from math import fabs
from sys import argv

import h5py
import numpy as np

gamma = 5 / 3
YHe = 0.245421
Tcmb0 = 2.7255


def calculate_gas_internal_energy(omegab, hubble_param_, zstart_):
    astart_ = 1.0 / (1.0 + zstart_)
    if fabs(1.0 - gamma) > 1e-7:
        npol = 1.0 / (gamma - 1.)
    else:
        npol = 1.0
    unitv = 1e5
    adec = 1.0 / (160. * (omegab * hubble_param_ * hubble_param_ / 0.022) ** (2.0 / 5.0))
    if (astart_ < adec):
        Tini = Tcmb0 / astart_
    else:
        Tini = Tcmb0 / astart_ / astart_ * adec
    print("Tini", Tini)
    if Tini > 1.e4:
        mu = 4.0 / (8. - 5. * YHe)
    else:
        mu = 4.0 / (1. + 3. * (1. - YHe))
    print("mu", mu)
    ceint_ = 1.3806e-16 / 1.6726e-24 * Tini * npol / mu / unitv / unitv
    print("ceint", ceint_)
    return ceint_


def calculate_smoothing_length(boxsize, hubble_param_, levelmax):
    mean_interparte_separation = boxsize / 2 ** levelmax
    print("smoothing length", mean_interparte_separation)
    return mean_interparte_separation


with h5py.File(argv[1], "r+") as f:
    omegab = f["Cosmology"].attrs["Omega_b"]
    h = f["Cosmology"].attrs["h"]
    zstart = f["Header"].attrs["Redshift"]
    boxsize = f["Header"].attrs["BoxSize"]
    levelmax = f["Header"].attrs["Music_levelmax"]
    internal_energy = calculate_gas_internal_energy(omegab=omegab, hubble_param_=h, zstart_=zstart)
    smoothing_length = calculate_smoothing_length(boxsize=boxsize, hubble_param_=h, levelmax=levelmax)
    # exit()
    bary_mass = f["Header"].attrs["MassTable"][0]
    bary_count = f["Header"].attrs["NumPart_Total"][0]
    print("mass table", f["Header"].attrs["MassTable"])
    pt1 = f["PartType0"]
    masses_column = pt1.create_dataset(
        "Masses",
        data=np.full(bary_count, bary_mass),
        compression='gzip'
    )
    smoothing_length_column = pt1.create_dataset(
        "SmoothingLength",
        data=np.full(bary_count, smoothing_length),
        compression='gzip'
    )
    internal_energy_column = pt1.create_dataset(
        "InternalEnergy",
        data=np.full(bary_count, internal_energy),
        compression='gzip'
    )