#!/usr/bin/python

import os, os.path
import subprocess
import re

from optparse import OptionParser

def report_stderr(stderrdata):
    if stderrdata: 
        print "STDERR BEG (%d chars)",len(stderrdata)
        print stderrdata
        print "STDERR END (%d chars)",len(stderrdata)

def git_update (dir):
    os.chdir(dir)
    print "git pull in %s"%dir
    prog=subprocess.Popen(["git","pull"],stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    try:
        (stdoutdata, stderrdata) = prog.communicate()
    except KeyboardInterrupt:
        raise Exception, "Interrupted by user"
    prog.wait()
    print stdoutdata,
    report_stderr(stderrdata)


# this is ad hoc for sfa diffing ..
excludes=[ "*.git*", "*~" ]
excludes+= [ "*.pyc", "*.png", "*.pdf", "*.out" , "*.DS_Store", "*.lint" ]
excludes+= [ "listfiles.sh", "python.*" ]
excludes+= [ "*HEAD", "*txt" ]
excludes+= [ "*slab*", "senslab" ]

def run_diff(options):
    dir1=options.left_dir
    dir2=options.right_dir
    command=["diff","-r",]
    for exclude in excludes:
        command += [ "-x", "%s"%exclude]
    command += [dir1,dir2]
    prog=subprocess.Popen(command,stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    print "diffing -r %s %s"%(dir1,dir2)
    try:
        (stdoutdata, stderrdata) = prog.communicate()
    except KeyboardInterrupt:
        raise Exception, "Interrupted by user"
    prog.wait()
    report_stderr(stderrdata)

    re_only_left =re.compile("^Only in %s[:/]"%dir1)
    re_only_right=re.compile("^Only in %s[:/]"%dir2)
    re_binary    =re.compile("^Binary files %s.* and %s.*"%(dir1,dir2))
    re_start_diff=re.compile("diff -r.*%s/(?P<path>.*) %s/(?P=path)"%(dir1,dir2))

    only_left=[]
    only_right=[]
    ignored=[]
    
    class Context:
        def __init__ (self,diffs): 
            self.current_path=''
            self.current_diff=[]
            self.diffs=diffs
        def close_diff(self):
            if self.current_path: self.diffs[self.current_path]=self.current_diff
            elif self.current_diff: print """----------
WARNING, diff with no path %s
----------"""%self.current_diff
            self.current_path=''
            self.current_diff=[]
        def set_path (self,path):
            self.current_path=path
        def insert_line(self,line):
            self.current_diff.append(line)

    ### parse
    diffs={}
    context=Context(diffs)
    for line in stdoutdata.split("\n"):
        m=re_only_left.match(line)
        if m: 
            context.close_diff()
            only_left.append(line)
            continue
        m=re_only_right.match(line)
        if m: 
            context.close_diff()
            only_right.append(line)
            continue
        m=re_binary.match(line)
        if m:
            context.close_diff()
            ignored.append(line)
            continue
        m=re_start_diff.match(line)
        if m:
            context.close_diff()
            context.set_path(m.group('path'))
            continue
        context.insert_line(line)
        
    ### ignore some entries - maybe not needed if we're smart with diff
        
    # print report
    print "< < < < < %d old files/dirs"%len(only_left)
    for l in only_left:  print "< < < < < ",l
    print "> > > > > %d new files/dirs"%len(only_right)
    for l in only_right: print "> > > > > ",l
    print "= = = = = %d files"%len(diffs)
    for (path,contents) in diffs.iteritems():
        if options.verbose:
            print "= = = = =  Diffs in path %s"%path
            for line in contents: print line
        else:
            print "Diffs in path %s (%d lines)"%(path,len(contents))
            

left_default=os.path.expanduser("~/git/sfa")
right_default=os.path.expanduser("~/git/sfa-generic")

def main ():
    parser=OptionParser()
    parser.add_option("-g","--git",action='store_true',dest='git',default=False,
                      help="run git pull before diffing")
    parser.add_option("-l","--left",action='store',dest='left_dir',default=left_default,
                      help="left dir, default=%s"%left_default)
    parser.add_option("-r","--right",action='store',dest='right_dir',default=right_default,
                      help="right dir, default=%s"%right_default)
    parser.add_option("-v","--verbose",action='store_true',dest='verbose',default=False,
                      help="Show actual diff contents")
    (options,args)=parser.parse_args()
    if options.git:
        git_update(options.left_dir)
        git_update(options.right_dir)
    run_diff(options)

if __name__ == "__main__":
    main()