"use client";
import Image from "next/image";
import { useCallback, useEffect, useState } from "react";

import { ExtendedArtefact } from "@appTypes/ApiTypes";
import { Currency } from "@appTypes/StoreModel";
import BottomFooter from "@components/BottomFooter";
import { useStoreState } from "@hooks/store";

export default function Shop() {
	const [artefacts, setArtefacts] = useState<ExtendedArtefact[]>([]);
	const [hiddenArtefactIds, setHiddenArtefactIds] = useState<number[]>([]);
	const [loading, setLoading] = useState(true);

	const [cart, setCart] = useState<ExtendedArtefact[]>([]);
	const [showCartModal, setShowCartModal] = useState(false);

	const user = useStoreState((state) => state.user);

	useEffect(() => {
		async function fetchArtefacts() {
			setLoading(true);
			try {
				const res = await fetch("/api/artefacts");
				const data = await res.json();
				const transformed = data.artefact.map((a: any) => ({
					id: a.id,
					name: a.name,
					description: a.description,
					location: a.warehouseArea,
					earthquakeID: a.earthquakeId?.toString() ?? "",
					observatory: a.type ?? "",
					dateReleased: a.createdAt ? new Date(a.createdAt).toLocaleDateString() : "",
					image: "/artefactImages/" + (a.imageName || "NoImageFound.PNG"),
					price: a.shopPrice ?? 100,
				}));
				setArtefacts(transformed);
			} catch (e) {
				console.error("Failed to fetch artefacts", e);
			} finally {
				setLoading(false);
			}
		}
		fetchArtefacts();
	}, []);

	const [currentPage, setCurrentPage] = useState(1);
	const [selectedArtefact, setSelectedArtefact] = useState<ExtendedArtefact | null>(null);
	const [showPaymentModal, setShowPaymentModal] = useState(false);
	const [artefactToBuy, setArtefactToBuy] = useState<ExtendedArtefact | null>(null);
	const [cartCheckout, setCartCheckout] = useState(false); // true = checkout cart (not single artefact)
	const [showThankYouModal, setShowThankYouModal] = useState(false);
	const [orderNumber, setOrderNumber] = useState<string | null>(null);

	const artefactsPerPage = 12;
	const indexOfLastArtefact = currentPage * artefactsPerPage;
	const indexOfFirstArtefact = indexOfLastArtefact - artefactsPerPage;
	const currentArtefacts = artefacts.slice(indexOfFirstArtefact, indexOfLastArtefact);

	const selectedCurrency = useStoreState((state) => state.currency.selectedCurrency);
	const conversionRates = useStoreState((state) => state.currency.conversionRates);
	const currencyTickers = useStoreState((state) => state.currency.tickers);

	const convertPrice = useCallback(
		(price: number, currency: Currency) => (price * conversionRates[currency]).toFixed(2),
		[conversionRates]
	);

	const handleNextPage = () => {
		if (indexOfLastArtefact < artefacts.length) setCurrentPage((prev) => prev + 1);
	};
	const handlePreviousPage = () => {
		if (currentPage > 1) setCurrentPage((prev) => prev - 1);
	};

	function ArtefactCard({ artefact }: { artefact: ExtendedArtefact }) {
		return (
			<div
				className="flex flex-col bg-white shadow-md rounded-md overflow-hidden cursor-pointer hover:scale-105 transition-transform"
				onClick={() => setSelectedArtefact(artefact)}
			>
				<Image src={artefact.image} alt={artefact.name} width={500} height={300} className="w-full h-56 object-cover" />
				<div className="p-4">
					<h3 className="text-lg font-semibold">{artefact.name}</h3>
					<p className="text-neutral-500 mb-2">{artefact.location}</p>
					<p className="text-neutral-500 mb-2">{artefact.earthquakeID}</p>
					<p className="text-black font-bold text-md mt-2">
						{currencyTickers[selectedCurrency]}
						{convertPrice(artefact.price, selectedCurrency)}
					</p>
				</div>
			</div>
		);
	}

	function Modal({ artefact }: { artefact: ExtendedArtefact }) {
		if (!artefact) return null;
		const handleOverlayClick = (e: React.MouseEvent) => {
			if (e.target === e.currentTarget) setSelectedArtefact(null);
		};
		const inCart = cart.some((a) => a.id === artefact.id);

