More work on permission utils and eager permission checks

backend/src/utils/canAssignRole.ts

@@ -0,0 +1,28 @@
+import { Constants, Guild, Member, Role } from "eris";
+import { getMissingPermissions } from "./getMissingPermissions";
+import { hasDiscordPermissions } from "./hasDiscordPermissions";
+
+export function canAssignRole(guild: Guild, member: Member, roleId: string) {
+  if (getMissingPermissions(member.permission, Constants.Permissions.manageRoles)) {
+    return false;
+  }
+
+  if (roleId === guild.id) {
+    return false;
+  }
+
+  const targetRole = guild.roles.get(roleId);
+  if (!targetRole) {
+    return false;
+  }
+
+  const memberRoles = member.roles.map(_roleId => guild.roles.get(_roleId));
+  const highestRoleWithManageRoles: Role = memberRoles.reduce((highest, role) => {
+    if (!hasDiscordPermissions(role.permissions, Constants.Permissions.manageRoles)) return highest;
+    if (highest == null) return role;
+    if (role.position > highest.position) return role;
+    return highest;
+  }, null);
+
+  return highestRoleWithManageRoles.position > targetRole.position;
+}

backend/src/utils/canReadChannel.ts

@@ -1,7 +1,8 @@
 import { Constants, GuildChannel, Member } from "eris";
-import { memberHasChannelPermissions } from "./memberHasChannelPermissions";
 import { readChannelPermissions } from "./readChannelPermissions";
+import { getMissingChannelPermissions } from "./getMissingChannelPermissions";
 
 export function canReadChannel(channel: GuildChannel, member: Member) {
-  return memberHasChannelPermissions(member, channel, readChannelPermissions);
+  // Not missing permissions required to read the channel = can read channel
+  return !getMissingChannelPermissions(member, channel, readChannelPermissions);
 }

backend/src/utils/getMissingChannelPermissions.ts

@@ -1,15 +1,15 @@
 import { Constants, GuildChannel, Member, Permission } from "eris";
-import { PluginData } from "knub";
-import { hasDiscordPermissions } from "./hasDiscordPermissions";
+import { getMissingPermissions } from "./getMissingPermissions";
 
 /**
  * @param requiredPermissions Bitmask of required permissions
+ * @return Bitmask of missing permissions
  */
-export function memberHasChannelPermissions(
+export function getMissingChannelPermissions(
   member: Member,
   channel: GuildChannel,
   requiredPermissions: number | bigint,
-) {
+): bigint {
   const memberChannelPermissions = channel.permissionsOf(member.id);
-  return hasDiscordPermissions(memberChannelPermissions, requiredPermissions);
+  return getMissingPermissions(memberChannelPermissions, requiredPermissions);
 }

backend/src/utils/getMissingPermissions.ts

@@ -0,0 +1,17 @@
+import { Constants, Permission } from "eris";
+
+/**
+ * @param resolvedPermissions A Permission object from e.g. GuildChannel#permissionsOf() or Member#permission
+ * @param requiredPermissions Bitmask of required permissions
+ * @return Bitmask of missing permissions
+ */
+export function getMissingPermissions(resolvedPermissions: Permission, requiredPermissions: number | bigint): bigint {
+  const allowedPermissions = BigInt(resolvedPermissions.allow);
+  const nRequiredPermissions = BigInt(requiredPermissions);
+
+  if (Boolean(allowedPermissions & BigInt(Constants.Permissions.administrator))) {
+    return BigInt(0);
+  }
+
+  return nRequiredPermissions & ~allowedPermissions;
+}

