'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;
    subtitle?: 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>
                {special.subtitle && (
                    <p style={{ fontSize: '1.125rem', color: '#4b5563', marginTop: '0.25rem' }}>
                        {special.subtitle}
                    </p>
                )}
                <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>
    );
}