'''
    A simple pythontool to sync two folders (or harddrives)
    Copyright (C) 2018  Yannis Gerlach aka MrBesen

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
'''
import os
from shutil import copy2

sync1 = '/home/yannis/Projects/ownsync/test/s1/'
sync2 = '/home/yannis/Projects/ownsync/test/s2/'
dataname = '.sync'

def endwithslash(str):
    if str[:-1] == '/':
        return str
    return str + '/'


def readfiletoarray(file):
    try:
        f = open(file, 'r')
        data = f.readlines()
        f.close()
        return data
    except Exception as e:
        print('Error reading sync data', e)
        return []


def shouldsync(fromfile, tofile, dataf, datat):
    if os.path.exists(tofile):
        return getlastchange(tofile) < getlastchange(fromfile)  # only if source file is newer
    elif tofile in dataf:  # should nver be the case
        return False  # file existed once, but was deleted on source
    elif tofile in datat:  # file was synced once, but deleted on target.
        return False
    return True  # file dont exists and never existed


def getlastchange(file):
    return os.path.getmtime(file)


def scandir(dir):
    data = []
    for file in os.listdir(dir):
        if os.path.isfile(dir + file):
            data.append(dir + file)
        else:
            data.append(dir + file)
            for f in scandir(dir + file + '/'):
                data.append(f)
    return data


def rm(path):
    if os.path.isfile(path):
        os.remove(path)
    else:
        os.rmdir(path)


def updatedata(path):
    data = scandir(path)
    f = open(path + dataname, 'w+')
    for d in data:
        d = d[len(path):]
        if d != dataname:
            f.write(d + '\n')
    f.close()


def syncnew(fro, to):
    #read data
    dataf = readfiletoarray(fro + dataname)
    datat = readfiletoarray(to + dataname)
    print(len(dataf), 'nodes loaded.')
    listffiles = scandir(fro)

    #remove prefix
    pos = -1
    for i in range(0, len(listffiles)):
        listffiles[i] = listffiles[i][len(fro):]
        if listffiles[i] == dataname:  # remove .sync file from list
            pos = i

    if pos > -1:
        del listffiles[pos]

    for f in listffiles:
        print('syncing: ', f)
        if (not os.path.isfile(fro + f)) and os.path.exists(fro + f):  # TODO: check if folder was deleted at target.
            if not os.path.exists(to + f):  # seperate if to not enter elif
                # print('make dir:', to + f)
                #if is folder and exists in from then create folder in to.
                os.makedirs(to + f)
        elif shouldsync(fro + f, to + f, dataf, datat):
            folder = to + f
            folder = folder[:folder.rfind('/')+1]
            # print('make required dir:', folder)
            if not os.path.exists(folder):
                os.makedirs(folder)

            print(fro + f, '->', to + f)
            copy2(fro + f, to + f)
        else:
            print('skipping', f)

    # delete files, that were deleted on source
    for f in dataf:
        f = f[:-1]  # remove trailing \n
        if not os.path.exists(fro + f):
            print('delete file', to + f)
            # rm(fro + f)


#MAIN
#setup
sync1 = endwithslash(sync1)
sync2 = endwithslash(sync2)

sync1ex = True
if os.path.exists(sync1):
    updatedata(sync1)
else:
    sync1ex = False

sync2ex = True
if os.path.exists(sync2):
    updatedata(sync2)
else:
    sync2ex = False

if not sync1ex and not sync2ex:
    print('both folders do not exists, exiting.')
else:
    print('Location A: ', sync1, '\nLocation B: ', sync2)
    if sync1ex:
        print('Sync A -> B')
        syncnew(sync1, sync2)
        print('update changes.')
        updatedata(sync2)  # update changes
        print('Done.')
    if sync2ex:
        print('Sync B -> A')
        syncnew(sync2, sync1)
        print('update changes.')
        updatedata(sync1)  # update changes
        print('Done.')
    print('Done.')