#!/usr/bin/env python2
# This code is part of the Biopython distribution and governed by its
# license.  Please see the LICENSE file that should have been included
# as part of this package.
#
# Bio.Wise contains modules for running and processing the output of
# some of the models in the Wise2 package by Ewan Birney available from:
# ftp://ftp.ebi.ac.uk/pub/software/unix/wise2/
# http://www.ebi.ac.uk/Wise2/
#
# Bio.Wise.psw is for protein Smith-Waterman alignments
# Bio.Wise.dnal is for Smith-Waterman DNA alignments

from __future__ import print_function

import re

#Importing with leading underscore as not intended to be exposed
from Bio._py3k import getoutput as _getoutput
from Bio._py3k import zip
from Bio._py3k import map

from Bio import Wise

_SCORE_MATCH = 4
_SCORE_MISMATCH = -1
_SCORE_GAP_START = -5
_SCORE_GAP_EXTENSION = -1

_CMDLINE_DNAL = ["dnal", "-alb", "-nopretty"]


def _build_dnal_cmdline(match, mismatch, gap, extension):
    res = _CMDLINE_DNAL[:]
    res.extend(["-match", str(match)])
    res.extend(["-mis", str(mismatch)])
    res.extend(["-gap", str(-gap)]) # negative: convert score to penalty
    res.extend(["-ext", str(-extension)])  # negative: convert score to penalty

    return res

_CMDLINE_FGREP_COUNT = "fgrep -c '%s' %s"


def _fgrep_count(pattern, file):
    return int(_getoutput(_CMDLINE_FGREP_COUNT % (pattern, file)))

_re_alb_line2coords = re.compile(r"^\[([^:]+):[^\[]+\[([^:]+):")


def _alb_line2coords(line):
    return tuple([int(coord)+1 # one-based -> zero-based
                  for coord
                  in _re_alb_line2coords.match(line).groups()])


def _get_coords(filename):
    alb = file(filename)

    start_line = None
    end_line = None

    for line in alb:
        if line.startswith("["):
            if not start_line:
                start_line = line # rstrip not needed
            else:
                end_line = line

    if end_line is None: # sequence is too short
        return [(0, 0), (0, 0)]

    return list(zip(*map(_alb_line2coords, [start_line, end_line]))) # returns [(start0, end0), (start1, end1)]


class Statistics(object):
    """
    Calculate statistics from an ALB report
    """
    def __init__(self, filename, match, mismatch, gap, extension):
        self.matches = _fgrep_count('"SEQUENCE" %s' % match, filename)
        self.mismatches = _fgrep_count('"SEQUENCE" %s' % mismatch, filename)
        self.gaps = _fgrep_count('"INSERT" %s' % gap, filename)

        if gap == extension:
            self.extensions = 0
        else:
            self.extensions = _fgrep_count('"INSERT" %s' % extension, filename)

        self.score = (match*self.matches +
                      mismatch*self.mismatches +
                      gap*self.gaps +
                      extension*self.extensions)

        if self.matches or self.mismatches or self.gaps or self.extensions:
            self.coords = _get_coords(filename)
        else:
            self.coords = [(0, 0), (0, 0)]

    def identity_fraction(self):
        return self.matches/(self.matches+self.mismatches)

    header = "identity_fraction\tmatches\tmismatches\tgaps\textensions"

    def __str__(self):
        return "\t".join(str(x) for x in (self.identity_fraction(),
                                          self.matches, self.mismatches,
                                          self.gaps, self.extensions))


def align(pair, match=_SCORE_MATCH, mismatch=_SCORE_MISMATCH, gap=_SCORE_GAP_START, extension=_SCORE_GAP_EXTENSION, **keywds):
    cmdline = _build_dnal_cmdline(match, mismatch, gap, extension)
    temp_file = Wise.align(cmdline, pair, **keywds)
    try:
        return Statistics(temp_file.name, match, mismatch, gap, extension)
    except AttributeError:
        try:
            keywds['dry_run']
            return None
        except KeyError:
            raise


def main():
    import sys
    stats = align(sys.argv[1:3])
    print("\n".join("%s: %s" % (attr, getattr(stats, attr))
                    for attr in ("matches", "mismatches", "gaps", "extensions")))
    print("identity_fraction: %s" % stats.identity_fraction())
    print("coords: %s" % stats.coords)


def _test(*args, **keywds):
    import doctest
    import sys
    doctest.testmod(sys.modules[__name__], *args, **keywds)

if __name__ == "__main__":
    if __debug__:
        _test()
    main()
