'use client';

import { useState, useEffect } from 'react';

interface Song {
    id: number;
    title: string;
    artist: string;
    filename: string;
    createdAt: string;
    activations: number;
}

type SortField = 'title' | 'artist' | 'createdAt';
type SortDirection = 'asc' | 'desc';

export default function AdminPage() {
    const [password, setPassword] = useState('');
    const [isAuthenticated, setIsAuthenticated] = useState(false);
    const [file, setFile] = useState<File | null>(null);
    const [message, setMessage] = useState('');
    const [songs, setSongs] = useState<Song[]>([]);

    // Edit state
    const [editingId, setEditingId] = useState<number | null>(null);
    const [editTitle, setEditTitle] = useState('');
    const [editArtist, setEditArtist] = useState('');

    // Sort state
    const [sortField, setSortField] = useState<SortField>('artist');
    const [sortDirection, setSortDirection] = useState<SortDirection>('asc');

    // Search and pagination state
    const [searchQuery, setSearchQuery] = useState('');
    const [currentPage, setCurrentPage] = useState(1);
    const itemsPerPage = 10;

    const handleLogin = async () => {
        const res = await fetch('/api/admin/login', {
            method: 'POST',
            body: JSON.stringify({ password }),
        });
        if (res.ok) {
            setIsAuthenticated(true);
            fetchSongs();
        } else {
            alert('Wrong password');
        }
    };

    const fetchSongs = async () => {
        const res = await fetch('/api/songs');
        if (res.ok) {
            const data = await res.json();
            setSongs(data);
        }
    };

    const handleUpload = async (e: React.FormEvent) => {
        e.preventDefault();
        if (!file) return;

        const formData = new FormData();
        formData.append('file', file);

        setMessage('Uploading...');
        const res = await fetch('/api/songs', {
            method: 'POST',
            body: formData,
        });

        if (res.ok) {
            setMessage('Song uploaded successfully!');
            setFile(null);
            fetchSongs();
        } else {
            setMessage('Upload failed.');
        }
    };

    const startEditing = (song: Song) => {
        setEditingId(song.id);
        setEditTitle(song.title);
        setEditArtist(song.artist);
    };

    const cancelEditing = () => {
        setEditingId(null);
        setEditTitle('');
        setEditArtist('');
    };

    const saveEditing = async (id: number) => {
        const res = await fetch('/api/songs', {
            method: 'PUT',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ id, title: editTitle, artist: editArtist }),
        });

        if (res.ok) {
            setEditingId(null);
            fetchSongs();
        } else {
            alert('Failed to update song');
        }
    };

    const handleDelete = async (id: number, title: string) => {
        if (!confirm(`Are you sure you want to delete "${title}"? This will also delete the file.`)) {
            return;
        }

        const res = await fetch('/api/songs', {
            method: 'DELETE',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ id }),
        });

        if (res.ok) {
            fetchSongs();
        } else {
            alert('Failed to delete song');
        }
    };

    const handleSort = (field: SortField) => {
        if (sortField === field) {
            setSortDirection(sortDirection === 'asc' ? 'desc' : 'asc');
        } else {
            setSortField(field);
            setSortDirection('asc');
        }
    };

    // Filter and sort songs
    const filteredSongs = songs.filter(song =>
        song.title.toLowerCase().includes(searchQuery.toLowerCase()) ||
        song.artist.toLowerCase().includes(searchQuery.toLowerCase())
    );

    const sortedSongs = [...filteredSongs].sort((a, b) => {
        const valA = a[sortField].toLowerCase();
        const valB = b[sortField].toLowerCase();

        if (valA < valB) return sortDirection === 'asc' ? -1 : 1;
        if (valA > valB) return sortDirection === 'asc' ? 1 : -1;
        return 0;
    });

    // Pagination
    const totalPages = Math.ceil(sortedSongs.length / itemsPerPage);
    const startIndex = (currentPage - 1) * itemsPerPage;
    const paginatedSongs = sortedSongs.slice(startIndex, startIndex + itemsPerPage);

