'use client';

import { useState, useEffect, useCallback, useRef } from 'react';
import { useAuth } from '@/contexts/AuthContext';
import { packagesApi } from '@/lib/api/packages';
import { productsApi } from '@/lib/api/products';
import ProductList from '@/components/admin/products/ProductList';
import ProductForm from '@/components/admin/products/ProductForm';
import PageHeader from '@/components/admin/PageHeader';
import ConfirmDialog from '@/components/admin/ConfirmDialog';
import { showToast } from '@/components/Toast';
import { PackageName } from '@/types/package';
import { Product, CreateProductData, UpdateProductData } from '@/types/product';
import { PlusIcon } from '@heroicons/react/24/outline';

export default function ProductsPage() {
    const { token } = useAuth();
    const [packages, setPackages] = useState<PackageName[]>([]);
    const [selectedPackage, setSelectedPackage] = useState<PackageName | null>(null);
    const [products, setProducts] = useState<Product[]>([]);
    const [selectedProduct, setSelectedProduct] = useState<Product | null>(null);
    const [isLoading, setIsLoading] = useState(false);
    const [isLoadingPackages, setIsLoadingPackages] = useState(false);
    const [isFormVisible, setIsFormVisible] = useState(false);
    const [error, setError] = useState<string | null>(null);
    const [deleteTarget, setDeleteTarget] = useState<Product | null>(null);

    const initialLoadRef = useRef(false);
    const prevPackageRef = useRef<string | null>(null);

    useEffect(() => {
        if (token && !initialLoadRef.current) {
            initialLoadRef.current = true;
            loadPackages();
        }
    }, [token]);

    const loadPackages = async () => {
        setIsLoadingPackages(true);
        setError(null);
        try {
            const data = await packagesApi.getAllPackages(token!);
            setPackages(data);
            if (data.length > 0 && !selectedPackage) {
                setSelectedPackage(data[0]);
            }
        } catch (err) {
            setError('خطا در دریافت لیست پکیج‌ها');
        } finally {
            setIsLoadingPackages(false);
        }
    };

    const loadProducts = useCallback(async (packageName: string, force = false) => {
        if (!force && prevPackageRef.current === packageName) {
            return;
        }

        setIsLoading(true);
        setError(null);
        prevPackageRef.current = packageName;

        try {
            const data = await productsApi.getProducts(packageName, token!);
            setProducts(data);
        } catch (err) {
            setError(err instanceof Error ? err.message : 'خطا در دریافت محصولات');
        } finally {
            setIsLoading(false);
        }
    }, [token]);

    useEffect(() => {
        if (selectedPackage?.name && token) {
            loadProducts(selectedPackage.name);
        } else {
            setProducts([]);
        }
    }, [selectedPackage?.name, token, loadProducts]);

    const handlePackageChange = (e: React.ChangeEvent<HTMLSelectElement>) => {
        const pkg = packages.find(p => p.name === e.target.value);
        setSelectedPackage(pkg || null);
        setIsFormVisible(false);
        setSelectedProduct(null);
        setError(null);
    };

    const handleCreate = () => {
        setSelectedProduct(null);
        setIsFormVisible(true);
    };

    const handleEdit = (product: Product) => {
        setSelectedProduct(product);
        setIsFormVisible(true);
    };

    const handleDelete = (product: Product) => {
        setDeleteTarget(product);
    };

    const confirmDelete = async () => {
        if (!selectedPackage || !deleteTarget) return;
        const product = deleteTarget;

        setIsLoading(true);
        setError(null);

        try {
            await productsApi.deleteProduct(selectedPackage.name!, product.id, token!);
            showToast('success', 'محصول با موفقیت حذف شد');
            if (selectedPackage.name) {
                prevPackageRef.current = null;
                await loadProducts(selectedPackage.name, true);
            }
        } catch (err) {
            setError(err instanceof Error ? err.message : 'خطا در حذف محصول');
        } finally {
            setIsLoading(false);
            setDeleteTarget(null);
        }
    };

    const handleSubmit = async (data: CreateProductData | UpdateProductData) => {
        if (!selectedPackage) return;

        setIsLoading(true);
        setError(null);

