/* global importScripts parseMozFormat parserlib CSSLint */
'use strict';

const loadScript = createLoadScript();
const loadParserLib = createLoadParserLib();

createAPI({
  csslint: (code, config) => {
    loadParserLib();
    loadScript(['/vendor-overwrites/csslint/csslint.js']);
    return CSSLint.verify(code, config).messages
      .map(m => Object.assign(m, {rule: {id: m.rule.id}}));
  },
  stylelint: () => {

  },
  parseMozFormat: data => {
    loadParserLib();
    loadScript(['/js/moz-parser.js']);
    return parseMozFormat(data);
  }
});

function createLoadParserLib() {
  let loaded = false;
  return () => {
    if (loaded) {
      return;
    }
    importScripts('/vendor-overwrites/csslint/parserlib.js');
    parserlib.css.Tokens[parserlib.css.Tokens.COMMENT].hide = false;
    loaded = true;
  };
}

function createLoadScript() {
  const loaded = new Set();
  return urls => {
    urls = urls.filter(u => !loaded.has(u));
    importScripts(...urls);
    urls.forEach(u => loaded.add(u));
  };
}

function createAPI(methods) {
  self.onmessage = e => {
    const message = e.data;
    Promise.resolve()
      .then(() => methods[message.action](...message.args))
      .then(result =>
        ({
          requestId: message.requestId,
          error: false,
          data: result
        })
      )
      .catch(err =>
        ({
          requestId: message.requestId,
          error: true,
          data: cloneError(err)
        })
      )
      .then(data => self.postMessage(data));
  };
}

function cloneError(err) {
  return Object.assign({
    name: err.name,
    stack: err.stack,
    message: err.message,
    lineNumber: err.lineNumber,
    columnNumber: err.columnNumber,
    fileName: err.fileName
  }, err);
}