Mav-Mobile-UI/src/hooks/useLatestSighting.ts

import { useQuery } from "@tanstack/react-query";
import { useCallback, useEffect, useRef } from "react";

async function fetchSighting() {
  const response = await fetch(
    // `http://100.82.205.44/api`
    `http://192.168.75.11/mergedHistory/sightingSummary?mostRecentRef=-1`
  );
  if (!response.ok) throw new Error("Failed to fetch sighting");
  return response.json();
}

export function useLatestSighting() {
  const latestUrlRef = useRef<string | null>(null);
  const canvasRef = useRef<HTMLCanvasElement | null>(null);
  const sightingImageRef = useRef<HTMLImageElement | null>(null);

  const drawImage = useCallback(() => {
    const canvas = canvasRef.current;
    const ctx = canvas?.getContext("2d");
    const img2 = sightingImageRef.current;

    if (!img2 || !canvas) return;

    canvas.width = canvas.clientWidth;
    canvas.height = canvas.clientHeight;

    ctx?.drawImage(img2, 0, 0, 200, 50);
  }, [sightingImageRef]);

  const { data } = useQuery({
    queryKey: ["latestSighting"],
    queryFn: fetchSighting,
    refetchInterval: 100,
  });

  useEffect(() => {
    const img = new Image();
    sightingImageRef.current = img;

    img.onload = () => {
      drawImage();
    };
    img.src = data?.plateUrlColour;

    if (latestUrlRef.current) {
      URL.revokeObjectURL(latestUrlRef.current);
    }
    latestUrlRef.current = img.src;

    return () => {
      if (latestUrlRef.current) {
        URL.revokeObjectURL(latestUrlRef.current);
        latestUrlRef.current = null;
      }
    };
  }, [data?.plateUrlColour, drawImage]);

  return { data, sightingImageRef, canvasRef };
}