage.bounds.minX = Math.min(frontPage.bounds.minX, frontX);
          frontPage.bounds.minY = Math.min(frontPage.bounds.minY, frontY);
          frontPage.bounds.maxX = Math.max(frontPage.bounds.maxX, frontX + cardWidth);
          frontPage.bounds.maxY = Math.max(frontPage.bounds.maxY, frontY + cardHeight);

          // 背面：逆转顺序排列（长边方向）
          // 对于竖向打印，长边是垂直方向，所以逆转行
          // 对于横向打印，长边是水平方向，所以逆转列
          const backRow = orientation() === 'portrait'
            ? (rowsPerPage - 1 - row)
            : row;
          const backCol = orientation() === 'portrait'
            ? col
            : (cardsPerRow - 1 - col);

          const backX = baseOffsetX + backCol * cardWidth;
          const backY = baseOffsetY + backRow * cardHeight;

          backPage.cards.push({ data: cards[i], x: backX, y: backY, side: 'back' as const });
          backPage.bounds.minX = Math.min(backPage.bounds.minX, backX);
          backPage.bounds.minY = Math.min(backPage.bounds.minY, backY);
          backPage.bounds.maxX = Math.max(backPage.bounds.maxX, backX + cardWidth);
          backPage.bounds.maxY = Math.max(backPage.bounds.maxY, backY + cardHeight);
        }
      }
    } else {
      // 单面打印模式：原有逻辑
      let currentPage: PageData = {
        pageIndex: 0,
        cards: [],
        bounds: { minX: Infinity, minY: Infinity, maxX: -Infinity, maxY: -Infinity },
        frameBounds: { minX: Infinity, minY: Infinity, maxX: -Infinity, maxY: -Infinity }
      };

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

        if (pageIndex !== currentPage.pageIndex) {
          result.push(currentPage);
          currentPage = {
            pageIndex,
            cards: [],
            bounds: { minX: Infinity, minY: Infinity, maxX: -Infinity, maxY: -Infinity },
            frameBounds: { minX: Infinity, minY: Infinity, maxX: -Infinity, maxY: -Infinity }
          };
        }

        const isOddPage = pageIndex % 2 === 0;
        const pageOffsetX = isOddPage ? frontOddPageOffsetX() : 0;
        const pageOffsetY = isOddPage ? frontOddPageOffsetY() : 0;

        const cardX = baseOffsetX + col * cardWidth + pageOffsetX;
        const cardY = baseOffsetY + row * cardHeight + pageOffsetY;

        currentPage.cards.push({ data: cards[i], x: cardX, y: cardY, side: 'front' as const });
        currentPage.bounds.minX = Math.min(currentPage.bounds.minX, cardX);
        currentPage.bounds.minY = Math.min(currentPage.bounds.minY, cardY);
        currentPage.bounds.maxX = Math.max(currentPage.bounds.maxX, cardX + cardWidth);
        currentPage.bounds.maxY = Math.max(currentPage.bounds.maxY, cardY + cardHeight);
      }

      if (currentPage.cards.length > 0) {
        result.push(currentPage);
      }
    }

    return result.map(page => {
      const offsetX = doubleSided() && page.pageIndex % 2 === 0 ? frontOddPageOffsetX() : 0;
      const offsetY = doubleSided() && page.pageIndex % 2 === 0 ? frontOddPageOffsetY() : 0;
      
      return {
        ...page,
        frameBounds: {
          minX: baseOffsetX + offsetX,
          minY: baseOffsetY + offsetY,
          maxX: baseOffsetX + maxGridWidth + offsetX,
          maxY: baseOffsetY + maxGridHeight + offsetY
        }
      };
    });
  });

  const cropMarks = createMemo<CropMarkData[]>(() => {
    const pagesData = pages();
    return pagesData.map(page => {
      const { frameBounds, cards } = page;
      const cardWidth = store.state.dimensions?.cardWidth || 56;
      const cardHeight = store.state.dimensions?.cardHeight || 88;

      const xPositions = new Set<number>();
      const yPositions = new Set<number>();

      cards.forEach(card => {
        xPositions.add(card.x);
        xPositions.add(card.x + cardWidth);
        yPositions.add(card.y);
        yPositions.add(card.y + cardHeight);
      });

      const sortedX = Array.from(xPositions).sort((a, b) => a - b);
      const sortedY = Array.from(yPositions).sort((a, b) => a - b);

      const OVERLAP = 3;

      const horizontalLines = sortedY.map(y => ({
        y,
        xStart: frameBounds.minX - OVERLAP,
        xEnd: frameBounds.maxX + OVERLAP
      }));

      const verticalLines = sortedX.map(x => ({
        x,
        yStart: frameBounds.minY - OVERLAP,
        yEnd: frameBounds.maxY + OVERLAP
      }));

      const frameBoundsWithMargin = {
        x: frameBounds.minX - 1,
        y: frameBounds.minY - 1,
        width: frameBounds.maxX - frameBounds.minX + 2,
        height: frameBounds.maxY - frameBounds.minY + 2
      };

      return { horizontalLines, verticalLines, frameBounds, frameBoundsWithMargin };
    });
  });

  return { getA4Size, pages, cropMarks };
}