feat: Special Curation feature with waveform editor

- Database: SpecialSong model with startTime field
- Backend: API endpoints for Special curation
- Admin: Waveform editor with segment markers, zoom, and playback
- Game: startTime support in AudioPlayer
- UI: Manual save button, hover preview, playback cursor
- Migration: Automatic migration on deployment

app/admin/page.tsx

@@ -690,7 +690,7 @@ export default function AdminPage() {
                             fontSize: '0.875rem'
                         }}>
                             <span>{special.name} ({special._count?.songs || 0})</span>
-                            <button onClick={() => startEditSpecial(special)} className="btn-primary" style={{ marginRight: '0.5rem' }}>Edit</button>
+                            <a href={`/admin/specials/${special.id}`} className="btn-primary" style={{ marginRight: '0.5rem', textDecoration: 'none' }}>Curate</a>
                             <button onClick={() => handleDeleteSpecial(special.id)} className="btn-danger">Delete</button>
                         </div>
                     ))}

app/admin/specials/[id]/page.tsx

@@ -0,0 +1,226 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { useParams, useRouter } from 'next/navigation';
+import WaveformEditor from '@/components/WaveformEditor';
+
+interface Song {
+    id: number;
+    title: string;
+    artist: string;
+    filename: string;
+}
+
+interface SpecialSong {
+    id: number;
+    songId: number;
+    startTime: number;
+    order: number | null;
+    song: Song;
+}
+
+interface Special {
+    id: number;
+    name: string;
+    maxAttempts: number;
+    unlockSteps: string;
+    songs: SpecialSong[];
+}
+
+export default function SpecialEditorPage() {
+    const params = useParams();
+    const router = useRouter();
+    const specialId = params.id as string;
+
+    const [special, setSpecial] = useState<Special | null>(null);
+    const [selectedSongId, setSelectedSongId] = useState<number | null>(null);
+    const [loading, setLoading] = useState(true);
+    const [saving, setSaving] = useState(false);
+    const [pendingStartTime, setPendingStartTime] = useState<number | null>(null);
+    const [hasUnsavedChanges, setHasUnsavedChanges] = useState(false);
+
+    useEffect(() => {
+        fetchSpecial();
+    }, [specialId]);
+
+    const fetchSpecial = async () => {
+        try {
+            const res = await fetch(`/api/specials/${specialId}`);
+            if (res.ok) {
+                const data = await res.json();
+                setSpecial(data);
+                if (data.songs.length > 0) {
+                    setSelectedSongId(data.songs[0].songId);
+                    // Initialize pendingStartTime with the current startTime of the first song
+                    setPendingStartTime(data.songs[0].startTime);
+                }
+            }
+        } catch (error) {
+            console.error('Error fetching special:', error);
+        } finally {
+            setLoading(false);
+        }
+    };
+
+    const handleStartTimeChange = (newStartTime: number) => {
+        setPendingStartTime(newStartTime);
+        setHasUnsavedChanges(true);
+    };
+
+    const handleSave = async () => {
+        if (!special || !selectedSongId || pendingStartTime === null) return;
+
+        setSaving(true);
+        try {
+            const res = await fetch(`/api/specials/${specialId}/songs`, {
+                method: 'PUT',
+                headers: { 'Content-Type': 'application/json' },
+                body: JSON.stringify({ songId: selectedSongId, startTime: pendingStartTime })
+            });
+
+            if (res.ok) {
+                // Update local state
+                setSpecial(prev => {
+                    if (!prev) return prev;
+                    return {
+                        ...prev,
+                        songs: prev.songs.map(ss =>
+                            ss.songId === selectedSongId ? { ...ss, startTime: pendingStartTime } : ss
+                        )
+                    };
+                });
+                setHasUnsavedChanges(false);
+                setPendingStartTime(null); // Reset pending state after saving
+            }
+        } catch (error) {
+            console.error('Error updating start time:', error);
+        } finally {
+            setSaving(false);
+        }
+    };
+
+    if (loading) {
+        return (
+            <div style={{ padding: '2rem', textAlign: 'center' }}>
+                <p>Loading...</p>
+            </div>
+        );
+    }
+
+    if (!special) {
+        return (
+            <div style={{ padding: '2rem', textAlign: 'center' }}>
+                <p>Special not found</p>
+                <button onClick={() => router.push('/admin')}>Back to Admin</button>
+            </div>
+        );
+    }
+
+    const selectedSpecialSong = special.songs.find(ss => ss.songId === selectedSongId);
+    const unlockSteps = JSON.parse(special.unlockSteps);
+    const totalDuration = unlockSteps[unlockSteps.length - 1];
+
+    return (
+        <div style={{ padding: '2rem', maxWidth: '1200px', margin: '0 auto' }}>
+            <div style={{ marginBottom: '2rem' }}>
+                <button
+                    onClick={() => router.push('/admin')}
+                    style={{
+                        padding: '0.5rem 1rem',
+                        background: '#e5e7eb',
+                        border: 'none',
+                        borderRadius: '0.5rem',
