#!/usr/bin/env python3


#
import datetime
import os
import shlex
import subprocess
import sys


#
class MikesBackup:
	
	#
	__log_dir = None
	__remote_host = None
	__remote_user = None
	__destination_dir_base = None
	#
	__ssh_key = None
	__quiet_ssh = True
	#
	__source_dirs = []
	__source_dir_excludes = []
	#
	__force_full = False
	__force_differential = False
	
	#
	def __init__(self):
		self.parse_args()
	
	#
	def eprint(*args, **kwargs):
		print(*args, file=sys.stderr, **kwargs)
	
	#
	def parse_args(self):
		
		# Simple mapped args
		args_map = {
			"--log-dir": "__log_dir",
			"--remote-host": "__remote_host",
			"--remote-user": "__remote_user",
			"--destination-dir": "__destination_dir_base",
			"--ssh-key": "__ssh_key"
		}
		
		#
		print()
		print("Parsing arguments")
		a = 1
		while a < len(sys.argv):
			
			#
			arg = sys.argv[a]
			
			#
			valid_arg = False
			for arg_name in args_map:
				if arg == arg_name:
					valid_arg = True
					self_var_name = args_map[arg_name]
					self_var_value = sys.argv[a + 1]
					self.__dict__[self_var_name] = self_var_value
					print("Found argument \"", arg_name, "\" ==>", self_var_value)
					a = a + 1
					break
			if arg == "":
				valid_arg = True
			elif arg == "--full":
				valid_arg = True
				self.__force_full = True
			elif arg == "--diff" or arg == "--differential":
				valid_arg = True
				self.__force_differential = True
			elif arg == "--source-dir":
				valid_arg = True
				self.__source_dirs.append(sys.argv[a + 1])
				print("Found source dir:", sys.argv[a + 1])
				a = a + 1
			elif arg == "--exclude":
				valid_arg = True
				self.__source_dir_excludes.append(sys.argv[a + 1])
				print("Found exclude dir:", sys.argv[a + 1])
				a = a + 1
			
			a = a + 1
			
			#
			if not valid_arg:
				raise Exception("Invalid argument:", arg)
	
	@staticmethod
	def get_datetime_for_filename():
		
		#
		return datetime.datetime.now().strftime('%Y-%b-%d_%I%M%p')
	
	#
	def is_using_ssh(self):
		
		#
		if (
			self.__remote_host is not None
			or self.__remote_user is not None
			or self.__ssh_key is not None
		):
			return True
		
		return False
	
	#
	def demand_ssh_config(self):
		
		#
		if self.is_using_ssh():
			if self.__remote_host is None:
				raise Exception("Please provide remote host")
			if self.__remote_user is None:
				raise Exception("Please provide remote user")
	
	#
	def demand_destination_directory_config(self):
		
		#
		if self.__destination_dir_base is None:
			raise Exception("Please provide backup destination directory")
	
	#
	def does_destination_directory_exist(self, destination_path):
		
		#
		print("Trying to determine if destination path exists:", destination_path)
		
		# Local?
		if not self.is_using_ssh():
			print("Checking for local destination path")
			if os.path.isdir(destination_path):
				print("Local destination path exists")
				return True
			else:
				print("Local destination path does not exist")
				return False
		
		#
		print("Checking for remote destination path")
		command = [
			"[ -d " + destination_path + " ]"
		]
		
		#
		code, stdout, stderr = self.execute_remote_ssh_command(command)
		if code == 0:
			print("Remote destination dir was found: " + destination_path)
			return True
		
		#
		print("Remote dir didn't seem to exist: " + destination_path)
		return False
	
	#
	def demand_destination_base_backup_directory(self):
		
		#
		self.demand_destination_directory_config()
		
		#
		destination_path = self.__destination_dir_base
		
		#
		if self.does_destination_directory_exist(destination_path) is False:
			raise Exception("Backup destination directory doesn't exist: " + destination_path)
		
	#
	def does_full_backup_destination_directory_exist(self):
		
		#
		dir_path = self.make_full_backup_destination_path()
		
		#
		print("Trying to determine if Full backup destination directory exists:", dir_path)
		return self.does_destination_directory_exist(dir_path)
	
	#
	def get_source_directories(self):
		
		#
		if len(self.__source_dirs) == 0:
			raise Exception("No source directories specified")
		
		return self.__source_dirs
	
	#
	def do_backup(self):
		
		#
		print()
		print("Enter: do_backup")
		
		# Remote base dir must exist
		self.demand_destination_base_backup_directory()
		
		# Forced full or differential by args?
		if self.__force_full is True or self.__force_differential is True:
			if self.__force_full is True:
				print("Forcing full backup")
				self.do_full_backup()
			else:
				print("Forcing differential backup")
				self.do_differential_backup()
			return
		
		# Automatically choose full or differential
		if self.does_full_backup_destination_directory_exist():
			print("Automatically choosing differential backup, because full backup destination directory already exists")
			self.do_differential_backup()
		else:
			print("Automatically choosing full backup, because full backup destination directory wasn't found")
			self.do_full_backup()
	
	#
	def do_full_backup(self):
		
		# Start args
		args = []
		
		# Get destination directory
		destination_dir = self.make_full_backup_destination_path()
		
		# Append source directories
		args.extend(self.get_source_directories())
		
		# Append remote destination directory
		# args.append( self.__remote_user + "@" + self.__remote_host + ":" + remote_dir)
		args.append(self.make_rsync_remote_destination_part(destination_dir))
		
