/* 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";

this.EXPORTED_SYMBOLS = ["LoginRecipesContent", "LoginRecipesParent"];

const { classes: Cc, interfaces: Ci, results: Cr, utils: Cu } = Components;
const REQUIRED_KEYS = ["hosts"];
const OPTIONAL_KEYS = ["description", "notUsernameSelector", "passwordSelector", "pathRegex", "usernameSelector"];
const SUPPORTED_KEYS = REQUIRED_KEYS.concat(OPTIONAL_KEYS);

Cu.importGlobalProperties(["URL"]);

Cu.import("resource://gre/modules/NetUtil.jsm");
Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/XPCOMUtils.jsm");

XPCOMUtils.defineLazyModuleGetter(this, "LoginHelper",
                                  "resource://gre/modules/LoginHelper.jsm");

XPCOMUtils.defineLazyGetter(this, "log", () => LoginHelper.createLogger("LoginRecipes"));

/**
 * Create an instance of the object to manage recipes in the parent process.
 * Consumers should wait until {@link initializationPromise} resolves before
 * calling methods on the object.
 *
 * @constructor
 * @param {String} [aOptions.defaults=null] the URI to load the recipes from.
 *                                          If it's null, nothing is loaded.
 *
*/
function LoginRecipesParent(aOptions = { defaults: null }) {
  if (Services.appinfo.processType != Ci.nsIXULRuntime.PROCESS_TYPE_DEFAULT) {
    throw new Error("LoginRecipesParent should only be used from the main process");
  }
  this._defaults = aOptions.defaults;
  this.reset();
}

LoginRecipesParent.prototype = {
  /**
   * Promise resolved with an instance of itself when the module is ready.
   *
   * @type {Promise}
   */
  initializationPromise: null,

  /**
   * @type {bool} Whether default recipes were loaded at construction time.
   */
  _defaults: null,

  /**
   * @type {Map} Map of hosts (including non-default port numbers) to Sets of recipes.
   *             e.g. "example.com:8080" => Set({...})
   */
  _recipesByHost: null,

  /**
   * @param {Object} aRecipes an object containing recipes to load for use. The object
   *                          should be compatible with JSON (e.g. no RegExp).
   * @return {Promise} resolving when the recipes are loaded
   */
  load(aRecipes) {
    let recipeErrors = 0;
    for (let rawRecipe of aRecipes.siteRecipes) {
      try {
        rawRecipe.pathRegex = rawRecipe.pathRegex ? new RegExp(rawRecipe.pathRegex) : undefined;
        this.add(rawRecipe);
      } catch (ex) {
        recipeErrors++;
        log.error("Error loading recipe", rawRecipe, ex);
      }
    }

    if (recipeErrors) {
      return Promise.reject(`There were ${recipeErrors} recipe error(s)`);
    }

    return Promise.resolve();
  },

  /**
   * Reset the set of recipes to the ones from the time of construction.
   */
  reset() {
    log.debug("Resetting recipes with defaults:", this._defaults);
    this._recipesByHost = new Map();

    if (this._defaults) {
      let channel = NetUtil.newChannel({uri: NetUtil.newURI(this._defaults, "UTF-8"),
                                        loadUsingSystemPrincipal: true});
      channel.contentType = "application/json";

      try {
        this.initializationPromise = new Promise(function(resolve) {
          NetUtil.asyncFetch(channel, function (stream, result) {
            if (!Components.isSuccessCode(result)) {
              throw new Error("Error fetching recipe file:" + result);
            }
            let count = stream.available();
            let data = NetUtil.readInputStreamToString(stream, count, { charset: "UTF-8" });
            resolve(JSON.parse(data));
          });
        }).then(recipes => {
          return this.load(recipes);
        }).then(resolve => {
          return this;
        });
      } catch (e) {
        throw new Error("Error reading recipe file:" + e);
      }
    } else {
      this.initializationPromise = Promise.resolve(this);
    }
  },

