#!/usr/bin/env python
#
#  git-bbdiff
#  
#  Created by Dan Preston on 4/09/08.
#
 
import sys, commands, os, tempfile, filecmp
from optparse import OptionParser
 
gToolName = "git-bbdiff"
gdiffVersion = gToolName + " version 1.2"
gTempDir = "/tmp/"
gConflictMarker = ".CONFLICT"
gTheirsMarker = ".THEIRS"
 
#----------------------------------------------------------------------------------------------------------------------------
#  fileNotPresentError
#----------------------------------------------------------------------------------------------------------------------------
 
def fileNotPresentError(repositoryPath, revision, chatty=True):
  if chatty:
    print "\tFile \"%s\" does not exist in repository at revision \"%s\"." % (repositoryPath, revision)
 
 
#----------------------------------------------------------------------------------------------------------------------------
#  createTempFileForRevision
#----------------------------------------------------------------------------------------------------------------------------
 
def createTempFileForRevision( revision, repositoryPath, chatty=True ):
  # Escape the path with quotes to handle the case where we have spaces.
  command = "git show " + revision + ':"' + repositoryPath + '"'
  
  # Use git show to get the contents of the head of the file.
  status, output = commands.getstatusoutput( command )
  if status != 0:
    fileNotPresentError( repositoryPath, revision, chatty )
    return None
  
  # git show doesn't seem to append the final carriage return.
  output = output + "\n"
  
  # Create the temp file name and write out the temp file.
  nameRoot, extension = os.path.splitext( repositoryPath )
  _, fileName = os.path.split( nameRoot )
  temp = tempfile.mktemp( "_" + fileName + extension, gToolName + "-" + revision + "_", gTempDir )
  f = open( temp, 'w' )
  f.write( output )
  f.close()
  
  return temp
 
 
#----------------------------------------------------------------------------------------------------------------------------
#  performDiff
#----------------------------------------------------------------------------------------------------------------------------
 
def performDiff(compareFile, revision, chatty=True):
  # Check that we have enough arguments.
  
  revision, _, revision2 = revision.partition("..")
  
  realpath = os.path.abspath( compareFile )
  
  head, relativePath = os.path.split( realpath )
  fileName = relativePath
  
  if os.path.isdir( realpath ):
    if chatty:
      print "\t\"" + relativePath + "\" is a directory. " + gToolName + " only compares files."
    return
  
  found = False;
  # Figure out what the relative path of the file is from the .git folder.
  while (found == False) and (head != "/"):
    gitPath = os.path.join( head, ".git" )
    found = os.path.exists( gitPath )
    if found == False:
      head, tail = os.path.split( head )
      relativePath = os.path.join( tail, relativePath )
  
  # Make sure we are actually in a git repository.
  if (found == False) and (head == "/"):
    if chatty:
      print "\tThat file is not in a git repository."
    return
  
  file1 = createTempFileForRevision( revision, relativePath, chatty )
  if revision2:
    file2 = createTempFileForRevision( revision2, relativePath, chatty )
  else:
    file2 = realpath
    if os.path.exists(file2) == False:
      fileNotPresentError( relativePath, "HEAD", chatty )
      file2 = None
    
  if (file1 == None) or (file2 == None):
    return
  
  same = filecmp.cmp( file2, file1 )
  if same:
    if chatty:
      print "\tThe file \"" + fileName + "\" has no differences."
  else:
    # Escape the files with quotes to allow for files with spaces.
    command = 'bbdiff "%s" "%s"' % ( file2, file1 )
    status, output = commands.getstatusoutput( command )
 
 
#----------------------------------------------------------------------------------------------------------------------------
#  cleanTmpDirectory
#----------------------------------------------------------------------------------------------------------------------------
 
def cleanTmpDirectory(chatty=True):
  tempContents = os.listdir( gTempDir )
  for tmpFile in tempContents:
    if tmpFile.startswith( gToolName + "-" ):
      filePath = gTempDir + tmpFile
      if chatty:
        print "\tRemoving temp file:\"%s\"" % filePath
      os.remove( filePath )
 
#----------------------------------------------------------------------------------------------------------------------------
#  numConflicts
#----------------------------------------------------------------------------------------------------------------------------
 
def numConflicts(conflictFile):
  foundStart = False
  foundMiddle = False
  
  conflicts = 0
  f = open(conflictFile, "r")
  line = f.readline()
  while line:
    if line.startswith("<<<<<<<") and (foundStart == False) and (foundMiddle == False):
      foundStart = True
    if line.startswith("=======") and foundStart and (foundMiddle == False):
      foundMiddle = True
    if line.startswith(">>>>>>>") and foundStart and foundMiddle:
      conflicts = conflicts + 1
      foundStart = False
      foundMiddle = False
    line = f.readline()
  f.close()
  
  return conflicts
 
#----------------------------------------------------------------------------------------------------------------------------
#  renameConflictFile
#----------------------------------------------------------------------------------------------------------------------------
 
def uniqueName(path, uniqueLabel):
  base, extension = os.path.splitext(path)
  digit = 2
  uniqueDigit = ""
  if os.path.exists(base + uniqueLabel + uniqueDigit + extension):
    uniqueDigit = str(digit)
    digit = digit + 1
  