		# print("Args", str(args))
		print("Destination dir:", destination_dir)
		
		self.execute_rsync(args)
	
	#
	def do_differential_backup(self):
		
		# Start args
		args = []
		
		# Get directories
		link_dest_dir = self.make_full_backup_destination_path()
		destination_dir = self.make_remote_differential_backup_path()
		self.ensure_destination_directory(destination_dir)
		
		# Add link dest arg
		args.append("--link-dest")
		args.append(link_dest_dir)
		
		# Append source directories
		args.extend(self.get_source_directories())
		
		# Append remote destination directory
		# args.append( self.__remote_user + "@" + self.__remote_host + ":" + remote_dir)
		args.append(self.make_rsync_remote_destination_part(destination_dir))
		
		# print("Args", str(args))
		print("Link destination dir:", link_dest_dir)
		print("Destination dir:", destination_dir)
		
		self.execute_rsync(args)
	
	#
	def make_log_directory_path(self):
		
		#
		log_dir = self.__log_dir
		if log_dir is None:
			print("No log directory specified; Defaulting to current working directory")
			log_dir = "."
		
		return log_dir
		
	#
	def make_log_path(self):
		
		# Log dir
		log_dir = self.make_log_directory_path()
		
		# Path
		log_path = os.path.join(log_dir, self.get_datetime_for_filename() + ".log")
		
		return log_path
	
	#
	def make_full_backup_destination_path(self):
		
		#
		if self.__destination_dir_base is None:
			raise Exception("No remote directory was specified")
		
		#
		return os.path.join(self.__destination_dir_base, "Full")
	
	#
	def make_remote_differential_backup_path(self):
		
		#
		if self.__destination_dir_base is None:
			raise Exception("No remote directory was specified")
		
		#
		return os.path.join(self.__destination_dir_base, "Differential", self.get_datetime_for_filename())
	
	#
	def make_rsync_remote_destination_part(self, destination_dir):
		
		#
		part = ""
		
		#
		if self.__remote_host is not None:
			if self.__remote_user is not None:
				part += self.__remote_user + "@"
			part += self.__remote_host + ":"
			
		#
		part += destination_dir
		
		return part
	
	@staticmethod
	def ensure_local_directory(d):
		
		#
		if not os.path.exists(d):
			os.makedirs(d)
	
	#
	def ensure_destination_directory(self, d):
		
		#
		if not self.does_destination_directory_exist(d):
			
			#
			print("Destination directory doesn't exist; Will create:", d)
			
			#
			if self.is_using_ssh():
				command = [
					"mkdir",
					"--parents",
					d
				]
				self.execute_remote_ssh_command(command)
			else:
				os.makedirs(d)
	
	#
	def start_rsync_args(self):
		
		#
		self.ensure_local_directory(self.make_log_directory_path())
		args = [
			"rsync",
			"--log-file", self.make_log_path(),
			"--archive",
			"--compress",
			"--progress",
			"--stats",
			"--human-readable",
			"--itemize-changes",
			"--one-file-system",
			"--delete",
			"--delete-excluded"
		]
		
		#
		for e in self.__source_dir_excludes:
			args.append("--exclude")
			args.append(e)
		
		#
		# args.append("--dry-run") # DEBUG !!!
		
		return args
	
	#
	def start_rsync_environment_variables(self):
		
		#
		env = {}
		
		#
		if self.__ssh_key is not None or self.__quiet_ssh is True:
			env["RSYNC_RSH"] = "ssh"
			if self.__ssh_key is not None:
				env["RSYNC_RSH"] += " -i " + shlex.quote(self.__ssh_key)
			if self.__quiet_ssh is True:
				env["RSYNC_RSH"] += " -q"
		
		return env
	
	#
	def execute_remote_ssh_command(self, command):
		
		#
		self.demand_ssh_config()
		
		#
		args = list()
		
		# ssh command
		args.append("ssh")
		
		# Quiet?
		if self.__quiet_ssh is True:
			args.append("-q")
		
		# ssh key
		if self.__ssh_key is not None:
			args.append("-i")
			args.append(self.__ssh_key)
		
		# ssh user@host
		args.append(self.__remote_user + "@" + self.__remote_host)
		
		# Append the command
		args.append("--")
		if isinstance(command, str):
			args.append(command)
		elif isinstance(command, list):
			args.extend(command)
		else:
			raise Exception("Unsupported command datatype")
		
		# Spawn SSH in shell
		# process = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
		process = subprocess.Popen(args)
		# stdout, stderr = process.communicate()
		process.communicate()
		stdout = ""
		stderr = ""
		# print(stderr.decode())
		
		return process.returncode, stdout, stderr
	
	#
	def execute_rsync(self, _args):
		
		# Demand stuff
		self.demand_destination_directory_config()
		if self.is_using_ssh():
			self.demand_ssh_config()
		
		#
		args = self.start_rsync_args()
		args.extend(_args)
		# print(str(args))
		
		#
		env = self.start_rsync_environment_variables()
		
		#
		# print("Debug -> Want to execute Rsync")
		# print("Args:", str(args))
		# print("Env:", str(env))
		# return (0, "", "")
		
		# Spawn Rsync in shell
		# process = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env)
		process = subprocess.Popen(args, env=env)
		# stdout, stderr = process.communicate()
		process.communicate()
		# self.eprint(stderr.decode())
		
		stdout = ""
		stderr = ""
		
		return process.returncode, stdout, stderr


def main():
	
	b = MikesBackup()
	b.do_backup()


#
if __name__ == "__main__":
	
	#
	main()