Refactor get_all_role_reaction_message (quicker)

src/reaction_roles.rs

-use crate::config::{CONFIG, ReactRoleMap};
+use crate::config::{ReactRoleMap, CONFIG};
 use crate::util::{get_react_from_string, get_string_from_react};
 use serenity::{
     client::Context,
@@ -174,28 +174,28 @@ pub fn sync_all_role_reactions(ctx: Context) {
     info!("Role reaction sync complete");
 }
 
-fn get_all_role_reaction_message(
-    ctx: &Context,
-) -> Vec<(
-    Message,
-    &'static ReactRoleMap,
-)> {
+fn get_all_role_reaction_message(ctx: &Context) -> Vec<(Message, &'static ReactRoleMap)> {
     let guild = ctx.http.get_guild(CONFIG.server_id).unwrap();
     info!("  Find role-react message: guild determined");
     let channels = ctx.http.get_channels(*guild.id.as_u64()).unwrap();
     info!("  Find role-react message: channels determined");
-    channels
-        .iter()
-        .flat_map(|channel| {
-            let ctxx = ctx.clone();
-            // since we don't know which channels the messages are in, we check every combination of message and
-            // channel and ignore the bad matches using .ok() and .filter_map()
-            CONFIG.react_role_messages.iter().filter_map(move |rrm| {
-                ctxx.http
-                    .get_message(*channel.id.as_u64(), *rrm.message.as_u64())
-                    .ok()
-                    .map(|m| (m, &rrm.mapping))
-            })
-        })
-        .collect()
+
+    let mut channel_search_indices: Vec<_> = (0..channels.len()).collect();
+    let mut results: Vec<(Message, &'static ReactRoleMap)> = Vec::new();
+    for react_role in CONFIG.react_role_messages.iter() {
+        for channel_index in &channel_search_indices {
+            if let Ok(msg) = ctx.http.get_message(
+                *channels[*channel_index].id.as_u64(),
+                *react_role.message.as_u64(),
+            ) {
+                results.push((msg, &react_role.mapping));
+                // move channel with message to front of index vector
+                let channel_index_clone = channel_index.to_owned();
+                channel_search_indices.retain(|&i| i != channel_index_clone);
+                channel_search_indices.insert(0, channel_index_clone);
+                break;
+            }
+        }
+    }
+    results
 }