"use client";

import { useCallback, useEffect, useRef, useState } from "react";
import type { AutosaveData } from "../editor/types";

const AUTOSAVE_INTERVAL = 30_000; // 30 seconds
const MAX_AUTOSAVE_AGE = 24 * 60 * 60 * 1000; // 24 hours

function getAutosaveKey(path: string) {
	return `editor-autosave:${path}`;
}

export function useAutosave(
	path: string,
	content: string,
	isDirty: boolean,
	initialContent: string,
) {
	const [showRecoveryPrompt, setShowRecoveryPrompt] = useState(false);
	const [recoveredData, setRecoveredData] = useState<AutosaveData | null>(null);

	// Use ref for content to avoid recreating interval on every content change
	const contentRef = useRef(content);
	useEffect(() => {
		contentRef.current = content;
	}, [content]);

	// Check for autosave on mount
	useEffect(() => {
		if (!path || typeof window === "undefined") return;

		const key = getAutosaveKey(path);
		const saved = localStorage.getItem(key);

		if (saved) {
			try {
				const data: AutosaveData = JSON.parse(saved);
				const age = Date.now() - data.timestamp;

				// If autosave is newer than 24h and different from initial content
				if (age < MAX_AUTOSAVE_AGE && data.content !== initialContent) {
					setRecoveredData(data);
					setShowRecoveryPrompt(true);
				} else {
					// Clear old autosave
					localStorage.removeItem(key);
				}
			} catch {
				// Clear invalid autosave
				localStorage.removeItem(key);
			}
		}
	}, [path, initialContent]);

	// Autosave when dirty - uses ref to avoid interval recreation on content changes
	useEffect(() => {
		if (!isDirty || !path || typeof window === "undefined") return;

		const timer = setInterval(() => {
			const data: AutosaveData = {
				content: contentRef.current,
				timestamp: Date.now(),
			};
			localStorage.setItem(getAutosaveKey(path), JSON.stringify(data));
		}, AUTOSAVE_INTERVAL);

		return () => clearInterval(timer);
	}, [isDirty, path]);

	// Clear autosave on successful save
	const clearAutosave = useCallback(() => {
		if (path) {
			localStorage.removeItem(getAutosaveKey(path));
		}
	}, [path]);

	// Handle recovery
	const handleRestore = useCallback(() => {
		setShowRecoveryPrompt(false);
		return recoveredData?.content;
	}, [recoveredData]);

	const handleDiscardRecovery = useCallback(() => {
		setShowRecoveryPrompt(false);
		setRecoveredData(null);
		if (path) {
			localStorage.removeItem(getAutosaveKey(path));
		}
	}, [path]);

	return {
		showRecoveryPrompt,
		recoveredData,
		clearAutosave,
		handleRestore,
		handleDiscardRecovery,
	};
}