#! /usr/bin/env node

/****************************************
 *
 *  tex2svg-filter "prefix"
 *
 *  Reads stdin for TeX commands and produces SVG files
 *  for each expression read.
 *
 *  An expression ends when a blank line is read.
 *
 *  The file names are the prefix followed by a number
 *  where the number is incremented for each expression.
 *
 * ----------------------------------------------------------------------
 *
 *  Copyright (c) 2014 The MathJax Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

var mjAPI = require("../lib/mj-single.js");
var readline = require('readline');
var fs = require('fs');

var argv = require("yargs")
  .demand(1).strict()
  .usage("Usage: tex2svg-filter [options] 'SVG-file-prefix'",{
    linebreaks: {
      boolean: true,
      describe: "perform automatic line-breaking"
    },
    speech: {
      boolean: true,
      describe: "include speech text"
    },
    speechrules: {
      default: "mathspeak",
      describe: "ruleset to use for speech text (chromevox or mathspeak)"
    },
    speechstyle: {
      default: "default",
      describe: "style to use for speech text (default, brief, sbrief)"
    },
    font: {
      default: "TeX",
      describe: "web font to use"
    },
    ex: {
      default: 6,
      describe: "ex-size in pixels"
    },
    width: {
      default: 100,
      describe: "width of container in ex"
    },
    extensions: {
      default: "",
      describe: "extra MathJax extensions e.g. 'Safe,TeX/noUndefined'"
    }
  })
  .argv;

if (argv.font === "STIX") argv.font = "STIX-Web";
mjAPI.config({MathJax: {SVG: {font: argv.font}}, extensions: argv.extensions});
mjAPI.start();

var prefix = argv._[0];  // the file prefix

//
//  Create interface for reading lines from stdin
//
var rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false
});

//
//  The accumulated TeX code, and file number
//  
var tex = [], n = 0;

//
//  Data passed to mj-single-svg to maintain state
//
var state = {};

//
//  Save an SVG file:
//    Increment the file number and create the file name.
//    Set the math to be the combined TeX lines (and clear them).
//    Remove dollar signs and set the format.
//    Typeset the math, and when finished:
//      if there is svg output,
//        write the output file,
//        and indicate that it is written.
//
function SaveSVG() {
  if (tex.length === 0) return;
  var data = {
    math:"", state:state,
    format: "TeX",
    svg:true,
    ex:argv.ex, width:argv.width,
    linebreaks: argv.linebreaks,
    speakText: argv.speech,
    speakRuleset: argv.speechrules.replace(/^chromevox$/i,"default"),
    speakStyle: argv.speechstyle
  };
  n++; var N = n; while (N.length < 3) {N = "0"+N}
  var file = prefix+N+".svg";
  var math = tex.join("\n"); tex = [];
  if (math.slice(0,2) === "$$" && math.slice(-2) === "$$") {
    math = math.slice(2,math.length-2);
  } else if (math.slice(0,1) === "$" && math.slice(-1) === "$") {
    math = math.slice(1,math.length-1);
    data.format = "inline-TeX";
  }
  data.math = math;
  mjAPI.typeset(data,function (result) {
    if (result.svg) {
      fs.writeFileSync(file,result.svg);
      console.log(file+" written");
    }
  });
}

//
//  For each line read from stdin:
//    If the line is not empty,
//      add it to the list of TeX lines,
//    Otherwise
//      Save the SVG output.
//
rl.on("line",function (line) {if (line.match(/\S/)) {tex.push(line)} else {SaveSVG()}});
rl.on("close",function () {SaveSVG()});