"use client";

import React, { useState, useEffect, useRef } from "react";
import { useTranslation } from "@/lib/i18n";

export default function NoteForm({ projectId, onNoteAdded }) {
	const { t } = useTranslation();
	const [note, setNote] = useState("");
	const [status, setStatus] = useState(null);
	const [projects, setProjects] = useState([]);
	const [showDropdown, setShowDropdown] = useState(false);
	const [filteredProjects, setFilteredProjects] = useState([]);
	const [cursorPosition, setCursorPosition] = useState(0);
	const [triggerChar, setTriggerChar] = useState(null);
	const [selectedIndex, setSelectedIndex] = useState(0);
	const textareaRef = useRef(null);

	useEffect(() => {
		async function fetchProjects() {
			try {
				const res = await fetch("/api/projects");
				if (res.ok) {
					const data = await res.json();
					setProjects(data);
				}
			} catch (error) {
				console.error("Failed to fetch projects:", error);
			}
		}
		fetchProjects();
	}, []);

	useEffect(() => {
		if (note && cursorPosition > 0) {
			const beforeCursor = note.slice(0, cursorPosition);
			const match = beforeCursor.match(/([@#])([^@#]*)$/);
			if (match) {
				const char = match[1];
				const query = match[2].toLowerCase();
				setTriggerChar(char);
				const filtered = projects.filter(project =>
					project.project_name.toLowerCase().includes(query)
				);
				setFilteredProjects(filtered);
				setShowDropdown(filtered.length > 0);
				setSelectedIndex(0);
			} else {
				setShowDropdown(false);
			}
		} else {
			setShowDropdown(false);
		}
	}, [note, cursorPosition, projects]);

	async function handleSubmit(e) {
		e.preventDefault();

		const res = await fetch("/api/notes", {
			method: "POST",
			headers: { "Content-Type": "application/json" },
			body: JSON.stringify({ project_id: projectId, note }),
		});

		if (res.ok) {
			const newNote = await res.json();
			setNote("");
			setStatus(t("common.addNoteSuccess"));
			// Call the callback to add the new note to the parent component's state
			if (onNoteAdded) {
				onNoteAdded(newNote);
			}
			// Clear status message after 3 seconds
			setTimeout(() => setStatus(null), 3000);
		} else {
			setStatus(t("common.addNoteError"));
		}
	}

	function handleKeyDown(e) {
		if (e.ctrlKey && e.key === 'Enter') {
			e.preventDefault();
			handleSubmit(e);
		}
		if (showDropdown) {
			if (e.key === 'ArrowDown') {
				e.preventDefault();
				setSelectedIndex((prev) => (prev + 1) % filteredProjects.length);
			} else if (e.key === 'ArrowUp') {
				e.preventDefault();
				setSelectedIndex((prev) => (prev - 1 + filteredProjects.length) % filteredProjects.length);
			} else if (e.key === 'Enter') {
				e.preventDefault();
				if (filteredProjects.length > 0) {
					selectProject(filteredProjects[selectedIndex]);
				}
			} else if (e.key === 'Escape') {
				setShowDropdown(false);
			}
		}
	}

	function handleInputChange(e) {
		setNote(e.target.value);
		setCursorPosition(e.target.selectionStart);
	}

	function handleInputBlur() {
		// Delay hiding dropdown to allow for clicks on dropdown items
		setTimeout(() => setShowDropdown(false), 150);
	}

	function selectProject(project) {
		const beforeCursor = note.slice(0, cursorPosition);
		const afterCursor = note.slice(cursorPosition);
		const match = beforeCursor.match(/([@#])([^@#]*)$/);
		if (match) {
			const start = match.index;
			const end = cursorPosition;
			const link = `[${triggerChar}${project.project_name}](/projects/${project.project_id})`;
			const newNote = note.slice(0, start) + link + afterCursor;
			setNote(newNote);
			setShowDropdown(false);
			// Set cursor after the inserted link
			setTimeout(() => {
				textareaRef.current.focus();
				textareaRef.current.setSelectionRange(start + link.length, start + link.length);
			}, 0);
		}
	}

	return (
		<form onSubmit={handleSubmit} className="space-y-2 mb-4 relative">
			<div className="relative">
				<textarea
					ref={textareaRef}
					value={note}
					onChange={handleInputChange}
					onKeyDown={handleKeyDown}
					onClick={(e) => setCursorPosition(e.target.selectionStart)}
					onKeyUp={(e) => setCursorPosition(e.target.selectionStart)}
					onBlur={handleInputBlur}
					placeholder={t("common.addNotePlaceholder")}
					className="border p-2 w-full"
					rows={3}
					required
				/>
				{showDropdown && (
					<div className="absolute top-full left-0 right-0 bg-white border border-gray-300 rounded shadow-lg z-10 max-h-40 overflow-y-auto">
						{filteredProjects.map((project, index) => (
							<div
								key={project.project_id}
								className={`p-2 cursor-pointer ${index === selectedIndex ? 'bg-blue-100' : 'hover:bg-gray-100'}`}
								onClick={() => selectProject(project)}
							>
								{triggerChar}{project.project_name}
							</div>
						))}
					</div>
				)}
			</div>
			<button
				type="submit"
				className="bg-blue-600 text-white px-4 py-2 rounded"
			>
				{t("common.addNote")}
			</button>
			{status && <p className="text-sm text-gray-600">{status}</p>}
		</form>
	);
}