add types

src/lib/stores.svelte.ts

@@ -0,0 +1,86 @@
+import { writable } from 'svelte/store';
+import { browser } from '$app/environment';
+import { SvelteSet } from 'svelte/reactivity';
+import type { Stream } from '$lib/types';
+
+export const currentStream = writable<Stream | null>(null);
+export const currentSongIndex = writable<number | null>(null);
+
+export const favoritedStreams = new SvelteSet<string>(
+    JSON.parse((browser && localStorage.getItem('favoritedStreams')) || '[]')
+);
+$effect.root(() => {
+    $effect(() => {
+        localStorage.setItem('favoritedStreams', JSON.stringify(Array.from(favoritedStreams)));
+    });
+});
+
+export const tagList = [
+    'acoustic',
+    'electronic',
+    'orchestral',
+    'rock',
+    'pop',
+    'metal',
+    'aggressive',
+    'folk',
+    'jazzy',
+    'dance.music',
+    'untz',
+    'breakbeats',
+    'electronica',
+    'chiptune',
+    'left.field',
+    'denpa',
+    'vocaloid',
+    'funky',
+    'lush',
+    'noisy',
+    'psychedelic',
+    'dark',
+    'calm',
+    'moody',
+    'uplifting'
+];
+
+let timestampList: number[];
+
+// utility
+
+function locationOf(element: number, array: number[], start?: number, end?: number): number {
+    start = start || 0;
+    end = end || array.length;
+    const pivot = parseInt(String(start + (end - start) / 2), 10);
+    if (end - start <= 1 || array[pivot] === element) return pivot;
+    if (array[pivot] < element) {
+        return locationOf(element, array, pivot, end);
+    } else {
+        return locationOf(element, array, start, pivot);
+    }
+}
+
+// exported methods
+
+export function getSongAtTime(currentTime: number): number {
+    return locationOf(currentTime, timestampList) - 1;
+}
+
+// less operations needed when doing regular lookups
+export function updateCurrentSong(currentTime: number, songIndex: number): void {
+    function updateCurrentSongRecurse(songIndex: number): number {
+        if (currentTime >= timestampList[songIndex + 2]) {
+            return updateCurrentSongRecurse(songIndex + 1);
+        } else if (currentTime < timestampList[songIndex + 1]) {
+            return updateCurrentSongRecurse(songIndex - 1);
+        }
+        return songIndex;
+    }
+
+    currentSongIndex.set(updateCurrentSongRecurse(songIndex));
+}
+
+export function updateCurrentStream(stream: Stream): void {
+    currentStream.set(stream);
+    timestampList = [-Infinity, ...stream.tracks.map((track) => track[0]), Infinity];
+    currentSongIndex.set(0);
+}