From a404c7a97f9b39b1b04ec6d94526d4fdd70779ab Mon Sep 17 00:00:00 2001
From: Dragory <2606411+Dragory@users.noreply.github.com>
Date: Fri, 7 Aug 2020 00:09:05 +0300
Subject: [PATCH] auto_reactions: check permissions ahead-of-time

---
 .../AutoReactions/events/AddReactionsEvt.ts   | 37 ++++++++++++-------
 .../src/plugins/Utility/commands/SourceCmd.ts |  2 +-
 backend/src/utils/canReadChannel.ts           |  4 +-
 ...ermissions.ts => hasChannelPermissions.ts} |  2 +-
 .../src/utils/memberHasChannelPermissions.ts  |  8 ++++
 5 files changed, 36 insertions(+), 17 deletions(-)
 rename backend/src/utils/{hasPermissions.ts => hasChannelPermissions.ts} (77%)
 create mode 100644 backend/src/utils/memberHasChannelPermissions.ts

diff --git a/backend/src/plugins/AutoReactions/events/AddReactionsEvt.ts b/backend/src/plugins/AutoReactions/events/AddReactionsEvt.ts
index 2a4edb57..ccdf5533 100644
--- a/backend/src/plugins/AutoReactions/events/AddReactionsEvt.ts
+++ b/backend/src/plugins/AutoReactions/events/AddReactionsEvt.ts
@@ -3,40 +3,51 @@ import { isDiscordRESTError } from "src/utils";
 import { LogType } from "src/data/LogType";
 import { logger } from "../../../logger";
 import { LogsPlugin } from "../../Logs/LogsPlugin";
+import { Constants, GuildChannel } from "eris";
+import { memberHasChannelPermissions } from "../../../utils/memberHasChannelPermissions";
+
+const p = Constants.Permissions;
 
 export const AddReactionsEvt = autoReactionsEvt({
   event: "messageCreate",
   allowBots: true,
   allowSelf: true,
 
-  async listener(meta) {
-    const pluginData = meta.pluginData;
-    const msg = meta.args.message;
-
-    const autoReaction = await pluginData.state.autoReactions.getForChannel(msg.channel.id);
+  async listener({ pluginData, args: { message } }) {
+    const autoReaction = await pluginData.state.autoReactions.getForChannel(message.channel.id);
     if (!autoReaction) return;
 
+    if (
+      !memberHasChannelPermissions(message.member, message.channel as GuildChannel, [
+        p.readMessages,
+        p.readMessageHistory,
+        p.addReactions,
+      ])
+    ) {
+      const logs = pluginData.getPlugin(LogsPlugin);
+      logs.log(LogType.BOT_ALERT, {
+        body: `Missing permissions to apply auto-reactions in <#${message.channel.id}>. Ensure I can read messages, read message history, and add reactions.`,
+      });
+      return;
+    }
+
     for (const reaction of autoReaction.reactions) {
       try {
-        await msg.addReaction(reaction);
+        await message.addReaction(reaction);
       } catch (e) {
         if (isDiscordRESTError(e)) {
-          logger.warn(
-            `Could not apply auto-reaction to ${msg.channel.id}/${msg.id} in guild ${pluginData.guild.name} (${pluginData.guild.id}) (error code ${e.code})`,
-          );
-
           const logs = pluginData.getPlugin(LogsPlugin);
           if (e.code === 10008) {
             logs.log(LogType.BOT_ALERT, {
-              body: `Could not apply auto-reactions in <#${msg.channel.id}> for message \`${msg.id}\`. Make sure nothing is deleting the message before the reactions are applied.`,
+              body: `Could not apply auto-reactions in <#${message.channel.id}> for message \`${message.id}\`. Make sure nothing is deleting the message before the reactions are applied.`,
             });
           } else {
             logs.log(LogType.BOT_ALERT, {
-              body: `Could not apply auto-reactions in <#${msg.channel.id}> for message \`${msg.id}\`. Error code ${e.code}.`,
+              body: `Could not apply auto-reactions in <#${message.channel.id}> for message \`${message.id}\`. Error code ${e.code}.`,
             });
           }
 
-          return;
+          break;
         } else {
           throw e;
         }
diff --git a/backend/src/plugins/Utility/commands/SourceCmd.ts b/backend/src/plugins/Utility/commands/SourceCmd.ts
index 2a4dc4c1..3ebc5b71 100644
--- a/backend/src/plugins/Utility/commands/SourceCmd.ts
+++ b/backend/src/plugins/Utility/commands/SourceCmd.ts
@@ -4,7 +4,7 @@ import { errorMessage } from "../../../utils";
 import { getBaseUrl, sendErrorMessage } from "../../../pluginUtils";
 import moment from "moment-timezone";
 import { Constants, TextChannel } from "eris";
-import { hasPermissions } from "../../../utils/hasPermissions";
+import { hasChannelPermissions } from "../../../utils/hasChannelPermissions";
 import { canReadChannel } from "../../../utils/canReadChannel";
 
 export const SourceCmd = utilityCmd({
diff --git a/backend/src/utils/canReadChannel.ts b/backend/src/utils/canReadChannel.ts
index 18feacb1..3f4de5dd 100644
--- a/backend/src/utils/canReadChannel.ts
+++ b/backend/src/utils/canReadChannel.ts
@@ -1,9 +1,9 @@
 import { Constants, GuildChannel } from "eris";
-import { hasPermissions } from "./hasPermissions";
+import { hasChannelPermissions } from "./hasChannelPermissions";
 
 export function canReadChannel(channel: GuildChannel, memberId: string) {
   const channelPermissions = channel.permissionsOf(memberId);
-  return hasPermissions(channelPermissions, [
+  return hasChannelPermissions(channelPermissions, [
     Constants.Permissions.readMessages,
     Constants.Permissions.readMessageHistory,
   ]);
diff --git a/backend/src/utils/hasPermissions.ts b/backend/src/utils/hasChannelPermissions.ts
similarity index 77%
rename from backend/src/utils/hasPermissions.ts
rename to backend/src/utils/hasChannelPermissions.ts
index 03e86d1e..1dfe4088 100644
--- a/backend/src/utils/hasPermissions.ts
+++ b/backend/src/utils/hasChannelPermissions.ts
@@ -1,6 +1,6 @@
 import { Constants, Permission } from "eris";
 
-export function hasPermissions(channelPermissions: Permission, permissions: number | number[]) {
+export function hasChannelPermissions(channelPermissions: Permission, permissions: number | number[]) {
   if (Boolean(channelPermissions.allow & Constants.Permissions.administrator)) {
     return true;
   }
diff --git a/backend/src/utils/memberHasChannelPermissions.ts b/backend/src/utils/memberHasChannelPermissions.ts
new file mode 100644
index 00000000..7e2f7d42
--- /dev/null
+++ b/backend/src/utils/memberHasChannelPermissions.ts
@@ -0,0 +1,8 @@
+import { Constants, GuildChannel, Member, Permission } from "eris";
+import { PluginData } from "knub";
+import { hasChannelPermissions } from "./hasChannelPermissions";
+
+export function memberHasChannelPermissions(member: Member, channel: GuildChannel, permissions: number | number[]) {
+  const memberChannelPermissions = channel.permissionsOf(member.id);
+  return hasChannelPermissions(memberChannelPermissions, permissions);
+}