frontend: Finish interactivity

frontend/src/api/player.tsx

@@ -0,0 +1,82 @@
+export interface NowPlayingResponse {
+  success: boolean;
+  nowPlaying: string;
+  isPaused: boolean;
+  volume: number;
+  isIdle: boolean;
+  currentFile: string;
+}
+
+export interface PlaylistItem {
+  filename: string;
+  title: string | null;
+  id: number;
+  playing: boolean | null;
+}
+
+export const API = {
+  async getPlaylist(): Promise<PlaylistItem[]> {
+    const response = await fetch('/api/playlist');
+    return response.json();
+  },
+  
+  async addToPlaylist(url: string): Promise<void> {
+    await fetch('/api/playlist', {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+      },
+      body: JSON.stringify({ url }),
+    });
+  },
+  
+  async removeFromPlaylist(index: number): Promise<void> {
+    await fetch(`/api/playlist/${index}`, {
+      method: 'DELETE',
+    });
+  },
+  
+  async play(): Promise<void> {
+    await fetch('/api/play', { method: 'POST' });
+  },
+  
+  async pause(): Promise<void> {
+    await fetch('/api/pause', { method: 'POST' });
+  },
+  
+  async skip(): Promise<void> {
+    await fetch('/api/skip', { method: 'POST' });
+  },
+
+  async skipTo(index: number): Promise<void> {
+    await fetch(`/api/skip/${index}`, { method: 'POST' });
+  },
+  
+  async previous(): Promise<void> {
+    await fetch('/api/previous', { method: 'POST' });
+  },
+  
+  async getNowPlaying(): Promise<NowPlayingResponse> {
+    const response = await fetch('/api/nowplaying');
+    return response.json();
+  },
+  
+  async setVolume(volume: number): Promise<void> {
+    await fetch('/api/volume', {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+      },
+      body: JSON.stringify({ volume }),
+    });
+  },
+  
+  subscribeToEvents(onMessage: (event: any) => void): WebSocket {
+    const ws = new WebSocket(`ws://${window.location.host}/api/events`);
+    ws.onmessage = (event) => {
+      onMessage(JSON.parse(event.data));
+    };
+
+    return ws;
+  }
+};

frontend/src/components/AddSongPanel.tsx

@@ -13,7 +13,7 @@ const AddSongPanel: React.FC<AddSongPanelProps> = ({ onAddURL }) => {
   }
   
   return (
-    <div className="flex items-center justify-center h-fit bg-black/50 rounded-b-2xl">
+    <div className="flex items-center justify-center h-fit bg-black/50 rounded-b-2xl text-white">
       <div className="flex flex-row items-center gap-4 w-full px-8 py-4">
         <input 
           type="text" 

frontend/src/components/App.tsx

@@ -1,30 +1,103 @@
-import React, { useState } from 'react';
+import React, { useState, useEffect } from 'react';
 import SongTable from './SongTable';
 import NowPlaying from './NowPlaying';
 import AddSongPanel from './AddSongPanel';
+import { API, PlaylistItem } from '../api/player';
+
 const App: React.FC = () => {
   const [isPlaying, setIsPlaying] = useState(false);
   const [nowPlayingSong, setNowPlayingSong] = useState<string | null>(null);
   const [nowPlayingFileName, setNowPlayingFileName] = useState<string | null>(null);
-  const [songs, setSongs] = useState<string[]>([]);
+  const [songs, setSongs] = useState<PlaylistItem[]>([]);
+  const [ws, setWs] = useState<WebSocket | null>(null);
+
+  const fetchPlaylist = async () => {
+    const playlist = await API.getPlaylist();
+    setSongs(playlist);
+  };
+
+  const fetchNowPlaying = async () => {
+    const nowPlaying = await API.getNowPlaying();
+    setNowPlayingSong(nowPlaying.nowPlaying);
+    setNowPlayingFileName(nowPlaying.currentFile);
+    setIsPlaying(!nowPlaying.isPaused);
+  };
 
   const handleAddURL = (url: string) => {
     const urlToAdd = url.trim();
     if (urlToAdd) {
-      setSongs([...songs, urlToAdd]);
+      API.addToPlaylist(urlToAdd);
+      fetchPlaylist();
     }
   };
 
   const handleDelete = (index: number) => {
     setSongs(songs.filter((_, i) => i !== index));
+    API.removeFromPlaylist(index);
+    fetchPlaylist();
+    fetchNowPlaying();
   };
 