backend/src/utils/getPermissionNames.ts

@@ -0,0 +1,29 @@
+import { Constants } from "eris";
+
+const camelCaseToTitleCase = str =>
+  str
+    .replace(/([a-z])([A-Z])/g, "$1 $2")
+    .split(" ")
+    .map(w => w[0].toUpperCase() + w.slice(1))
+    .join(" ");
+
+const permissionNumberToName: Map<bigint, string> = new Map();
+const ignoredPermissionConstants = ["all", "allGuild", "allText", "allVoice"];
+
+for (const key in Constants.Permissions) {
+  if (ignoredPermissionConstants.includes(key)) continue;
+  permissionNumberToName.set(BigInt(Constants.Permissions[key]), camelCaseToTitleCase(key));
+}
+
+/**
+ * @param permissions Bitmask of permissions to get the names for
+ */
+export function getPermissionNames(permissions: number | bigint): string[] {
+  const permissionNames = [];
+  for (const [permissionNumber, permissionName] of permissionNumberToName.entries()) {
+    if (BigInt(permissions) & permissionNumber) {
+      permissionNames.push(permissionName);
+    }
+  }
+  return permissionNames;
+}

backend/src/utils/missingPermissionError.ts

@@ -0,0 +1,6 @@
+import { getPermissionNames } from "./getPermissionNames";
+
+export function missingPermissionError(missingPermissions: number | bigint): string {
+  const permissionNames = getPermissionNames(missingPermissions);
+  return `Missing permissions: **${permissionNames.join("**, **")}**`;
+}

backend/src/utils/readChannelPermissions.ts

@@ -3,5 +3,9 @@ import { Constants } from "eris";
 /**
  * Bitmask of permissions required to read messages in a channel
  */
-export const readChannelPermissions =
-  BigInt(Constants.Permissions.readMessages) | BigInt(Constants.Permissions.readMessageHistory);
+export const readChannelPermissions = Constants.Permissions.readMessages | Constants.Permissions.readMessageHistory;
+
+/**
+ * Bitmask of permissions required to read messages in a channel (bigint)
+ */
+export const nReadChannelPermissions = BigInt(readChannelPermissions);

backend/src/utils/verifyPermissions.ts

@@ -1,54 +0,0 @@
-import { Constants, Permission } from "eris";
-import { PluginData } from "knub";
-import { hasDiscordPermissions } from "./hasDiscordPermissions";
-import { LogsPlugin } from "../plugins/Logs/LogsPlugin";
-import { LogType } from "../data/LogType";
-
-const defaultErrorText = `Missing permissions.`;
-
-const camelCaseToTitleCase = str =>
-  str
-    .replace(/([a-z])([A-Z])/g, "$1 $2")
-    .split(" ")
-    .map(w => w[0].toUpperCase() + w.slice(1))
-    .join(" ");
-
-const permissionNumberToName: Map<bigint, string> = new Map();
-for (const key in Constants.Permissions) {
-  permissionNumberToName.set(BigInt(Constants.Permissions[key]), camelCaseToTitleCase(key));
-}
-
-/**
- *
- * @param resolvedPermissions A Permission object from e.g. GuildChannel#permissionsOf() or Member#permission
- * @param requiredPermissions Bitmask of required permissions
- * @param errorText Custom error text
- */
-export function verifyPermissions(
-  pluginData: PluginData<any>,
-  resolvedPermissions: Permission,
-  requiredPermissions: number | bigint,
-  errorText?: string,
-) {
-  const nRequiredPermissions = BigInt(requiredPermissions);
-
-  if (!hasDiscordPermissions(resolvedPermissions, nRequiredPermissions)) {
-    const requiredPermissionNames = [];
-    for (const [permissionNumber, permissionName] of permissionNumberToName.entries()) {
-      if (nRequiredPermissions & permissionNumber) {
-        requiredPermissionNames.push(permissionName);
-      }
-    }
-
-    const logs = pluginData.getPlugin(LogsPlugin);
-    logs.log(LogType.BOT_ALERT, {
-      body: `${errorText ||
-        defaultErrorText} Please ensure I have the following permissions: **${requiredPermissionNames.join(
-        "**, **",
-      )}**`.trim(),
-    });
-    return false;
-  }
-
-  return true;
-}