#!/usr/bin/python

import sys
import os

progname = os.path.basename(sys.argv[0])

def usage():
  print("Usage: %s SOURCEURL WCPATH [r]REVNUM[,] [...]" % progname)
  print("Try '%s --help' for more information" % progname)

def help():
  val = """This script is meant to ease the pain of merging and
reviewing revision(s) on a release branch (although it can be used to
merge and review revisions from any line of development to another).

To allow cutting and pasting from the STATUS file, revision numbers
can be space or comma-separated, and may also include the prefix
'r'.

Lastly, a file (named 'rev1-rev2-rev3.log') is created for you.
This file contains each merge command that was run, the log of the
revision that was merged, and the diff from the previous revision.

Examples:

  %s http://svn.apache.org/repos/asf/subversion/trunk svn-1.2.x-branch \
    r14041, r14149, r14186, r14194, r14238, r14273

  %s http://svn.apache.org/repos/asf/subversion/trunk svn-1.2.x-branch \
    14041 14149 14186 14194 14238 14273""" % (progname, progname)
  print(val)


if len(sys.argv) > 1 and sys.argv[1] == '--help':
  help()
  sys.exit(0)

if len(sys.argv) < 4:
  usage()
  sys.exit(255)

src_url = sys.argv[1]
wc_path = sys.argv[2]

# Tolerate comma separated lists of revs (e.g. "r234, r245, r251")
revs = []
for rev in sys.argv[3:]:
  orig_rev = rev
  if rev[-1:] == ',':
    rev = rev[:-1]

  if rev[:1] == 'r':
    rev = rev[1:]

  try:
    rev = int(rev)
  except ValueError:
    print("Encountered non integer revision '%s'" % orig_rev)
    usage()
    sys.exit(254)
  revs.append(rev)

# Make an easily reviewable logfile
logfile = "-".join([str(x) for x in revs]) + ".log"
log = open(logfile, 'w')

for rev in revs:
  merge_cmd = ("svn merge -r%i:%i %s %s" % (rev - 1, rev, src_url, wc_path))
  log_cmd = 'svn log -v -r%i %s' % (rev, src_url)
  diff_cmd = 'svn diff -r%i:%i %s' % (rev -1, rev, src_url)

  # Do the merge
  os.system(merge_cmd)

  # Write our header
  log.write("=" * 72 + '\n')
  log.write(merge_cmd + '\n')

  # Get our log
  fh = os.popen(log_cmd)
  while 1:
    line = fh.readline()
    if not line:
      break
    log.write(line)
  fh.close()

  # Get our diff
  fh = os.popen(diff_cmd)
  while 1:
    line = fh.readline()
    if not line:
      break
    log.write(line)

  # Write our footer
  log.write("=" * 72 + '\n' * 10)


log.close()
print("\nYour logfile is '%s'" % logfile)