import React, { useState, useEffect, useRef } from 'react';
import { BookOpen, Plus, Pencil, Trash2, Upload, Download, X, Save, Search } from 'lucide-react';

interface Subject {
    id: number;
    name: string;
}

interface ManageSubjectsProps {
    onClose?: () => void;
}

const ManageSubjects: React.FC<ManageSubjectsProps> = ({ onClose }) => {
    const [subjects, setSubjects] = useState<Subject[]>([]);
    const [loading, setLoading] = useState(true);
    const [searchTerm, setSearchTerm] = useState('');
    const [showForm, setShowForm] = useState(false);
    const [editingSubject, setEditingSubject] = useState<Subject | null>(null);
    const [formData, setFormData] = useState({ name: '' });
    const [saving, setSaving] = useState(false);
    const [importResult, setImportResult] = useState<string | null>(null);
    const fileInputRef = useRef<HTMLInputElement>(null);

    const API_URL = import.meta.env.VITE_API_URL || '/api';

    useEffect(() => {
        fetchSubjects();
    }, []);

    const fetchSubjects = async () => {
        try {
            const response = await fetch(`${API_URL}/subjects`);
            const result = await response.json();
            if (result.status === 'success') {
                setSubjects(result.data);
            }
        } catch (error) {
            console.error('Error fetching subjects:', error);
        } finally {
            setLoading(false);
        }
    };

    const handleSubmit = async (e: React.FormEvent) => {
        e.preventDefault();
        setSaving(true);

        try {
            const url = editingSubject
                ? `${API_URL}/subjects/${editingSubject.id}`
                : `${API_URL}/subjects`;

            const response = await fetch(url, {
                method: editingSubject ? 'PUT' : 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify(formData)
            });

            const result = await response.json();
            if (result.status === 'success') {
                alert(result.message);
                fetchSubjects();
                setShowForm(false);
                setEditingSubject(null);
                setFormData({ name: '' });
            } else {
                alert(result.message);
            }
        } catch (error) {
            alert('Gagal menyimpan data');
        } finally {
            setSaving(false);
        }
    };

    const handleDelete = async (id: number) => {
        if (!confirm('Yakin ingin menghapus mata pelajaran ini?')) return;

        try {
            const response = await fetch(`${API_URL}/subjects/${id}`, { method: 'DELETE' });
            const result = await response.json();
            if (result.status === 'success') {
                fetchSubjects();
            }
        } catch (error) {
            alert('Gagal menghapus data');
        }
    };

    const handleEdit = (subject: Subject) => {
        setEditingSubject(subject);
        setFormData({ name: subject.name });
        setShowForm(true);
    };

    const handleImport = async (e: React.ChangeEvent<HTMLInputElement>) => {
        const file = e.target.files?.[0];
        if (!file) return;

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

        try {
            const response = await fetch(`${API_URL}/subjects/import`, {
                method: 'POST',
                body: formData
            });
            const result = await response.json();
            setImportResult(result.message);
            fetchSubjects();
        } catch (error) {
            setImportResult('Gagal import data');
        }

        if (fileInputRef.current) fileInputRef.current.value = '';
    };

    const downloadTemplate = () => {
        window.open(`${API_URL}/subjects/template`, '_blank');
    };

    const filteredSubjects = subjects.filter(s =>
        s.name.toLowerCase().includes(searchTerm.toLowerCase())
    );

    return (
        <div className="bg-white rounded-2xl shadow-lg border border-slate-100 overflow-hidden">
            <div className="bg-school-900 p-6 text-white flex items-center justify-between">
                <div className="flex items-center gap-3">
                    <BookOpen size={24} className="text-accent-yellow" />
                    <div>
                        <h2 className="font-heading text-xl font-bold">Kelola Mata Pelajaran</h2>
                        <p className="text-blue-200 text-sm">Tambah, edit, hapus, atau import dari Excel</p>
                    </div>
                </div>
                {onClose && (
                    <button onClick={onClose} className="text-white/70 hover:text-white">
                        <X size={24} />
                    </button>
                )}
            </div>

            <div className="p-6 space-y-4">
                {/* Actions Bar */}
                <div className="flex flex-wrap gap-3 items-center justify-between">
                    <div className="relative flex-1 min-w-[200px]">
                        <Search className="absolute left-3 top-1/2 -translate-y-1/2 text-slate-400" size={18} />
                        <input
                            type="text"
                            placeholder="Cari mata pelajaran..."
                            value={searchTerm}
                            onChange={(e) => setSearchTerm(e.target.value)}
                            className="w-full pl-10 pr-4 py-2 rounded-xl border border-slate-200 focus:border-school-800 outline-none"
                        />
                    </div>
                    <div className="flex gap-2">
                        <button
                            onClick={downloadTemplate}
                            className="flex items-center gap-2 px-4 py-2 bg-slate-100 text-slate-700 rounded-xl hover:bg-slate-200 transition font-medium"
                        >
                            <Download size={18} /> Template
                        </button>
                        <label className="flex items-center gap-2 px-4 py-2 bg-green-500 text-white rounded-xl hover:bg-green-600 transition font-medium cursor-pointer">
                            <Upload size={18} /> Import Excel
                            <input
                                ref={fileInputRef}
                                type="file"
                                accept=".xlsx,.xls"
                                onChange={handleImport}
                                className="hidden"
                            />
                        </label>
                        <button
                            onClick={() => { setShowForm(true); setEditingSubject(null); setFormData({ name: '' }); }}
                            className="flex items-center gap-2 px-4 py-2 bg-school-900 text-white rounded-xl hover:bg-school-800 transition font-medium"
                        >
                            <Plus size={18} /> Tambah Mapel
                        </button>
                    </div>
                </div>