+                        cursor: 'pointer',
+                        marginBottom: '1rem'
+                    }}
+                >
+                    ← Back to Admin
+                </button>
+                <h1 style={{ fontSize: '2rem', fontWeight: 'bold' }}>
+                    Edit Special: {special.name}
+                </h1>
+                <p style={{ color: '#666', marginTop: '0.5rem' }}>
+                    Max Attempts: {special.maxAttempts} | Puzzle Duration: {totalDuration}s
+                </p>
+            </div>
+
+            {special.songs.length === 0 ? (
+                <div style={{ padding: '2rem', background: '#f3f4f6', borderRadius: '0.5rem', textAlign: 'center' }}>
+                    <p>No songs assigned to this special yet.</p>
+                    <p style={{ fontSize: '0.875rem', color: '#666', marginTop: '0.5rem' }}>
+                        Go back to the admin dashboard to add songs to this special.
+                    </p>
+                </div>
+            ) : (
+                <div>
+                    <div style={{ marginBottom: '2rem' }}>
+                        <h2 style={{ fontSize: '1.25rem', fontWeight: 'bold', marginBottom: '1rem' }}>
+                            Select Song to Curate
+                        </h2>
+                        <div style={{ display: 'grid', gridTemplateColumns: 'repeat(auto-fill, minmax(250px, 1fr))', gap: '1rem' }}>
+                            {special.songs.map(ss => (
+                                <div
+                                    key={ss.songId}
+                                    onClick={() => setSelectedSongId(ss.songId)}
+                                    style={{
+                                        padding: '1rem',
+                                        background: selectedSongId === ss.songId ? '#4f46e5' : '#f3f4f6',
+                                        color: selectedSongId === ss.songId ? 'white' : 'black',
+                                        borderRadius: '0.5rem',
+                                        cursor: 'pointer',
+                                        border: selectedSongId === ss.songId ? '2px solid #4f46e5' : '2px solid transparent'
+                                    }}
+                                >
+                                    <div style={{ fontWeight: 'bold' }}>{ss.song.title}</div>
+                                    <div style={{ fontSize: '0.875rem', opacity: 0.8 }}>{ss.song.artist}</div>
+                                    <div style={{ fontSize: '0.75rem', marginTop: '0.5rem', opacity: 0.7 }}>
+                                        Start: {ss.startTime}s
+                                    </div>
+                                </div>
+                            ))}
+                        </div>
+                    </div>
+
+                    {selectedSpecialSong && (
+                        <div>
+                            <h2 style={{ fontSize: '1.25rem', fontWeight: 'bold', marginBottom: '1rem' }}>
+                                Curate: {selectedSpecialSong.song.title}
+                            </h2>
+                            <div style={{ background: '#f9fafb', padding: '1.5rem', borderRadius: '0.5rem' }}>
+                                <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: '1rem' }}>
+                                    <p style={{ fontSize: '0.875rem', color: '#666', margin: 0 }}>
+                                        Click on the waveform to select where the puzzle should start. The highlighted region shows what players will hear.
+                                    </p>
+                                    <button
+                                        onClick={handleSave}
+                                        disabled={!hasUnsavedChanges || saving}
+                                        style={{
+                                            padding: '0.5rem 1.5rem',
+                                            background: hasUnsavedChanges ? '#10b981' : '#e5e7eb',
+                                            color: hasUnsavedChanges ? 'white' : '#9ca3af',
+                                            border: 'none',
+                                            borderRadius: '0.5rem',
+                                            cursor: hasUnsavedChanges && !saving ? 'pointer' : 'not-allowed',
+                                            fontWeight: 'bold',
+                                            fontSize: '0.875rem',
+                                            whiteSpace: 'nowrap'
+                                        }}
+                                    >
+                                        {saving ? '💾 Saving...' : hasUnsavedChanges ? '💾 Save Changes' : '✓ Saved'}
+                                    </button>
+                                </div>
+                                <WaveformEditor
+                                    audioUrl={`/uploads/${selectedSpecialSong.song.filename}`}
+                                    startTime={pendingStartTime ?? selectedSpecialSong.startTime}
+                                    duration={totalDuration}
+                                    unlockSteps={unlockSteps}
+                                    onStartTimeChange={handleStartTimeChange}
+                                />
+                            </div>
+                        </div>
+                    )}
+                </div>
+            )}
+        </div>
+    );
+}

