'use client';

import { useState } from 'react';
import WaveformEditor from '@/components/WaveformEditor';

export type LocalizedString = string | { de: string; en: string };

export interface CurateSpecialSong {
    id: number;
    songId: number;
    startTime: number;
    order: number | null;
    song: {
        id: number;
        title: string;
        artist: string;
        filename: string;
    };
}

export interface CurateSpecial {
    id: number;
    name: LocalizedString;
    subtitle?: LocalizedString | null;
    maxAttempts: number;
    unlockSteps: string;
    songs: CurateSpecialSong[];
}

export interface CurateSpecialEditorProps {
    special: CurateSpecial;
    locale: 'de' | 'en';
    onBack: () => void;
    onSaveStartTime: (songId: number, startTime: number) => Promise<void>;
    backLabel?: string;
    headerPrefix?: string;
    noSongsHint?: string;
    noSongsSubHint?: string;
    instructionsText?: string;
    savingLabel?: string;
    saveChangesLabel?: string;
    savedLabel?: string;
}

const resolveLocalized = (value: LocalizedString | null | undefined, locale: 'de' | 'en'): string | undefined => {
    if (!value) return undefined;
    if (typeof value === 'string') return value;
    return value[locale] ?? value.en ?? value.de;
};

export default function CurateSpecialEditor({
    special,
    locale,
    onBack,
    onSaveStartTime,
    backLabel = '← Back',
    headerPrefix = 'Edit Special:',
    noSongsHint = 'No songs assigned to this special yet.',
    noSongsSubHint = 'Go back to the dashboard to add songs to this special.',
    instructionsText = 'Click on the waveform to select where the puzzle should start. The highlighted region shows what players will hear.',
    savingLabel = '💾 Saving...',
    saveChangesLabel = '💾 Save Changes',
    savedLabel = '✓ Saved',
}: CurateSpecialEditorProps) {
    const [selectedSongId, setSelectedSongId] = useState<number | null>(
        special.songs.length > 0 ? special.songs[0].songId : null
    );
    const [pendingStartTime, setPendingStartTime] = useState<number | null>(
        special.songs.length > 0 ? special.songs[0].startTime : null
    );
    const [hasUnsavedChanges, setHasUnsavedChanges] = useState(false);
    const [saving, setSaving] = useState(false);

    const specialName = resolveLocalized(special.name, locale) ?? `Special #${special.id}`;
    const specialSubtitle = resolveLocalized(special.subtitle ?? null, locale);

    const unlockSteps = JSON.parse(special.unlockSteps);
    const totalDuration = unlockSteps[unlockSteps.length - 1];

    const selectedSpecialSong = special.songs.find(ss => ss.songId === selectedSongId) ?? null;

    const handleStartTimeChange = (newStartTime: number) => {
        setPendingStartTime(newStartTime);
        setHasUnsavedChanges(true);
    };

    const handleSave = async () => {
        if (!selectedSongId || pendingStartTime === null) return;
        setSaving(true);
        try {
            await onSaveStartTime(selectedSongId, pendingStartTime);
            setHasUnsavedChanges(false);
        } finally {
            setSaving(false);
        }
    };

    return (
        <div style={{ padding: '2rem', maxWidth: '1200px', margin: '0 auto' }}>
            <div style={{ marginBottom: '2rem' }}>
                <h1 style={{ fontSize: '2rem', fontWeight: 'bold' }}>
                    {headerPrefix} {specialName}
                </h1>
                {specialSubtitle && (
                    <p style={{ fontSize: '1.125rem', color: '#4b5563', marginTop: '0.25rem' }}>
                        {specialSubtitle}
                    </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>{noSongsHint}</p>
                    <p style={{ fontSize: '0.875rem', color: '#666', marginTop: '0.5rem' }}>
                        {noSongsSubHint}
                    </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);
                                        setPendingStartTime(ss.startTime);
                                        setHasUnsavedChanges(false);
                                    }}
                                    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 }}>
                                        {instructionsText}
                                    </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 ? savingLabel : hasUnsavedChanges ? saveChangesLabel : savedLabel}
                                    </button>
                                </div>
                                <WaveformEditor
                                    audioUrl={`/uploads/${selectedSpecialSong.song.filename}`}
                                    startTime={pendingStartTime ?? selectedSpecialSong.startTime}
                                    duration={totalDuration}
                                    unlockSteps={unlockSteps}
                                    onStartTimeChange={handleStartTimeChange}
                                />
                            </div>
                        </div>
                    )}
                </div>
            )}
        </div>
    );
}