    // Reset to page 1 when search changes
    useEffect(() => {
        setCurrentPage(1);
    }, [searchQuery]);

    if (!isAuthenticated) {
        return (
            <div className="container" style={{ justifyContent: 'center' }}>
                <h1 className="title" style={{ marginBottom: '1rem', fontSize: '1.5rem' }}>Admin Login</h1>
                <input
                    type="password"
                    value={password}
                    onChange={e => setPassword(e.target.value)}
                    className="form-input"
                    style={{ marginBottom: '1rem', maxWidth: '300px' }}
                    placeholder="Password"
                />
                <button onClick={handleLogin} className="btn-primary">Login</button>
            </div>
        );
    }

    return (
        <div className="admin-container">
            <h1 className="title" style={{ marginBottom: '2rem' }}>Admin Dashboard</h1>

            <div className="admin-card" style={{ marginBottom: '2rem' }}>
                <h2 style={{ fontSize: '1.25rem', fontWeight: 'bold', marginBottom: '1rem' }}>Upload New Song</h2>
                <form onSubmit={handleUpload}>
                    <div className="form-group">
                        <label className="form-label">MP3 File (Title and Artist will be extracted from ID3 tags)</label>
                        <input
                            type="file"
                            accept="audio/mpeg"
                            onChange={e => setFile(e.target.files?.[0] || null)}
                            className="form-input"
                            required
                        />
                    </div>
                    <button type="submit" className="btn-primary">
                        Upload Song
                    </button>
                    {message && <p style={{ textAlign: 'center', marginTop: '0.5rem' }}>{message}</p>}
                </form>
            </div>

            <div className="admin-card">
                <h2 style={{ fontSize: '1.25rem', fontWeight: 'bold', marginBottom: '1rem' }}>Song Library</h2>

                {/* Search */}
                <div style={{ marginBottom: '1rem' }}>
                    <input
                        type="text"
                        placeholder="Search by title or artist..."
                        value={searchQuery}
                        onChange={e => setSearchQuery(e.target.value)}
                        className="form-input"
                    />
                </div>

                <div style={{ overflowX: 'auto' }}>
                    <table style={{ width: '100%', borderCollapse: 'collapse', fontSize: '0.875rem' }}>
                        <thead>
                            <tr style={{ borderBottom: '2px solid #e5e7eb', textAlign: 'left' }}>
                                <th style={{ padding: '0.75rem' }}>ID</th>
                                <th
                                    style={{ padding: '0.75rem', cursor: 'pointer', userSelect: 'none' }}
                                    onClick={() => handleSort('title')}
                                >
                                    Title {sortField === 'title' && (sortDirection === 'asc' ? '↑' : '↓')}
                                </th>
                                <th
                                    style={{ padding: '0.75rem', cursor: 'pointer', userSelect: 'none' }}
                                    onClick={() => handleSort('artist')}
                                >
                                    Artist {sortField === 'artist' && (sortDirection === 'asc' ? '↑' : '↓')}
                                </th>
                                <th
                                    style={{ padding: '0.75rem', cursor: 'pointer', userSelect: 'none' }}
                                    onClick={() => handleSort('createdAt')}
                                >
                                    Added {sortField === 'createdAt' && (sortDirection === 'asc' ? '↑' : '↓')}
                                </th>
                                <th style={{ padding: '0.75rem' }}>Activations</th>
                                <th style={{ padding: '0.75rem' }}>Actions</th>
                            </tr>
                        </thead>
                        <tbody>
                            {paginatedSongs.map(song => (
                                <tr key={song.id} style={{ borderBottom: '1px solid #e5e7eb' }}>
                                    <td style={{ padding: '0.75rem' }}>{song.id}</td>

