from datetime import datetime
from zipfile import ZipFile
import os
import shutil

# base directory
basedir = "/media/hd/cloud"

# list of the paths to the files and directories to be copied, relative to the base directory
filelist = "/media/hd/cloud/Tilman/Computer/selective-backup/filelist.txt"

# duration for backups to be kept
days_to_keep = 5
months_to_keep = 5

# directories to backup to
daily_dir = "/media/hd/cloud/Tilman/Computer/selective-backup/daily/"
monthly_dir = "/media/hd/cloud/Tilman/Computer/selective-backup/monthly/"

now = datetime.now()
today = datetime.today()
target_filename = today.strftime('%Y-%m-%d') + "_selective-backup.zip"

with open(filelist) as file:
	lines = [line.rstrip() for line in file]

# backup directories and files
with ZipFile(daily_dir + target_filename, 'w') as zip:
	for line in lines:
		if os.path.isdir(basedir + line):
			for root, dirs, files in os.walk(basedir + line):
				for file in files:
					file_path = os.path.join(root, file)
					zip.write(file_path)
		else:
			zip.write(basedir + line)

# if first of month, copy over
if now.day == 1:
	shutil.copy(daily_dir + target_filename, monthly_dir)

# delete old backups
for filename in os.listdir(daily_dir):
	date_object = datetime.strptime(filename[:10], '%Y-%m-%d')
	delta = today - date_object
	if delta.days > days_to_keep:
		os.remove(daily_dir + filename)

for filename in os.listdir(monthly_dir):
	date_object = datetime.strptime(filename[:10], '%Y-%m-%d')
	num_months = (today.year - date_object.year) * 12 + (today.month - date_object.month)
	if num_months > months_to_keep:
		os.remove(monthly_dir + filename)