'use strict';

var crypto = require('crypto');

var path = require('path');

var defaultOptions = require('../static/babelrc.json');

var babel = null;

var babelVersionDirectory = null;

var PREFIXES = [

'/** @babel */',

'"use babel"',

"'use babel'",

'/* @flow */',

'// @flow'

];

var PREFIX_LENGTH = Math.max.apply(

Math,

PREFIXES.map(function(prefix) {

return prefix.length;

})

);

exports.shouldCompile = function(sourceCode) {

var start = sourceCode.substr(0, PREFIX_LENGTH);

return PREFIXES.some(function(prefix) {

return start.indexOf(prefix) === 0;

});

};

exports.getCachePath = function(sourceCode) {

if (babelVersionDirectory == null) {

var babelVersion = require('babel-core/package.json').version;

babelVersionDirectory = path.join(

'js',

'babel',

createVersionAndOptionsDigest(babelVersion, defaultOptions)

);

}

return path.join(

babelVersionDirectory,

crypto

.createHash('sha1')

.update(sourceCode, 'utf8')

.digest('hex') + '.js'

);

};

exports.compile = function(sourceCode, filePath) {

if (!babel) {

babel = require('babel-core');

var Logger = require('babel-core/lib/transformation/file/logger');

var noop = function() {};

Logger.prototype.debug = noop;

Logger.prototype.verbose = noop;

}

if (process.platform === 'win32') {

filePath = 'file:///' + path.resolve(filePath).replace(/\\/g, '/');

}

var options = { filename: filePath };

for (var key in defaultOptions) {

options[key] = defaultOptions[key];

}

return babel.transform(sourceCode, options).code;

};

function createVersionAndOptionsDigest(version, options) {

return crypto

.createHash('sha1')

.update('babel-core', 'utf8')

.update('\0', 'utf8')

.update(version, 'utf8')

.update('\0', 'utf8')

.update(JSON.stringify(options), 'utf8')

.digest('hex');

}