'use strict';

// begin:nanographql - Tiny graphQL client library
// License: MIT

const getOpname = /(query|mutation) ?([\w\d-_]+)? ?\(.*?\)? \{/;
const gql = str => {
  str = Array.isArray(str) ? str.join('') : str;
  const name = getOpname.exec(str);
  return function (variables) {
    const data = {query: str};
    if (variables) data.variables = JSON.stringify(variables);
    if (name && name.length) {
      const operationName = name[2];
      if (operationName) data.operationName = name[2];
    }
    return JSON.stringify(data);
  };
};

// end:nanographql

const api = 'https://api.openusercss.org';
const doQuery = ({id}, queryString) => new Promise((resolve, reject) => {
  const query = gql(queryString);

  fetch(api, {
    'method': 'POST',
    'headers': new Headers({
      'Content-Type': 'application/json'
    }),
    'body': query({
      id
    })
  })
  .then(res => {
    res.json()
    .then(response => {
      if (response.errors) {
        reject(new Error(JSON.stringify(response.errors)));
      }
      resolve(response);
    });
  })
  .catch(reject);
});

window.API_METHODS = Object.assign(window.API_METHODS || {}, {
  /**
   *   This function can be used to retrieve a theme object from the
   *   GraphQL API, set above
   *
   *   Example:
   *   chrome.runtime.sendMessage({
   *     'method': 'oucThemeById',
   *     'id':     '5a2f819f7c57c751001b49df'
   *   }, console.log);
   *
   *   @param {ID} $0.id MongoDB style ID
   *   @returns {Promise.<{data: object}>} The GraphQL result with the `theme` object
   */

  'oucThemeById': params => doQuery(params, `
    query($id: ID!) {
      theme(id: $id) {
        _id
        title
        description
        createdAt
        lastUpdate
        version
        screenshots
        user {
          _id
          displayname
        }
      }
    }
  `),

  /**
   *   This function can be used to retrieve a user object from the
   *   GraphQL API, set above
   *
   *   Example:
   *   chrome.runtime.sendMessage({
   *     'method': 'oucUserById',
   *     'id':     '5a2f0361ba666f0b00b9c827'
   *   }, console.log);
   *
   *   @param {ID} $0.id MongoDB style ID
   *   @returns {Promise.<{data: object}>} The GraphQL result with the `user` object
   */

  'oucUserById': params => doQuery(params, `
    query($id: ID!) {
      user(id: $id) {
        _id
        displayname
        avatarUrl
        smallAvatarUrl
        bio
      }
    }
  `),
});