"use client";

import {
	createContext,
	useCallback,
	useContext,
	useEffect,
	useMemo,
	useState,
} from "react";
import type {
	SearchContextValue,
	SearchProviderProps,
	SearchResult,
} from "./searchbox-types";

const SearchContext = createContext<SearchContextValue | null>(null);

const DEFAULT_DEBOUNCE_MS = 150;

export function useSearchContext() {
	const context = useContext(SearchContext);
	if (!context) {
		throw new Error("useSearchContext must be used within SearchProvider");
	}
	return context;
}

export function SearchProvider({
	children,
	documents = [],
	debounceMs = DEFAULT_DEBOUNCE_MS,
}: SearchProviderProps) {
	const [isOpen, setIsOpen] = useState(false);
	const [query, setQuery] = useState("");
	const [results, setResults] = useState<SearchResult[]>([]);
	const [isLoading, setIsLoading] = useState(false);
	const [error, setError] = useState<string | null>(null);

	// Keyboard shortcut (⌘K / Ctrl+K)
	useEffect(() => {
		const handleKeyDown = (e: KeyboardEvent) => {
			if ((e.metaKey || e.ctrlKey) && e.key === "k") {
				e.preventDefault();
				setIsOpen((prev) => !prev);
			}
		};
		document.addEventListener("keydown", handleKeyDown);
		return () => document.removeEventListener("keydown", handleKeyDown);
	}, []);

	// Reset query when dialog closes
	useEffect(() => {
		if (!isOpen) {
			setQuery("");
			setError(null);
		}
	}, [isOpen]);

	// Search when query changes
	useEffect(() => {
		if (!query) {
			setResults([]);
			setError(null);
			return;
		}

		setIsLoading(true);

		const timer = setTimeout(() => {
			const filtered = filterDocuments(documents, query);
			setResults(filtered);
			setIsLoading(false);
		}, debounceMs);

		return () => clearTimeout(timer);
	}, [query, documents, debounceMs]);

	const selectResult = useCallback((result: SearchResult) => {
		// Navigate to the result URL
		if (result.url) {
			window.location.href = result.url;
		}
		setQuery("");
		setIsOpen(false);
	}, []);

	const contextValue = useMemo<SearchContextValue>(
		() => ({
			isOpen,
			setIsOpen,
			query,
			setQuery,
			results,
			isLoading,
			error,
			selectResult,
		}),
		[isOpen, query, results, isLoading, error, selectResult],
	);

	return (
		<SearchContext.Provider value={contextValue}>
			{children}
		</SearchContext.Provider>
	);
}

function filterDocuments(
	documents: SearchResult[],
	query: string,
): SearchResult[] {
	const lowerQuery = query.toLowerCase();

	return documents
		.map((doc) => {
			// Calculate relevance score based on matches
			let score = 0;

			// Title match (highest weight)
			if (doc.title.toLowerCase().includes(lowerQuery)) {
				score += 10;
			}

			// Tag match
			if (doc.tag?.toLowerCase().includes(lowerQuery)) {
				score += 5;
			}

			// Breadcrumb match
			if (doc.breadcrumbs?.some((b) => b.toLowerCase().includes(lowerQuery))) {
				score += 3;
			}

			// Match content and sections
			const matchingMatches = doc.matches.filter((m) => {
				if (m.type === "section") {
					return (
						m.heading.toLowerCase().includes(lowerQuery) ||
						m.snippet.toLowerCase().includes(lowerQuery)
					);
				}
				return m.snippet.toLowerCase().includes(lowerQuery);
			});
			score += matchingMatches.length * 2;

			return { doc, score };
		})
		.filter(({ score }) => score > 0)
		.sort((a, b) => b.score - a.score)
		.map(({ doc }) => doc);
}