From e28f11d9bb3ccd05fa7b28ca23c76ff0861046ae Mon Sep 17 00:00:00 2001
From: Rafael Bradley <rafabradleyrb@gmail.com>
Date: Thu, 21 Aug 2025 19:19:02 -0300
Subject: [PATCH] Make permissions checking not depend on the cache

---
 Cargo.toml                        |  2 +-
 src/groups/servers/permissions.rs | 66 ++++++++++++++++++++++---------
 src/main.rs                       |  1 -
 3 files changed, 48 insertions(+), 21 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 7313c8b..4222937 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -33,7 +33,7 @@ twilight-cache-inmemory = { version = "0.16.0", features = ["permission-calculat
 twilight-gateway = "0.16.0"
 twilight-http = { version = "0.16.0", features = ["simd-json"] }
 twilight-model = "0.16.0"
-twilight-util = { version = "0.16.0", features = ["builder"] }
+twilight-util = { version = "0.16.0", features = ["builder", "permission-calculator"] }
 twilight-validate = "0.16.0"
 unicode-segmentation = "1.12.0"
 unidecode = "0.3.0"
diff --git a/src/groups/servers/permissions.rs b/src/groups/servers/permissions.rs
index 535fc17..0499045 100644
--- a/src/groups/servers/permissions.rs
+++ b/src/groups/servers/permissions.rs
@@ -1,5 +1,9 @@
 use async_trait::async_trait;
-use twilight_model::guild::Permissions;
+use twilight_model::{
+    guild::Permissions,
+    id::{Id, marker::RoleMarker},
+};
+use twilight_util::permission_calculator::PermissionCalculator;
 
 use crate::{
     framework::commands::{CommandError, context::CommandContext, permissions::Permission},
@@ -31,28 +35,52 @@ pub struct ServerModeratorPermission;
 impl Permission<State> for ServerModeratorPermission {
     async fn check(&self, ctx: &CommandContext<State>) -> Result<bool, CommandError> {
         if let Some(guild_id) = ctx.event.guild_id {
-            let permissions = ctx
+            let Some(guild) = ctx.rt.cache.guild(guild_id) else {
+                log::warn!("Could not get guild for ID {guild_id}!");
+
+                return Ok(false);
+            };
+
+            let member = ctx
                 .rt
-                .cache
-                .permissions()
-                .root(ctx.event.author.id, guild_id);
+                .http
+                .guild_member(guild_id, ctx.event.author.id)
+                .await
+                .map_err(CommandError::DiscordAPIFailed)?
+                .model()
+                .await
+                .map_err(CommandError::DiscordDeserializationFailed)?;
 
-            if let Ok(permissions) = permissions {
-                let guild = ctx
-                    .rt
-                    .cache
-                    .guild(guild_id)
-                    .ok_or(CommandError::CacheStateInconsistent)?;
+            let Some(everyone_role) = ctx.rt.cache.role(guild_id.cast()) else {
+                log::warn!("Could not get @everyone role for guild ID {guild_id}!");
 
-                Ok(permissions
-                    .contains(Permissions::MANAGE_CHANNELS | Permissions::MANAGE_MESSAGES)
-                    || guild.owner_id() == ctx.event.author.id)
-            } else {
-                Err(CommandError::CacheStateInconsistent)
-            }
-        } else {
-            Ok(true)
+                return Ok(false);
+            };
+
+            let member_roles: Vec<(Id<RoleMarker>, Permissions)> = member
+                .roles
+                .into_iter()
+                .filter_map(|role_id| {
+                    ctx.rt
+                        .cache
+                        .role(role_id)
+                        .map(|role| (role.id, role.permissions))
+                })
+                .collect();
+
+            let calculator = PermissionCalculator::new(
+                guild_id,
+                ctx.event.author.id,
+                everyone_role.permissions,
+                &member_roles,
+            )
+            .owner_id(guild.owner_id());
+
+            return Ok(calculator.root().contains(Permissions::MANAGE_CHANNELS | Permissions::MANAGE_MESSAGES));
         }
+
+        // DMs channel, the user has all permissions.
+        Ok(true)
     }
 
     async fn on_handle_denied(&self, ctx: &CommandContext<State>) -> Result<(), CommandError> {
diff --git a/src/main.rs b/src/main.rs
index 6c62343..baafd51 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -244,7 +244,6 @@ async fn start(
         .shard(shard)
         .intent(Intents::GUILDS)
         .intent(Intents::GUILD_MESSAGES)
-        .intent(Intents::GUILD_MEMBERS)
         .intent(Intents::MESSAGE_CONTENT)
         .command(HelpCommand)
         .command(CallCommand::new())