# Manual Installation of geant4 on macOS
# Will require about 3GB of storage space including Geant4 datasets

# System software required by geant4
xcode-select --install
brew install cmake qt6 expat

# Create your workspace folder and enter the folder, e.g.
mkdir -p $HOME/software/geant4 && cd $_

# Download Geant4 distribution
GEANT_RELEASE=v11.4.0
wget https://gitlab.cern.ch/geant4/geant4/-/archive/${GEANT_RELEASE}/geant4-${GEANT_RELEASE}.tar.gz

# If download successful, uncompress the archive
tar zxvf geant4-${GEANT_RELEASE}.tar.gz

# create build directory
mv geant4-${GEANT_RELEASE}{,-src}
mkdir geant4-${GEANT_RELEASE}{,-build}
cd geant4-${GEANT_RELEASE}-build

# Now prepare makefiles with cmake
cmake -DCMAKE_INSTALL_PREFIX=../geant4-${GEANT_RELEASE} \
      -DGEANT4_BUILD_MULTITHREADED=OFF \
      -DGEANT4_INSTALL_DATA=OFF \
      -DGEANT4_USE_QT=ON ../geant4-${GEANT_RELEASE}-src

# now compile and install
make -jN ## (e.g N=4 based on the number of cores on your system)
make install

# Installation complete!

# Copy GEANT4 datasets (OPTIONAL)
# Warning! Large amount of data will be downloaded
# Check if you can copy the datasets offline
mkdir -p ../geant4-${GEANT_RELEASE}/share/Geant4/data && cd $_
for dset in $(echo https://cern.ch/geant4-data/datasets/G4NDL.4.7.1.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4EMLOW.8.8.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4PhotonEvaporation.6.1.2.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4RadioactiveDecay.6.1.2.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4PARTICLEXS.4.2.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4PII.1.3.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4RealSurface.2.2.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4SAIDDATA.2.0.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4ABLA.3.3.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4INCL.1.3.tar.gz \
		   https://cern.ch/geant4-data/datasets/G4ENSDFSTATE.3.0.tar.gz)
do
  wget $dset && tar zxvf $(basename $dset)
done

# After successful installation of geant4, build applications (e.g B1)
cd $HOME/software/geant4

# copy the examples folder from the geant4 src directory
rsync -avz --progress geant4-${GEANT_RELEASE}-src/examples .
cd examples/basic
mkdir -p B1-build && cd $_
cmake -DCMAKE_PREFIX_PATH=$HOME/software/geant4/geant4-${GEANT_RELEASE} ../B1
make

# finally, you can run the example now
# Note that, geant4 datasets should be available by now
source $HOME/software/geant4/geant4-${GEANT_RELEASE}/bin/geant4.sh
./exampleB1