###############################################################################
# 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
import numpy as np

# Generates a swift IC file for the Smoothed Metallicity test
# in a periodic cubic box

# Parameters
gamma = 5.0 / 3.0  # Gas adiabatic index
rho0 = 1.0  # Background density
P0 = 1e-6  # Background pressure
Nelem = 10  # Gear: 10, EAGLE: 9
low_metal = -6  # Low iron fraction
high_metal = -5.5  # high iron fraction
max_shift = 1  # Shift between the different elements
sigma_metal = 0.2  # relative standard deviation for the metallicities
fileName = "smoothed_metallicity.hdf5"

# shift all metals in order to obtain nicer plots
low_metal = [low_metal] * Nelem + np.linspace(0, max_shift, Nelem)
low_metal = 10 ** low_metal

high_metal = [high_metal] * Nelem + np.linspace(0, max_shift, Nelem)
high_metal = 10 ** high_metal

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

# Read particle positions and h from the glass
pos = glass["/PartType0/Coordinates"][:, :]
h = glass["/PartType0/SmoothingLength"][:]

numPart = np.size(h)
vol = 1.0

# Generate extra arrays
v = np.zeros((numPart, 3))
ids = np.linspace(1, numPart, numPart)
m = np.zeros(numPart)
u = np.zeros(numPart)
r = np.zeros(numPart)
mass_frac = np.zeros((numPart, Nelem))

m[:] = rho0 * vol / numPart
u[:] = P0 / (rho0 * (gamma - 1))

# set metallicities
select = pos[:, 0] < 0.5
nber = sum(select)
mass_frac[select, :] = low_metal * (
    1 + np.random.normal(loc=0.0, scale=sigma_metal, size=(nber, Nelem))
)
nber = numPart - nber
mass_frac[~select, :] = high_metal * (
    1 + np.random.normal(loc=0.0, scale=sigma_metal, size=(nber, Nelem))
)

v[select, 2] = 1
v[~select, 2] = -1

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

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

# Header
grp = file.create_group("/Header")
grp.attrs["BoxSize"] = [1.0, 1.0, 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, 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

# Units
grp = file.create_group("/Units")
grp.attrs["Unit length in cgs (U_L)"] = 1.0
grp.attrs["Unit mass in cgs (U_M)"] = 1.0
grp.attrs["Unit time in cgs (U_t)"] = 1.0
grp.attrs["Unit current in cgs (U_I)"] = 1.0
grp.attrs["Unit temperature in cgs (U_T)"] = 1.0

# 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")
grp.create_dataset("MetalMassFraction", data=mass_frac, dtype="d")
grp.create_dataset("ElementAbundance", data=mass_frac, dtype="d")


file.close()