-  const handleSkipTo = (index: number) => {
-    setNowPlayingSong(songs[index]);
-    setNowPlayingFileName(songs[index].split('/').pop() || null);
-    setIsPlaying(true);
+  const handleSkipTo = async (index: number) => {
+    const song = songs[index];
+    if (song.playing) {
+      togglePlayPause();
+    } else {
+      await API.skipTo(index);
+      await API.play();
+    }
+
+    fetchNowPlaying();
+    fetchPlaylist();
   };
 
+  const togglePlayPause = async () => {
+    if (isPlaying) {
+      await API.pause();
+    } else {
+      await API.play();
+    }
+
+    fetchNowPlaying();
+  };
+
+  const handleSkip = async () => {
+    await API.skip();
+    fetchNowPlaying();
+  };
+
+  const handlePrevious = async () => {
+    await API.previous();
+    fetchNowPlaying();
+  };
+
+  const watchForEvents = () => {
+    const ws = API.subscribeToEvents((event) => {
+      switch (event.event) {
+        case 'user_modify':
+        case 'end-file':
+        case 'playback-restart':
+          fetchPlaylist();
+          fetchNowPlaying();
+          break;
+      }
+    });
+
+    return ws;
+  };
+
+  useEffect(() => {
+    fetchPlaylist();
+    fetchNowPlaying();
+    setWs(watchForEvents());
+
+    return () => {
+      if (ws) {
+        ws.close();
+      }
+    };
+  }, []);
+
   return (
     <div className="flex items-center justify-center h-screen w-screen bg-black py-10">
       <div className="bg-violet-900 w-full md:max-w-xl h-full md:max-h-xl md:border md:rounded-2xl flex flex-col">
@@ -33,14 +106,15 @@ const App: React.FC = () => {
           songName={nowPlayingSong || "(Not Playing)"} 
           fileName={nowPlayingFileName || ""} 
           isPlaying={isPlaying} 
-          onPlayPause={() => setIsPlaying(!isPlaying)} 
-          onStepForward={() => {}} 
-          onStepBackward={() => {}} 
+          onPlayPause={togglePlayPause} 
+          onSkip={handleSkip} 
+          onPrevious={handlePrevious} 
         />
 
         {songs.length > 0 ? (
           <SongTable 
             songs={songs}
+            isPlaying={isPlaying}
             onDelete={handleDelete} 
             onSkipTo={handleSkipTo} 
           />

frontend/src/components/NowPlaying.tsx

@@ -7,27 +7,27 @@ interface NowPlayingProps extends HTMLAttributes<HTMLDivElement> {
   fileName: string;
   isPlaying: boolean;
   onPlayPause: () => void;
-  onStepForward: () => void;
-  onStepBackward: () => void; 
+  onSkip: () => void;
+  onPrevious: () => void;
 }
 
 const NowPlaying: React.FC<NowPlayingProps> = (props) => {
   return (
-    <div className={classNames(props.className, 'bg-violet-100/50 h-[150px] p-5')}>
+    <div className={classNames(props.className, 'bg-black/50 h-[150px] p-5')}>
       <div className="flex flex-col w-full gap-2">
         <div className="flex flex-row w-full h-full bg-black/50 rounded-lg p-5 items-center">
-          <div className="flex-grow">
-            <div className="text-white text-lg font-bold">{props.songName}</div>
-            <div className="text-white text-sm">{props.fileName}</div>
+          <div className="flex-grow min-w-0">
+            <div className="text-white text-lg font-bold truncate">{props.songName}</div>
+            <div className="text-white text-sm truncate">{props.fileName}</div>
           </div>
           <div className="flex flex-row gap-4">
-            <button className="text-white hover:text-violet-300 transition-colors" onClick={props.onStepBackward}>
+            <button className="text-white hover:text-violet-300 transition-colors" onClick={props.onPrevious}>
               <FaStepBackward size={24} />
             </button>
             <button className="text-white hover:text-violet-300 transition-colors" onClick={props.onPlayPause}>
               {props.isPlaying ? <FaPause size={24} /> : <FaPlay size={24} />}
             </button>
-            <button className="text-white hover:text-violet-300 transition-colors" onClick={props.onStepForward}>
+            <button className="text-white hover:text-violet-300 transition-colors" onClick={props.onSkip}>
               <FaStepForward size={24} />
             </button>
           </div>

frontend/src/components/SongRow.tsx

@@ -1,13 +1,22 @@
+import classNames from 'classnames';
 import React, { useState, useRef, useEffect } from 'react';
-import { FaPlay } from 'react-icons/fa';
+import { FaPlay, FaVolumeUp, FaVolumeOff } from 'react-icons/fa';
+import { PlaylistItem } from '../api/player';
 