app/api/songs/route.ts

@@ -12,11 +12,15 @@ export async function GET() {
         include: {
             puzzles: true,
             genres: true,
-            specials: true,
+            specials: {
+                include: {
+                    special: true
+                }
+            },
         },
     });
 
-    // Map to include activation count
+    // Map to include activation count and flatten specials
     const songsWithActivations = songs.map(song => ({
         id: song.id,
         title: song.title,
@@ -27,7 +31,7 @@ export async function GET() {
         activations: song.puzzles.length,
         puzzles: song.puzzles,
         genres: song.genres,
-        specials: song.specials,
+        specials: song.specials.map(ss => ss.special),
     }));
 
     return NextResponse.json(songsWithActivations);
@@ -178,16 +182,51 @@ export async function PUT(request: Request) {
             };
         }
 
-        if (specialIds) {
-            data.specials = {
-                set: specialIds.map((sId: number) => ({ id: sId }))
-            };
+        // Handle SpecialSong relations separately
+        if (specialIds !== undefined) {
+            // First, get current special assignments
+            const currentSpecials = await prisma.specialSong.findMany({
+                where: { songId: Number(id) }
+            });
+
+            const currentSpecialIds = currentSpecials.map(ss => ss.specialId);
+            const newSpecialIds = specialIds as number[];
+
+            // Delete removed specials
+            const toDelete = currentSpecialIds.filter(sid => !newSpecialIds.includes(sid));
+            if (toDelete.length > 0) {
+                await prisma.specialSong.deleteMany({
+                    where: {
+                        songId: Number(id),
+                        specialId: { in: toDelete }
+                    }
+                });
+            }
+
+            // Add new specials
+            const toAdd = newSpecialIds.filter(sid => !currentSpecialIds.includes(sid));
+            if (toAdd.length > 0) {
+                await prisma.specialSong.createMany({
+                    data: toAdd.map(specialId => ({
+                        songId: Number(id),
+                        specialId,
+                        startTime: 0
+                    }))
+                });
+            }
         }
 
         const updatedSong = await prisma.song.update({
             where: { id: Number(id) },
             data,
-            include: { genres: true, specials: true }
+            include: {
+                genres: true,
+                specials: {
+                    include: {
+                        special: true
+                    }
+                }
+            }
         });
 
         return NextResponse.json(updatedSong);

app/api/specials/[id]/route.ts

@@ -0,0 +1,62 @@
+import { NextResponse } from 'next/server';
+import { PrismaClient } from '@prisma/client';
+
+const prisma = new PrismaClient();
+
+export async function GET(
+    request: Request,
+    { params }: { params: Promise<{ id: string }> }
+) {
+    try {
+        const { id } = await params;
+        const specialId = parseInt(id);
+
+        const special = await prisma.special.findUnique({
+            where: { id: specialId },
+            include: {
+                songs: {
+                    include: {
+                        song: true
+                    },
+                    orderBy: {
+                        order: 'asc'
+                    }
+                }
+            }
+        });
+
+        if (!special) {
+            return NextResponse.json({ error: 'Special not found' }, { status: 404 });
+        }
+
+        return NextResponse.json(special);
+    } catch (error) {
+        console.error('Error fetching special:', error);
+        return NextResponse.json({ error: 'Internal Server Error' }, { status: 500 });
+    }
+}
+
+export async function PUT(
+    request: Request,
+    { params }: { params: Promise<{ id: string }> }
+) {
+    try {
+        const { id } = await params;
+        const specialId = parseInt(id);
+        const { name, maxAttempts, unlockSteps } = await request.json();
+
+        const special = await prisma.special.update({
+            where: { id: specialId },
+            data: {
+                name,
+                maxAttempts,
+                unlockSteps: JSON.stringify(unlockSteps)
+            }
+        });
+
+        return NextResponse.json(special);
+    } catch (error) {
+        console.error('Error updating special:', error);
+        return NextResponse.json({ error: 'Internal Server Error' }, { status: 500 });
+    }
+}

app/api/specials/[id]/songs/route.ts

@@ -0,0 +1,89 @@
+import { NextResponse } from 'next/server';
+import { PrismaClient } from '@prisma/client';
+
+const prisma = new PrismaClient();
+
+export async function POST(
+    request: Request,
+    { params }: { params: Promise<{ id: string }> }
+) {
+    try {
+        const { id } = await params;
+        const specialId = parseInt(id);
+        const { songId, startTime = 0, order } = await request.json();
+
+        const specialSong = await prisma.specialSong.create({
+            data: {
+                specialId,
+                songId,
+                startTime,
+                order
+            },
+            include: {
+                song: true
+            }
+        });
+
+        return NextResponse.json(specialSong);
+    } catch (error) {
+        console.error('Error adding song to special:', error);
+        return NextResponse.json({ error: 'Internal Server Error' }, { status: 500 });
+    }
+}
+
+export async function PUT(
+    request: Request,
+    { params }: { params: Promise<{ id: string }> }
+) {
+    try {
+        const { id } = await params;
+        const specialId = parseInt(id);
+        const { songId, startTime, order } = await request.json();
+
+        const specialSong = await prisma.specialSong.update({
+            where: {
+                specialId_songId: {
+                    specialId,
+                    songId
+                }
+            },
+            data: {
+                startTime,
+                order
+            },
+            include: {
+                song: true
+            }
+        });
+
+        return NextResponse.json(specialSong);
+    } catch (error) {
+        console.error('Error updating special song:', error);
+        return NextResponse.json({ error: 'Internal Server Error' }, { status: 500 });
+    }
+}
+
+export async function DELETE(
+    request: Request,
+    { params }: { params: Promise<{ id: string }> }
+) {
+    try {
+        const { id } = await params;
+        const specialId = parseInt(id);
+        const { songId } = await request.json();
+
+        await prisma.specialSong.delete({
+            where: {
+                specialId_songId: {
+                    specialId,
+                    songId
+                }
+            }
+        });
+
+        return NextResponse.json({ success: true });
+    } catch (error) {
+        console.error('Error removing song from special:', error);
+        return NextResponse.json({ error: 'Internal Server Error' }, { status: 500 });
+    }
+}

components/AudioPlayer.tsx

@@ -5,11 +5,12 @@ import { useState, useRef, useEffect } from 'react';
 interface AudioPlayerProps {
     src: string;
     unlockedSeconds: number; // 2, 4, 7, 11, 16, 30 (or full length)
+    startTime?: number; // Start offset in seconds (for curated specials)
     onPlay?: () => void;
     autoPlay?: boolean;
 }
 
