From 6a0f1d7d3f20b09f7f059fc2d3183491805a1fec Mon Sep 17 00:00:00 2001
From: Justin Edmund <justin@jedmund.com>
Date: Fri, 13 Jun 2025 22:18:05 -0400
Subject: [PATCH] Realtime now playing

---
 src/lib/components/Album.svelte         |  23 ++-
 src/lib/components/StreamStatus.svelte  |  78 ++++++++++
 src/lib/stores/now-playing-stream.ts    | 133 ++++++++++++++++
 src/routes/about/+page.svelte           |   3 +
 src/routes/api/lastfm/stream/+server.ts | 196 ++++++++++++++++++++++++
 5 files changed, 426 insertions(+), 7 deletions(-)
 create mode 100644 src/lib/components/StreamStatus.svelte
 create mode 100644 src/lib/stores/now-playing-stream.ts
 create mode 100644 src/routes/api/lastfm/stream/+server.ts

diff --git a/src/lib/components/Album.svelte b/src/lib/components/Album.svelte
index b4e1b4c..3844195 100644
--- a/src/lib/components/Album.svelte
+++ b/src/lib/components/Album.svelte
@@ -2,6 +2,7 @@
 	import { spring } from 'svelte/motion'
 	import type { Album } from '$lib/types/lastfm'
 	import { audioPreview } from '$lib/stores/audio-preview'
+	import { nowPlayingStream } from '$lib/stores/now-playing-stream'
 	import NowPlaying from './NowPlaying.svelte'
 
 	interface AlbumProps {
@@ -81,16 +82,24 @@
 
 	const hasPreview = $derived(!!album?.appleMusicData?.previewUrl)
 	
-	// Debug log
+	// Subscribe to real-time now playing updates
+	let realtimeNowPlaying = $state<{ isNowPlaying: boolean; nowPlayingTrack?: string } | null>(null)
+	
 	$effect(() => {
 		if (album) {
-			console.log(`Album ${album.name}:`, {
-				hasAppleMusicData: !!album.appleMusicData,
-				previewUrl: album.appleMusicData?.previewUrl,
-				hasPreview
+			const unsubscribe = nowPlayingStream.isAlbumPlaying.subscribe(checkAlbum => {
+				const status = checkAlbum(album.artist.name, album.name)
+				if (status !== null) {
+					realtimeNowPlaying = status
+				}
 			})
+			return unsubscribe
 		}
 	})
+	
+	// Combine initial state with real-time updates
+	const isNowPlaying = $derived(realtimeNowPlaying?.isNowPlaying ?? album?.isNowPlaying ?? false)
+	const nowPlayingTrack = $derived(realtimeNowPlaying?.nowPlayingTrack ?? album?.nowPlayingTrack)
 </script>
 
