#!/usr/bin/python

########################################################
##################  ksharman v0.1.1  ###################
###  This script is a part of KozConfigurator v0.4.0 ###
########################################################
#########  Leonid Kozarin <kozalo@nekochan.ru  #########
#########  License: MIT                        #########
#########  (c) Copyright Kozalo.Ru, 2017       #########
########################################################

import os
import re
import json
import argparse
import subprocess

SMB_CONF_PATH = "/etc/samba/smb.conf"


class SmbConf:
    """A class for working with very simple Samba configuration files."""

    def __init__(self):
        self._nodes = {}
        self._open_node = None
        self.read()

    def read(self):
        """Reads the configuration file and stores its values in one of fields of the class."""

        with open(SMB_CONF_PATH, "r") as smb_conf:
            for line in smb_conf:
                line = line.strip()
                section_name = re.match("^\[(.+)]$", line)
                option_pair = re.match("^(.+) ?= ?(.*)$", line)

                if option_pair and self._open_node is not None:
                    self._open_node[option_pair.group(1).strip()] = option_pair.group(2).strip()
                elif line == "" and self._open_node is not None:
                    self._open_node = None
                elif section_name and self._open_node is None:
                    new_node = {}
                    self._nodes[section_name.group(1).strip()] = new_node
                    self._open_node = new_node
                else:
                    print("Wrong structure of the file!")
                    exit(3)

    def __str__(self):
        return json.dumps(self._nodes, indent=4)

    def add(self, path, readonly=False, guest=False):
        """Adds a new folder to the list of shared directories. It takes the following arguments:
        path -- a path to the folder which must exists;
        readonly -- if True, the folder will be shared as a read-only directory;
        guest -- if True, guests will have access to the folder.
        """

        if not os.path.isdir(path):
            print("The path does not exist!")
            exit(4)

        section_name = os.path.basename(path)
        if section_name.lower() == "global":
            print("Forbidden name for a folder!")
            exit(7)

        self._nodes[section_name] = {
            'path': path,
            'readonly': 'yes' if readonly else 'no',
            'guest ok': 'yes' if guest else 'no'
        }

    def remove(self, section):
        """Removes the folder from the list of shared directories.
        As a parameter takes either a path to the folder or just its name.
        """

        if section not in self._nodes:
            print("The section does not exist!")
            exit(6)
        elif section.lower() == "global":
            print('Cannot remove the "global" section!')
            exit(5)

        del self._nodes[section]

    def edit(self, section_name, key, value):
        """Modifies the parameter 'key' of the folder 'section_name' to the 'value'."""
        self._nodes[section_name][key] = value

    def write(self):
        """Writes the changes to the file."""

        global_section = self._nodes['global']
        del self._nodes['global']

        with open(SMB_CONF_PATH, "w") as smb_conf:
            self.__write_section(smb_conf, "global", global_section)

            for section_name, section_pairs in self._nodes.items():
                self.__write_section(smb_conf, section_name, section_pairs)

    @staticmethod
    def __write_section(file, section_name, section_pairs):
        file.write("[%s]\n" % section_name)
        for key, value in section_pairs.items():
            file.write("%s = %s\n" % (key, value))
        file.write("\n")


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="This script will help you to share new folders or hide some old ones via Samba.",
        epilog="(c) Leonid Kozarin <kozalo@nekochan.ru> (Kozalo.Ru, 2017)")
    parser.add_argument("action", choices=('list', 'share', 'hide'), help="What would you do? Share a folder or hide it?")
    parser.add_argument("-p", "--path", type=str, help="A path to a folder. If you're going to hide the folder, you may use only its name.")
    parser.add_argument("-w", "--writable", action="store_true", default=False, help="By default, other users are able to only read your folders.")
    parser.add_argument("-g", "--guest", action="store_true", default=False, help="Will guests have access to the folder? By default, it's false.")
    args = parser.parse_args()

    conf = SmbConf()

    if args.action == "list":
        print(conf)
        exit()

    if args.path is None:
        print("Path is a required parameter for any actions except listing!")
        exit(1)

    name = os.path.basename(args.path)

    if args.action == "share":
        conf.add(args.path, not args.writable, args.guest)
    elif args.action == "hide":
        conf.remove(name)
    else:
        print("Undefined action!")
        exit(2)

    conf.write()
    subprocess.call("service smbd restart", shell=True)