-export default function AudioPlayer({ src, unlockedSeconds, onPlay, autoPlay = false }: AudioPlayerProps) {
+export default function AudioPlayer({ src, unlockedSeconds, startTime = 0, onPlay, autoPlay = false }: AudioPlayerProps) {
     const audioRef = useRef<HTMLAudioElement>(null);
     const [isPlaying, setIsPlaying] = useState(false);
     const [progress, setProgress] = useState(0);
@@ -17,7 +18,7 @@ export default function AudioPlayer({ src, unlockedSeconds, onPlay, autoPlay = f
     useEffect(() => {
         if (audioRef.current) {
             audioRef.current.pause();
-            audioRef.current.currentTime = 0;
+            audioRef.current.currentTime = startTime;
             setIsPlaying(false);
             setProgress(0);
 
@@ -36,7 +37,7 @@ export default function AudioPlayer({ src, unlockedSeconds, onPlay, autoPlay = f
                 }
             }
         }
-    }, [src, unlockedSeconds, autoPlay]);
+    }, [src, unlockedSeconds, startTime, autoPlay]);
 
     const togglePlay = () => {
         if (!audioRef.current) return;
@@ -54,12 +55,13 @@ export default function AudioPlayer({ src, unlockedSeconds, onPlay, autoPlay = f
         if (!audioRef.current) return;
 
         const current = audioRef.current.currentTime;
-        const percent = (current / unlockedSeconds) * 100;
+        const elapsed = current - startTime;
+        const percent = (elapsed / unlockedSeconds) * 100;
         setProgress(Math.min(percent, 100));
 
-        if (current >= unlockedSeconds) {
+        if (elapsed >= unlockedSeconds) {
             audioRef.current.pause();
-            audioRef.current.currentTime = 0;
+            audioRef.current.currentTime = startTime;
             setIsPlaying(false);
             setProgress(0);
         }

components/Game.tsx

@@ -16,6 +16,7 @@ interface GameProps {
         title: string;
         artist: string;
         coverImage: string | null;
+        startTime?: number;
     } | null;
     genre?: string | null;
     isSpecial?: boolean;
@@ -195,6 +196,7 @@ export default function Game({ dailyPuzzle, genre = null, isSpecial = false, max
                     <AudioPlayer
                         src={dailyPuzzle.audioUrl}
                         unlockedSeconds={unlockedSeconds}
+                        startTime={dailyPuzzle.startTime}
                         autoPlay={lastAction === 'SKIP'}
                     />
                 </div>

