#!/usr/bin/env python
# Copyright (c) 2020, Anthony Latorre <tlatorre at uchicago>
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU 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 General Public License along with
# this program. If not, see <https://www.gnu.org/licenses/>.
"""
Script to do convert GENIE reweight ROOT files into HDF5 files. To run it just
run:

    $ ./convert-genie-rw [filename] -o [output filename]
"""
from __future__ import print_function, division
import ROOT

if __name__ == '__main__':
    import argparse
    import sys
    import h5py
    import numpy as np

    parser = argparse.ArgumentParser("convert GENIE reweight files from ROOT -> HDF5")
    parser.add_argument("filename", help="input filename")
    parser.add_argument("-o", "--output", required=True, help="output filename")
    args = parser.parse_args()

    f = ROOT.TFile(args.filename)
    weights = f.Get("weights")

    weights.GetEntry(0)
    nuniverses = len(weights.weights)

    data = np.empty(weights.GetEntries()*nuniverses,dtype=[('run',np.int32),('evn',np.int32),('universe',np.int32),('weight',np.float32)])

    for i, event in enumerate(weights):
        for j in range(nuniverses):
            data[i*nuniverses+j] = event.runnum, event.eventnum, j, event.weights[j]

    f.Close()

    with h5py.File(args.output,"w") as fout:
        fout.create_dataset('weights',data=data)