src/utils.ts

import * as _DEFAULT_RULES from '../data/rules.json';

/**
 * Default rules.
 */
export const DEFAULT_RULES: Rule[] = _DEFAULT_RULES as Rule[];

/**
 * Retrieves default rules from remote rules file, fallback to existing DEFAULT_RULES
 */
export async function getDefaultRules() {
  // try fetch from remote
  const remoteRulesUrl =
    'https://gerrit.googlesource.com/gerrit-fe-dev-helper/+/refs/heads/master/data/rules.json?format=TEXT';
  try {
    const response = await fetch(remoteRulesUrl);
    const encodedText = await response.text();
    return JSON.parse(atob(encodedText));
  } catch (e) {
    console.log(e);
  }

  // fallback to existing default rules
  return DEFAULT_RULES;
}

/**
 * Returns if it's a valid rule (syntax only).
 */
export function isValidRule(rule: Rule) {
  return (
    Object.values(Operator).includes(rule.operator) &&
    ((rule.operator === Operator.BLOCK && rule.target) ||
      (rule.operator === Operator.REDIRECT &&
        rule.target &&
        rule.destination) ||
      !!rule.destination)
  );
}

/**
 * Returns if it's a inject rule.
 */
export function isInjectRule(rule: Rule) {
  return [
    Operator.INJECT_JS_MODULE_PLUGIN,
    Operator.INJECT_JS_PLUGIN,
    Operator.INJECT_HTML_CODE,
    Operator.INJECT_HTML_PLUGIN,
    Operator.INJECT_JS_CODE,
    Operator.INJECT_EXP,
  ].some(op => op === rule.operator);
}

/**
 * Supported operators.
 */
export enum Operator {
  BLOCK = 'block',
  REDIRECT = 'redirect',
  INJECT_HTML_PLUGIN = 'injectHtmlPlugin',
  INJECT_HTML_CODE = 'injectHtmlCode',
  INJECT_JS_PLUGIN = 'injectJSPlugin',
  INJECT_JS_MODULE_PLUGIN = 'injectJSModule',
  INJECT_JS_CODE = 'injectJSCode',
  REMOVE_RESPONSE_HEADER = 'rRespHeader',
  ADD_RESPONSE_HEADER = 'addRespHeader',
  ADD_REQUEST_HEADER = 'addReqHeader',
  INJECT_EXP = 'injectExp',
}

/**
 * Rule type.
 */
export interface Rule {
  disabled: boolean;
  target: string;
  operator: Operator;
  destination: string;
}

/**
 * Util to get url parameters
 */
export function getUrlParameter(param: string) {
  const qs = window.location.search.substring(1);
  const partials = qs.split('&');
  const res = [];
  for (let i = 0; i < partials.length; i++) {
    const name = partials[i].split('=');
    if (name[0] == param) {
      res.push(name[1]);
    }
  }
  return res;
}

// Note that this does not work from a content script. It does not have access
// to the `chrome.tabs` API.
export async function getActiveTab(): Promise<chrome.tabs.Tab | undefined> {
  const activeTabs = await chrome.tabs.query({
    active: true,
    currentWindow: true,
  });
  const activeTab = activeTabs[0];
  if (!activeTab?.id || !activeTab?.url) return undefined;
  return activeTab;
}