#!/usr/bin/env node

//=================================================================================================
//
// This script is used to regenerate the example visualizations
//
//=================================================================================================

var fs    = require('fs'),
    path  = require('path'),
    child = require('child_process');

//-------------------------------------------------------------------------------------------------

fs.readdirSync('examples')
  .filter(function(file) { return path.extname(file) === ".js" })
  .map(visualize);

//-------------------------------------------------------------------------------------------------

function visualize(example) {
  var name = path.basename(example, '.js'),
      fsm  = require('../examples/' + example),
      dot  = fsm.visualize(),
      svg  = dot2svg(dot),
      png  = dot2png(dot);
  console.log('visualizing examples/' + example);
  fs.writeFileSync('examples/' + name + '.dot', dot);
  fs.writeFileSync('examples/' + name + '.svg', svg);
  fs.writeFileSync('examples/' + name + '.png', png, 'binary');
}

//-------------------------------------------------------------------------------------------------

function dot2svg(dot) {
  var result = child.spawnSync("dot", ["-Tsvg"], { input: dot });
  if (result.error)
    dotError(result.error.errno);
  return result.stdout.toString();
}

//-------------------------------------------------------------------------------------------------

function dot2png(dot) {
  var result = child.spawnSync("dot", ["-Tpng"], { input: dot });
  if (result.error)
    dotError(result.error.errno);
  return result.stdout;
}

//-------------------------------------------------------------------------------------------------

function dotError(errno) {
  if (errno === 'ENOENT')
    throw new Error("dot program not found. Install graphviz (http://graphviz.org)")
  else
    throw new Error("unexpected error: " + errno)
}

//-------------------------------------------------------------------------------------------------