components/WaveformEditor.tsx

@@ -0,0 +1,440 @@
+'use client';
+
+import { useEffect, useRef, useState } from 'react';
+
+interface WaveformEditorProps {
+    audioUrl: string;
+    startTime: number;
+    duration: number; // Total puzzle duration (e.g., 60s)
+    unlockSteps: number[]; // e.g., [2, 4, 7, 11, 16, 30, 60]
+    onStartTimeChange: (newStartTime: number) => void;
+}
+
+export default function WaveformEditor({ audioUrl, startTime, duration, unlockSteps, onStartTimeChange }: WaveformEditorProps) {
+    const canvasRef = useRef<HTMLCanvasElement>(null);
+    const [audioBuffer, setAudioBuffer] = useState<AudioBuffer | null>(null);
+    const [audioDuration, setAudioDuration] = useState(0);
+    const [isPlaying, setIsPlaying] = useState(false);
+    const [playingSegment, setPlayingSegment] = useState<number | null>(null);
+    const [zoom, setZoom] = useState(1); // 1 = full view, higher = zoomed in
+    const [viewOffset, setViewOffset] = useState(0); // Offset in seconds for panning
+    const [playbackPosition, setPlaybackPosition] = useState<number | null>(null); // Current playback position in seconds
+    const [hoverPreviewTime, setHoverPreviewTime] = useState<number | null>(null); // Preview position on hover
+    const audioContextRef = useRef<AudioContext | null>(null);
+    const sourceRef = useRef<AudioBufferSourceNode | null>(null);
+    const playbackStartTimeRef = useRef<number>(0); // When playback started
+    const playbackOffsetRef = useRef<number>(0); // Offset in the audio file
+    const animationFrameRef = useRef<number | null>(null);
+
+    useEffect(() => {
+        const loadAudio = async () => {
+            try {
+                const response = await fetch(audioUrl);
+                const arrayBuffer = await response.arrayBuffer();
+
+                const audioContext = new (window.AudioContext || (window as any).webkitAudioContext)();
+                audioContextRef.current = audioContext;
+
+                const buffer = await audioContext.decodeAudioData(arrayBuffer);
+                setAudioBuffer(buffer);
+                setAudioDuration(buffer.duration);
+            } catch (error) {
+                console.error('Error loading audio:', error);
+            }
+        };
+
+        loadAudio();
+
+        return () => {
+            if (sourceRef.current) {
+                sourceRef.current.stop();
+            }
+            if (animationFrameRef.current) {
+                cancelAnimationFrame(animationFrameRef.current);
+            }
+        };
+    }, [audioUrl]);
+
+    useEffect(() => {
+        if (!audioBuffer || !canvasRef.current) return;
+
+        const canvas = canvasRef.current;
+        const ctx = canvas.getContext('2d');
+        if (!ctx) return;
+
+        const width = canvas.width;
+        const height = canvas.height;
+
+        // Calculate visible range based on zoom and offset
+        const visibleDuration = audioDuration / zoom;
+        const visibleStart = Math.max(0, Math.min(viewOffset, audioDuration - visibleDuration));
+        const visibleEnd = Math.min(audioDuration, visibleStart + visibleDuration);
+
+        // Clear canvas
+        ctx.fillStyle = '#f3f4f6';
+        ctx.fillRect(0, 0, width, height);
+
+        // Draw waveform for visible range
+        const data = audioBuffer.getChannelData(0);
+        const samplesPerPixel = Math.ceil((data.length * visibleDuration / audioDuration) / width);
+        const startSample = Math.floor(data.length * visibleStart / audioDuration);
+        const amp = height / 2;
+
+        ctx.fillStyle = '#4f46e5';
+        for (let i = 0; i < width; i++) {
+            let min = 1.0;
+            let max = -1.0;
+            const sampleIndex = startSample + (i * samplesPerPixel);
+            for (let j = 0; j < samplesPerPixel && sampleIndex + j < data.length; j++) {
+                const datum = data[sampleIndex + j];
+                if (datum < min) min = datum;
+                if (datum > max) max = datum;
+            }
+            ctx.fillRect(i, (1 + min) * amp, 1, Math.max(1, (max - min) * amp));
+        }
+
+        // Draw selection overlay
+        const selectionStartPx = ((startTime - visibleStart) / visibleDuration) * width;
+        const selectionWidthPx = (duration / visibleDuration) * width;
+
+        if (selectionStartPx + selectionWidthPx > 0 && selectionStartPx < width) {
+            ctx.fillStyle = 'rgba(79, 70, 229, 0.3)';
+            ctx.fillRect(Math.max(0, selectionStartPx), 0, Math.min(selectionWidthPx, width - selectionStartPx), height);
+
+            // Draw selection borders
+            ctx.strokeStyle = '#4f46e5';
+            ctx.lineWidth = 2;
+            ctx.strokeRect(Math.max(0, selectionStartPx), 0, Math.min(selectionWidthPx, width - selectionStartPx), height);
+        }
+
+        // Draw segment markers (vertical lines)
+        ctx.strokeStyle = '#ef4444';
+        ctx.lineWidth = 1;
+        ctx.setLineDash([5, 5]);
+
+        let cumulativeTime = 0;
+        unlockSteps.forEach((step, index) => {
+            const segmentTime = startTime + cumulativeTime;
+            const segmentPx = ((segmentTime - visibleStart) / visibleDuration) * width;
+
+            if (segmentPx >= 0 && segmentPx <= width) {
+                ctx.beginPath();
+                ctx.moveTo(segmentPx, 0);
+                ctx.lineTo(segmentPx, height);
+                ctx.stroke();
+
+                // Draw segment number
+                ctx.setLineDash([]);
+                ctx.fillStyle = '#ef4444';
+                ctx.font = 'bold 12px sans-serif';
+                ctx.fillText(`${index + 1}`, segmentPx + 3, 15);
+                ctx.setLineDash([5, 5]);
+            }
+
+            cumulativeTime = step;
+        });
+        ctx.setLineDash([]);
+
+        // Draw hover preview (semi-transparent)
+        if (hoverPreviewTime !== null) {
+            const previewStartPx = ((hoverPreviewTime - visibleStart) / visibleDuration) * width;
+            const previewWidthPx = (duration / visibleDuration) * width;
+
+            if (previewStartPx + previewWidthPx > 0 && previewStartPx < width) {
