euler/lib/utils/generator.js

a commandline tool for greasing up your rusty programming and math skills through Project Euler challenges.

'use strict';

var fs = require('fs');
var find = require('./finder');
var get = require('./getter');

var marks = {
  coffee: '#',
  js: '//'
};

var solutions = {
  coffee: '# solution\n',
  js: '/* solution */;\n'
};

var getPrompt = function(data, suffix, number) {
  var prompt, mark, output;
  prompt = data.split('\n\n\n')[+number - 1]; // remove leading zeros
  mark = marks[suffix];

  if (prompt && suffix) {
    prompt = mark + ' ' + prompt.split('\n').join('\n' + mark + ' ')  +
            '\n\n\n\n' + mark + ' TODO: return your answer for this prompt.' +
            '\nreturn ' + solutions[suffix];
  }

  return prompt;
};

var copy = function(from, to, failure) {
  fs.createReadStream(from + to).pipe(fs.createWriteStream(to));
};

var write = function(success, failure, suffix, number, prompt) {
  var file, data, resources, i;

  // write current prompt
  file = 'euler_' + number + '.' + suffix;
  fs.writeFileSync(file, prompt, 'utf8');

  // if any resources exist, write them also
  resources = get.data(__dirname + '/../data/resources.json', failure);
  resources = JSON.parse(resources)[+number];
  if (resources) {
    if (Array.isArray(resources)) {
      for (i = 0; i < resources.length; i++) {
        copy(__dirname + '/../data/resources/', resources[i], failure);
      }
    } else {
      copy(__dirname + '/../data/resources/', resources, failure);
    }
  }

  success(prompt);
};

var generateOutput = function(success, failure, suffix, number) {
  var data, prompt;

  number = number ? number : find.highest();
  data = get.data(__dirname + '/../data/problems.txt', failure, number);
  if (data) {
    prompt = getPrompt(data, suffix, number);

    if (prompt) {
      success(prompt);
    } else {
      failure();
    }
  }
};

var generate = {};

generate.preview = function(success, failure, number) {
  generateOutput(success, failure, null, number);
};

generate.file = function(success, failure, suffix, number) {
  var writer;
  writer = write.bind(null, success, failure, suffix, number);
  generateOutput(writer, failure, suffix, number);
};

module.exports = generate;