%s

#! /usr/bin/env python

text1 = """Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Integer
eu lacus accumsan arcu fermentum euismod. Donec pulvinar porttitor
tellus. Aliquam venenatis. Donec facilisis pharetra tortor. In nec
mauris eget magna consequat convallis. Nam sed sem vitae odio
pellentesque interdum. Sed consequat viverra nisl. Suspendisse arcu
metus, blandit quis, rhoncus ac, pharetra eget, velit. Mauris
urna. Morbi nonummy molestie orci. Praesent nisi elit, fringilla ac,
suscipit non, tristique vel, mauris. Curabitur vel lorem id nisl porta
adipiscing. Suspendisse eu lectus. In nunc. Duis vulputate tristique
enim. Donec quis lectus a justo imperdiet tempus.
Make them the same"""
text1_lines = text1.splitlines()

text2 = """Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Integer
eu lacus accumsan arcu fermentum euismod. Donec pulvinar, porttitor
tellus. Aliquam venenatis. Donec facilisis pharetra tortor. In nec
mauris eget magna consequat convallis. Nam cras vitae mi vitae odio
pellentesque interdum. Sed consequat viverra nisl. Suspendisse arcu
metus, blandit quis, rhoncus ac, pharetra eget, velit. Mauris
urna. Morbi nonummy molestie orci. Praesent nisi elit, fringilla ac,
suscipit non, tristique vel, mauris. Curabitur vel lorem id nisl porta
adipiscing. Duis vulputate tristique enim. Donec quis lectus a justo
imperdiet tempus. Suspendisse eu lectus. In nunc. 
Make them the same"""
text2_lines = text2.splitlines()

from pprint import pprint
import difflib
import re

nonSpaceRE  = re.compile (r'\S')
plusMinusRE = re.compile (r'[\+,\-]+')
startDiff  = '_%_START_%_'
endDiff    = '_%_END_%_'
#startDiff  = '<'
#endDiff    = '>'
startRE    = re.compile (startDiff)
endRE      = re.compile (endDiff)
fixHtmlREs = [ (re.compile (r'&'), '&amp;'),
               (re.compile (r'<'), '&lt;'),
               (re.compile (r'>'), '&gt;'), ]

class DiffLines (object):
    def __init__ (self, line, command):
        self.line    = line.rstrip ('\n')
        self.command = command
        self._ranges  = []

    def __str__ (self):
        return "%s : %s" % (self.command, self.line)

    def setRanges (self, ranges):
        self._ranges = sorted (ranges)
        self._ranges.reverse()

    def _markDiffs (self):
        retval = self.line
        ## We worted the ranges in reverse order so that this
        ## works. The reason this is important as wehn we add the
        ## markers for the start and end of a change, it changes the
        ## length of the line.  To make sure this doesn't affect us
        ## adversely, we go from the end o fthe line to the beginning.
        for start, end in self._ranges:
            retval = retval[0:end]   + endDiff   + retval [end:]
            retval = retval[0:start] + startDiff + retval [start:]
        return retval

    def asHtml (self):
        retval = self._markDiffs()
        for tup in fixHtmlREs:
            retval = tup[0].sub (tup[1], retval)
        if self.command == '+' or self.command == '-':
            name = 'firstDiff'
            if self.command == '-':
                name = 'secondDiff'
            retval = startRE.sub ('<font class="%s">' % name, retval)
            retval = endRE.sub ('</font>', retval)
        return retval

    @staticmethod
    def asSingleColumnHtml (diffList, title = ''):
        firstNum = 0
        secondNum = 0
        retval = '''<html>\n<head>\n<title>%s</title>\n
<link rel ="stylesheet" type="text/css" href ="diff.css">
</head><h1>%s</h1><pre>\n''' % (title, title)
        for obj in diffList:
            if obj.command == ' ':
                name = 'both'
                firstNum += 1
                secondNum += 1
                firstAs  = '%d' % firstNum
                secondAs = '%d' % secondNum
            elif obj.command == '-':
                name = 'first'
                firstNum += 1
                firstAs  = '%d' % firstNum
                secondAs = ''
            elif obj.command == '+':
                name = 'second'
                secondNum += 1
                firstAs  = ''
                secondAs = '%d' % secondNum
            else:
                raise RuntimeError, "shouldn't be here"
            retval += '<font class="firstNumber">%4s</font> <font class="secondNumber">%4s</font> ' % (firstAs, secondAs)
            retval += '<font class="%s">%s</font>\n' % (name, obj.asHtml())
        retval += '</pre></html>\n'
        return retval

d = difflib.Differ()
diff = d.compare(text1_lines, text2_lines)

diffList =[]

for line in diff:
    # is this a blank lineyes
    if not nonSpaceRE.search (line):
        continue
    command = line[0:1]
    rest    = line[2:]
    if command == '?':
        # this line is just for pointing out what is differnt
        last.setRanges ( [(m.start(),m.end()) \
                          for m in plusMinusRE.finditer (rest)] )
    else:
        # this is a text line
        last = DiffLines (rest, command)
        diffList.append (last)

print DiffLines.asSingleColumnHtml (diffList)