###############################################################################
# This file is part of SWIFT.
# Copyright (c) 2016 Matthieu Schaller (schaller@strw.leidenuniv.nl)
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
##############################################################################

import h5py
from numpy import *

# Some constants
solar_mass_cgs = 1.988480e33
kpc_in_cm = 3.085678e21
mp_cgs = 1.67e-24
boltzmann_k_cgs = 1.38e-16

# Parameters
gamma = 5.0 / 3.0  # Gas adiabatic index
rho_cgs = mp_cgs  # Background density
u0_cgs = 1.2e12  # Desired initial internal energy (1.2e12 ~ 10^4K)
P_cgs = rho_cgs * u0_cgs * (gamma - 1.0)  # Background pressure
fileName = "stellar_evolution.hdf5"

# Units
unit_l_cgs = 3.085678e24  # kpc
unit_m_cgs = 1.988480e43  # 10^10 Msun
unit_v_cgs = 1e5  # km / s
unit_A_cgs = 1.0
unit_T_cgs = 1.0
unit_t_cgs = unit_l_cgs / unit_v_cgs

boxsize_cgs = 10.0 * kpc_in_cm
vol_cgs = boxsize_cgs ** 3

# ---------------------------------------------------
glass = h5py.File("glassCube_32.hdf5", "r")

# Read particle positions and h from the glass
pos = glass["/PartType0/Coordinates"][:, :]
eps = 1e-6
pos = (pos - pos.min()) / (pos.max() - pos.min() + eps) * boxsize_cgs / unit_l_cgs
h = glass["/PartType0/SmoothingLength"][:] * boxsize_cgs / unit_l_cgs

numPart = size(h)

# Generate extra arrays
v = zeros((numPart, 3))
ids = linspace(1, numPart, numPart)
m_cgs = zeros(numPart)
u_cgs = zeros(numPart)
m = zeros(numPart)
u = zeros(numPart)

m_cgs[:] = rho_cgs * vol_cgs / numPart
u_cgs[:] = P_cgs / (rho_cgs * (gamma - 1))

# Stars
star_pos = zeros((1, 3))
star_pos[:, :] = 0.5 * boxsize_cgs / unit_l_cgs

star_v = zeros((1, 3))
star_v[:, :] = 0.0

# increase mass to keep it at center
star_m_cgs = m_cgs[0]
star_ids = array([numPart + 1])
star_h = array([h.max()])

# --------------------------------------------------

# Check quantities are correct for debugging
print(
    "part mass/msun "
    + str(m_cgs[0] / solar_mass_cgs)
    + " stellar mass/msun "
    + str(star_m_cgs / solar_mass_cgs)
)
print("boxsize kpc " + str(boxsize_cgs / kpc_in_cm))
print("density cm^-3 " + str(rho_cgs / mp_cgs))
print(
    "initial temperature K " + str(u_cgs[0] / boltzmann_k_cgs * ((gamma - 1) * rho_cgs))
)

# Convert to internal units
star_m = star_m_cgs / unit_m_cgs
m[:] = m_cgs / unit_m_cgs
u[:] = u_cgs * unit_v_cgs ** -2
boxsize = boxsize_cgs / unit_l_cgs


# --------------------------------------------------

# File
file = h5py.File(fileName, "w")

# Header
grp = file.create_group("/Header")
grp.attrs["BoxSize"] = [boxsize] * 3
grp.attrs["NumPart_Total"] = [numPart, 0, 0, 0, 1, 0]
# grp.attrs["NumPart_Total"] =  [numPart, 0, 0, 0, 0, 0]
grp.attrs["NumPart_Total_HighWord"] = [0, 0, 0, 0, 0, 0]
grp.attrs["NumPart_ThisFile"] = [numPart, 0, 0, 0, 1, 0]
# grp.attrs["NumPart_ThisFile"] = [numPart, 0, 0, 0, 0, 0]
grp.attrs["Time"] = 0.0
grp.attrs["NumFilesPerSnapshot"] = 1
grp.attrs["MassTable"] = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
grp.attrs["Flag_Entropy_ICs"] = 0
grp.attrs["Dimension"] = 3

# Runtime parameters
grp = file.create_group("/RuntimePars")
grp.attrs["PeriodicBoundariesOn"] = 0

# Units
grp = file.create_group("/Units")
grp.attrs["Unit length in cgs (U_L)"] = unit_l_cgs
grp.attrs["Unit mass in cgs (U_M)"] = unit_m_cgs
grp.attrs["Unit time in cgs (U_t)"] = unit_t_cgs
grp.attrs["Unit current in cgs (U_I)"] = unit_A_cgs
grp.attrs["Unit temperature in cgs (U_T)"] = unit_T_cgs

# Particle group
grp = file.create_group("/PartType0")
grp.create_dataset("Coordinates", data=pos, dtype="d")
grp.create_dataset("Velocities", data=v, dtype="f")
grp.create_dataset("Masses", data=m, dtype="f")
grp.create_dataset("SmoothingLength", data=h, dtype="f")
grp.create_dataset("InternalEnergy", data=u, dtype="f")
grp.create_dataset("ParticleIDs", data=ids, dtype="L")

# stellar group
grp = file.create_group("/PartType4")
grp.create_dataset("Coordinates", data=star_pos, dtype="d")
grp.create_dataset("Velocities", data=star_v, dtype="f")
grp.create_dataset("Masses", data=star_m, dtype="f")
grp.create_dataset("SmoothingLength", data=star_h, dtype="f")
grp.create_dataset("ParticleIDs", data=star_ids, dtype="L")

file.close()