###############################################################################
# This file is part of SWIFT.
# Copyright (c) 2018 Bert Vandenbroucke (bert.vandenbroucke@gmail.com)
#
# 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 numpy as np
import h5py

# Generates an overdensity within a vacuum to test the vacuum resolving
# capabilities of the code

# Parameters
gamma = 5.0 / 3.0  # Gas adiabatic index

fileName = "vacuum.hdf5"

# ---------------------------------------------------
glass = h5py.File("glassCube_64.hdf5", "r")

# Read particle positions and h from the glass
pos = glass["/PartType0/Coordinates"][:, :]
h = glass["/PartType0/SmoothingLength"][:] * 0.3

# Make 8 copies of the glass to get more particles
pos *= 0.5
h *= 0.5
pos = np.append(pos, pos + np.array([0.5, 0.0, 0.0]), axis=0)
pos = np.append(pos, pos + np.array([0.0, 0.5, 0.0]), axis=0)
pos = np.append(pos, pos + np.array([0.0, 0.0, 0.5]), axis=0)
h = np.append(h, h)
h = np.append(h, h)
h = np.append(h, h)

radius = np.sqrt(
    (pos[:, 0] - 0.5) ** 2 + (pos[:, 1] - 0.5) ** 2 + (pos[:, 2] - 0.5) ** 2
)
index = radius < 0.25
pos = pos[index]
h = h[index]

numPart = len(h)
vol = 4.0 * np.pi / 3.0 * 0.25 ** 3

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

m[:] = 1.0 * vol / numPart
u[:] = 1.0 / (1.0 * (gamma - 1.0))

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

# 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")

file.close()