bentopdf/src/js/logic/cbz-to-pdf-page.ts

import { showLoader, hideLoader, showAlert } from '../ui.js';
import { downloadFile, formatBytes } from '../utils/helpers.js';
import { state } from '../state.js';
import { createIcons, icons } from 'lucide';
import { isWasmAvailable, getWasmBaseUrl } from '../config/wasm-cdn-config.js';
import { showWasmRequiredDialog } from '../utils/wasm-provider.js';
import { loadPyMuPDF, isPyMuPDFAvailable } from '../utils/pymupdf-loader.js';
import JSZip from 'jszip';
import { PDFDocument } from 'pdf-lib';

const EXTENSIONS = ['.cbz', '.cbr'];
const TOOL_NAME = 'CBZ';
const ALL_IMAGE_EXTENSIONS = [
  '.jpg',
  '.jpeg',
  '.png',
  '.gif',
  '.bmp',
  '.tiff',
  '.tif',
  '.webp',
  '.avif',
  '.jxl',
  '.heic',
  '.heif',
];

const IMAGE_SIGNATURES = {
  jpeg: [0xff, 0xd8, 0xff],
  png: [0x89, 0x50, 0x4e, 0x47],
  gif: [0x47, 0x49, 0x46],
  bmp: [0x42, 0x4d],
  webp: [0x52, 0x49, 0x46, 0x46],
  avif: [0x00, 0x00, 0x00],
};

function matchesSignature(
  data: Uint8Array,
  signature: number[],
  offset = 0
): boolean {
  for (let i = 0; i < signature.length; i++) {
    if (data[offset + i] !== signature[i]) return false;
  }
  return true;
}

function detectImageFormat(
  data: Uint8Array
): 'jpeg' | 'png' | 'gif' | 'bmp' | 'webp' | 'avif' | 'unknown' {
  if (data.length < 12) return 'unknown';
  if (matchesSignature(data, IMAGE_SIGNATURES.jpeg)) return 'jpeg';
  if (matchesSignature(data, IMAGE_SIGNATURES.png)) return 'png';
  if (matchesSignature(data, IMAGE_SIGNATURES.gif)) return 'gif';
  if (matchesSignature(data, IMAGE_SIGNATURES.bmp)) return 'bmp';
  if (
    matchesSignature(data, IMAGE_SIGNATURES.webp) &&
    data[8] === 0x57 &&
    data[9] === 0x45 &&
    data[10] === 0x42 &&
    data[11] === 0x50
  ) {
    return 'webp';
  }
  if (
    data[4] === 0x66 &&
    data[5] === 0x74 &&
    data[6] === 0x79 &&
    data[7] === 0x70
  ) {
    const brand = String.fromCharCode(data[8], data[9], data[10], data[11]);
    if (
      brand === 'avif' ||
      brand === 'avis' ||
      brand === 'mif1' ||
      brand === 'miaf'
    ) {
      return 'avif';
    }
  }
  return 'unknown';
}

function isCbzFile(filename: string): boolean {
  return filename.toLowerCase().endsWith('.cbz');
}

async function convertImageToPng(
  imageData: ArrayBuffer,
  filename: string
): Promise<Blob> {
  return new Promise((resolve, reject) => {
    const blob = new Blob([imageData]);
    const url = URL.createObjectURL(blob);
    const img = new Image();
    img.onload = () => {
      const canvas = document.createElement('canvas');
      canvas.width = img.width;
      canvas.height = img.height;
      const ctx = canvas.getContext('2d');
      if (!ctx) {
        URL.revokeObjectURL(url);
        reject(new Error('Failed to get canvas context'));
        return;
      }
      ctx.drawImage(img, 0, 0);
      canvas.toBlob((pngBlob) => {
        URL.revokeObjectURL(url);
        if (pngBlob) {
          resolve(pngBlob);
        } else {
          reject(new Error(`Failed to convert ${filename} to PNG`));
        }
      }, 'image/png');
    };
    img.onerror = () => {
      URL.revokeObjectURL(url);
      reject(new Error(`Failed to load image: ${filename}`));
    };
    img.src = url;
  });
}

