/* @flow */
"use strict";

const _ = require("lodash");
const requireRule = require("./requireRule");

// Rule settings can take a number of forms, e.g.
// a. "rule-name": null
// b. "rule-name": [null, ...]
// c. "rule-name": primaryOption
// d. "rule-name": [primaryOption]
// e. "rule-name": [primaryOption, secondaryOption]
// Where primaryOption can be anything: primitive, Object, or Array.
//
// This function normalizes all the possibilities into the
// standard form: [primaryOption, secondaryOption]
// Except in the cases with null, a & b, in which case
// null is returned
module.exports = function(
  rawSettings /*: ?stylelint$configRuleSettings*/,
  ruleName /*: string*/,
  // If primaryOptionArray is not provided, we try to get it from the
  // rules themselves, which will not work for plugins
  primaryOptionArray /*:: ?: boolean*/
) /*: [any, Object] | Array<any | [any, Object]> | null*/ {
  if (rawSettings === null) {
    return null;
  }

  if (!Array.isArray(rawSettings)) {
    return [rawSettings];
  }
  // Everything below is an array ...

  if (rawSettings[0] === null) {
    return null;
  }

  if (primaryOptionArray === undefined) {
    const rule /*: Function*/ = requireRule(ruleName);

    primaryOptionArray = _.get(rule, "primaryOptionArray");
  }

  if (!primaryOptionArray) {
    return rawSettings;
  }
  // Everything below is a rule that CAN have an array for a primary option ...
  // (they might also have something else, e.g. rule-properties-order can
  // have the string "alphabetical")

  if (rawSettings.length === 1 && Array.isArray(rawSettings[0])) {
    return rawSettings;
  }

  if (
    rawSettings.length === 2 &&
    !_.isPlainObject(rawSettings[0]) &&
    _.isPlainObject(rawSettings[1])
  ) {
    return rawSettings;
  }

  return [rawSettings];
};