From 2f0af295cd75d64943edb4f1af0ebcd950297893 Mon Sep 17 00:00:00 2001
From: Nathan Perry <avaglir@gmail.com>
Date: Mon, 18 Feb 2019 21:30:14 -0500
Subject: improve randomizer

---
 src/commands/meme.rs | 28 +++++-----------------------
 src/db/mod.rs        | 44 ++++++++++++++++++++++++++------------------
 2 files changed, 31 insertions(+), 41 deletions(-)

diff --git a/src/commands/meme.rs b/src/commands/meme.rs
index 9cba630..0f9cda8 100644
--- a/src/commands/meme.rs
+++ b/src/commands/meme.rs
@@ -30,7 +30,10 @@ use crate::{
         PlayQueue,
     },
     commands::send,
-    db::*,
+    db::{
+        *,
+        rand_meme as db_rand_meme,
+    },
     Result,
 };
 
@@ -238,29 +241,8 @@ fn rand_meme(ctx: &Context, message: &Message) -> Result<()> {
     let conn = connection()?;
 
     let should_audio = ctx.currently_playing() && ctx.users_listening()?;
-    let modulus = if should_audio { 3 } else { 2 };
 
-    let mem = match thread_rng().gen::<u32>() % modulus {
-        0 => rand_text(&conn),
-        1 => rand_image(&conn),
-        2 => rand_audio(&conn),
-        _ => unreachable!(),
-    }
-        .or_else(|_| rand_text(&conn))
-        .and_then(|mut mem| {
-            let mut ctr = 0;
-            while !should_audio && mem.audio_id.is_some() {
-                mem = rand_text(&conn)?;
-
-                ctr += 1;
-                if ctr > 10 {
-                    send(message.channel_id, "yer listenin to somethin else", message.tts)?;
-                    bail!("looped too many times trying to find a non-audio meme");
-                }
-            }
-
-            Ok(mem)
-        });
+    let mem = db_rand_meme(&conn, should_audio);
 
     match mem {
         Ok(mem) => {
diff --git a/src/db/mod.rs b/src/db/mod.rs
index 1ff05ce..1c2a032 100644
--- a/src/db/mod.rs
+++ b/src/db/mod.rs
@@ -102,26 +102,34 @@ pub fn delete_meme<T: AsRef<str>>(conn: &PgConnection, search: T, deleted_by: u6
     })
 }
 
-pub fn rand_text(conn: &PgConnection) -> Result<Meme> {
-    memes::table
-        .filter(memes::content.is_not_null())
-        .order(random.desc())
-        .first::<Meme>(conn)
-        .map_err(Error::from)
-}
-
-pub fn rand_image(conn: &PgConnection) -> Result<Meme> {
-    memes::table
-        .filter(memes::image_id.is_not_null())
-        .order(random.desc())
-        .first::<Meme>(conn)
-        .map_err(Error::from)
-}
+pub fn rand_meme(conn: &PgConnection, audio: bool) -> Result<Meme> {
+    use rand::{thread_rng, seq::SliceRandom};
+    use failure::err_msg;
+    use std::ops::Try;
+
+    let ids: Vec<i32> = if audio {
+        memes::table
+            .select(memes::id)
+            .filter(memes::content.is_not_null()
+                .or(memes::image_id.is_not_null())
+                .or(memes::audio_id.is_not_null()))
+            .load(conn)
+            .map_err(Error::from)?
+    } else {
+        memes::table
+            .select(memes::id)
+            .filter(memes::content.is_not_null()
+                .or(memes::image_id.is_not_null()))
+            .load(conn)
+            .map_err(Error::from)?
+    };
+
+    let id = ids.choose(&mut thread_rng())
+        .into_result()
+        .map_err( |_| err_msg("couldn't load meme"))?;
 
-pub fn rand_audio(conn: &PgConnection) -> Result<Meme> {
     memes::table
-        .filter(memes::audio_id.is_not_null())
-        .order(random.desc())
+        .find(id)
         .first::<Meme>(conn)
         .map_err(Error::from)
 }
-- 
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