+                ctx.fillStyle = 'rgba(16, 185, 129, 0.2)'; // Light green
+                ctx.fillRect(Math.max(0, previewStartPx), 0, Math.min(previewWidthPx, width - previewStartPx), height);
+
+                // Draw preview borders
+                ctx.strokeStyle = '#10b981';
+                ctx.lineWidth = 2;
+                ctx.setLineDash([5, 5]);
+                ctx.strokeRect(Math.max(0, previewStartPx), 0, Math.min(previewWidthPx, width - previewStartPx), height);
+                ctx.setLineDash([]);
+            }
+        }
+
+        // Draw playback cursor
+        if (playbackPosition !== null) {
+            const cursorPx = ((playbackPosition - visibleStart) / visibleDuration) * width;
+            if (cursorPx >= 0 && cursorPx <= width) {
+                ctx.strokeStyle = '#10b981'; // Green
+                ctx.lineWidth = 2;
+                ctx.beginPath();
+                ctx.moveTo(cursorPx, 0);
+                ctx.lineTo(cursorPx, height);
+                ctx.stroke();
+
+                // Draw playhead triangle
+                ctx.fillStyle = '#10b981';
+                ctx.beginPath();
+                ctx.moveTo(cursorPx, 0);
+                ctx.lineTo(cursorPx - 5, 10);
+                ctx.lineTo(cursorPx + 5, 10);
+                ctx.closePath();
+                ctx.fill();
+            }
+        }
+
+    }, [audioBuffer, startTime, duration, audioDuration, zoom, viewOffset, unlockSteps, playbackPosition, hoverPreviewTime]);
+
+    const handleCanvasClick = (e: React.MouseEvent<HTMLCanvasElement>) => {
+        if (!canvasRef.current || !audioDuration) return;
+
+        const rect = canvasRef.current.getBoundingClientRect();
+        const x = e.clientX - rect.left;
+        const visibleDuration = audioDuration / zoom;
+        const visibleStart = Math.max(0, Math.min(viewOffset, audioDuration - visibleDuration));
+        const clickedTime = visibleStart + (x / rect.width) * visibleDuration;
+
+        // Center the selection on the clicked point
+        let newStartTime = clickedTime - (duration / 2);
+
+        // Clamp to valid range
+        newStartTime = Math.max(0, Math.min(newStartTime, audioDuration - duration));
+
+        onStartTimeChange(Math.floor(newStartTime));
+    };
+
+    const handleCanvasMouseMove = (e: React.MouseEvent<HTMLCanvasElement>) => {
+        if (!canvasRef.current || !audioDuration) return;
+
+        const rect = canvasRef.current.getBoundingClientRect();
+        const x = e.clientX - rect.left;
+        const visibleDuration = audioDuration / zoom;
+        const visibleStart = Math.max(0, Math.min(viewOffset, audioDuration - visibleDuration));
+        const hoveredTime = visibleStart + (x / rect.width) * visibleDuration;
+
+        // Calculate where the selection would be centered on this point
+        let previewStartTime = hoveredTime - (duration / 2);
+        previewStartTime = Math.max(0, Math.min(previewStartTime, audioDuration - duration));
+
+        setHoverPreviewTime(previewStartTime);
+    };
+
+    const handleCanvasMouseLeave = () => {
+        setHoverPreviewTime(null);
+    };
+
+    const stopPlayback = () => {
+        sourceRef.current?.stop();
+        setIsPlaying(false);
+        setPlayingSegment(null);
+        setPlaybackPosition(null);
+        if (animationFrameRef.current) {
+            cancelAnimationFrame(animationFrameRef.current);
+            animationFrameRef.current = null;
+        }
+    };
+
+    // Animation loop for playback cursor
+    useEffect(() => {
+        if (!isPlaying || !audioContextRef.current) {
+            return;
+        }
+
+        const animate = () => {
+            if (!audioContextRef.current || !isPlaying) return;
+
+            const elapsed = audioContextRef.current.currentTime - playbackStartTimeRef.current;
+            const currentPos = playbackOffsetRef.current + elapsed;
+            setPlaybackPosition(currentPos);
+
+            animationFrameRef.current = requestAnimationFrame(animate);
+        };
+
+        animationFrameRef.current = requestAnimationFrame(animate);
+
+        return () => {
+            if (animationFrameRef.current) {
+                cancelAnimationFrame(animationFrameRef.current);
+            }
+        };
+    }, [isPlaying]);
+
+    const handlePlaySegment = (segmentIndex: number) => {
+        if (!audioBuffer || !audioContextRef.current) return;
+
+        stopPlayback();
+
+        const source = audioContextRef.current.createBufferSource();
+        source.buffer = audioBuffer;
+        source.connect(audioContextRef.current.destination);
+
+        // Calculate segment start and duration
+        const segmentStart = startTime + (segmentIndex > 0 ? unlockSteps[segmentIndex - 1] : 0);
+        const segmentDuration = unlockSteps[segmentIndex] - (segmentIndex > 0 ? unlockSteps[segmentIndex - 1] : 0);
+
+        playbackStartTimeRef.current = audioContextRef.current.currentTime;
+        playbackOffsetRef.current = segmentStart;
+
+        source.start(0, segmentStart, segmentDuration);
+        sourceRef.current = source;
+        setIsPlaying(true);
+        setPlayingSegment(segmentIndex);
+        setPlaybackPosition(segmentStart);
+
+        source.onended = () => {
+            setIsPlaying(false);
+            setPlayingSegment(null);
+            setPlaybackPosition(null);
+            if (animationFrameRef.current) {
+                cancelAnimationFrame(animationFrameRef.current);
+                animationFrameRef.current = null;
+            }
+        };
+    };
+
+    const handlePlayFull = () => {
+        if (!audioBuffer || !audioContextRef.current) return;
+
+        if (isPlaying) {
+            stopPlayback();
+        } else {
+            const source = audioContextRef.current.createBufferSource();
+            source.buffer = audioBuffer;
+            source.connect(audioContextRef.current.destination);
+
+            playbackStartTimeRef.current = audioContextRef.current.currentTime;
+            playbackOffsetRef.current = startTime;
+
+            source.start(0, startTime, duration);
+            sourceRef.current = source;
+            setIsPlaying(true);
