#!/bin/python3

import json
import subprocess
import sys
import os

if len(sys.argv) < 3:
	# Check commands arguments.
	print("Usage: ")
	print("ksrackup {backup_name} init :: Initialize backup repository.")
	print("ksrackup {backup_name} backup :: Perform a new backup.")
	print("ksrackup {backup_name} prune :: Prune outdated backups.")
	print("ksrackup {backup_name} restic :: Execute an arbitrary restic command.")
	exit(1)

# Get command parameters.
backup_name = sys.argv[1]
command = sys.argv[2]  # The executed command.

# Open and read a backup configuration file.
backup_file = open(backup_name + ".json")
backup_data = json.load(backup_file)

# Setup the restic environment from backup configuration.
restic_environment = {
	"RESTIC_REPOSITORY": backup_data["restic"]["repository"],
	"RESTIC_PASSWORD": backup_data["restic"]["password"],
	"AWS_ACCESS_KEY_ID": backup_data["restic"]["access_key_id"],
	"AWS_SECRET_ACCESS_KEY": backup_data["restic"]["secret_access_key"],
}

# Create the backup directory.
os.makedirs(backup_name, exist_ok=True)
# Move to the backup directory.
os.chdir(backup_name)

# Open error log file.
error_log = open("error.log", "a")

# Execute the command.
if command == "init":
	# Initialize a backup repository.
	subprocess.run(["restic", "init"], env=restic_environment)
elif command == "backup":

	# Perform the right backup operations depending on its type.
	if backup_data["type"] == "postgresql":
		with open("database.sql", "w") as database_sql:
			# Dump of the PostgreSQL database.
			subprocess.run([
				"docker", "exec", backup_data["postgresql"]["container_name"],
				"pg_dump", "-U", backup_data["postgresql"]["username"], backup_data["postgresql"]["database"],
			], stdout=database_sql, stderr=error_log)
		# Save the dump in the restic repository.
		subprocess.run(["restic", "backup", "database.sql"], env=restic_environment, stderr=error_log)
	elif backup_data["type"] == "mysql":
		with open("database.sql", "w") as database_sql:
			# Dump of the MySQL database.
			subprocess.run([
				"docker", "exec", backup_data["mysql"]["container_name"],
				"mysqldump", "-u", backup_data["mysql"]["username"], "-p" + backup_data["mysql"]["password"], backup_data["mysql"]["database"],
			], stdout=database_sql, stderr=error_log)
		# Save the dump in the restic repository.
		subprocess.run(["restic", "backup", "database.sql"], env=restic_environment, stderr=error_log)
	elif backup_data["type"] == "files":
		# Save the files in the restic repository.
		subprocess.run(["restic", "backup", backup_data["files"]["path"]], env=restic_environment, stderr=error_log)

elif command == "prune":
	# Define backups conservation policy.
	prune_params = [
		"--keep-within", "28d",
		"--keep-within-daily", "4m",
		"--keep-within-weekly", "2y",
		"--keep-monthly", "100",
	]
	# Remove outdated backups.
	subprocess.run(["restic", "forget", "--prune"] + prune_params, env=restic_environment, stderr=error_log)
elif command == "restic":
	# Execute the arbitrary restic command.
	subprocess.run(["restic"] + sys.argv[3:], env=restic_environment)