From de176acd8f13b5a18e2dd8bb9a09085b05cb128f Mon Sep 17 00:00:00 2001
From: Izan Gil <66965250+SrIzan10@users.noreply.github.com>
Date: Sat, 31 May 2025 17:58:52 +0200
Subject: [PATCH] chore: use fisheryates for array shuffle

---
 src/lib/fisheryates.ts    | 13 +++++++++++++
 src/lib/state.svelte.ts   |  2 +-
 src/lib/stations/sleep.ts |  4 +++-
 src/lib/types.ts          |  4 ++--
 4 files changed, 19 insertions(+), 4 deletions(-)
 create mode 100644 src/lib/fisheryates.ts

diff --git a/src/lib/fisheryates.ts b/src/lib/fisheryates.ts
new file mode 100644
index 0000000..f2804b6
--- /dev/null
+++ b/src/lib/fisheryates.ts
@@ -0,0 +1,13 @@
+// source: https://decipher.dev/30-seconds-of-typescript/docs/shuffle/
+// modified to use existing SIMDMersenneTwister constructor for random number generation
+
+import type { SIMDMersenneTwister } from "./mersenne";
+
+export const fisherYates = (sfml: SIMDMersenneTwister, ...arr: any[]) => {
+  let m = arr.length;
+  while (m) {
+    const i = Math.floor(sfml.random() * m--);
+    [arr[m], arr[i]] = [arr[i], arr[m]];
+  }
+  return arr;
+};
\ No newline at end of file
diff --git a/src/lib/state.svelte.ts b/src/lib/state.svelte.ts
index 1676588..b239225 100644
--- a/src/lib/state.svelte.ts
+++ b/src/lib/state.svelte.ts
@@ -14,7 +14,7 @@ export const state = $state({
   isLoading: true,
   error: null as string | null,
   currentTime: 0,
-  duration: 0 as number | undefined,
+  duration: 0,
 
   presets: [] as Preset[],
   stations: [] as Station[],
diff --git a/src/lib/stations/sleep.ts b/src/lib/stations/sleep.ts
index c5448f6..a570446 100644
--- a/src/lib/stations/sleep.ts
+++ b/src/lib/stations/sleep.ts
@@ -1,5 +1,6 @@
 import type { Song } from "@/types";
 import { SIMDMersenneTwister } from "@/mersenne";
+import { fisherYates } from "@/fisheryates";
 
 export async function getSleepStationSongs(): Promise<Song[]> {
   const m = new SIMDMersenneTwister();
@@ -16,9 +17,10 @@ export async function getSleepStationSongs(): Promise<Song[]> {
       title: title,
       image: `https://lofi-cdn.srizan.dev/sleep/thumbs/${file.replace('.opus', '')}.webp`,
       label: 'Chilled Cat',
+      duration: 0, // TODO: get duration for all songs and put them in list.json
     };
   }) as Song[];
 
-  const shuffled = mapped.sort(() => 0.5 - m.random()).slice(0, 5);
+  const shuffled = fisherYates(m, mapped).slice(0, 5);
   return shuffled;
 }
diff --git a/src/lib/types.ts b/src/lib/types.ts
index b67f9e5..1e97caa 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -3,9 +3,9 @@ export interface Song {
   title: string;
   endpoint: string;
   image: string;
+  duration: number; // not really used right now
   label?: string; // optional record label
-  spotifyId?: string; // TODO: enforce in the future for all spotify scraped stations
-  duration?: number; // TODO: enforce in all stations
+  spotifyId?: string; // TODO: enforce in the future for all spotify scraped stations, unused atm.
 }
 
 export interface CHSong {