+            setPlaybackPosition(startTime);
+
+            source.onended = () => {
+                setIsPlaying(false);
+                setPlaybackPosition(null);
+                if (animationFrameRef.current) {
+                    cancelAnimationFrame(animationFrameRef.current);
+                    animationFrameRef.current = null;
+                }
+            };
+        }
+    };
+
+    const handleZoomIn = () => setZoom(prev => Math.min(prev * 1.5, 10));
+    const handleZoomOut = () => setZoom(prev => Math.max(prev / 1.5, 1));
+    const handlePanLeft = () => {
+        const visibleDuration = audioDuration / zoom;
+        setViewOffset(prev => Math.max(0, prev - visibleDuration * 0.2));
+    };
+    const handlePanRight = () => {
+        const visibleDuration = audioDuration / zoom;
+        setViewOffset(prev => Math.min(audioDuration - visibleDuration, prev + visibleDuration * 0.2));
+    };
+
+    return (
+        <div style={{ marginTop: '1rem' }}>
+            {/* Zoom and Pan Controls */}
+            <div style={{ marginBottom: '0.5rem', display: 'flex', gap: '0.5rem', alignItems: 'center' }}>
+                <button
+                    onClick={handleZoomOut}
+                    disabled={zoom <= 1}
+                    style={{
+                        padding: '0.25rem 0.5rem',
+                        background: zoom <= 1 ? '#e5e7eb' : '#4f46e5',
+                        color: zoom <= 1 ? '#9ca3af' : 'white',
+                        border: 'none',
+                        borderRadius: '0.25rem',
+                        cursor: zoom <= 1 ? 'not-allowed' : 'pointer',
+                        fontSize: '0.875rem'
+                    }}
+                >
+                    🔍−
+                </button>
+                <button
+                    onClick={handleZoomIn}
+                    disabled={zoom >= 10}
+                    style={{
+                        padding: '0.25rem 0.5rem',
+                        background: zoom >= 10 ? '#e5e7eb' : '#4f46e5',
+                        color: zoom >= 10 ? '#9ca3af' : 'white',
+                        border: 'none',
+                        borderRadius: '0.25rem',
+                        cursor: zoom >= 10 ? 'not-allowed' : 'pointer',
+                        fontSize: '0.875rem'
+                    }}
+                >
+                    🔍+
+                </button>
+                <span style={{ fontSize: '0.75rem', color: '#666' }}>Zoom: {zoom.toFixed(1)}x</span>
+                {zoom > 1 && (
+                    <>
+                        <button onClick={handlePanLeft} style={{ padding: '0.25rem 0.5rem', background: '#4f46e5', color: 'white', border: 'none', borderRadius: '0.25rem', cursor: 'pointer', fontSize: '0.875rem' }}>
+                            ←
+                        </button>
+                        <button onClick={handlePanRight} style={{ padding: '0.25rem 0.5rem', background: '#4f46e5', color: 'white', border: 'none', borderRadius: '0.25rem', cursor: 'pointer', fontSize: '0.875rem' }}>
+                            →
+                        </button>
+                    </>
+                )}
+            </div>
+
+            <canvas
+                ref={canvasRef}
+                width={800}
+                height={150}
+                onClick={handleCanvasClick}
+                onMouseMove={handleCanvasMouseMove}
+                onMouseLeave={handleCanvasMouseLeave}
+                style={{
+                    width: '100%',
+                    height: 'auto',
+                    cursor: 'pointer',
+                    border: '1px solid #e5e7eb',
+                    borderRadius: '0.5rem'
+                }}
+            />
+
+            {/* Playback Controls */}
+            <div style={{ marginTop: '1rem', display: 'flex', gap: '1rem', alignItems: 'center', flexWrap: 'wrap' }}>
+                <button
+                    onClick={handlePlayFull}
+                    style={{
+                        padding: '0.5rem 1rem',
+                        background: '#4f46e5',
+                        color: 'white',
+                        border: 'none',
+                        borderRadius: '0.5rem',
+                        cursor: 'pointer',
+                        fontWeight: 'bold'
+                    }}
+                >
+                    {isPlaying && playingSegment === null ? '⏸ Pause' : '▶ Play Full Selection'}
+                </button>
+
+                <div style={{ fontSize: '0.875rem', color: '#666' }}>
+                    Start: {startTime}s | Duration: {duration}s | Total: {Math.floor(audioDuration)}s
+                </div>
+            </div>
+
+            {/* Segment Playback Buttons */}
+            <div style={{ marginTop: '1rem', display: 'flex', gap: '0.5rem', flexWrap: 'wrap' }}>
+                <span style={{ fontSize: '0.875rem', color: '#666', marginRight: '0.5rem' }}>Play Segments:</span>
+                {unlockSteps.map((step, index) => {
+                    const segmentStart = index > 0 ? unlockSteps[index - 1] : 0;
+                    const segmentDuration = step - segmentStart;
+                    return (
+                        <button
+                            key={index}
+                            onClick={() => handlePlaySegment(index)}
+                            style={{
+                                padding: '0.25rem 0.75rem',
+                                background: playingSegment === index ? '#ef4444' : '#f3f4f6',
+                                color: playingSegment === index ? 'white' : '#374151',
+                                border: '1px solid #e5e7eb',
+                                borderRadius: '0.25rem',
+                                cursor: 'pointer',
+                                fontSize: '0.75rem',
+                                fontWeight: playingSegment === index ? 'bold' : 'normal'
+                            }}
+                        >
+                            {index + 1} ({segmentDuration}s)
+                        </button>
+                    );
+                })}
+            </div>
+        </div>
+    );
+}