-interface SongRowProps {
-  song: string;
+export enum PlayState {
+  NotPlaying, 
+  Playing,
+  Paused,
+}
+
+export interface SongRowProps {
+  song: PlaylistItem;
+  playState: PlayState;
   onDelete: () => void;
   onPlay: () => void;
 }
 
-const SongRow: React.FC<SongRowProps> = ({ song, onDelete, onPlay }) => {
+const SongRow: React.FC<SongRowProps> = ({ song, playState, onDelete, onPlay }) => {
   const [showDeleteConfirm, setShowDeleteConfirm] = useState(false);
   const buttonRef = useRef<HTMLButtonElement>(null);
   
@@ -28,20 +37,40 @@ const SongRow: React.FC<SongRowProps> = ({ song, onDelete, onPlay }) => {
   }, [showDeleteConfirm]);
   
   return (
-    <div className="flex flex-row w-full h-[100px] bg-black/40 px-2 py-5 items-center border-b gap-2 hover:bg-black/50 transition-colors">
+    <div className={classNames("flex flex-row w-full h-[100px] px-2 py-5 items-center border-b gap-2 transition-colors", {
+      "bg-black/10": (playState === PlayState.Playing || playState === PlayState.Paused),
+      "bg-black/30": playState === PlayState.NotPlaying,
+    })}>
       <div className="flex flex-row gap-2">
         <button 
-          className="text-white/40 hover:text-white transition-colors px-3 py-1 bg-white/10 rounded"
+          className="text-white/40 hover:text-white transition-colors px-3 py-1 rounded"
           onClick={onPlay}
         >
-          <FaPlay size={12} />
+          {
+            playState === PlayState.Playing ? <FaVolumeUp size={12} /> 
+            : playState === PlayState.Paused ? <FaVolumeOff size={12} /> 
+            : <FaPlay size={12} />
+          }
         </button>
       </div>
       
       <div className="flex-grow min-w-0">
-        <div className="text-white text-md truncate">
-          {song}
-        </div>
+        { 
+          song.title ? (
+            <div>
+              <div className="text-white text-md truncate text-bold">
+                {song.title}
+              </div>
+              <div className="text-white/80 text-xs truncate">
+                {song.filename}
+              </div>
+            </div>
+          ) : (
+          <div className="text-white text-md truncate text-bold">
+            {song.filename}
+          </div>
+          )
+        }
       </div>
       
       <div className="flex flex-row gap-2">

frontend/src/components/SongTable.tsx

@@ -1,19 +1,35 @@
-import React from "react";
-import SongRow from "./SongRow";
+import React, { useEffect, useRef } from "react";
+import SongRow, { PlayState } from "./SongRow";
+import { PlaylistItem } from "../api/player";
 
 interface SongTableProps {
-  songs: string[];
+  songs: PlaylistItem[];
+  isPlaying: boolean;
   onDelete: (index: number) => void;
   onSkipTo: (index: number) => void;
 }
 
-const SongTable: React.FC<SongTableProps> = ({ songs, onDelete, onSkipTo }) => {
+const SongTable: React.FC<SongTableProps> = ({ songs, isPlaying, onDelete, onSkipTo }) => {
+  const nowPlayingIndex = songs.findIndex(song => song.playing ?? false);
+  const songTableRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const songTable = songTableRef.current;
+    if (songTable) {
+      songTable.scrollTop = nowPlayingIndex * 100;
+    }
+  }, [nowPlayingIndex]);
+
   return (
-    <div className="flex flex-col w-full h-full overflow-y-auto border-y">
+    <div className="flex flex-col w-full h-full overflow-y-auto border-y" ref={songTableRef}>
       {songs.map((song, index) => (
         <SongRow 
           key={index} 
           song={song} 
+          playState={
+            (song.playing ?? false) ? (isPlaying ? PlayState.Playing : PlayState.Paused)
+            : PlayState.NotPlaying
+          }
           onDelete={() => onDelete(index)} 
           onPlay={() => onSkipTo(index)} 
         />

frontend/vite.config.ts

@@ -10,7 +10,8 @@ export default defineConfig({
     proxy: {
       '/api': {
         target: 'http://localhost:3000',
-        changeOrigin: true
+        changeOrigin: true,
+        ws: true
       }
     }
   }