                {/* Import Result */}
                {importResult && (
                    <div className="bg-blue-50 border border-blue-200 text-blue-800 px-4 py-3 rounded-xl flex justify-between items-center">
                        <span>{importResult}</span>
                        <button onClick={() => setImportResult(null)}><X size={18} /></button>
                    </div>
                )}

                {/* Form Modal */}
                {showForm && (
                    <div className="fixed inset-0 bg-black/50 flex items-center justify-center z-50 p-4">
                        <div className="bg-white rounded-2xl p-6 w-full max-w-md">
                            <h3 className="text-lg font-bold mb-4">{editingSubject ? 'Edit Mata Pelajaran' : 'Tambah Mata Pelajaran Baru'}</h3>
                            <form onSubmit={handleSubmit} className="space-y-4">
                                <div>
                                    <label className="block text-sm font-medium text-slate-600 mb-1">Nama Mata Pelajaran *</label>
                                    <input
                                        type="text"
                                        required
                                        value={formData.name}
                                        onChange={(e) => setFormData({ ...formData, name: e.target.value })}
                                        className="w-full px-4 py-2 rounded-xl border border-slate-200 focus:border-school-800 outline-none"
                                        placeholder="Contoh: Matematika"
                                    />
                                </div>
                                <div className="flex gap-2 pt-2">
                                    <button
                                        type="button"
                                        onClick={() => setShowForm(false)}
                                        className="flex-1 px-4 py-2 bg-slate-100 text-slate-700 rounded-xl hover:bg-slate-200 transition font-medium"
                                    >
                                        Batal
                                    </button>
                                    <button
                                        type="submit"
                                        disabled={saving}
                                        className="flex-1 flex items-center justify-center gap-2 px-4 py-2 bg-school-900 text-white rounded-xl hover:bg-school-800 transition font-medium disabled:opacity-50"
                                    >
                                        <Save size={18} /> {saving ? 'Menyimpan...' : 'Simpan'}
                                    </button>
                                </div>
                            </form>
                        </div>
                    </div>
                )}

                {/* Table */}
                {loading ? (
                    <div className="text-center py-8 text-slate-400">Memuat data...</div>
                ) : (
                    <div className="overflow-x-auto">
                        <table className="w-full">
                            <thead>
                                <tr className="bg-slate-50 border-b border-slate-200">
                                    <th className="text-left px-4 py-3 font-semibold text-slate-600 w-16">No</th>
                                    <th className="text-left px-4 py-3 font-semibold text-slate-600">Mata Pelajaran</th>
                                    <th className="text-center px-4 py-3 font-semibold text-slate-600 w-32">Aksi</th>
                                </tr>
                            </thead>
                            <tbody>
                                {filteredSubjects.map((subject, index) => (
                                    <tr key={subject.id} className="border-b border-slate-100 hover:bg-slate-50">
                                        <td className="px-4 py-3 text-slate-500">{index + 1}</td>
                                        <td className="px-4 py-3 font-medium">{subject.name}</td>
                                        <td className="px-4 py-3">
                                            <div className="flex justify-center gap-2">
                                                <button
                                                    onClick={() => handleEdit(subject)}
                                                    className="p-2 text-blue-600 hover:bg-blue-50 rounded-lg transition"
                                                >
                                                    <Pencil size={16} />
                                                </button>
                                                <button
                                                    onClick={() => handleDelete(subject.id)}
                                                    className="p-2 text-red-600 hover:bg-red-50 rounded-lg transition"
                                                >
                                                    <Trash2 size={16} />
                                                </button>
                                            </div>
                                        </td>
                                    </tr>
                                ))}
                                {filteredSubjects.length === 0 && (
                                    <tr>
                                        <td colSpan={3} className="px-4 py-8 text-center text-slate-400">
                                            Tidak ada data mata pelajaran
                                        </td>
                                    </tr>
                                )}
                            </tbody>
                        </table>
                    </div>
                )}

                <div className="text-sm text-slate-500 pt-2">
                    Total: {filteredSubjects.length} mata pelajaran
                </div>
            </div>
        </div>
    );
};

export default ManageSubjects;