var path = require('path'),
    utils = require('../utils');

module.exports = exec;

/**
 * Discovers all the options required to run the script
 * and if a custom exec has been passed in, then it will
 * also try to work out what extensions to monitor and
 * whether there's a special way of running that script.
 *
 * @param  {String} script
 * @param  {Object} nodemonOptions
 * @param  {Object} extentionMap
 * @return {Object} updated version of nodemonOptions
 */
function exec(script, nodemonOptions, extentionMap) {
  if (!extentionMap) {
    extentionMap = {};
  }

  script = path.basename(script);

  var options = utils.clone(nodemonOptions || {}),
      scriptExt = path.extname(script),
      extention = options.ext || scriptExt || 'js';

  if (options.exec === undefined) {
    options.exec = 'node';
  }
  options.execArgs = [];


  if (options.exec.indexOf(' ') !== -1) {
    var execOptions = options.exec.split(' ');
    options.exec = execOptions.splice(0, 1)[0];
    options.execArgs = execOptions;
  }

  if (extentionMap[extention] !== undefined) {
    options.exec = extentionMap[extention];
  }

  // note: indexOf('coffee') handles both .coffee and .litcoffee
  else if (options.exec === 'node' && scriptExt.indexOf('coffee') !== -1) {
    options.exec = 'coffee';
    // ensure that we call: `coffee --nodejs ...`
    if (options.execArgs === undefined) options.execArgs = [];

    if (options.execArgs.indexOf('--nodejs') === -1) {
      options.execArgs.unshift('--nodejs');
    }
  }

  else if (options.exec === 'node' && options.nodeArgs && options.nodeArgs.length) {
    options.execArgs = options.execArgs.concat(options.nodeArgs);
  }

  if (options.exec === 'coffee') {
    // coffeescript requires --nodejs --debug
    // this code is a dance to get the order of the debug flags right when combined with coffeescript
    if (options.nodeArgs) {
      options.execArgs = options.execArgs.concat(options.nodeArgs);
    }

    // don't override user specified extention tracking
    if (!options.ext) {
      extention = '.coffee|.litcoffee|.js';
    }

    // because windows can't find 'coffee', it needs the real file 'coffee.cmd'
    if (utils.isWindows) {
      options.exec += '.cmd';
    }
  }

  options.ext = extention;

  // if (!options.watch) {
  //   options.watch = [];
  // }

  // add(options, 'watch', new RegExp('^((?!' + extention.replace(/\./g, '\\.') + '$).)*$'));

  return options;
}