  newPath = base + uniqueLabel + uniqueDigit + extension
  
  return newPath
 
#----------------------------------------------------------------------------------------------------------------------------
#  createConflictFiles
#----------------------------------------------------------------------------------------------------------------------------
 
def createConflictFiles(minePath, theirPath, conflictFile):
  orig = open(conflictFile, "r")
  mine = open(minePath, "w")
  theirs = open(theirPath, "w")
  
  placeInTheirs = True
  placeInMine = True
  
  line = orig.readline()
  while line:
    if line.startswith("<<<<<<<") and placeInTheirs and placeInMine:
      placeInMine = False
    elif line.startswith("=======") and placeInTheirs and (placeInMine == False):
      placeInTheirs = False
      placeInMine = True
    elif line.startswith(">>>>>>>") and (placeInTheirs == False) and placeInMine:
      placeInTheirs = True
    else:
      if placeInMine:
        mine.write(line)
      if placeInTheirs:
        theirs.write(line)
    line = orig.readline()
    
  orig.close()
  mine.close()
  theirs.close()
 
#----------------------------------------------------------------------------------------------------------------------------
#  diffConflict
#----------------------------------------------------------------------------------------------------------------------------
 
def diffConflict(conflictFile, chatty=True):
  conflicts = numConflicts(conflictFile)
  if (conflicts == 0) and chatty:
    basePath, fileName = os.path.split( conflictFile )
    print "\tThe file \"%s\" does not contain any conflicts. SKIPPING." % fileName
  else:
    newConflictPath = uniqueName(conflictFile, gConflictMarker)
    os.rename(conflictFile, newConflictPath)
    
    theirPath = uniqueName(conflictFile, gTheirsMarker)
    
    createConflictFiles(conflictFile, theirPath, newConflictPath)
    command = 'bbdiff "%s" "%s"' % ( conflictFile, theirPath )
    status, output = commands.getstatusoutput( command )
 
#----------------------------------------------------------------------------------------------------------------------------
#  cleanConflictRelatedFiles
#----------------------------------------------------------------------------------------------------------------------------
 
def cleanConflictRelatedFiles(conflictFile, chatty=True):
  filePath, extension = os.path.splitext( conflictFile )
  
  # Remove .CONFLICT files.
  tempfile = filePath + gConflictMarker + extension
  if os.path.exists( tempfile ):
    if chatty:
      _, base = os.path.split( filePath )
      base = base + gConflictMarker + extension
      print "\tDeleting file \"%s\"." % base
    command = "rm " + tempfile
    os.remove( tempfile )
  
  #remove .THEIRS files.
  tempfile = filePath + gTheirsMarker + extension
  if os.path.exists( tempfile ):
    if chatty:
      _, base = os.path.split( filePath )
      base = base + gTheirsMarker + extension
      print "\tDeleting file \"%s\"." % base
    command = "rm " + tempfile
    os.remove( tempfile )
 
#----------------------------------------------------------------------------------------------------------------------------
#  main
#----------------------------------------------------------------------------------------------------------------------------
 
def main(argv=None):
  if argv is None:
    argv = sys.argv
  
  # Set up options for the command line that we support.
  description="A utility to compare files in a git repository using bbedit."
  usage = "usage: %prog [--version] | [-h | --help] | [-q | --quiet] [--clean] [[-c | --conflict] | [-r | --revision <revision(s)>]] file1 [file2 ...]"
  
  parser = OptionParser(version=gdiffVersion, description=description, usage=usage)
  parser.add_option("-r", "--revision", dest="revision", help="Pass a revision or a revision range using the git syntax (ie: 98d4cf..bfced5) for " + gToolName + " to compare. This option is mutually exclusive to the '-c' option.")
  parser.add_option("--clean", action="store_true", dest="cleanUp", default=False, help="Delete all of the temp files that " + gToolName + " has created. If any files are passed as arguments, their --conflict related files (\"" + gConflictMarker + "\", \"" + gTheirsMarker + "\") will be deleted.")
  parser.add_option("-q", "--quiet", action="store_false", dest="chatty", default=True, help="Reduce the chatter of " + gToolName + ".")
  parser.add_option("-c", "--conflict", action="store_true", dest="conflict", default=False, help="The files being diffed have conflict markers that need to be resolved. This option is mutually exclusive to the '-r' option.")
  
  printUsage = True
  (options, args) = parser.parse_args(argv[1:])
  if options.cleanUp:
    cleanTmpDirectory(options.chatty)
    for gitFile in args:
      cleanConflictRelatedFiles(gitFile, options.chatty)
    return 0
  if len(args) > 0:
    printUsage = False
  
  # These options are mutually exclusive.
  if options.revision and options.conflict:
    printUsage = True
  
  # See if we can see any reason that we need to print the usage for the app.
  if printUsage:
    parser.print_help()
    return 2
  else:
    if options.conflict:
      for gitFile in args:
        if options.chatty:
          print "Diffing Conflict \"%s\"." % gitFile
        diffConflict(gitFile, options.chatty)
    else:
      if options.revision:
        rev = options.revision
      else:
        rev = "HEAD"
      for gitFile in args:
        if options.chatty:
          print "Comparing \"%s\"." % gitFile
        performDiff(gitFile, rev, options.chatty)
  return 0
 
if __name__ == "__main__":
  sys.exit(main())