# A Python script to synchronize the contents of a folder to another folder using the sha-256 algorithm
import fnmatch
import os
import hashlib
import shutil
import getopt
import sys

# a generic function to generate the SHA of a file
def hash_SHA_256(filename):
    f = open(filename, 'rb')
    hashtype = hashlib.sha256()
    readbuffer = 65536

    data = f.read(readbuffer)
    while len(data) > 0:
        hashtype.update(data)
        data = f.read(readbuffer)
    return hashtype.digest()

# the main application
if __name__ == "__main__":
    input_folder = ""
    output_folder = ""
    remove_files = False
    remove_folders = False

    # use getopt to handle command line arguments
    optlist, args = getopt.getopt(sys.argv[1:], 'i:o:rf?')
    for o, a in optlist:
        if o == "-?":
            print "*"*60
            print "-i\tInput Folder"
            print "-o\tOutput Folder"
            print "-r\tRemove files from the output folder that are missing in input folder"
            print "-f\tRemove Empty Folders from the output folder"
            print "-?\tHelp"
            print "*"*60
            exit()
        elif o == "-i":
            input_folder = a
        elif o == "-o":
            output_folder = a
        elif o == "-r":
            remove_files = True
        elif o == "-f":
            remove_folders = True
        else:
            print "Error: Bad Parameters"
            exit()

    print "Processing input folder"
    # Get a list of all input subdirectory files and folders
    local_matchs = []
    for root, dirnames, filenames in os.walk(input_folder):
        for filename in fnmatch.filter(filenames, '*.*'):
            targetpath = os.path.join(root, filename)
            basepath = targetpath.replace(input_folder,"")
            targethash = hash_SHA_256(targetpath)
            local_matchs.append((basepath,targetpath,targethash))

    print "Processing output folder"
    # Get a list of all output subdirectory files and folders
    remote_matchs = []
    for root, dirnames, filenames in os.walk(output_folder):
        for filename in fnmatch.filter(filenames, '*.*'):
            targetpath = os.path.join(root, filename)
            basepath = targetpath.replace(output_folder,"")
            targethash = hash_SHA_256(targetpath)
            remote_matchs.append((basepath,targetpath,targethash))

    #If file is missing copy file
    #If file is not the same copy file
    for local in local_matchs:
        loc_base,loc_target,loc_hash = local
        cancopy = True
        for remote in remote_matchs:
            rem_base,rem_target,rem_hash = remote
            if not loc_base == rem_base:
                continue
            else:
                if rem_hash == loc_hash:
                    cancopy = False
                remote_matchs.remove(remote)
                break
        if cancopy:
            outputloc = output_folder+loc_base
            print "Copy %s to %s" % (loc_target,outputloc)
            if not os.path.exists(os.path.dirname(outputloc)):
                os.makedirs(os.path.dirname(outputloc))
            shutil.copy2(loc_target,outputloc)

    # Remove Missing Files
    if remove_files:
        print "Removing Missing Files"
        for remote in remote_matchs:
            rem_base,rem_target,rem_hash = remote
            print "Removing %s" % rem_target
            os.remove(rem_target)

    if remove_folders:
        # Remove Missing Folders
        print "Removing Empty Folders"
        action = True
        while action:
            action = False
            for root, dirnames, filenames in os.walk(output_folder):
                for name in dirnames:
                    target = os.path.join(root,name)
                    if not os.listdir(target):
                        print "Remove Empty Folder %s" % target
                        os.rmdir(target)
                        action = True