 <div class="album">
@@ -110,8 +119,8 @@
 						style="transform: scale({$scale})"
 						loading="lazy"
 					/>
-					{#if album.isNowPlaying}
-						<NowPlaying trackName={album.nowPlayingTrack !== album.name ? album.nowPlayingTrack : undefined} />
+					{#if isNowPlaying}
+						<NowPlaying trackName={nowPlayingTrack !== album.name ? nowPlayingTrack : undefined} />
 					{/if}
 					{#if hasPreview && isHovering}
 						<button
diff --git a/src/lib/components/StreamStatus.svelte b/src/lib/components/StreamStatus.svelte
new file mode 100644
index 0000000..47451b7
--- /dev/null
+++ b/src/lib/components/StreamStatus.svelte
@@ -0,0 +1,78 @@
+<script lang="ts">
+	import { nowPlayingStream } from '$lib/stores/now-playing-stream'
+	
+	let isConnected = $state(false)
+	
+	$effect(() => {
+		const unsubscribe = nowPlayingStream.subscribe(state => {
+			isConnected = state.connected
+		})
+		return unsubscribe
+	})
+</script>
+
+{#if isConnected}
+	<div class="stream-status connected" title="Live updates active">
+		<span class="dot"></span>
+	</div>
+{/if}
+
+<style lang="scss">
+	.stream-status {
+		position: fixed;
+		bottom: $unit * 2;
+		right: $unit * 2;
+		display: flex;
+		align-items: center;
+		gap: $unit-half;
+		padding: $unit-half $unit;
+		background: rgba(0, 0, 0, 0.8);
+		color: white;
+		border-radius: $unit * 2;
+		font-size: $font-size-small;
+		z-index: 1000;
+		animation: fadeIn 0.3s ease-out;
+		
+		&.connected {
+			.dot {
+				background: #4caf50;
+				animation: pulse 2s ease-in-out infinite;
+			}
+		}
+		
+		.dot {
+			width: 8px;
+			height: 8px;
+			border-radius: 50%;
+		}
+	}
+	
+	@keyframes fadeIn {
+		from {
+			opacity: 0;
+			transform: translateY(10px);
+		}
+		to {
+			opacity: 1;
+			transform: translateY(0);
+		}
+	}
+	
+	@keyframes pulse {
+		0%, 100% {
+			opacity: 1;
+			transform: scale(1);
+		}
+		50% {
+			opacity: 0.6;
+			transform: scale(0.9);
+		}
+	}
+	
+	@include breakpoint('phone') {
+		.stream-status {
+			bottom: $unit;
+			right: $unit;
+		}
+	}
+</style>
\ No newline at end of file
diff --git a/src/lib/stores/now-playing-stream.ts b/src/lib/stores/now-playing-stream.ts
new file mode 100644
index 0000000..5cd9180
--- /dev/null
+++ b/src/lib/stores/now-playing-stream.ts
@@ -0,0 +1,133 @@
+import { writable, derived, get, type Readable } from 'svelte/store'
+import { browser } from '$app/environment'
+
+interface NowPlayingUpdate {
+	albumName: string
+	artistName: string
+	isNowPlaying: boolean
+	nowPlayingTrack?: string
+}
+
+interface NowPlayingState {
+	connected: boolean
+	updates: Map<string, NowPlayingUpdate>
+	lastUpdate: Date | null
+}
+
+function createNowPlayingStream() {
+	const { subscribe, set, update } = writable<NowPlayingState>({
+		connected: false,
+		updates: new Map(),
+		lastUpdate: null
+	})
+	
+	let eventSource: EventSource | null = null
+	let reconnectTimeout: NodeJS.Timeout | null = null
+	let reconnectAttempts = 0
+	
+	function connect() {
+		if (!browser || eventSource?.readyState === EventSource.OPEN) return
+		
+		// Clean up existing connection
+		disconnect()
+		
+		eventSource = new EventSource('/api/lastfm/stream')
+		
