/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";

const MAIN_MESSAGE_TYPE = "ActivityStream:Main";
const CONTENT_MESSAGE_TYPE = "ActivityStream:Content";

const actionTypes = [
  "INIT",
  "UNINIT",
  "NEW_TAB_INITIAL_STATE",
  "NEW_TAB_LOAD",
  "NEW_TAB_UNLOAD",
  "PERFORM_SEARCH",
  "SCREENSHOT_UPDATED",
  "SEARCH_STATE_UPDATED",
  "TOP_SITES_UPDATED"
// The line below creates an object like this:
// {
//   INIT: "INIT",
//   UNINIT: "UNINIT"
// }
// It prevents accidentally adding a different key/value name.
].reduce((obj, type) => { obj[type] = type; return obj; }, {});

// Helper function for creating routed actions between content and main
// Not intended to be used by consumers
function _RouteMessage(action, options) {
  const meta = action.meta ? Object.assign({}, action.meta) : {};
  if (!options || !options.from || !options.to) {
    throw new Error("Routed Messages must have options as the second parameter, and must at least include a .from and .to property.");
  }
  // For each of these fields, if they are passed as an option,
  // add them to the action. If they are not defined, remove them.
  ["from", "to", "toTarget", "fromTarget", "skipOrigin"].forEach(o => {
    if (typeof options[o] !== "undefined") {
      meta[o] = options[o];
    } else if (meta[o]) {
      delete meta[o];
    }
  });
  return Object.assign({}, action, {meta});
}

/**
 * SendToMain - Creates a message that will be sent to the Main process.
 *
 * @param  {object} action Any redux action (required)
 * @param  {object} options
 * @param  {string} options.fromTarget The id of the content port from which the action originated. (optional)
 * @return {object} An action with added .meta properties
 */
function SendToMain(action, options = {}) {
  return _RouteMessage(action, {
    from: CONTENT_MESSAGE_TYPE,
    to: MAIN_MESSAGE_TYPE,
    fromTarget: options.fromTarget
  });
}

/**
 * BroadcastToContent - Creates a message that will be sent to ALL content processes.
 *
 * @param  {object} action Any redux action (required)
 * @return {object} An action with added .meta properties
 */
function BroadcastToContent(action) {
  return _RouteMessage(action, {
    from: MAIN_MESSAGE_TYPE,
    to: CONTENT_MESSAGE_TYPE
  });
}

/**
 * SendToContent - Creates a message that will be sent to a particular Content process.
 *
 * @param  {object} action Any redux action (required)
 * @param  {string} target The id of a content port
 * @return {object} An action with added .meta properties
 */
function SendToContent(action, target) {
  if (!target) {
    throw new Error("You must provide a target ID as the second parameter of SendToContent. If you want to send to all content processes, use BroadcastToContent");
  }
  return _RouteMessage(action, {
    from: MAIN_MESSAGE_TYPE,
    to: CONTENT_MESSAGE_TYPE,
    toTarget: target
  });
}

this.actionTypes = actionTypes;

this.actionCreators = {
  SendToMain,
  SendToContent,
  BroadcastToContent
};

// These are helpers to test for certain kinds of actions
this.actionUtils = {
  isSendToMain(action) {
    if (!action.meta) {
      return false;
    }
    return action.meta.to === MAIN_MESSAGE_TYPE && action.meta.from === CONTENT_MESSAGE_TYPE;
  },
  isBroadcastToContent(action) {
    if (!action.meta) {
      return false;
    }
    if (action.meta.to === CONTENT_MESSAGE_TYPE && !action.meta.toTarget) {
      return true;
    }
    return false;
  },
  isSendToContent(action) {
    if (!action.meta) {
      return false;
    }
    if (action.meta.to === CONTENT_MESSAGE_TYPE && action.meta.toTarget) {
      return true;
    }
    return false;
  },
  _RouteMessage
};

this.EXPORTED_SYMBOLS = [
  "actionTypes",
  "actionCreators",
  "actionUtils",
  "MAIN_MESSAGE_TYPE",
  "CONTENT_MESSAGE_TYPE"
];