#! /usr/bin/env python
# -*- mode: python; make-backup-files: nil -*-

# Changelog:
# Version 0.1: initial release
# Version 0.2: changed mmap call to use access= parameter
#              got rid of tab indents


import os
import md5
from stat import S_ISDIR, S_ISREG, ST_MODE, ST_SIZE
from mmap import mmap, ACCESS_READ
from netrc import netrc
from ftplib import FTP,error_perm


def log(s):
    print s


def sort(l):
    nl = list(l)
    nl.sort()
    return nl


def reversesort(l):
    nl = list(l)
    nl.sort()
    nl.reverse()
    return nl


def archive_md5s(root_directory):

    def rootopen(pathname, mode):
        return os.open(os.path.join(root_directory,pathname),mode)

    def rootstat(pathname):
        return os.stat(os.path.join(root_directory,pathname))

    def rootlistdir(directory):
        return os.listdir(os.path.join(root_directory,directory))

    def file_md5(pathname, size):
        fd = rootopen(pathname,os.O_RDONLY)
        try:
            m = mmap(fd,size,access=ACCESS_READ)
            d = md5.new()
            d.update(m)
            m.close()
            del m
            return d.hexdigest()
        finally:
            os.close(fd)

    def sub_archive_md5s(reldir):
        pathnames = [ os.path.join(reldir,filename)
                      for filename in rootlistdir(reldir) ]
        stats = [ (pathname,rootstat(pathname))
                  for pathname in pathnames ]
        subdirs = [ s for s in stats if S_ISDIR(s[1][ST_MODE]) ]
        files = [ s for s in stats if S_ISREG(s[1][ST_MODE]) ]

        checksums = {}
        dirstructure = { reldir: 'dir' }

        for pathname,stat in files:
            checksums[pathname] = file_md5(pathname, stat[ST_SIZE])

        for subdir,stat in subdirs:
            if subdir[:1] == '.' or subdir[-7:] == '.unused':
                continue
            c, d = sub_archive_md5s(subdir)
            checksums.update(c)
            dirstructure.update(d)

        return checksums, dirstructure

    return sub_archive_md5s('')


def write_checksums(filename, checksums, dirstructure):
    f = open(filename, "w")
    try:
        for a in sort(dirstructure.keys()):
            f.write("dir %s\n" % a)
        for a,b in sort(checksums.items()):
            f.write("%s %s\n" % (b,a))
    finally:
        f.close()


def read_checksums(filename):
    checksums = {}
    dirstructure = {}
    f = open(filename, "r")
    try:
        for line in f:
            if line[-1:] == '\n':
                line = line[:-1]
            c,p = line.split(' ',1)
            if c == 'dir':
                dirstructure[p] = "dir"
            else:
                checksums[p] = c
        return checksums, dirstructure
    finally:
        f.close()



def login(server,server_dir):
    n = netrc()
    auth = n.authenticators(server)
    if auth == None:
        login, account, password = '','',''
    else:
        login, account, password = auth
    ftp = FTP(server, login, password, account)
    ftp.cwd(server_dir)
    return ftp


def sync(archive_dir, server, server_dir, sync_dir = ''):

    sync_file = os.path.join(sync_dir, "sync,%s,%s" % (server,server_dir))
    check_file = os.path.join(sync_dir, "chek,%s,%s" % (server,server_dir))

    log("Reading sync file '%s'" % sync_file)
    ftp_checksums, ftp_dirstructure = read_checksums(sync_file)

    log("Determining archive md5s")
    arc_checksums, arc_dirstructure = archive_md5s(archive_dir)

    if (arc_checksums == ftp_checksums and
        arc_dirstructure == ftp_dirstructure):
        log("No changes to be made")
        return

    log("Logging into server '%s'" % server)
    ftp = login(server,server_dir)

    try:
        log("Making new directories")
        for arcdir in sort(arc_dirstructure.keys()):
            if not ftp_dirstructure.has_key(arcdir) and arcdir:
                log("    %s" % arcdir)
                ftp.mkd(arcdir)
                ftp_dirstructure[arcdir] = "dir"

        log("Renaming moved files")
        for ftpfile,ftpmd5 in ftp_checksums.items():
            if (arc_checksums.has_key(ftpfile) and
                arc_checksums[ftpfile] == ftpmd5):
                continue
            for arcfile,arcmd5 in arc_checksums.items():
                if (ftpmd5 == arcmd5
                    and (not ftp_checksums.has_key(arcfile)
                     or ftp_checksums[arcfile] != arcmd5)):
                    break
            else:
                continue
            log("    %s -> %s" % (ftpfile,arcfile))
            ftp.rename(ftpfile,arcfile)
            del ftp_checksums[ftpfile]
            ftp_checksums[arcfile] = ftpmd5
                    
        log("Uploading new and changed files")
        for arcfile,arcmd5 in arc_checksums.items():
            if (not ftp_checksums.has_key(arcfile)
                or arcmd5 != ftp_checksums[arcfile]):
                log("    %s" % arcfile)
                f = open(os.path.join(archive_dir,arcfile))
                ftp.storbinary("STOR %s" % arcfile, f)
                f.close()
                ftp_checksums[arcfile] = arcmd5

        log("Removing deleted files")
        for ftpfile in ftp_checksums.keys():
            if not arc_checksums.has_key(ftpfile):
                log("    %s" % ftpfile)
                ftp.delete(ftpfile)
                del ftp_checksums[ftpfile]

        log("Removing deleted directories")
        for ftpdir in reversesort(ftp_dirstructure.keys()):
            if not arc_dirstructure.has_key(ftpdir):
                log("    %s" % ftpdir)
                ftp.rmd(ftpdir)
                del ftp_dirstructure[ftpdir]

    finally:
        log("Writing sync file")
        write_checksums(sync_file,ftp_checksums,ftp_dirstructure)

        log("Writing archive check file")
        write_checksums(check_file,arc_checksums,arc_dirstructure)

        log("Logging off")
        ftp.quit()



if __name__ == '__main__':
    import sys
    sync(*sys.argv[1:])