/*
 * Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with
 * the License. A copy of the License is located at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
 * CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions
 * and limitations under the License.
 */

const createPropertyFormatter = require('./createPropertyFormatter')
const sortByReference = require('./sortByReference')

const defaultFormatting = {
  lineSeparator: '\n',
}

/**
 *
 * This is used to create lists of variables like Sass variables or CSS custom properties
 * @memberof module:formatHelpers
 * @param {Object} options
 * @param {String} options.format - What type of variables to output. Options are: css, sass, less, and stylus
 * @param {Object} options.dictionary - The dictionary object that gets passed to the formatter method.
 * @param {Boolean} options.outputReferences - Whether or not to output references
 * @param {Object} options.formatting - Custom formatting properties that define parts of a declaration line in code. This will get passed to `formatHelpers.createPropertyFormatter` and used for the `lineSeparator` between lines of code.
 * @returns {String}
 * @example
 * ```js
 * StyleDictionary.registerFormat({
 *   name: 'myCustomFormat',
 *   formatter: function({ dictionary, options }) {
 *     return formattedVariables('less', dictionary, options.outputReferences);
 *   }
 * });
 * ```
 */
function formattedVariables({ format, dictionary, outputReferences = false, formatting = {} }) {
  let { allTokens } = dictionary

  const { lineSeparator } = Object.assign({}, defaultFormatting, formatting)

  // Some languages are imperative, meaning a variable has to be defined
  // before it is used. If `outputReferences` is true, check if the token
  // has a reference, and if it does send it to the end of the array.
  // We also need to account for nested references, a -> b -> c. They
  // need to be defined in reverse order: c, b, a so that the reference always
  // comes after the definition
  if (outputReferences) {
    // note: using the spread operator here so we get a new array rather than
    // mutating the original
    allTokens = [...allTokens].sort(sortByReference(dictionary))
  }

  return allTokens
    .map(createPropertyFormatter({ outputReferences, dictionary, format, formatting }))
    .filter(function (strVal) {
      return !!strVal
    })
    .join(lineSeparator)
}

module.exports = formattedVariables