		return (
			<div
				className="fixed inset-0 bg-neutral-900 bg-opacity-50 flex justify-center items-center z-50"
				onClick={handleOverlayClick}
			>
				<div className="bg-white rounded-xl shadow-2xl max-w-lg w-full p-6">
					<h3 className="text-2xl font-bold mb-4">{artefact.name}</h3>
					<Image
						src={artefact.image}
						alt={artefact.name}
						width={500}
						height={300}
						className="w-full h-64 object-cover rounded-md"
					/>
					<p className="text-xl font-bold">
						{currencyTickers[selectedCurrency]}
						{convertPrice(artefact.price, selectedCurrency)}
					</p>
					<p className="text-neutral-600 mt-2">{artefact.description}</p>
					<p className="text-neutral-500 font-bold mt-1">Location: {artefact.location}</p>
					<p className="text-neutral-500 mb-2">{artefact.earthquakeID}</p>
					<p className="text-neutral-500 mb-2">{artefact.observatory}</p>
					<p className="text-neutral-500 mb-2">{artefact.dateReleased}</p>
					<div className="flex flex-col sm:flex-row justify-end gap-4 mt-4 mr-2">
						<button
							onClick={() => {
								if (!inCart) setCart((cart) => [...cart, artefact]);
							}}
							disabled={inCart}
							className={`px-6 py-2 rounded-md font-bold border 
                                ${
																	inCart
																		? "bg-gray-300 text-gray-400 cursor-not-allowed"
																		: "bg-green-500 hover:bg-green-600 text-white"
																}
                            `}
						>
							{inCart ? "In Cart" : "Add to Cart"}
						</button>
						<button
							onClick={() => {
								setArtefactToBuy(artefact);
								setShowPaymentModal(true);
								setCartCheckout(false);
								setSelectedArtefact(null);
							}}
							className="px-8 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700"
						>
							Buy Now
						</button>
					</div>
				</div>
			</div>
		);
	}

	function CartModal() {
		const total = cart.reduce((sum, art) => sum + art.price, 0);

		const handleOverlayClick = (e: React.MouseEvent) => {
			if (e.target === e.currentTarget) setShowCartModal(false);
		};

		return (
			<div
				className="fixed inset-0 bg-neutral-900 bg-opacity-60 flex justify-center items-center z-[999]"
				onClick={handleOverlayClick}
			>
				<div className="bg-white rounded-xl shadow-2xl max-w-2xl w-full p-8">
					<div className="flex justify-between items-center mb-4">
						<h2 className="text-2xl font-bold">Your Cart</h2>
						<button onClick={() => setShowCartModal(false)} className="text-xl font-bold px-2 py-1 rounded">
							✖
						</button>
					</div>
					{cart.length === 0 ? (
						<p className="text-neutral-500">Your cart is empty.</p>
					) : (
						<>
							<ul className="mb-4">
								{cart.map((art) => (
									<li key={art.id} className="flex items-center border-b py-2">
										<div className="flex-shrink-0 mr-3">
											<Image src={art.image} alt={art.name} width={60} height={40} className="rounded" />
										</div>
										<div className="flex-grow">
											<p className="font-bold">{art.name}</p>
											<p className="text-neutral-500 text-sm">{art.location}</p>
										</div>
										<p className="font-bold mr-2">
											{currencyTickers[selectedCurrency]}
											{convertPrice(art.price, selectedCurrency)}
										</p>
										<button
											className="px-3 py-1 bg-red-400 hover:bg-red-500 text-white rounded"
											onClick={() => setCart((c) => c.filter((a) => a.id !== art.id))}
										>
											Remove
										</button>
									</li>
								))}
							</ul>
							<div className="flex justify-between items-center mb-2">
								<span className="font-bold">Total:</span>
								<span className="text-lg font-bold">
									{currencyTickers[selectedCurrency]}
									{convertPrice(total, selectedCurrency)}
								</span>
							</div>
							<div className="text-right">
								<button
									className="px-8 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700"
									onClick={() => {
										setShowCartModal(false);
										setArtefactToBuy(null);
										setShowPaymentModal(true);
										setCartCheckout(true);
									}}
								>
									Checkout
								</button>
							</div>
						</>
					)}
				</div>
			</div>
		);
	}

	function PaymentModal({
		artefact,
		onClose,
		cartItems,
	}: {
		artefact?: ExtendedArtefact;
		onClose: () => void;
		cartItems?: ExtendedArtefact[];
	}) {
		const [cardNumber, setCardNumber] = useState("");
		const [expiry, setExpiry] = useState("");
		const [cvc, setCvc] = useState("");
		const [name, setName] = useState("");
		const [email, setEmail] = useState(user?.email || "");
		const [remember, setRemember] = useState(false);
		const [error, setError] = useState("");

		const artefactsToBuy = artefact ? [artefact] : cartItems || [];
		const total = artefactsToBuy.reduce((sum, art) => sum + art.price, 0);

