From 625f4bd0065824e6bf14d8e079a5e56ea845c2bd Mon Sep 17 00:00:00 2001
From: Antoine Gersant <antoine.gersant@lesforges.org>
Date: Wed, 18 Sep 2024 21:19:59 -0700
Subject: [PATCH] Adds seed support to get_random_albums

---
 src/app/index.rs            | 11 +++++++++--
 src/app/index/collection.rs | 28 ++++++++++++++++++++++------
 src/server/axum/api.rs      | 14 ++++++++++----
 src/server/dto/v8.rs        |  7 +++++++
 4 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/src/app/index.rs b/src/app/index.rs
index ce2501a..c37e29b 100644
--- a/src/app/index.rs
+++ b/src/app/index.rs
@@ -178,12 +178,19 @@ impl Manager {
 		.unwrap()
 	}
 
-	pub async fn get_random_albums(&self, count: usize) -> Result<Vec<Album>, Error> {
+	pub async fn get_random_albums(
+		&self,
+		seed: Option<u64>,
+		offset: usize,
+		count: usize,
+	) -> Result<Vec<Album>, Error> {
 		spawn_blocking({
 			let index_manager = self.clone();
 			move || {
 				let index = index_manager.index.read().unwrap();
-				Ok(index.collection.get_random_albums(&index.strings, count))
+				Ok(index
+					.collection
+					.get_random_albums(&index.strings, seed, offset, count))
 			}
 		})
 		.await
diff --git a/src/app/index/collection.rs b/src/app/index/collection.rs
index 57585ae..26d9301 100644
--- a/src/app/index/collection.rs
+++ b/src/app/index/collection.rs
@@ -5,7 +5,7 @@ use std::{
 };
 
 use lasso2::{Rodeo, RodeoReader, Spur};
-use rand::{rngs::ThreadRng, seq::IteratorRandom};
+use rand::{rngs::StdRng, seq::SliceRandom, SeedableRng};
 use serde::{Deserialize, Serialize};
 use tinyvec::TinyVec;
 use unicase::UniCase;
@@ -140,11 +140,27 @@ impl Collection {
 		})
 	}
 
-	pub fn get_random_albums(&self, strings: &RodeoReader, count: usize) -> Vec<Album> {
-		self.albums
-			.keys()
-			.choose_multiple(&mut ThreadRng::default(), count)
+	pub fn get_random_albums(
+		&self,
+		strings: &RodeoReader,
+		seed: Option<u64>,
+		offset: usize,
+		count: usize,
+	) -> Vec<Album> {
+		let shuffled = {
+			let mut rng = match seed {
+				Some(seed) => StdRng::seed_from_u64(seed),
+				None => StdRng::from_entropy(),
+			};
+			let mut s = self.albums.keys().collect::<Vec<_>>();
+			s.shuffle(&mut rng);
+			s
+		};
+
+		shuffled
 			.into_iter()
+			.skip(offset)
+			.take(count)
 			.filter_map(|k| self.get_album(strings, k.clone()))
 			.collect()
 	}
@@ -545,7 +561,7 @@ mod test {
 			},
 		]));
 
-		let albums = collection.get_random_albums(&strings, 10);
+		let albums = collection.get_random_albums(&strings, None, 0, 10);
 		assert_eq!(albums.len(), 2);
 
 		assert_eq!(
diff --git a/src/server/axum/api.rs b/src/server/axum/api.rs
index 52134c3..9a4d0ac 100644
--- a/src/server/axum/api.rs
+++ b/src/server/axum/api.rs
@@ -478,8 +478,14 @@ async fn get_random_albums(
 	_auth: Auth,
 	api_version: APIMajorVersion,
 	State(index_manager): State<index::Manager>,
+	Query(options): Query<dto::GetRandomAlbumsParameters>,
 ) -> Response {
-	let albums = match index_manager.get_random_albums(20).await {
+	let offset = options.offset.unwrap_or(0);
+	let count = options.count.unwrap_or(20);
+	let albums = match index_manager
+		.get_random_albums(options.seed, offset, count)
+		.await
+	{
 		Ok(d) => d,
 		Err(e) => return APIError::from(e).into_response(),
 	};
@@ -490,10 +496,10 @@ async fn get_recent_albums(
 	_auth: Auth,
 	api_version: APIMajorVersion,
 	State(index_manager): State<index::Manager>,
-	Query(option): Query<dto::GetRecentAlbumsParameters>,
+	Query(options): Query<dto::GetRecentAlbumsParameters>,
 ) -> Response {
-	let offset = option.offset.unwrap_or(0);
-	let count = option.count.unwrap_or(20);
+	let offset = options.offset.unwrap_or(0);
+	let count = options.count.unwrap_or(20);
 	let albums = match index_manager.get_recent_albums(offset, count).await {
 		Ok(d) => d,
 		Err(e) => return APIError::from(e).into_response(),
diff --git a/src/server/dto/v8.rs b/src/server/dto/v8.rs
index 26f1853..8e18ea9 100644
--- a/src/server/dto/v8.rs
+++ b/src/server/dto/v8.rs
@@ -436,6 +436,13 @@ pub struct GetSongsBulkOutput {
 	pub not_found: Vec<PathBuf>,
 }
 
+#[derive(Clone, Serialize, Deserialize)]
+pub struct GetRandomAlbumsParameters {
+	pub seed: Option<u64>,
+	pub offset: Option<usize>,
+	pub count: Option<usize>,
+}
+
 #[derive(Clone, Serialize, Deserialize)]
 pub struct GetRecentAlbumsParameters {
 	pub offset: Option<usize>,