package com.hawhamburg.micr0bu

import com.hawhamburg.micr0bu.domain.asn1.CamUperCodec
import com.hawhamburg.micr0bu.domain.cam.StationType
import org.junit.Assert.assertEquals
import org.junit.Assert.assertNotNull
import org.junit.Test

/**
 * A roadside unit's CAM must decode, not be dropped.
 *
 * ETSI's `HighFrequencyContainer` is a CHOICE, and an RSU picks `rsuContainerHighFrequency`
 * instead of `basicVehicleContainerHighFrequency`. That container holds no kinematics at all -
 * only an optional protected-zone list - so an earlier version of the decoder bailed on it and
 * every RSU CAM was silently discarded. The bench RSU sends CAM and SPATEM from the same station
 * id, so dropping its CAM meant the one station a rider most wants to see never appeared.
 *
 * The fixture is a real 26-byte RSU CAM taken live from the OBU's `v2x/rx/cam` topic; the
 * expected values are asn1tools' decoding of those same bytes using the ETSI modules in the
 * `C-ITS-Parser` checkout.
 */
class RsuCamDecodeTest {

    private val rsuCam = "020239b9de898b8b00fab215af6e286477c0c20c200033fa4e80"

    private fun String.hexToBytes(): ByteArray =
        chunked(2).map { it.toInt(16).toByte() }.toByteArray()

    @Test
    fun `decodes a roadside unit CAM for position and station type`() {
        val cam = CamUperCodec.decode(rsuCam.hexToBytes(), receivedAtEpochMs = 1_787_100_000_000L)
        assertNotNull("an RSU CAM must not be dropped", cam)
        cam!!

        assertEquals(968_482_441L, cam.stationId)
        assertEquals(StationType.ROAD_SIDE_UNIT, cam.stationType)
        assertEquals(15, cam.stationType) // the enumeration jumps 11 -> 15; 12 would be wrong

        assertEquals(53.5544955, cam.latitude, 1e-7)
        assertEquals(10.0225470, cam.longitude, 1e-7)

        // An RSU has no kinematics to report. Zero is a placeholder, which is only safe because
        // CamUseCaseRepository keeps RSU CAMs out of UseCaseDetectionEngine - otherwise this
        // would read as a permanently stopped vehicle and raise a standing false alert.
        assertEquals(0.0, cam.speedMps, 0.0)
        assertEquals(0.0, cam.headingDeg, 0.0)
    }
}