#!/usr/bin/python
#
# by Erik Osheim
#
# available under the GNU GPL version 2.
#
# This program is designed to provide analysis of patches or diff files.

import optparse
import re
import sys

# matches the diff stanza, which have no leading identifier
diff_re = re.compile('^[0-9a-zA-Z,]+$')

# analyze a particular patch, which is assumed to contain multiple files
def info(f, verbose=False):
    paths = []
    l = 0
    first = True
    for line in f:
        if first:
            if diff_re.match(line):
                paths.append(['-', 0, 0, 0, 0])
            first = False

        if diff_re.match(line):
            if not paths:
                paths.append(['-', 0, 0, 0, 0])
            paths[-1][1] += 1
        elif line.startswith('diff'):
            path = line.split()[-1]
            l = max(l, len(path))
            paths.append([path, 0, 0, 0, 0])
        elif line.startswith('Index'):
            path = line.split()[1]
            l = max(l, len(path))
            paths.append([path, 0, 0, 0, 0])
        elif line.startswith('---') or line.startswith('+++') or line.startswith('='):
            pass
        elif line.startswith('@@'):
            paths[-1][1] += 1
        elif line.startswith('+') or line.startswith('>'):
            paths[-1][2] += 1
            paths[-1][3] += 1
        elif line.startswith('-') or line.startswith('<'):
            paths[-1][2] -= 1
            paths[-1][4] += 1

    if len(paths) != 1:
        title = '%d paths' % len(paths)
    else:
        title = '1 path'

    if verbose:
        title = 'TOTAL ' + title
    else:
        l = len(title)

    totals = [0, 0, 0, 0]
    for info in paths:
        for i in range(0, 4):
            totals[i] += info[i + 1]

    lens = [len(str(n)) + 1 for n in totals[:2]]
    fmt  = '%%-%ds %%%dd groups, %%+%dd lines (+%%d -%%d)' % tuple([l] + lens)
    for info in paths:
        if verbose:
            print fmt % tuple(info)

    print fmt % tuple([title] + totals)

if __name__ == "__main__":
    op = optparse.OptionParser()
    op.add_option('-v', '--verbose', dest='verbose', action='store_true')

    opts, args = op.parse_args()

    if args:
        for arg in args:
            info(open(arg, 'r'), verbose=opts.verbose)
    else:
        info(sys.stdin, verbose=opts.verbose)