// Entry point for Node.

var fs = require('fs');
var glob = require('glob');
var path = require('path');
var traceur = require('traceur');

exports.RUNTIME_PATH = traceur.RUNTIME_PATH;
var TRACEUR_PATH = traceur.RUNTIME_PATH.replace('traceur-runtime.js', 'traceur.js');
var SELF_SOURCE_REGEX = /transpiler\/src/;
var SELF_COMPILE_OPTIONS = {
  modules: 'register',
  moduleName: true,
  script: false // parse as a module
};

var needsReload = true;
var oldSystemGet = System.get;

exports.reloadSources = function() {
  needsReload = true;
};

exports.compile = function compile(options, paths, source) {
  if (needsReload) {
    reloadCompiler();
    needsReload = false;
  }
  var inputPath, outputPath, moduleName;
  if (typeof paths === 'string') {
    inputPath = outputPath = paths;
  } else {
    inputPath = paths.inputPath;
    outputPath = paths.inputPath;
    moduleName = paths.moduleName;
  }
  outputPath = outputPath || inputPath;
  moduleName = moduleName || inputPath;
  moduleName = moduleName.replace(/\.\w*$/, '');

  var localOptions = extend(options, {
    moduleName: moduleName
  });
  var CompilerCls = System.get('transpiler/src/compiler').Compiler;

  var compiler = new CompilerCls(localOptions);
  var result = {
    js: compiler.compile(source, inputPath, outputPath),
    sourceMap: null
  };

  var sourceMapString = compiler.getSourceMap();
  if (sourceMapString) {
    result.sourceMap = JSON.parse(sourceMapString);
  }

  return result;
};

// Transpile and evaluate the code in `src`.
// Use existing traceur to compile our sources.
function reloadCompiler() {
  loadModule(TRACEUR_PATH, false);
  glob.sync(__dirname + '/src/**/*.js').forEach(function(fileName) {
    loadModule(fileName, true);
  });

  // Traceur modules are register with the ".js" extension but we don't want
  // to add it to all the import statements.
  System.get = function get(normalizedName) {
    var m = oldSystemGet.call(this, normalizedName);
    if (!m && normalizedName.indexOf('traceur') == 0) {
      m = oldSystemGet.call(this, normalizedName + '.js');
    }
    return m;
  };
}

function loadModule(filepath, transpile) {
  var data = fs.readFileSync(filepath, 'utf8');

  if (!data) {
    throw new Error('Failed to import ' + filepath);
  }

  if (transpile) {
    var moduleName = path.normalize(filepath)
      .replace(__dirname, 'transpiler')
      .replace(/\\/g, '/')
      .replace(/\.\w*$/, '');
    data = (new traceur.NodeCompiler(
      extend(SELF_COMPILE_OPTIONS, { moduleName: moduleName } )
    )).compile(data, filepath, filepath);
  }

  ('global', eval)(data);
}

function extend(source, props) {
  var res = {};
  for (var prop in source) {
    res[prop] = source[prop];
  }
  for (var prop in props) {
    res[prop] = props[prop];
  }
  return res;
}