"""Constants and schema for trajectory ETL (NC → Arrow)."""

BLOCK_SIZE = 24  # steps per block (same as frontend)

# Default variable names to look for in NetCDF (first match wins)
LON_NAMES = ("lon", "longitude", "x", "Lon")
LAT_NAMES = ("lat", "latitude", "y", "Lat")
U_NAMES = ("u", "u_vel", "velocity_x", "U")
V_NAMES = ("v", "v_vel", "velocity_y", "V")
BEACHED_NAMES = ("beached", "status", "mask", "beach")
TIME_NAMES = ("time", "obs", "step", "t")

# Arrow table schema for one block (frontend expects this)
ARROW_SCHEMA = {
    "step": "int32",
    "particle_id": "int32",
    "lon": "float32",
    "lat": "float32",
    "u": "float32",
    "v": "float32",
    "beached": "int8",
}