+		eventSource.addEventListener('connected', () => {
+			console.log('Now Playing stream connected')
+			reconnectAttempts = 0
+			update(state => ({ ...state, connected: true }))
+		})
+		
+		eventSource.addEventListener('nowplaying', (event) => {
+			try {
+				const updates: NowPlayingUpdate[] = JSON.parse(event.data)
+				update(state => {
+					const newUpdates = new Map(state.updates)
+					
+					for (const album of updates) {
+						const key = `${album.artistName}:${album.albumName}`
+						newUpdates.set(key, album)
+					}
+					
+					return {
+						...state,
+						updates: newUpdates,
+						lastUpdate: new Date()
+					}
+				})
+			} catch (error) {
+				console.error('Error parsing now playing update:', error)
+			}
+		})
+		
+		eventSource.addEventListener('heartbeat', () => {
+			// Heartbeat received, connection is healthy
+		})
+		
+		eventSource.addEventListener('error', (error) => {
+			console.error('Now Playing stream error:', error)
+			update(state => ({ ...state, connected: false }))
+			
+			// Attempt to reconnect with exponential backoff
+			if (reconnectAttempts < 5) {
+				const delay = Math.min(1000 * Math.pow(2, reconnectAttempts), 30000)
+				reconnectTimeout = setTimeout(() => {
+					reconnectAttempts++
+					connect()
+				}, delay)
+			}
+		})
+		
+		eventSource.addEventListener('open', () => {
+			update(state => ({ ...state, connected: true }))
+		})
+	}
+	
+	function disconnect() {
+		if (eventSource) {
+			eventSource.close()
+			eventSource = null
+		}
+		
+		if (reconnectTimeout) {
+			clearTimeout(reconnectTimeout)
+			reconnectTimeout = null
+		}
+		
+		update(state => ({ ...state, connected: false }))
+	}
+	
+	// Auto-connect in browser
+	if (browser) {
+		connect()
+		
+		// Reconnect on visibility change
+		document.addEventListener('visibilitychange', () => {
+			const currentState = get({ subscribe })
+			if (document.visibilityState === 'visible' && !currentState.connected) {
+				connect()
+			}
+		})
+	}
+	
+	return {
+		subscribe,
+		connect,
+		disconnect,
+		// Helper to check if a specific album is now playing
+		isAlbumPlaying: derived(
+			{ subscribe },
+			($state) => (artistName: string, albumName: string) => {
+				const key = `${artistName}:${albumName}`
+				const update = $state.updates.get(key)
+				return update ? {
+					isNowPlaying: update.isNowPlaying,
+					nowPlayingTrack: update.nowPlayingTrack
+				} : null
+			}
+		) as Readable<(artistName: string, albumName: string) => { isNowPlaying: boolean; nowPlayingTrack?: string } | null>
+	}
+}
+
+export const nowPlayingStream = createNowPlayingStream()
\ No newline at end of file
diff --git a/src/routes/about/+page.svelte b/src/routes/about/+page.svelte
index db82861..d0f2058 100644
--- a/src/routes/about/+page.svelte
+++ b/src/routes/about/+page.svelte
@@ -4,6 +4,7 @@
 	import MentionList from '$components/MentionList.svelte'
 	import Page from '$components/Page.svelte'
 	import RecentAlbums from '$components/RecentAlbums.svelte'
+	import StreamStatus from '$components/StreamStatus.svelte'
 	import { generateMetaTags } from '$lib/utils/metadata'
 	import { page } from '$app/stores'
 