async function convertCbzToPdf(file: File): Promise<Blob> {
  const zip = await JSZip.loadAsync(file);
  const pdfDoc = await PDFDocument.create();

  const imageFiles = Object.keys(zip.files)
    .filter((name) => {
      if (zip.files[name].dir) return false;
      const ext = name.toLowerCase().substring(name.lastIndexOf('.'));
      return ALL_IMAGE_EXTENSIONS.includes(ext);
    })
    .sort((a, b) =>
      a.localeCompare(b, undefined, { numeric: true, sensitivity: 'base' })
    );

  for (const filename of imageFiles) {
    const zipEntry = zip.files[filename];
    const imageData = await zipEntry.async('arraybuffer');
    const dataArray = new Uint8Array(imageData);
    const actualFormat = detectImageFormat(dataArray);

    let imageBytes: Uint8Array;
    let embedMethod: 'png' | 'jpg';

    if (actualFormat === 'jpeg') {
      imageBytes = dataArray;
      embedMethod = 'jpg';
    } else if (actualFormat === 'png') {
      imageBytes = dataArray;
      embedMethod = 'png';
    } else {
      const pngBlob = await convertImageToPng(imageData, filename);
      imageBytes = new Uint8Array(await pngBlob.arrayBuffer());
      embedMethod = 'png';
    }

    const image =
      embedMethod === 'png'
        ? await pdfDoc.embedPng(imageBytes)
        : await pdfDoc.embedJpg(imageBytes);
    const page = pdfDoc.addPage([image.width, image.height]);
    page.drawImage(image, {
      x: 0,
      y: 0,
      width: image.width,
      height: image.height,
    });
  }

  const pdfBytes = await pdfDoc.save();
  return new Blob([pdfBytes.buffer as ArrayBuffer], {
    type: 'application/pdf',
  });
}

async function convertCbrToPdf(file: File): Promise<Blob> {
  const pymupdf = await loadPyMuPDF();
  return await (pymupdf as any).convertToPdf(file, { filetype: 'cbz' });
}

document.addEventListener('DOMContentLoaded', () => {
  const fileInput = document.getElementById('file-input') as HTMLInputElement;
  const dropZone = document.getElementById('drop-zone');
  const processBtn = document.getElementById('process-btn');
  const fileDisplayArea = document.getElementById('file-display-area');
  const fileControls = document.getElementById('file-controls');
  const addMoreBtn = document.getElementById('add-more-btn');
  const clearFilesBtn = document.getElementById('clear-files-btn');
  const backBtn = document.getElementById('back-to-tools');

  if (backBtn) {
    backBtn.addEventListener('click', () => {
      window.location.href = import.meta.env.BASE_URL;
    });
  }

  const updateUI = async () => {
    if (!fileDisplayArea || !processBtn || !fileControls) return;

    if (state.files.length > 0) {
      fileDisplayArea.innerHTML = '';

      for (let index = 0; index < state.files.length; index++) {
        const file = state.files[index];
        const fileDiv = document.createElement('div');
        fileDiv.className =
          'flex items-center justify-between bg-gray-700 p-3 rounded-lg text-sm';

        const infoContainer = document.createElement('div');
        infoContainer.className = 'flex flex-col overflow-hidden';

        const nameSpan = document.createElement('div');
        nameSpan.className = 'truncate font-medium text-gray-200 text-sm mb-1';
        nameSpan.textContent = file.name;

        const metaSpan = document.createElement('div');
        metaSpan.className = 'text-xs text-gray-400';
        metaSpan.textContent = formatBytes(file.size);

        infoContainer.append(nameSpan, metaSpan);

        const removeBtn = document.createElement('button');
        removeBtn.className =
          'ml-4 text-red-400 hover:text-red-300 flex-shrink-0';
        removeBtn.innerHTML = '<i data-lucide="trash-2" class="w-4 h-4"></i>';
        removeBtn.onclick = () => {
          state.files = state.files.filter((_, i) => i !== index);
          updateUI();
        };

        fileDiv.append(infoContainer, removeBtn);
        fileDisplayArea.appendChild(fileDiv);
      }

