##
## This script is called without parameters.
##
## It moves passport images from a reload folder to their right place in
## the media folder.
##
## Configuration is done below.
##
##
## Please note that for changing groups of files/directories, you
## normally have to be root. This script is therefore normally run with
## sudo.
##

## ######################################################################
## CONFIGURATION
##

## The folder where all source docs can be found (can be any folder)
#SRC_DIR = "/kofa/uniben/var/datacenter/media/students/reload"
SRC_DIR = "/kofa/uniben_passport_reload"

## The students folder in Kofa where files should go to
DST_DIR = "/kofa/uniben/var/datacenter/media/students"


## Permissions to be set on new files/dirs. Set OWNER and/or GROUP to
## None to leave them unchanged after creation.
UMASK = 0664
OWNER = 'kofa'
GROUP = 'kofa'
LETTER = 'B'

##
## CONFIGURATION END
## ######################################################################

import csv
import os
import shutil
import sys
from grp import getgrnam
from pwd import getpwnam

OWNER_ID = OWNER and getpwnam(OWNER)[2] or -1
GRP_ID = GROUP and getgrnam(GROUP)[2] or -1
DIR_UMASK = UMASK | 0111  # directories need extra x-permission

def set_perms(path):
    # set permissions and ownership for path
    if os.path.isdir(path):
        os.chmod(path, DIR_UMASK)
    else:
        os.chmod(path, UMASK)
    os.chown(path, OWNER_ID, GRP_ID)
    return

def new_and_old_id(filename):
    try:
        stud_id, ext = filename.split('.')
    except:
        return None, None
    if ext != 'jpg':
        return None, None
    if len(stud_id) == 7:
        return LETTER + stud_id, stud_id
    if len(stud_id) == 8:
        return stud_id, stud_id
    return None, None

def final_subfolder(stud_id):
    # compute new folder name from stud_id
    try:
        num = int(stud_id[1:])
        if len(stud_id) == 7:
            # old stud_id
            num = num / 10000 * 10
        if len(stud_id) == 8:
            # new stud_id
            num = num / 1000
    except ValueError:
        # new old stud_ids
        num = int(stud_id[2:])
        num = num / 10000 * 10
    return '%05d' % num

def copy_file(file_src, file_dst):
    print "COPY FILE: %s -> %s" % (file_src, file_dst)
    shutil.copyfile(file_src, file_dst)
    set_perms(file_dst)
    return

def create_path(path):
    # create path with subdirs, if it does not exist (completely)
    if os.path.exists(path):
        return
    parent = os.path.dirname(path)
    if not os.path.exists(parent):
        # create parent first
        create_path(parent)
    print "CREATE PATH ", path
    os.mkdir(path)
    set_perms(path)
    return

if not os.path.exists(SRC_DIR):
    sys.exit("No source folder %s. Skipping." % SRC_DIR)

if len(os.listdir(SRC_DIR)) == 0:
    sys.exit("Empty source folder for %s. Skipping." % SRC_DIR)

for filename in os.listdir(SRC_DIR):
    new_stud_id, stud_id = new_and_old_id(filename)
    if not new_stud_id:
        print "Wrong filename: %s" % filename
        continue
    subfolder = final_subfolder(stud_id)
    dst_folder = os.path.join(DST_DIR, subfolder, new_stud_id)
    if not os.path.exists(dst_folder):
        #print "Destination folder does not exist: %s. Skipping" % (dst_folder)
        #continue
        create_path(dst_folder)
    dst_file = os.path.join(DST_DIR, subfolder, new_stud_id,
        'passport_%s.jpg' % new_stud_id)
    if os.path.exists(dst_file):
        print "Destination file exists: %s. Skipping" % (dst_file)
        continue
    file_src = os.path.join(SRC_DIR, filename)
    file_dst = os.path.join(dst_file)
    copy_file(file_src, file_dst)