/* Any copyright is dedicated to the Public Domain.
 * http://creativecommons.org/publicdomain/zero/1.0/ */

//
// Node tool to dump SVG output into a file.
//

var fs = require('fs');
var util = require('util');
var path = require('path');
var stream = require('stream');

// HACK few hacks to let PDF.js be loaded not as a module in global space.
require('./domstubs.js').setStubs(global);

// Run `gulp dist-install` to generate 'pdfjs-dist' npm package files.
var pdfjsLib = require('pdfjs-dist');

// Loading file from file system into typed array
var pdfPath = process.argv[2] || '../../web/compressed.tracemonkey-pldi-09.pdf';
var data = new Uint8Array(fs.readFileSync(pdfPath));

var outputDirectory = './svgdump';

try {
  // Note: This creates a directory only one level deep. If you want to create
  // multiple subdirectories on the fly, use the mkdirp module from npm.
  fs.mkdirSync(outputDirectory);
} catch (e) {
  if (e.code !== 'EEXIST') {
    throw e;
  }
}

// Dumps svg outputs to a folder called svgdump
function getFilePathForPage(pageNum) {
  var name = path.basename(pdfPath, path.extname(pdfPath));
  return path.join(outputDirectory, name + '-' + pageNum + '.svg');
}

/**
 * A readable stream which offers a stream representing the serialization of a
 * given DOM element (as defined by domstubs.js).
 *
 * @param {object} options
 * @param {DOMElement} options.svgElement The element to serialize
 */
function ReadableSVGStream(options) {
  if (!(this instanceof ReadableSVGStream)) {
    return new ReadableSVGStream(options);
  }
  stream.Readable.call(this, options);
  this.serializer = options.svgElement.getSerializer();
}
util.inherits(ReadableSVGStream, stream.Readable);
// Implements https://nodejs.org/api/stream.html#stream_readable_read_size_1
ReadableSVGStream.prototype._read = function() {
  var chunk;
  while ((chunk = this.serializer.getNext()) !== null) {
    if (!this.push(chunk)) {
      return;
    }
  }
  this.push(null);
};

// Streams the SVG element to the given file path.
function writeSvgToFile(svgElement, filePath) {
  var readableSvgStream = new ReadableSVGStream({
    svgElement: svgElement,
  });
  var writableStream = fs.createWriteStream(filePath);
  return new Promise(function(resolve, reject) {
    readableSvgStream.once('error', reject);
    writableStream.once('error', reject);
    writableStream.once('finish', resolve);
    readableSvgStream.pipe(writableStream);
  }).catch(function(err) {
    readableSvgStream = null; // Explicitly null because of v8 bug 6512.
    writableStream.end();
    throw err;
  });
}

// Will be using promises to load document, pages and misc data instead of
// callback.
pdfjsLib.getDocument({
  data: data,
  // Try to export JPEG images directly if they don't need any further processing.
  nativeImageDecoderSupport: pdfjsLib.NativeImageDecoding.DISPLAY
}).then(function (doc) {
  var numPages = doc.numPages;
  console.log('# Document Loaded');
  console.log('Number of Pages: ' + numPages);
  console.log();

  var lastPromise = Promise.resolve(); // will be used to chain promises
  var loadPage = function (pageNum) {
    return doc.getPage(pageNum).then(function (page) {
      console.log('# Page ' + pageNum);
      var viewport = page.getViewport(1.0 /* scale */);
      console.log('Size: ' + viewport.width + 'x' + viewport.height);
      console.log();

      return page.getOperatorList().then(function (opList) {
        var svgGfx = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs);
        svgGfx.embedFonts = true;
        return svgGfx.getSVG(opList, viewport).then(function (svg) {
          return writeSvgToFile(svg, getFilePathForPage(pageNum)).then(function () {
            console.log('Page: ' + pageNum);
          }, function(err) {
            console.log('Error: ' + err);
          });
        });
      });
    });
  };

  for (var i = 1; i <= numPages; i++) {
    lastPromise = lastPromise.then(loadPage.bind(null, i));
  }
  return lastPromise;
}).then(function () {
  console.log('# End of Document');
}, function (err) {
  console.error('Error: ' + err);
});