'use client';

import { useState, useEffect } from 'react';
import { useParams, useRouter } from 'next/navigation';
import { Book } from '@/lib/types';
import { ArrowLeft, Save } from 'lucide-react';

export default function EditBookPage() {
  const params = useParams();
  const router = useRouter();
  const bookId = params.id as string;
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [error, setError] = useState<string | null>(null);
  
  const [formData, setFormData] = useState({
    isbn: '',
    title: '',
    authors: '',
    publisher: '',
    publishDate: '',
    price: '',
    classificationNo: '',
    location: '',
    totalCopies: '1',
    availableCopies: '1',
    status: 'normal',
    description: '',
    coverUrl: '',
  });

  useEffect(() => {
    const fetchBook = async () => {
      try {
        const response = await fetch(`/api/books/${bookId}`);
        if (!response.ok) {
          throw new Error('Failed to fetch book');
        }
        const book: Book = await response.json();
        
        setFormData({
          isbn: book.isbn,
          title: book.title,
          authors: book.authors.join(', '),
          publisher: book.publisher || '',
          publishDate: book.publishDate || '',
          price: book.price || '',
          classificationNo: book.classificationNo || '',
          location: book.location || '',
          totalCopies: book.totalCopies.toString(),
          availableCopies: book.availableCopies.toString(),
          status: book.status,
          description: book.description || '',
          coverUrl: book.coverUrl || '',
        });
      } catch (err) {
        setError(err instanceof Error ? err.message : 'Unknown error');
      } finally {
        setLoading(false);
      }
    };

    if (bookId) {
      fetchBook();
    }
  }, [bookId]);

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

    try {
      const updateData = {
        ...formData,
        authors: formData.authors.split(',').map(author => author.trim()).filter(Boolean),
        price: formData.price ? parseFloat(formData.price) : null,
        totalCopies: parseInt(formData.totalCopies),
        availableCopies: parseInt(formData.availableCopies),
        publishDate: formData.publishDate || null,
        publisher: formData.publisher || null,
        classificationNo: formData.classificationNo || null,
        location: formData.location || null,
        description: formData.description || null,
        coverUrl: formData.coverUrl || null,
      };

      const response = await fetch(`/api/books/${bookId}`, {
        method: 'PUT',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify(updateData),
      });

      if (response.ok) {
        router.push(`/admin/books/${bookId}`);
      } else {
        const errorData = await response.json();
        alert(`更新失败: ${errorData.error || 'Unknown error'}`);
      }
    } catch (error) {
      console.error('Update error:', error);
      alert('更新失败');
    } finally {
      setSaving(false);
    }
  };

  const handleChange = (e: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement | HTMLSelectElement>) => {
    const { name, value } = e.target;
    setFormData(prev => ({
      ...prev,
      [name]: value
    }));
  };

  if (loading) {
    return (
      <div className="min-h-screen bg-gray-50 flex items-center justify-center">
        <div className="text-lg">加载中...</div>
      </div>
    );
  }

  if (error) {
    return (
      <div className="min-h-screen bg-gray-50 flex items-center justify-center">
        <div className="text-red-600">错误: {error}</div>
      </div>
    );
  }

  return (
    <div className="min-h-screen bg-gray-50">
      <div className="max-w-4xl mx-auto p-6">
        {/* Header */}
        <div className="flex items-center justify-between mb-6">
          <div className="flex items-center gap-4">
            <button
              onClick={() => router.back()}
              className="flex items-center gap-2 text-gray-600 hover:text-gray-900"
            >
              <ArrowLeft size={20} />
              返回
            </button>
            <h1 className="text-2xl font-bold text-gray-900">编辑图书</h1>
          </div>
        </div>

        {/* Form */}
        <div className="bg-white rounded-lg shadow-sm border p-6">
          <form onSubmit={handleSubmit} className="space-y-6">
            <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  ISBN *
                </label>
                <input
                  type="text"
                  name="isbn"
                  value={formData.isbn}
                  onChange={handleChange}
                  required
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  书名 *
                </label>
                <input
                  type="text"
                  name="title"
                  value={formData.title}
                  onChange={handleChange}
                  required
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  作者 * (多个作者用逗号分隔)
                </label>
                <input
                  type="text"
                  name="authors"
                  value={formData.authors}
                  onChange={handleChange}
                  required
                  placeholder="张三, 李四"
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  出版社
                </label>
                <input
                  type="text"
                  name="publisher"
                  value={formData.publisher}
                  onChange={handleChange}
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  出版日期
                </label>
                <input
                  type="date"
                  name="publishDate"
                  value={formData.publishDate}
                  onChange={handleChange}
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  价格
                </label>
                <input
                  type="number"
                  name="price"
                  value={formData.price}
                  onChange={handleChange}
                  step="0.01"
                  min="0"
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  分类号
                </label>
                <input
                  type="text"
                  name="classificationNo"
                  value={formData.classificationNo}
                  onChange={handleChange}
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  位置
                </label>
                <input
                  type="text"
                  name="location"
                  value={formData.location}
                  onChange={handleChange}
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  总册数 *
                </label>
                <input
                  type="number"
                  name="totalCopies"
                  value={formData.totalCopies}
                  onChange={handleChange}
                  required
                  min="1"
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  可借册数 *
                </label>
                <input
                  type="number"
                  name="availableCopies"
                  value={formData.availableCopies}
                  onChange={handleChange}
                  required
                  min="0"
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  状态 *
                </label>
                <select
                  name="status"
                  value={formData.status}
                  onChange={handleChange}
                  required
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                >
                  <option value="normal">正常</option>
                  <option value="damaged">损坏</option>
                  <option value="removed">已移除</option>
                </select>
              </div>

              <div>
                <label className="block text-sm font-medium text-gray-700 mb-2">
                  封面链接
                </label>
                <input
                  type="url"
                  name="coverUrl"
                  value={formData.coverUrl}
                  onChange={handleChange}
                  className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                />
              </div>
            </div>

            <div>
              <label className="block text-sm font-medium text-gray-700 mb-2">
                描述
              </label>
              <textarea
                name="description"
                value={formData.description}
                onChange={handleChange}
                rows={4}
                className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
              />
            </div>

            <div className="flex justify-end gap-4">
              <button
                type="button"
                onClick={() => router.back()}
                className="px-6 py-2 border border-gray-300 text-gray-700 rounded-lg hover:bg-gray-50"
              >
                取消
              </button>
              <button
                type="submit"
                disabled={saving}
                className="flex items-center gap-2 px-6 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 disabled:opacity-50"
              >
                <Save size={16} />
                {saving ? '保存中...' : '保存'}
              </button>
            </div>
          </form>
        </div>
      </div>
    </div>
  );
}