// ===== 환경 설정 =====
// PDF.js ES Module 파일 경로 (unpkg에서 받으신 파일을 서버에 저장한 경로로 맞추세요)
import * as pdfjsLib from 'https://cslabs.co.kr/js/pdf.min.mjs';

// 워커 경로 (같은 폴더에 저장했으면 상대경로 유지)
pdfjsLib.GlobalWorkerOptions.workerSrc = 'https://cslabs.co.kr/js/pdf.worker.min.mjs';

// 하드코딩할 PDF 경로
const urlDefault = 'https://cslabs.co.kr//pdfs/cslabs.pdf';

// ===== 요소 참조 =====
const canvas = document.getElementById('pdf-canvas');
const ctx = canvas.getContext('2d');
const pageCountEl = document.getElementById('page-count');
const pageNumEl   = document.getElementById('page-num');
const zoomLevelEl = document.getElementById('zoom-level');

const btn = {
  prev: document.getElementById('prev-page'),
  next: document.getElementById('next-page'),
  zoomIn: document.getElementById('zoom-in'),
  zoomOut: document.getElementById('zoom-out'),
  rotL: document.getElementById('rotate-left'),
  rotR: document.getElementById('rotate-right'),
  fitW: document.getElementById('fit-width'),
  fitP: document.getElementById('fit-page'),
  dl: document.getElementById('download-btn'),
};

// ===== 상태값 =====
let pdfDoc = null;
let pageNum = 1;
let scale = 1.0;
let rotation = 0;

// ===== 유틸 =====
function enableControls(on = true) {
  Object.values(btn).forEach(b => b.disabled = !on);
}

function renderPage(num) {
  return pdfDoc.getPage(num).then(page => {
    const viewport = page.getViewport({ scale, rotation });
    canvas.width = viewport.width;
    canvas.height = viewport.height;
    const renderCtx = { canvasContext: ctx, viewport };
    return page.render(renderCtx).promise;
  }).then(() => {
    pageCountEl.textContent = pdfDoc.numPages;
    pageNumEl.value = num;
    zoomLevelEl.textContent = Math.round(scale * 100) + '%';
  });
}

function queueRenderPage(num) {
  if (!pdfDoc) return;
  if (num < 1) num = 1;
  if (num > pdfDoc.numPages) num = pdfDoc.numPages;
  pageNum = num;
  renderPage(pageNum);
}

async function loadPdf(url) {
  try {
    enableControls(false);
    const pdf = await pdfjsLib.getDocument(url).promise;
    pdfDoc = pdf;
    pageNum = 1;
    rotation = 0;
    scale = 1.0;
    await renderPage(pageNum);
    enableControls(true);
  } catch (err) {
    console.error(err);
    alert('PDF 로드 실패: ' + err.message);
  }
}

// ===== 이벤트 =====
btn.prev.addEventListener('click', () => { if (pdfDoc && pageNum > 1) queueRenderPage(pageNum - 1); });
btn.next.addEventListener('click', () => { if (pdfDoc && pageNum < pdfDoc.numPages) queueRenderPage(pageNum + 1); });
pageNumEl.addEventListener('change', e => { if (pdfDoc) queueRenderPage(parseInt(e.target.value, 10) || 1); });

btn.zoomIn.addEventListener('click', () => { if (!pdfDoc) return; scale = Math.min(scale + 0.25, 4); queueRenderPage(pageNum); });
btn.zoomOut.addEventListener('click', () => { if (!pdfDoc) return; scale = Math.max(scale - 0.25, 0.25); queueRenderPage(pageNum); });

btn.rotL.addEventListener('click', () => { if (!pdfDoc) return; rotation = (rotation - 90 + 360) % 360; queueRenderPage(pageNum); });
btn.rotR.addEventListener('click', () => { if (!pdfDoc) return; rotation = (rotation + 90) % 360; queueRenderPage(pageNum); });

btn.fitW.addEventListener('click', async () => {
  if (!pdfDoc) return;
  const containerWidth = document.getElementById('viewer-container').clientWidth - 32;
  const page = await pdfDoc.getPage(pageNum);
  const vp = page.getViewport({ scale: 1, rotation });
  scale = containerWidth / vp.width;
  queueRenderPage(pageNum);
});

btn.fitP.addEventListener('click', async () => {
  if (!pdfDoc) return;
  const container = document.getElementById('viewer-container');
  const cw = container.clientWidth - 32;
  const ch = container.clientHeight - 32;
  const page = await pdfDoc.getPage(pageNum);
  const vp = page.getViewport({ scale: 1, rotation });
  const scaleX = cw / vp.width;
  const scaleY = ch / vp.height;
  scale = Math.min(scaleX, scaleY);
  queueRenderPage(pageNum);
});

btn.dl.addEventListener('click', () => {
  if (!pdfDoc) { alert('PDF가 아직 로드되지 않았습니다.'); return; }
  const a = document.createElement('a');
  a.href = urlDefault;
  a.download = '';
  document.body.appendChild(a);
  a.click();
  a.remove();
});

// ===== 초기 로드 =====
loadPdf(urlDefault);