                                    {editingId === song.id ? (
                                        <>
                                            <td style={{ padding: '0.75rem' }}>
                                                <input
                                                    type="text"
                                                    value={editTitle}
                                                    onChange={e => setEditTitle(e.target.value)}
                                                    className="form-input"
                                                    style={{ padding: '0.25rem' }}
                                                />
                                            </td>
                                            <td style={{ padding: '0.75rem' }}>
                                                <input
                                                    type="text"
                                                    value={editArtist}
                                                    onChange={e => setEditArtist(e.target.value)}
                                                    className="form-input"
                                                    style={{ padding: '0.25rem' }}
                                                />
                                            </td>
                                            <td style={{ padding: '0.75rem', color: '#666', fontSize: '0.75rem' }}>
                                                {new Date(song.createdAt).toLocaleDateString('de-DE')}
                                            </td>
                                            <td style={{ padding: '0.75rem', color: '#666' }}>{song.activations}</td>
                                            <td style={{ padding: '0.75rem' }}>
                                                <div style={{ display: 'flex', gap: '0.5rem' }}>
                                                    <button
                                                        onClick={() => saveEditing(song.id)}
                                                        style={{ fontSize: '1.25rem', cursor: 'pointer', border: 'none', background: 'none' }}
                                                        title="Save"
                                                    >
                                                        ✅
                                                    </button>
                                                    <button
                                                        onClick={cancelEditing}
                                                        style={{ fontSize: '1.25rem', cursor: 'pointer', border: 'none', background: 'none' }}
                                                        title="Cancel"
                                                    >
                                                        ❌
                                                    </button>
                                                </div>
                                            </td>
                                        </>
                                    ) : (
                                        <>
                                            <td style={{ padding: '0.75rem', fontWeight: 'bold' }}>{song.title}</td>
                                            <td style={{ padding: '0.75rem' }}>{song.artist}</td>
                                            <td style={{ padding: '0.75rem', color: '#666', fontSize: '0.75rem' }}>
                                                {new Date(song.createdAt).toLocaleDateString('de-DE')}
                                            </td>
                                            <td style={{ padding: '0.75rem', color: '#666' }}>{song.activations}</td>
                                            <td style={{ padding: '0.75rem' }}>
                                                <div style={{ display: 'flex', gap: '0.5rem' }}>
                                                    <button
                                                        onClick={() => startEditing(song)}
                                                        style={{ fontSize: '1.25rem', cursor: 'pointer', border: 'none', background: 'none' }}
                                                        title="Edit"
                                                    >
                                                        ✏️
                                                    </button>
                                                    <button
                                                        onClick={() => handleDelete(song.id, song.title)}
                                                        style={{ fontSize: '1.25rem', cursor: 'pointer', border: 'none', background: 'none' }}
                                                        title="Delete"
                                                    >
                                                        🗑️
                                                    </button>
                                                </div>
                                            </td>
                                        </>
                                    )}
                                </tr>
                            ))}
                            {paginatedSongs.length === 0 && (
                                <tr>
                                    <td colSpan={6} style={{ padding: '1rem', textAlign: 'center', color: '#666' }}>
                                        {searchQuery ? 'No songs found matching your search.' : 'No songs uploaded yet.'}
                                    </td>
                                </tr>
                            )}
                        </tbody>
                    </table>
                </div>

                {/* Pagination */}
                {totalPages > 1 && (
                    <div style={{ marginTop: '1rem', display: 'flex', justifyContent: 'center', gap: '0.5rem', alignItems: 'center' }}>
                        <button
                            onClick={() => setCurrentPage(p => Math.max(1, p - 1))}
                            disabled={currentPage === 1}
                            style={{
                                padding: '0.5rem 1rem',
                                border: '1px solid #d1d5db',
                                background: currentPage === 1 ? '#f3f4f6' : '#fff',
                                cursor: currentPage === 1 ? 'not-allowed' : 'pointer',
                                borderRadius: '0.25rem'
                            }}
                        >
                            Previous
                        </button>
                        <span style={{ color: '#666' }}>
                            Page {currentPage} of {totalPages}
                        </span>
                        <button
                            onClick={() => setCurrentPage(p => Math.min(totalPages, p + 1))}
                            disabled={currentPage === totalPages}
                            style={{
                                padding: '0.5rem 1rem',
                                border: '1px solid #d1d5db',
                                background: currentPage === totalPages ? '#f3f4f6' : '#fff',
                                cursor: currentPage === totalPages ? 'not-allowed' : 'pointer',
                                borderRadius: '0.25rem'
                            }}
                        >
                            Next
                        </button>
                    </div>
                )}
            </div>
        </div>
    );
}