  /**
   * Validate the recipe is sane and then add it to the set of recipes.
   *
   * @param {Object} recipe
   */
  add(recipe) {
    log.debug("Adding recipe:", recipe);
    let recipeKeys = Object.keys(recipe);
    let unknownKeys = recipeKeys.filter(key => SUPPORTED_KEYS.indexOf(key) == -1);
    if (unknownKeys.length > 0) {
      throw new Error("The following recipe keys aren't supported: " + unknownKeys.join(", "));
    }

    let missingRequiredKeys = REQUIRED_KEYS.filter(key => recipeKeys.indexOf(key) == -1);
    if (missingRequiredKeys.length > 0) {
      throw new Error("The following required recipe keys are missing: " + missingRequiredKeys.join(", "));
    }

    if (!Array.isArray(recipe.hosts)) {
      throw new Error("'hosts' must be a array");
    }

    if (!recipe.hosts.length) {
      throw new Error("'hosts' must be a non-empty array");
    }

    if (recipe.pathRegex && recipe.pathRegex.constructor.name != "RegExp") {
      throw new Error("'pathRegex' must be a regular expression");
    }

    const OPTIONAL_STRING_PROPS = ["description", "passwordSelector", "usernameSelector"];
    for (let prop of OPTIONAL_STRING_PROPS) {
      if (recipe[prop] && typeof(recipe[prop]) != "string") {
        throw new Error(`'${prop}' must be a string`);
      }
    }

    // Add the recipe to the map for each host
    for (let host of recipe.hosts) {
      if (!this._recipesByHost.has(host)) {
        this._recipesByHost.set(host, new Set());
      }
      this._recipesByHost.get(host).add(recipe);
    }
  },

  /**
   * Currently only exact host matches are returned but this will eventually handle parent domains.
   *
   * @param {String} aHost (e.g. example.com:8080 [non-default port] or sub.example.com)
   * @return {Set} of recipes that apply to the host ordered by host priority
   */
  getRecipesForHost(aHost) {
    let hostRecipes = this._recipesByHost.get(aHost);
    if (!hostRecipes) {
      return new Set();
    }

    return hostRecipes;
  },
};


var LoginRecipesContent = {
  /**
   * @param {Set} aRecipes - Possible recipes that could apply to the form
   * @param {FormLike} aForm - We use a form instead of just a URL so we can later apply
   * tests to the page contents.
   * @return {Set} a subset of recipes that apply to the form with the order preserved
   */
  _filterRecipesForForm(aRecipes, aForm) {
    let formDocURL = aForm.ownerDocument.location;
    let hostRecipes = aRecipes;
    let recipes = new Set();
    log.debug("_filterRecipesForForm", aRecipes);
    if (!hostRecipes) {
      return recipes;
    }

    for (let hostRecipe of hostRecipes) {
      if (hostRecipe.pathRegex && !hostRecipe.pathRegex.test(formDocURL.pathname)) {
        continue;
      }
      recipes.add(hostRecipe);
    }

    return recipes;
  },

  /**
   * Given a set of recipes that apply to the host, choose the one most applicable for
   * overriding login fields in the form.
   *
   * @param {Set} aRecipes The set of recipes to consider for the form
   * @param {FormLike} aForm The form where login fields exist.
   * @return {Object} The recipe that is most applicable for the form.
   */
  getFieldOverrides(aRecipes, aForm) {
    let recipes = this._filterRecipesForForm(aRecipes, aForm);
    log.debug("getFieldOverrides: filtered recipes:", recipes);
    if (!recipes.size) {
      return null;
    }

    let chosenRecipe = null;
    // Find the first (most-specific recipe that involves field overrides).
    for (let recipe of recipes) {
      if (!recipe.usernameSelector && !recipe.passwordSelector &&
          !recipe.notUsernameSelector) {
        continue;
      }

      chosenRecipe = recipe;
      break;
    }

    return chosenRecipe;
  },

  /**
   * @param {HTMLElement} aParent the element to query for the selector from.
   * @param {CSSSelector} aSelector the CSS selector to query for the login field.
   * @return {HTMLElement|null}
   */
  queryLoginField(aParent, aSelector) {
    if (!aSelector) {
      return null;
    }
    let field = aParent.ownerDocument.querySelector(aSelector);
    if (!field) {
      log.debug("Login field selector wasn't matched:", aSelector);
      return null;
    }
    if (!(field instanceof aParent.ownerDocument.defaultView.HTMLInputElement)) {
      log.warn("Login field isn't an <input> so ignoring it:", aSelector);
      return null;
    }
    return field;
  },
};
