import { useEffect, useState } from "react";
import { useCurrency } from "../hooks/useCurrency";
import { useItems } from "../hooks/useItems";
import { useSyncSetupItems } from "../hooks/useSetups";
import { useWeightUnit } from "../hooks/useWeightUnit";
import { formatPrice, formatWeight } from "../lib/formatters";
import { LucideIcon } from "../lib/iconData";
import { SlideOutPanel } from "./SlideOutPanel";

interface ItemPickerProps {
	setupId: number;
	currentItemIds: number[];
	isOpen: boolean;
	onClose: () => void;
}

export function ItemPicker({
	setupId,
	currentItemIds,
	isOpen,
	onClose,
}: ItemPickerProps) {
	const { data: items } = useItems();
	const syncItems = useSyncSetupItems(setupId);
	const unit = useWeightUnit();
	const currency = useCurrency();
	const [selectedIds, setSelectedIds] = useState<Set<number>>(new Set());

	// Reset selected IDs when panel opens
	useEffect(() => {
		if (isOpen) {
			setSelectedIds(new Set(currentItemIds));
		}
	}, [isOpen, currentItemIds]);

	function handleToggle(itemId: number) {
		setSelectedIds((prev) => {
			const next = new Set(prev);
			if (next.has(itemId)) {
				next.delete(itemId);
			} else {
				next.add(itemId);
			}
			return next;
		});
	}

	function handleDone() {
		syncItems.mutate(Array.from(selectedIds), {
			onSuccess: () => onClose(),
		});
	}

	// Group items by category
	const grouped = new Map<
		number,
		{
			categoryName: string;
			categoryIcon: string;
			items: NonNullable<typeof items>;
		}
	>();

	if (items) {
		for (const item of items) {
			const group = grouped.get(item.categoryId);
			if (group) {
				group.items.push(item);
			} else {
				grouped.set(item.categoryId, {
					categoryName: item.categoryName,
					categoryIcon: item.categoryIcon,
					items: [item],
				});
			}
		}
	}

	return (
		<SlideOutPanel isOpen={isOpen} onClose={onClose} title="Select Items">
			<div className="flex flex-col h-full">
				<div className="flex-1 overflow-y-auto -mx-6 px-6">
					{!items || items.length === 0 ? (
						<div className="py-8 text-center">
							<p className="text-sm text-gray-500">
								No items in your collection yet.
							</p>
						</div>
					) : (
						Array.from(grouped.entries()).map(
							([
								categoryId,
								{ categoryName, categoryIcon, items: catItems },
							]) => (
								<div key={categoryId} className="mb-4">
									<h3 className="text-xs font-semibold text-gray-500 uppercase tracking-wider mb-2">
										<LucideIcon
											name={categoryIcon}
											size={16}
											className="inline-block mr-1 text-gray-500"
										/>{" "}
										{categoryName}
									</h3>
									<div className="space-y-1">
										{catItems.map((item) => (
											<label
												key={item.id}
												className="flex items-center gap-3 px-3 py-2 rounded-lg hover:bg-gray-50 cursor-pointer transition-colors"
											>
												<input
													type="checkbox"
													checked={selectedIds.has(item.id)}
													onChange={() => handleToggle(item.id)}
													className="rounded border-gray-300 text-gray-600 focus:ring-gray-400"
												/>
												<span className="flex-1 text-sm text-gray-900 truncate">
													{item.name}
												</span>
												<span className="text-xs text-gray-400 shrink-0">
													{item.weightGrams != null &&
														formatWeight(item.weightGrams, unit)}
													{item.weightGrams != null &&
														item.priceCents != null &&
														" · "}
													{item.priceCents != null &&
														formatPrice(item.priceCents, currency)}
												</span>
											</label>
										))}
									</div>
								</div>
							),
						)
					)}
				</div>

				{/* Action buttons */}
				<div className="flex gap-3 pt-4 border-t border-gray-100 -mx-6 px-6 pb-2">
					<button
						type="button"
						onClick={onClose}
						className="flex-1 px-4 py-2 text-sm font-medium text-gray-700 bg-gray-100 hover:bg-gray-200 rounded-lg transition-colors"
					>
						Cancel
					</button>
					<button
						type="button"
						onClick={handleDone}
						disabled={syncItems.isPending}
						className="flex-1 px-4 py-2 text-sm font-medium text-white bg-gray-700 hover:bg-gray-800 disabled:opacity-50 rounded-lg transition-colors"
					>
						{syncItems.isPending ? "Saving..." : "Done"}
					</button>
				</div>
			</div>
		</SlideOutPanel>
	);
}