#!/usr/bin/env python

"""
    Converts tRNAScan output back to fasta-sequences.
"""
import sys
from Bio import SeqIO
from Bio.SeqRecord import SeqRecord
import subprocess

def main(args):
    """
        Call from galaxy:
        tRNAscan.py $organism $mode $showPrimSecondOpt $disablePseudo $showCodons $tabular_output $inputfile $fasta_output

            tRNAscan-SE $organism $mode $showPrimSecondOpt $disablePseudo $showCodons -Q -y -q -b -o $tabular_output $inputfile;
    """
    cmd = """tRNAscan-SE -Q -y -q -b %s""" % ' '.join( args[:-1] )
    child = subprocess.Popen(cmd.split(),
        stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = child.communicate()
    return_code = child.returncode
    if return_code:
        sys.stdout.write(stdout)
        sys.stderr.write(stderr)
        sys.stderr.write("Return error code %i from command:\n" % return_code)
        sys.stderr.write("%s\n" % cmd)
    else:
        sys.stdout.write(stdout)
        sys.stdout.write(stderr)

    outfile = args[-1]
    sequence_file = args[-2]
    tRNAScan_file = args[-3]

    with open( sequence_file ) as sequences:
        sequence_recs = SeqIO.to_dict(SeqIO.parse(sequences, "fasta"))

    tRNAs = []
    with open(tRNAScan_file) as tRNA_handle:
        for line in tRNA_handle:
            line = line.strip()
            if not line or line.startswith('#'):
                continue
            cols = line.split()
            iid = cols[0].strip()
            start = int(cols[2])
            end = int(cols[3])
            aa = cols[4]
            codon = cols[5]
            rec = sequence_recs[ iid ]
            if start > end:
                new_rec = rec[end:start]
                new_rec.seq = new_rec.seq.reverse_complement()
                new_rec.description = "%s %s %s %s %s" % (rec.description, aa, codon, start, end)
                new_rec.id = rec.id
                new_rec.name = rec.name
                tRNAs.append( new_rec )
            else:
                new_rec = rec[start:end]
                new_rec.id = rec.id
                new_rec.name = rec.name
                new_rec.description = "%s %s %s %s %s" % (rec.description, aa, codon, start, end)
                tRNAs.append( new_rec )

    SeqIO.write(tRNAs, open(outfile, 'w+'), "fasta")


if __name__ == '__main__':
    main(sys.argv[1:])