		function validateEmail(email: string) {
			return (
				email.includes("@") &&
				(email.endsWith(".com") || email.endsWith(".co.uk") || email.endsWith(".org") || email.endsWith(".org.uk"))
			);
		}
		function validateCardNumber(number: string) {
			return /^\d{12,19}$/.test(number.replace(/\s/g, "")); // 12-19 digits
		}
		function validateCVC(number: string) {
			return /^\d{3,4}$/.test(number);
		}
		function validateExpiry(exp: string) {
			return /^\d{2}\/\d{2}$/.test(exp);
		}
		function handlePay() {
			setError("");
			const paymentEmail = user?.email || email;
			if (!validateEmail(paymentEmail)) {
				setError("Please enter a valid email");
				return;
			}
			if (!validateCardNumber(cardNumber)) {
				setError("Card number must be 12-19 digits.");
				return;
			}
			if (!validateExpiry(expiry)) {
				setError("Expiry must be in MM/YY format.");
				return;
			}
			if (!validateCVC(cvc)) {
				setError("CVC must be 3 or 4 digits.");
				return;
			}
			// remove all artefacts that were bought (works for both cart and single)
			setHiddenArtefactIds((ids) => [...ids, ...artefactsToBuy.map((a) => a.id)]);
			// todo create receiving api route
			// todo handle sending to api route
			const genOrder = () => "#" + Math.random().toString(36).substring(2, 10).toUpperCase();
			setOrderNumber(genOrder());
			onClose();
			setShowThankYouModal(true);
			setCart((c) => c.filter((a) => !artefactsToBuy.map((x) => x.id).includes(a.id)));
		}
		const handleOverlayClick = (e: React.MouseEvent) => {
			if (e.target === e.currentTarget) onClose();
		};
		return (
			<div
				className="fixed inset-0 bg-neutral-900 bg-opacity-60 flex justify-center items-center z-[12000]"
				onClick={handleOverlayClick}
			>
				<div className="bg-white rounded-xl shadow-2xl max-w-md w-full p-6">
					<h2 className="text-2xl font-bold mb-4">
						Checkout {artefact ? artefact.name : artefactsToBuy.length + " item(s)"}
						{!artefact && <span className="ml-1">({artefactsToBuy.map((x) => x.name).join(", ")})</span>}
					</h2>
					<form
						onSubmit={(e) => {
							e.preventDefault();
							handlePay();
						}}
					>
						{/* Email autofill */}
						<input
							className="w-full mb-2 px-3 py-2 border rounded"
							placeholder="Email Address"
							value={user?.email ? user.email : email}
							onChange={(e) => setEmail(e.target.value)}
							type="email"
							required
							autoFocus
							disabled={!!user?.email}
						/>
						{user?.email && (
							<p className="text-sm text-gray-500 mb-2">
								Signed in as <span className="font-bold">{user.email}</span>
							</p>
						)}
						<input
							className="w-full mb-2 px-3 py-2 border rounded"
							placeholder="Cardholder Name"
							value={name}
							onChange={(e) => setName(e.target.value)}
							required
						/>
						<input
							className="w-full mb-2 px-3 py-2 border rounded"
							placeholder="Card Number"
							value={cardNumber}
							onChange={(e) => setCardNumber(e.target.value.replace(/\D/g, ""))}
							maxLength={19}
							required
							inputMode="numeric"
							pattern="\d*"
						/>
						<div className="flex gap-2">
							<input
								className="w-1/2 mb-2 px-3 py-2 border rounded"
								placeholder="MM/YY"
								value={expiry}
								onChange={(e) => setExpiry(e.target.value.replace(/[^0-9/]/g, ""))}
								maxLength={5}
								required
								inputMode="numeric"
							/>
							<input
								className="w-1/2 mb-2 px-3 py-2 border rounded"
								placeholder="CVC"
								value={cvc}
								onChange={(e) => setCvc(e.target.value.replace(/\D/g, ""))}
								maxLength={4}
								required
								inputMode="numeric"
							/>
						</div>
						<label className="inline-flex items-center mb-4">
							<input type="checkbox" checked={remember} onChange={() => setRemember((r) => !r)} className="mr-2" />
							Remember me
						</label>
						{error && <p className="text-red-600 mb-2">{error}</p>}
						<div className="flex justify-between items-center mb-2">
							<span className="font-bold">Total:</span>
							<span className="text-lg font-bold">
								{currencyTickers[selectedCurrency]}
								{convertPrice(total, selectedCurrency)}
							</span>
						</div>
						<div className="flex justify-end gap-2 mt-2">
							<button type="button" onClick={onClose} className="px-4 py-2 bg-gray-300 text-gray-700 rounded-md mr-2">
								Cancel
							</button>
							<button type="submit" className="px-6 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700">
								Pay
							</button>
						</div>
					</form>
				</div>
			</div>
		);
	}

