#!/usr/bin/env python
"""Log splitter for Rowe Technology DVL/ADCP ensemble files.

"""

def export_ensembles_as_mat_files(infile, number_of_ensembles=9):
    """Read a Rowe DVL/ADCP ensemble file (.ENS) and write several ensembles
    out as separate MATLAB files (.MAT).
    
    """
    with open(infile, 'rb') as f:
        raw = f.read() # reads entire file. There's probably a smarter option.
        delimiter = '\x80'*16 # look for first 16 bytes of header
        ensembles = raw.split(delimiter)[2:2+number_of_ensembles] 
            # line above discards any data before first header and any data 
            # past specified number_of_ensembles
        for ensemble_number, ensemble in enumerate(ensembles):
            with open('{0}.mat'.format(ensemble_number),'wb') as outfile:
                outfile.write(ensemble[16:-4]) # discard header & checksum 


if __name__ == "__main__":
    import argparse
    parser = argparse.ArgumentParser(description='RTI ensemble splitter')
    parser.add_argument('-V', '--version', action='version', 
        version='%(prog)s 0.0.1',
        help='display version information and exit')
    parser.add_argument('-i', '--infile', metavar='filename', 
        type=str, help='input file (RTI .ENS)')
    parser.add_argument('-n','--number-of-ensembles', default=9, 
        help='number of ensembles to split')
    args = parser.parse_args()
    export_ensembles_as_mat_files(**args.__dict__)