import { useCallback, useEffect, useState, useRef, useMemo } from "react";
import { useProjectId, useEnv } from "@/lib/state";
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
import { useToast } from "@/hooks/use-toast";

// ANSI escape sequence regex
// eslint-disable-next-line no-control-regex
const ANSI_ESCAPE_REGEX = /\x1B(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])/g;

function cleanAnsiEscapeSequences(text: string): string {
	return text.replace(ANSI_ESCAPE_REGEX, "");
}

export function Logs() {
	const { toast } = useToast();
	const projectId = useProjectId();
	const env = useEnv();
	const [selectedService, setSelectedService] = useState<string>("");
	const [logs, setLogs] = useState<string>("");
	const preRef = useRef<HTMLPreElement>(null);
	const wasAtBottom = useRef(true);

	const checkIfAtBottom = useCallback(() => {
		if (!preRef.current) return;
		const { scrollTop, scrollHeight, clientHeight } = preRef.current;
		wasAtBottom.current = Math.abs(scrollHeight - clientHeight - scrollTop) < 10;
	}, []);

	const scrollToBottom = useCallback(() => {
		if (!preRef.current) return;
		preRef.current.scrollTop = preRef.current.scrollHeight;
	}, []);

	const fetchLogs = useCallback(
		async (service: string) => {
			if (!projectId || !service) return;

			try {
				const resp = await fetch(`/api/project/${projectId}/logs/${service}`);
				if (!resp.ok) {
					throw new Error("Failed to fetch logs");
				}
				const data = await resp.json();
				setLogs(data.logs || "");
			} catch (e) {
				console.error(e);
				toast({
					variant: "destructive",
					title: "Failed to fetch logs",
				});
			}
		},
		[projectId, toast],
	);

	useEffect(() => {
		if (selectedService) {
			// Initial fetch
			fetchLogs(selectedService);

			// Set up interval for periodic updates
			const interval = setInterval(() => {
				fetchLogs(selectedService);
			}, 5000);

			// Cleanup interval on unmount or when service changes
			return () => clearInterval(interval);
		}
	}, [selectedService, fetchLogs]);

	// Handle scroll events
	useEffect(() => {
		const pre = preRef.current;
		if (!pre) return;

		const handleScroll = () => {
			checkIfAtBottom();
		};

		pre.addEventListener("scroll", handleScroll);
		return () => pre.removeEventListener("scroll", handleScroll);
	}, [checkIfAtBottom]);

	// Auto-scroll when new logs arrive
	useEffect(() => {
		if (wasAtBottom.current) {
			scrollToBottom();
		}
	}, [logs, scrollToBottom]);

	const sortedServices = useMemo(() => (env?.services ? [...env.services].sort() : []), [env]);

	// Auto-select first service when services are available
	useEffect(() => {
		if (sortedServices.length && !selectedService) {
			setSelectedService(sortedServices[0]);
		}
	}, [sortedServices, selectedService]);

	return (
		<div className="flex flex-col h-full">
			<div className="flex-none w-full flex flex-row justify-start items-center gap-2 px-4 py-1">
				<div>Service</div>
				<Select value={selectedService} onValueChange={setSelectedService}>
					<SelectTrigger className="w-1/4">
						<SelectValue placeholder="Select a service" />
					</SelectTrigger>
					<SelectContent>
						{sortedServices.map((service) => (
							<SelectItem key={service} value={service}>
								{service}
							</SelectItem>
						))}
					</SelectContent>
				</Select>
			</div>
			{selectedService && (
				<pre
					ref={preRef}
					className="flex-1 h-full p-4 bg-muted overflow-auto font-['JetBrains_Mono'] text-xs whitespace-pre-wrap break-all"
				>
					{cleanAnsiEscapeSequences(logs) || "No logs available"}
				</pre>
			)}
		</div>
	);
}