import { useCallback, useEffect, useMemo, useRef, useState } from "react";
import { createPortal } from "react-dom";
import { iconGroups, LucideIcon } from "../lib/iconData";

interface IconPickerProps {
	value: string;
	onChange: (icon: string) => void;
	size?: "sm" | "md";
}

export function IconPicker({
	value,
	onChange,
	size = "md",
}: IconPickerProps) {
	const [isOpen, setIsOpen] = useState(false);
	const [search, setSearch] = useState("");
	const [activeGroup, setActiveGroup] = useState(0);
	const [position, setPosition] = useState<{ top: number; left: number }>({
		top: 0,
		left: 0,
	});
	const triggerRef = useRef<HTMLButtonElement>(null);
	const popoverRef = useRef<HTMLDivElement>(null);
	const searchRef = useRef<HTMLInputElement>(null);

	const updatePosition = useCallback(() => {
		if (!triggerRef.current) return;
		const rect = triggerRef.current.getBoundingClientRect();
		const popoverHeight = 360;
		const spaceBelow = window.innerHeight - rect.bottom;
		const openUpward = spaceBelow < popoverHeight && rect.top > spaceBelow;

		setPosition({
			top: openUpward ? rect.top - popoverHeight : rect.bottom + 4,
			left: Math.min(rect.left, window.innerWidth - 288 - 8),
		});
	}, []);

	// Position the popover when opened
	useEffect(() => {
		if (!isOpen) return;
		updatePosition();
	}, [isOpen, updatePosition]);

	// Stop mousedown from propagating out of the portal so parent
	// click-outside handlers (e.g. CategoryPicker) don't close.
	useEffect(() => {
		const el = popoverRef.current;
		if (!isOpen || !el) return;
		function stopProp(e: MouseEvent) {
			e.stopPropagation();
		}
		el.addEventListener("mousedown", stopProp);
		return () => el.removeEventListener("mousedown", stopProp);
	}, [isOpen]);

	// Close on click-outside
	useEffect(() => {
		if (!isOpen) return;
		function handleClickOutside(e: MouseEvent) {
			const target = e.target as Node;
			if (
				triggerRef.current?.contains(target) ||
				popoverRef.current?.contains(target)
			) {
				return;
			}
			setIsOpen(false);
			setSearch("");
		}
		document.addEventListener("mousedown", handleClickOutside);
		return () => document.removeEventListener("mousedown", handleClickOutside);
	}, [isOpen]);

	// Close on Escape
	useEffect(() => {
		if (!isOpen) return;
		function handleKeyDown(e: KeyboardEvent) {
			if (e.key === "Escape") {
				setIsOpen(false);
				setSearch("");
			}
		}
		document.addEventListener("keydown", handleKeyDown);
		return () => document.removeEventListener("keydown", handleKeyDown);
	}, [isOpen]);

	// Focus search input when opened
	useEffect(() => {
		if (isOpen) {
			requestAnimationFrame(() => searchRef.current?.focus());
		}
	}, [isOpen]);

	const filteredIcons = useMemo(() => {
		if (!search.trim()) return null;
		const q = search.toLowerCase();
		const results = iconGroups.flatMap((group) =>
			group.icons.filter(
				(icon) =>
					icon.name.includes(q) ||
					icon.keywords.some((kw) => kw.includes(q)),
			),
		);
		// Deduplicate by name (some icons appear in multiple groups)
		const seen = new Set<string>();
		return results.filter((icon) => {
			if (seen.has(icon.name)) return false;
			seen.add(icon.name);
			return true;
		});
	}, [search]);

	function handleSelect(iconName: string) {
		onChange(iconName);
		setIsOpen(false);
		setSearch("");
	}

	const buttonSize =
		size === "sm" ? "w-10 h-10" : "w-12 h-12";
	const iconSize = size === "sm" ? 20 : 24;

	return (
		<>
			<button
				ref={triggerRef}
				type="button"
				onClick={() => setIsOpen(!isOpen)}
				className={`${buttonSize} flex items-center justify-center border border-gray-200 rounded-md hover:border-gray-300 hover:bg-gray-50 transition-colors`}
			>
				{value ? (
					<LucideIcon name={value} size={iconSize} className="text-gray-500" />
				) : (
					<span className="text-gray-300 text-lg">+</span>
				)}
			</button>

			{isOpen &&
				createPortal(
					<div
						ref={popoverRef}
						data-icon-picker
						className="fixed z-50 w-72 bg-white border border-gray-200 rounded-lg shadow-lg"
						style={{ top: position.top, left: position.left }}
					>
						{/* Search */}
						<div className="p-2 border-b border-gray-100">
							<input
								ref={searchRef}
								type="text"
								value={search}
								onChange={(e) => {
									setSearch(e.target.value);
									setActiveGroup(0);
								}}
								placeholder="Search icons..."
								className="w-full px-2 py-1.5 text-sm border border-gray-200 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent"
							/>
						</div>

						{/* Group tabs */}
						{!search.trim() && (
							<div className="flex gap-0.5 px-2 py-1.5 border-b border-gray-100">
								{iconGroups.map((group, i) => (
									<button
										key={group.name}
										type="button"
										onClick={() => setActiveGroup(i)}
										className={`flex-1 flex items-center justify-center py-1 rounded transition-colors ${
											i === activeGroup
												? "bg-blue-50 text-blue-700"
												: "hover:bg-gray-50 text-gray-500"
										}`}
										title={group.name}
									>
										<LucideIcon
											name={group.icon}
											size={16}
											className={
												i === activeGroup
													? "text-blue-700"
													: "text-gray-400"
											}
										/>
									</button>
								))}
							</div>
						)}

						{/* Icon grid */}
						<div className="max-h-56 overflow-y-auto p-2">
							{search.trim() ? (
								filteredIcons && filteredIcons.length > 0 ? (
									<div className="grid grid-cols-6 gap-0.5">
										{filteredIcons.map((icon) => (
											<button
												key={icon.name}
												type="button"
												onClick={() => handleSelect(icon.name)}
												className="w-10 h-10 flex items-center justify-center rounded hover:bg-gray-100 transition-colors"
												title={icon.name}
											>
												<LucideIcon
													name={icon.name}
													size={20}
													className="text-gray-600"
												/>
											</button>
										))}
									</div>
								) : (
									<p className="text-sm text-gray-400 text-center py-4">
										No icons found
									</p>
								)
							) : (
								<div className="grid grid-cols-6 gap-0.5">
									{iconGroups[activeGroup].icons.map((icon) => (
										<button
											key={icon.name}
											type="button"
											onClick={() => handleSelect(icon.name)}
											className="w-10 h-10 flex items-center justify-center rounded hover:bg-gray-100 transition-colors"
											title={icon.name}
										>
											<LucideIcon
												name={icon.name}
												size={20}
												className="text-gray-600"
											/>
										</button>
									))}
								</div>
							)}
						</div>
					</div>,
					document.body,
				)}
		</>
	);
}