	function ThankYouModal({ orderNumber, onClose }: { orderNumber: string; onClose: () => void }) {
		const handleOverlayClick = (e: React.MouseEvent) => {
			if (e.target === e.currentTarget) onClose();
		};
		return (
			<div
				className="fixed inset-0 bg-neutral-900 bg-opacity-60 flex justify-center items-center z-50"
				onClick={handleOverlayClick}
			>
				<div className="bg-white rounded-xl shadow-2xl max-w-md w-full p-8 text-center">
					<h2 className="text-3xl font-bold mb-4">Thank you for your purchase!</h2>
					<p className="mb-4">Your order number is:</p>
					<p className="text-2xl font-mono font-bold mb-6">{orderNumber}</p>
					<button className="px-8 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700" onClick={onClose}>
						Close
					</button>
				</div>
			</div>
		);
	}
	return (
		<div
			className="min-h-screen bg-blue-50 relative flex flex-col"
			style={{
				backgroundImage: "url('/EarthHighRes.jpg')",
				backgroundSize: "cover",
				backgroundPosition: "center",
			}}
		>
			<div className="absolute inset-0 bg-black bg-opacity-0 z-0"></div>
			{/* --- Cart Button fixed at top right --- */}
			<button
				className="absolute top-6 right-6 z-[11000] bg-white border border-blue-500 shadow-lg rounded-full p-3 hover:bg-blue-100 flex flex-row items-center"
				onClick={() => setShowCartModal(true)}
				aria-label="Open your cart"
			>
				<span className="mr-2 font-bold">{cart.length || ""}</span>
				<svg
					xmlns="http://www.w3.org/2000/svg"
					className="w-7 h-7 text-blue-600"
					fill="none"
					viewBox="0 0 24 24"
					stroke="currentColor"
				>
					<path
						strokeLinecap="round"
						strokeLinejoin="round"
						strokeWidth={2}
						d="M3 3h2l.4 2M7 13h10l4-8H5.4M7 13l-1.35 2.7a1 1 0 00.9 1.45h12.2M7 13l1.2-2.4M3 3l.01 0"
					/>
				</svg>
			</button>
			<div className="relative z-10 flex flex-col items-center w-full px-2 py-12">
				<h1 className="text-4xl md:text-4xl font-bold text-center text-blue-300 mb-2 tracking-tight drop-shadow-lg">
					Artefact Shop
				</h1>
				<p className="text-lg md:text-xl text-center text-white mb-10 drop-shadow-md max-w-2xl">
					Discover extraordinary artefacts and collectibles from major seismic events from around the world - Previously studied
					by our scientists, now available for purchase.
				</p>
				<div className="w-full max-w-7xl grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-10 p-2">
					{currentArtefacts
						.filter((x) => !hiddenArtefactIds.includes(x.id))
						.map((artefact) => (
							<ArtefactCard key={artefact.id} artefact={artefact} />
						))}
				</div>
				<footer className="mt-10 bg-white bg-opacity-90 border-neutral-300 py-3 text-center flex justify-center items-center w-100 max-w-7xl rounded-lg">
					<button
						onClick={handlePreviousPage}
						disabled={currentPage === 1}
						className={`mx-2 px-4 py-1 bg-blue-500 text-white rounded-md font-bold shadow-md ${
							currentPage === 1 ? "opacity-50 cursor-not-allowed" : "hover:bg-blue-600"
						}`}
					>
						&larr; Previous
					</button>
					<p className="mx-3 text-lg font-bold">{currentPage}</p>
					<button
						onClick={handleNextPage}
						disabled={indexOfLastArtefact >= artefacts.length}
						className={`mx-2 px-4 py-1 bg-blue-500 text-white rounded-md font-bold shadow-md ${
							indexOfLastArtefact >= artefacts.length ? "opacity-50 cursor-not-allowed" : "hover:bg-blue-600"
						}`}
					>
						Next &rarr;
					</button>
				</footer>
			</div>
			{selectedArtefact && <Modal artefact={selectedArtefact} />}
			{showCartModal && <CartModal />}
			{showPaymentModal && (cartCheckout || artefactToBuy) && (
				<PaymentModal
					artefact={cartCheckout ? undefined : artefactToBuy!}
					cartItems={cartCheckout ? cart : undefined}
					onClose={() => {
						setShowPaymentModal(false);
						setArtefactToBuy(null);
						setCartCheckout(false);
					}}
				/>
			)}
			{showThankYouModal && orderNumber && (
				<ThankYouModal orderNumber={orderNumber} onClose={() => setShowThankYouModal(false)} />
			)}
			{!selectedArtefact && !showPaymentModal && !showThankYouModal && !showCartModal && (
				<div className="relative z-50">
					<BottomFooter />
				</div>
			)}
		</div>
	);
}