/* eslint global-require: 0 */

import crypto from 'crypto';
import {NylasAPI, AccountStore, RegExpUtils, IdentityStore} from 'nylas-exports';

const IMAP_FIELDS = new Set([
  "imap_host",
  "imap_port",
  "imap_username",
  "imap_password",
  "smtp_host",
  "smtp_port",
  "smtp_username",
  "smtp_password",
  "ssl_required",
]);

function base64url(inBuffer) {
  let buffer;
  if (typeof inBuffer === "string") {
    buffer = new Buffer(inBuffer);
  } else if (inBuffer instanceof Buffer) {
    buffer = inBuffer;
  } else {
    throw new Error(`${inBuffer} must be a string or Buffer`)
  }
  return buffer.toString('base64')
    .replace(/\+/g, '-')  // Convert '+' to '-'
    .replace(/\//g, '_'); // Convert '/' to '_'
}

export function makeGmailOAuthRequest(sessionKey, callback) {
  NylasAPI.makeRequest({
    remote: true,
    path: `/auth/gmail/token?key=${sessionKey}`,
    method: "GET",
    error: callback,
    auth: {
      user: '',
      pass: '',
      sendImmediately: true,
    },
    success: (json) => {
      if (json && json.data) {
        callback(null, JSON.parse(json.data));
      } else {
        callback(null, null);
      }
    },
  });
}

export function buildGmailSessionKey() {
  return base64url(crypto.randomBytes(40));
}

export function buildGmailAuthURL(sessionKey) {
  const encryptionKey = base64url(crypto.randomBytes(24));
  const encryptionIv = base64url(crypto.randomBytes(16));
  return `${NylasAPI.RemoteAPIRoot}/auth/gmail?state=${sessionKey},${encryptionKey},${encryptionIv}`;
}

export function runAuthRequest(accountInfo) {
  const {username, type, email, name} = accountInfo;

  const data = {
    provider: type,
    email: email,
    name: name,
    settings: Object.assign({}, accountInfo),
  };

  // handle special case for exchange/outlook/hotmail username field
  data.settings.username = username || email;

  if (data.settings.imap_port) {
    data.settings.imap_port /= 1;
  }
  if (data.settings.smtp_port) {
    data.settings.smtp_port /= 1;
  }
  // if there's an account with this email, get the ID for it to notify the backend of re-auth
  const account = AccountStore.accountForEmail(accountInfo.email);
  const reauthParam = account ? `&reauth=${account.id}` : "";

  /**
   * Only include the required IMAP fields. Auth validation does not allow
   * extra fields
   */
  if (type === "imap") {
    for (const key of Object.keys(data.settings)) {
      if (!IMAP_FIELDS.has(key)) {
        delete data.settings[key]
      }
    }
  }

  // Send the form data directly to Nylas to get code
  // If this succeeds, send the received code to N1 server to register the account
  // Otherwise process the error message from the server and highlight UI as needed
  return NylasAPI.makeRequest({
    path: `/auth?client_id=${NylasAPI.AppID}&n1_id=${IdentityStore.identityId()}${reauthParam}`,
    method: 'POST',
    body: data,
    returnsModel: false,
    timeout: 150000,
    auth: {
      user: '',
      pass: '',
      sendImmediately: true,
    },
  })
}

export function isValidHost(value) {
  return RegExpUtils.domainRegex().test(value) || RegExpUtils.ipAddressRegex().test(value);
}

export function accountInfoWithIMAPAutocompletions(existingAccountInfo) {
  const CommonProviderSettings = require('./common-provider-settings.json');

  const email = existingAccountInfo.email;
  const domain = email.split('@').pop().toLowerCase();
  const template = CommonProviderSettings[domain] || {};

  const usernameWithFormat = (format) => {
    if (format === 'email') {
      return email
    }
    if (format === 'email-without-domain') {
      return email.split('@').shift();
    }
    return undefined;
  }

  // always pre-fill SMTP / IMAP username, password and port.
  const defaults = {
    imap_host: template.imap_host,
    imap_port: template.imap_port || 993,
    imap_username: usernameWithFormat(template.imap_user_format),
    imap_password: existingAccountInfo.password,
    smtp_host: template.smtp_host,
    smtp_port: template.smtp_port || 587,
    smtp_username: usernameWithFormat(template.smtp_user_format),
    smtp_password: existingAccountInfo.password,
    ssl_required: (template.ssl === '1'),
  }

  return Object.assign({}, existingAccountInfo, defaults);
}