import { readPdfPages } from './pdfDocumentReader.js';

async function openPdf(file) {
  const pdfjs = await import('pdfjs-dist');
  pdfjs.GlobalWorkerOptions.workerSrc = (await import('pdfjs-dist/build/pdf.worker.min.mjs?url')).default;
  let task;
  try {
    task = pdfjs.getDocument({data:await file.arrayBuffer()});
    return {doc:await task.promise,task};
  }
  catch(error) {
    await task?.destroy();
    if(error.name === 'InvalidPDFException') throw new Error('PDF dosyası bozuk veya geçerli PDF biçiminde değil.');
    if(error.name === 'PasswordException') throw new Error('PDF parola korumalı; okunabilir bir kopyasını yükleyin.');
    throw new Error('PDF okunamadı. Dosyayı kontrol edip yeniden deneyin.');
  }
}

async function readPdf(file,{ocr=false,forceOcr=false,maxPages=Infinity,onProgress}={}) {
  const {doc,task}=await openPdf(file);
  let worker;
  try {
    const result=await readPdfPages(doc,{maxPages,forceOcr,onProgress,ocrPage:ocr ? async(page)=>{
      if(!worker) {
        const {createWorker}=await import('tesseract.js');
        worker=await createWorker('tur');
      }
      const viewport=page.getViewport({scale:2});
      const canvas=document.createElement('canvas');
      canvas.width=viewport.width;canvas.height=viewport.height;
      try {
        await page.render({canvasContext:canvas.getContext('2d'),viewport}).promise;
        return (await worker.recognize(canvas)).data.text;
      } finally { canvas.width=0;canvas.height=0; }
    } : undefined});
    return result;
  } finally {
    try { if(worker) await worker.terminate(); }
    finally { await task.destroy(); }
  }
}

export const extractPdfText=(file,options={})=>readPdf(file,{...options,ocr:false});
export const ocrPdfText=(file,options={})=>readPdf(file,{...options,ocr:true,forceOcr:true});
export async function extractPlainText(file) {
  return {text:(await file.text()).trim(),pageCount:1,usedPages:1,complete:true};
}
export async function extractText(file,{ocr=true,onProgress}={}) {
  if((file.name || '').toLowerCase().endsWith('.pdf') || file.type==='application/pdf')
    return readPdf(file,{ocr,onProgress});
  return extractPlainText(file);
}