#!/usr/bin/env python

from commands import getoutput
from datetime import date
from os import path, environ
import sys

import re
import fileinput

#TODO: Make the Date/Name/Email line optional
cl_name = environ.get('CHANGE_LOG_NAME')
cl_email = environ.get('CHANGE_LOG_EMAIL_ADDRESS')

diff_cmd = ""
is_git = False
is_svn = False

def print_message_line(l):
    global is_git
    if is_git:
        print "%s" % l
    else:
        print l

if path.isdir('./.svn'):
    diff_cmd = "svn diff"
    is_svn = True
elif path.isdir('./.git'):
    # Require pwd to be root of git repo, since diff is *not* relative, to avoid confusion.
    # Since this is done just before a commit, only capture staged changes.
    # Use --no-prefix to look more like an svn diff.
    diff_cmd = "git diff --cached --no-prefix"
    is_git = True
else:
    print "ERROR: Called from outside a Subversion checkout or root of git repository"
    sys.exit(-1)

first_line = True;
if is_svn:
    print "--This line, and those below, will be ignored--"

print_message_line("%s  %s  <%s>" % (date.today().strftime('%Y-%m-%d'), cl_name, cl_email))
print_message_line("")

df = getoutput("%s | filterdiff -i'*ChangeLog' | grep ^+" % diff_cmd)
for line in df.split('\n'):
    line = line.strip('+')

    if line == "":
        continue

    # Example: +++ UIAutomationWinforms/ChangeLog   (working copy)
    m = re.match('^ (.*)/ChangeLog', line)
    if not m == None:
        if first_line: first_line = False
        else: print_message_line("")

        print_message_line('In %s/:' % m.group(1))
        continue

    m = re.match('^\d{4}-\d{2}-\d{2}', line)
    if not m == None:
        continue

    print_message_line(line)