1 files changed, 82 insertions, 0 deletions
diff --git a/comm/chat/protocols/matrix/matrixPowerLevels.sys.mjs b/comm/chat/protocols/matrix/matrixPowerLevels.sys.mjs
new file mode 100644
index 0000000000..4ee1027428
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+++ b/comm/chat/protocols/matrix/matrixPowerLevels.sys.mjs
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+/* 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/. */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+import { l10nHelper } from "resource:///modules/imXPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+XPCOMUtils.defineLazyGetter(lazy, "_", () =>
+  l10nHelper("chrome://chat/locale/matrix.properties")
+);
+
+// See https://matrix.org/docs/spec/client_server/r0.5.0#m-room-power-levels
+export var MatrixPowerLevels = {
+  user: 0,
+  voice: 10,
+  moderator: 50,
+  admin: 100,
+  /**
+   * Turns a power level into a human readable string.
+   * Only exactly matching level names are returned, except for restricted
+   * power levels.
+   *
+   * @param {number} powerLevel - Power level to format.
+   * @param {number} [defaultLevel=0] - The default power level in the room.
+   * @returns {string} Representation of the power level including the raw level.
+   */
+  toText(powerLevel, defaultLevel = MatrixPowerLevels.user) {
+    let levelName = lazy._("powerLevel.custom");
+    if (powerLevel == MatrixPowerLevels.admin) {
+      levelName = lazy._("powerLevel.admin");
+    } else if (powerLevel == MatrixPowerLevels.moderator) {
+      levelName = lazy._("powerLevel.moderator");
+    } else if (powerLevel < defaultLevel) {
+      levelName = lazy._("powerLevel.restricted");
+    } else if (powerLevel == defaultLevel) {
+      levelName = lazy._("powerLevel.default");
+    }
+    return lazy._("powerLevel.detailed", levelName, powerLevel);
+  },
+  /**
+   * @param {object} powerLevels - m.room.power_levels event contents.
+   * @param {string} key - Power level key to get.
+   * @returns {number} The power level if given in the event, else 0.
+   */
+  _getDefaultLevel(powerLevels, key) {
+    const fullKey = `${key}_default`;
+    if (Number.isSafeInteger(powerLevels?.[fullKey])) {
+      return powerLevels[fullKey];
+    }
+    return 0;
+  },
+  /**
+   * @param {object} powerLevels - m.room.power_levels event contents.
+   * @returns {number} The default power level of users in the room.
+   */
+  getUserDefaultLevel(powerLevels) {
+    return this._getDefaultLevel(powerLevels, "users");
+  },
+  /**
+   *
+   * @param {object} powerLevels - m.room.power_levels event contents.
+   * @returns {number} The default power level required to send events in the
+   *  room.
+   */
+  getEventDefaultLevel(powerLevels) {
+    return this._getDefaultLevel(powerLevels, "events");
+  },
+  /**
+   *
+   * @param {object} powerLevels - m.room.power_levels event contents.
+   * @param {string} event - Event ID to get the required power level for.
+   * @returns {number} The power level required to send this event in the room.
+   */
+  getEventLevel(powerLevels, event) {
+    if (Number.isSafeInteger(powerLevels?.events?.[event])) {
+      return powerLevels.events[event];
+    }
+    return this.getEventDefaultLevel(powerLevels);
+  },
+};