        try {
            if (selectedProduct) {
                await productsApi.updateProduct(selectedPackage.name!, selectedProduct.id, data, token!);
                showToast('success', 'محصول با موفقیت به‌روزرسانی شد');
            } else {
                await productsApi.createProduct(selectedPackage.name!, data as CreateProductData, token!);
                showToast('success', 'محصول با موفقیت ایجاد شد');
            }

            if (selectedPackage.name) {
                prevPackageRef.current = null;
                await loadProducts(selectedPackage.name, true);
            }

            setIsFormVisible(false);
            setSelectedProduct(null);
        } catch (err) {
            setError(err instanceof Error ? err.message : 'خطا در ذخیره محصول');
        } finally {
            setIsLoading(false);
        }
    };

    const handleCancel = () => {
        setIsFormVisible(false);
        setSelectedProduct(null);
        setError(null);
    };

    return (
        <div className="p-4 sm:p-8">
            <div className="max-w-7xl mx-auto">
                <PageHeader title="مدیریت محصولات" />

                {/* Package Selector */}
                <div className="bg-white dark:bg-gray-900 p-4 rounded-2xl ring-1 ring-gray-200 dark:ring-gray-800 shadow-sm mb-6">
                    <label htmlFor="package" className="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
                        انتخاب پکیج
                    </label>
                    <select
                        id="package"
                        value={selectedPackage?.name || ''}
                        onChange={handlePackageChange}
                        disabled={isLoadingPackages}
                        className="block w-full px-3 py-2.5 text-gray-900 dark:text-gray-100 border border-gray-200 dark:border-gray-700 rounded-xl shadow-sm focus:ring-2 focus:ring-indigo-500 focus:border-transparent sm:text-sm disabled:opacity-50 dark:bg-gray-800/80 transition-colors"
                    >
                        {isLoadingPackages ? (
                            <option>در حال بارگذاری پکیج‌ها...</option>
                        ) : (
                            packages.map((pkg) => (
                                <option key={pkg.id} value={pkg.name || ''}>
                                    {pkg.title} ({pkg.name})
                                </option>
                            ))
                        )}
                    </select>
                </div>

                {error && (
                    <div className="mb-4 rounded-xl bg-red-50 dark:bg-red-950/40 ring-1 ring-red-200 dark:ring-red-800/60 p-4 flex items-center gap-3">
                        <p className="text-sm text-red-700 dark:text-red-300">{error}</p>
                        <button onClick={() => setError(null)} className="mr-auto text-red-400 hover:text-red-600">
                            <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" strokeWidth={2} stroke="currentColor">
                                <path strokeLinecap="round" strokeLinejoin="round" d="M6 18 18 6M6 6l12 12" />
                            </svg>
                        </button>
                    </div>
                )}

                {selectedPackage && (
                    <>
                        {!isFormVisible && (
                            <div className="mb-4 flex justify-end">
                                <button
                                    onClick={handleCreate}
                                    disabled={isLoading}
                                    className="inline-flex items-center gap-2 px-4 py-2.5 bg-indigo-600 text-white rounded-xl text-sm font-medium hover:bg-indigo-700 focus:outline-none focus:ring-2 focus:ring-offset-2 dark:focus:ring-offset-gray-900 focus:ring-indigo-500 disabled:opacity-50 transition-colors shadow-sm shadow-indigo-500/20"
                                >
                                    <PlusIcon className="h-4 w-4" />
                                    محصول جدید
                                </button>
                            </div>
                        )}

                        {isFormVisible ? (
                            <ProductForm
                                product={selectedProduct}
                                packageName={selectedPackage.name!}
                                onSubmit={handleSubmit}
                                onCancel={handleCancel}
                                isLoading={isLoading}
                            />
                        ) : (
                            <ProductList
                                products={products}
                                packageName={selectedPackage.name!}
                                onEdit={handleEdit}
                                onDelete={handleDelete}
                                isLoading={isLoading}
                            />
                        )}
                    </>
                )}

                <ConfirmDialog
                    open={!!deleteTarget}
                    title="حذف محصول"
                    message={`آیا از حذف محصول «${deleteTarget?.title || ''}» اطمینان دارید؟`}
                    confirmLabel="حذف"
                    isLoading={isLoading}
                    onConfirm={confirmDelete}
                    onCancel={() => setDeleteTarget(null)}
                />
            </div>
        </div>
    );
}