import { useEffect } from 'react'
import { useCesiumViewer } from './cesiumContext'
import { useMapStore } from '../store/mapStore'
import { rectangleToBbox } from './geoUtils'

/**
 * Attaches a scene.preUpdate listener that writes camera height and
 * the current view bbox to mapStore on every frame.
 *
 * Throttled so the store update fires at most once per 200 ms to avoid
 * triggering expensive API queries on every rendered frame.
 */
export function useCesiumCamera() {
  const viewer = useCesiumViewer()
  const setCameraState = useMapStore((s) => s.setCameraState)

  useEffect(() => {
    let lastFired = 0
    const THROTTLE_MS = 200

    const removeListener = viewer.scene.preUpdate.addEventListener(() => {
      const now = Date.now()
      if (now - lastFired < THROTTLE_MS) return
      lastFired = now

      const height = viewer.camera.positionCartographic.height
      const rect = viewer.camera.computeViewRectangle()
      if (rect) {
        setCameraState(height, rectangleToBbox(rect))
      }
    })

    return () => {
      removeListener()
    }
  }, [viewer, setCameraState])
}