#!/usr/bin/env python
"""
 Copyright 2018 Johns Hopkins University  (Author: Jesus Villalba)
 Apache 2.0  (http://www.apache.org/licenses/LICENSE-2.0)
"""
"""
Trains linear Gaussian back-end
"""

import sys
import os
import argparse
import time
import logging

import numpy as np

from hyperion.hyp_defs import config_logger
from hyperion.helpers import VectorClassReader as VCR
from hyperion.transforms import TransformList
from hyperion.classifiers import LinearGBE as GBE


def train_linear_gbe(iv_file, train_list, preproc_file,
                     output_path,
                     **kwargs):
    
    if preproc_file is not None:
        preproc = TransformList.load(preproc_file)
    else:
        preproc = None

    vcr_args = VCR.filter_args(**kwargs)
    vcr_train = VCR(iv_file, train_list, preproc, **vcr_args)
    x, class_ids = vcr_train.read()

    t1 = time.time()

    model_args = GBE.filter_train_args(**kwargs)
    model = GBE(**model_args)
    model.fit(x, class_ids)
    logging.info('Elapsed time: %.2f s.' % (time.time()-t1))

    model.save(output_path)
    
    

if __name__ == "__main__":

    parser=argparse.ArgumentParser(
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
        fromfile_prefix_chars='@',
        description='Train linear GBE')

    parser.add_argument('--iv-file', dest='iv_file', required=True)
    parser.add_argument('--train-list', dest='train_list', required=True)
    parser.add_argument('--preproc-file', dest='preproc_file', default=None)

    VCR.add_argparse_args(parser)
    GBE.add_argparse_train_args(parser)

    parser.add_argument('--output-path', dest='output_path', required=True)
    parser.add_argument('-v', '--verbose', dest='verbose', default=1, choices=[0, 1, 2, 3], type=int)
    
    args=parser.parse_args()
    config_logger(args.verbose)
    del args.verbose
    logging.debug(args)
        
    train_linear_gbe(**vars(args))

            