lib/dailyPuzzle.ts

@@ -146,32 +146,36 @@ export async function getOrCreateSpecialPuzzle(specialName: string) {
         });
 
         if (!dailyPuzzle) {
-            // Get songs available for this special
-            const allSongs = await prisma.song.findMany({
-                where: { specials: { some: { id: special.id } } },
+            // Get songs available for this special through SpecialSong
+            const specialSongs = await prisma.specialSong.findMany({
+                where: { specialId: special.id },
                 include: {
-                    puzzles: {
-                        where: { specialId: special.id }
-                    },
-                },
+                    song: {
+                        include: {
+                            puzzles: {
+                                where: { specialId: special.id }
+                            }
+                        }
+                    }
+                }
             });
 
-            if (allSongs.length === 0) return null;
+            if (specialSongs.length === 0) return null;
 
             // Calculate weights
-            const weightedSongs = allSongs.map(song => ({
-                song,
-                weight: 1.0 / (song.puzzles.length + 1),
+            const weightedSongs = specialSongs.map(specialSong => ({
+                specialSong,
+                weight: 1.0 / (specialSong.song.puzzles.length + 1),
             }));
 
             const totalWeight = weightedSongs.reduce((sum, item) => sum + item.weight, 0);
             let random = Math.random() * totalWeight;
-            let selectedSong = weightedSongs[0].song;
+            let selectedSpecialSong = weightedSongs[0].specialSong;
 
             for (const item of weightedSongs) {
                 random -= item.weight;
                 if (random <= 0) {
-                    selectedSong = item.song;
+                    selectedSpecialSong = item.specialSong;
                     break;
                 }
             }
@@ -180,7 +184,7 @@ export async function getOrCreateSpecialPuzzle(specialName: string) {
                 dailyPuzzle = await prisma.dailyPuzzle.create({
                     data: {
                         date: today,
-                        songId: selectedSong.id,
+                        songId: selectedSpecialSong.songId,
                         specialId: special.id
                     },
                     include: { song: true },
@@ -198,6 +202,16 @@ export async function getOrCreateSpecialPuzzle(specialName: string) {
 
         if (!dailyPuzzle) return null;
 
+        // Fetch the startTime from SpecialSong
+        const specialSong = await prisma.specialSong.findUnique({
+            where: {
+                specialId_songId: {
+                    specialId: special.id,
+                    songId: dailyPuzzle.songId
+                }
+            }
+        });
+
         // Calculate puzzle number
         const puzzleCount = await prisma.dailyPuzzle.count({
             where: {
@@ -218,7 +232,8 @@ export async function getOrCreateSpecialPuzzle(specialName: string) {
             coverImage: dailyPuzzle.song.coverImage ? `/uploads/covers/${dailyPuzzle.song.coverImage}` : null,
             special: specialName,
             maxAttempts: special.maxAttempts,
-            unlockSteps: JSON.parse(special.unlockSteps)
+            unlockSteps: JSON.parse(special.unlockSteps),
+            startTime: specialSong?.startTime || 0
         };
 
     } catch (error) {

prisma/migrations/20251123012308_add_special_song_model/migration.sql

@@ -0,0 +1,21 @@
+-- CreateTable
+CREATE TABLE "SpecialSong" (
+    "id" INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+    "specialId" INTEGER NOT NULL,
+    "songId" INTEGER NOT NULL,
+    "startTime" INTEGER NOT NULL DEFAULT 0,
+    "order" INTEGER,
+    CONSTRAINT "SpecialSong_specialId_fkey" FOREIGN KEY ("specialId") REFERENCES "Special" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT "SpecialSong_songId_fkey" FOREIGN KEY ("songId") REFERENCES "Song" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- Migrate data from _SongToSpecial to SpecialSong
+INSERT INTO "SpecialSong" ("specialId", "songId", "startTime")
+SELECT "B" as "specialId", "A" as "songId", 0 as "startTime"
+FROM "_SongToSpecial";
+
+-- DropTable
+DROP TABLE "_SongToSpecial";
+
+-- CreateIndex
+CREATE UNIQUE INDEX "SpecialSong_specialId_songId_key" ON "SpecialSong"("specialId", "songId");

prisma/schema.prisma

@@ -19,7 +19,7 @@ model Song {
   createdAt DateTime @default(now())
   puzzles   DailyPuzzle[]
   genres    Genre[]
-  specials  Special[]
+  specials  SpecialSong[]
 }
 
 model Genre {
@@ -35,10 +35,22 @@ model Special {
   maxAttempts Int      @default(7)
   unlockSteps String   // JSON array: "[2,4,7,11,16,30,60]"
   createdAt   DateTime @default(now())
-  songs       Song[]
+  songs       SpecialSong[]
   dailyPuzzles DailyPuzzle[]
 }
 
+model SpecialSong {
+  id        Int     @id @default(autoincrement())
+  specialId Int
+  special   Special @relation(fields: [specialId], references: [id], onDelete: Cascade)
+  songId    Int
+  song      Song    @relation(fields: [songId], references: [id], onDelete: Cascade)
+  startTime Int     @default(0) // Start time in seconds
+  order     Int?    // For manual ordering
+
+  @@unique([specialId, songId])
+}
+
 model DailyPuzzle {
   id        Int      @id @default(autoincrement())
   date      String   // Format: YYYY-MM-DD