      createIcons({ icons });
      fileControls.classList.remove('hidden');
      processBtn.classList.remove('hidden');
      (processBtn as HTMLButtonElement).disabled = false;
    } else {
      fileDisplayArea.innerHTML = '';
      fileControls.classList.add('hidden');
      processBtn.classList.add('hidden');
      (processBtn as HTMLButtonElement).disabled = true;
    }
  };

  const resetState = () => {
    state.files = [];
    state.pdfDoc = null;
    updateUI();
  };

  const convertToPdf = async () => {
    try {
      if (state.files.length === 0) {
        showAlert('No Files', `Please select at least one ${TOOL_NAME} file.`);
        return;
      }

      if (state.files.length === 1) {
        const originalFile = state.files[0];
        showLoader(`Converting ${originalFile.name}...`);

        let pdfBlob: Blob;
        if (isCbzFile(originalFile.name)) {
          pdfBlob = await convertCbzToPdf(originalFile);
        } else {
          pdfBlob = await convertCbrToPdf(originalFile);
        }

        const fileName = originalFile.name.replace(/\.[^.]+$/, '') + '.pdf';
        downloadFile(pdfBlob, fileName);
        hideLoader();

        showAlert(
          'Conversion Complete',
          `Successfully converted ${originalFile.name} to PDF.`,
          'success',
          () => resetState()
        );
      } else {
        showLoader('Converting files...');
        const outputZip = new JSZip();

        for (let i = 0; i < state.files.length; i++) {
          const file = state.files[i];
          showLoader(
            `Converting ${i + 1}/${state.files.length}: ${file.name}...`
          );

          let pdfBlob: Blob;
          if (isCbzFile(file.name)) {
            pdfBlob = await convertCbzToPdf(file);
          } else {
            pdfBlob = await convertCbrToPdf(file);
          }

          const baseName = file.name.replace(/\.[^.]+$/, '');
          const pdfBuffer = await pdfBlob.arrayBuffer();
          outputZip.file(`${baseName}.pdf`, pdfBuffer);
        }

        const zipBlob = await outputZip.generateAsync({ type: 'blob' });
        downloadFile(zipBlob, 'comic-converted.zip');

        hideLoader();

        showAlert(
          'Conversion Complete',
          `Successfully converted ${state.files.length} ${TOOL_NAME} file(s) to PDF.`,
          'success',
          () => resetState()
        );
      }
    } catch (e: any) {
      console.error(`[${TOOL_NAME}2PDF] ERROR:`, e);
      hideLoader();
      showAlert(
        'Error',
        `An error occurred during conversion. Error: ${e.message}`
      );
    }
  };

  const handleFileSelect = (files: FileList | null) => {
    if (files && files.length > 0) {
      state.files = [...state.files, ...Array.from(files)];
      updateUI();
    }
  };

  if (fileInput && dropZone) {
    fileInput.addEventListener('change', (e) => {
      handleFileSelect((e.target as HTMLInputElement).files);
    });

    dropZone.addEventListener('dragover', (e) => {
      e.preventDefault();
      dropZone.classList.add('bg-gray-700');
    });

    dropZone.addEventListener('dragleave', (e) => {
      e.preventDefault();
      dropZone.classList.remove('bg-gray-700');
    });

    dropZone.addEventListener('drop', (e) => {
      e.preventDefault();
      dropZone.classList.remove('bg-gray-700');
      const files = e.dataTransfer?.files;
      if (files && files.length > 0) {
        const validFiles = Array.from(files).filter((f) => {
          const name = f.name.toLowerCase();
          return EXTENSIONS.some((ext) => name.endsWith(ext));
        });
        if (validFiles.length > 0) {
          const dataTransfer = new DataTransfer();
          validFiles.forEach((f) => dataTransfer.items.add(f));
          handleFileSelect(dataTransfer.files);
        }
      }
    });

    fileInput.addEventListener('click', () => {
      fileInput.value = '';
    });
  }

  if (addMoreBtn) {
    addMoreBtn.addEventListener('click', () => {
      fileInput.click();
    });
  }

  if (clearFilesBtn) {
    clearFilesBtn.addEventListener('click', () => {
      resetState();
    });
  }

  if (processBtn) {
    processBtn.addEventListener('click', convertToPdf);
  }
});