@@ -101,6 +102,8 @@
 		{/if}
 	</section> -->
 	</Page>
+	
+	<StreamStatus />
 </section>
 
 <style lang="scss">
diff --git a/src/routes/api/lastfm/stream/+server.ts b/src/routes/api/lastfm/stream/+server.ts
new file mode 100644
index 0000000..eeb625d
--- /dev/null
+++ b/src/routes/api/lastfm/stream/+server.ts
@@ -0,0 +1,196 @@
+import { LastClient } from '@musicorum/lastfm'
+import type { RequestHandler } from './$types'
+import type { Album } from '$lib/types/lastfm'
+import { findAlbum, transformAlbumData } from '$lib/server/apple-music-client'
+import redis from '../../redis-client'
+
+const LASTFM_API_KEY = process.env.LASTFM_API_KEY
+const USERNAME = 'jedmund'
+const UPDATE_INTERVAL = 30000 // 30 seconds
+
+interface NowPlayingUpdate {
+	albumName: string
+	artistName: string
+	isNowPlaying: boolean
+	nowPlayingTrack?: string
+}
+
+// Store recent tracks for duration-based detection
+interface TrackPlayInfo {
+	albumName: string
+	trackName: string
+	scrobbleTime: Date
+	durationMs?: number
+}
+
+let recentTracks: TrackPlayInfo[] = []
+
+export const GET: RequestHandler = async ({ request }) => {
+	const encoder = new TextEncoder()
+	
+	const stream = new ReadableStream({
+		async start(controller) {
+			const client = new LastClient(LASTFM_API_KEY || '')
+			let lastNowPlayingState: Map<string, boolean> = new Map()
+			
+			// Send initial connection message
+			controller.enqueue(encoder.encode('event: connected\ndata: {}\n\n'))
+			
+			const checkForUpdates = async () => {
+				try {
+					const nowPlayingAlbums = await getNowPlayingAlbums(client)
+					const updates: NowPlayingUpdate[] = []
+					
+					// Check for changes
+					for (const album of nowPlayingAlbums) {
+						const key = `${album.artistName}:${album.albumName}`
+						const wasPlaying = lastNowPlayingState.get(key) || false
+						
+						if (album.isNowPlaying !== wasPlaying) {
+							updates.push(album)
+							lastNowPlayingState.set(key, album.isNowPlaying)
+						}
+					}
+					
+					// Send updates if any
+					if (updates.length > 0) {
+						const data = JSON.stringify(updates)
+						controller.enqueue(encoder.encode(`event: nowplaying\ndata: ${data}\n\n`))
+					}
+					
+					// Send heartbeat to keep connection alive
+					controller.enqueue(encoder.encode('event: heartbeat\ndata: {}\n\n'))
+				} catch (error) {
+					console.error('Error checking for updates:', error)
+				}
+			}
+			
+			// Initial check
+			await checkForUpdates()
+			
+			// Set up interval
+			const intervalId = setInterval(checkForUpdates, UPDATE_INTERVAL)
+			
+			// Handle client disconnect
+			request.signal.addEventListener('abort', () => {
+				clearInterval(intervalId)
+				controller.close()
+			})
+		},
+		
+		cancel() {
+			// Cleanup when stream is cancelled
+			console.log('SSE stream cancelled')
+		}
+	})
+	
+	return new Response(stream, {
+		headers: {
+			'Content-Type': 'text/event-stream',
+			'Cache-Control': 'no-cache',
+			'Connection': 'keep-alive',
+			'X-Accel-Buffering': 'no' // Disable Nginx buffering
+		}
+	})
+}
+
+async function getNowPlayingAlbums(client: LastClient): Promise<NowPlayingUpdate[]> {
+	const recentTracksResponse = await client.user.getRecentTracks(USERNAME, { limit: 50, extended: true })
+	const albums: Map<string, NowPlayingUpdate> = new Map()
+	
+	// Clear old tracks and collect new track play information
+	recentTracks = []
+	
+	for (const track of recentTracksResponse.tracks) {
+		// Store track play information
+		if (track.date) {
+			recentTracks.push({
+				albumName: track.album.name,
+				trackName: track.name,
+				scrobbleTime: track.date
+			})
+		}
+		
+		const albumKey = `${track.artist.name}:${track.album.name}`
+		
+		if (!albums.has(albumKey)) {
+			const album: NowPlayingUpdate = {
+				albumName: track.album.name,
+				artistName: track.artist.name,
+				isNowPlaying: track.nowPlaying || false,
+				nowPlayingTrack: track.nowPlaying ? track.name : undefined
+			}
+			
+			// If not marked as now playing by Last.fm, check with duration-based detection
+			if (!album.isNowPlaying) {
+				const updatedStatus = await checkNowPlayingWithDuration(album.albumName, album.artistName)
+				if (updatedStatus) {
+					album.isNowPlaying = updatedStatus.isNowPlaying
+					album.nowPlayingTrack = updatedStatus.nowPlayingTrack
+				}
+			}
+			
+			albums.set(albumKey, album)
+		}
+	}
+	
+	return Array.from(albums.values())
+}
+
+async function checkNowPlayingWithDuration(
+	albumName: string, 
+	artistName: string
+): Promise<{ isNowPlaying: boolean; nowPlayingTrack?: string } | null> {
+	try {
+		// Check cache for Apple Music data
+		const cacheKey = `apple:album:${artistName}:${albumName}`
+		const cached = await redis.get(cacheKey)
+		
+		if (!cached) {
+			// Try to fetch from Apple Music if not cached
+			const appleMusicAlbum = await findAlbum(artistName, albumName)
+			if (!appleMusicAlbum) return null
+			
+			const transformedData = await transformAlbumData(appleMusicAlbum)
+			await redis.set(cacheKey, JSON.stringify(transformedData), 'EX', 86400)
+			return checkWithTracks(albumName, transformedData.tracks)
+		}
+		
+		const appleMusicData = JSON.parse(cached)
+		return checkWithTracks(albumName, appleMusicData.tracks)
+	} catch (error) {
+		console.error(`Error checking duration for ${albumName}:`, error)
+		return null
+	}
+}
+
+function checkWithTracks(
+	albumName: string, 
+	tracks?: Array<{ name: string; durationMs?: number }>
+): { isNowPlaying: boolean; nowPlayingTrack?: string } | null {
+	if (!tracks) return null
+	
+	const now = new Date()
+	const SCROBBLE_LAG = 3 * 60 * 1000 // 3 minutes
+	
+	for (const trackInfo of recentTracks) {
+		if (trackInfo.albumName !== albumName) continue
+		
+		const trackData = tracks.find(t => 
+			t.name.toLowerCase() === trackInfo.trackName.toLowerCase()
+		)
+		
+		if (trackData?.durationMs) {
+			const trackEndTime = new Date(trackInfo.scrobbleTime.getTime() + trackData.durationMs + SCROBBLE_LAG)
+			
+			if (now < trackEndTime) {
+				return {
+					isNowPlaying: true,
+					nowPlayingTrack: trackInfo.trackName
+				}
+			}
+		}
+	}
+	
+	return { isNowPlaying: false }
+}
\ No newline at end of file