import os
import sys
import random
import string
import configparser
from ee.core.variables import EEVariables
from ee.core.aptget import EEAptGet
from ee.core.apt_repo import EERepo
from ee.cli.plugins.eestack import EEStack
from ee.core.shellexec import EEShellExec
from ee.core.shellexec import CommandExecutionError
from ee.core.logging import Log
from ee.cli.main import app


class EEMysqlStack(EEStack):
    """
        EasyEngine MYSQL stack
    """
    packages_name = ["mariadb-server", "percona-toolkit"]
    log = app.log

    def __init__(self, packages_name=None):
        """
        Initialize packages list in stack
        pkgs_name : list of packages to be intialized for operations 
                    in stack
        """

        self.packages_name = self._get_stack()  
        super(EEMysqlStack, self).__init__(self.packages_name)

    def _get_stack(self):
        return EEMysqlStack.packages_name

    def _add_repo(self):
        """
          Add repository for packages to be downloaded from
        """
        self.log.info("Adding MySQL repository, please wait...")
        mysql_pref = ("Package: *\nPin: origin mirror.aarnet.edu.au"
                      "\nPin-Priority: 1000\n")
        with open('/etc/apt/preferences.d/'
                  'MariaDB.pref', 'w') as mysql_pref_file:
            mysql_pref_file.write(mysql_pref)

        # Add repository
        if EEVariables.ee_platform_codename != 'jessie':
            EERepo.add(self, repo_url=EEVariables.ee_mysql_repo)
            self.log.debug('Adding key for {0}'
                      .format(EEVariables.ee_mysql_repo))
            EERepo.add_key(self, '0xcbcb082a1bb943db',
                           keyserver="keyserver.ubuntu.com")
        EEAptGet.update(self)

    def _pre_install_stack(self):
        """
        Defines pre-install activities done before installing mysql stack
        """
        self._add_repo()
        # Predefine MySQL Credentials
        chars = ''.join(random.sample(string.ascii_letters, 8))
        self.log.info("Pre-seeding MySQL")
        self.log.debug("echo \"mariadb-server-10.0 "
                       "mysql-server/root_password "
                       "password \" | "
                       "debconf-set-selections")
        try:
            EEShellExec.cmd_exec(self, "echo \"mariadb-server-10.0 "
                                 "mysql-server/root_password "
                                 "password {chars}\" | "
                                 "debconf-set-selections"
                                 .format(chars=chars),
                                 log=False)
        except CommandExecutionError as e:
            self.log.error("Failed to initialize MySQL package")

        # Predefine MySQL credentials
        self.log.debug("echo \"mariadb-server-10.0 "
                       "mysql-server/root_password_again "
                       "password \" | "
                       "debconf-set-selections")
        try:
            EEShellExec.cmd_exec(self, "echo \"mariadb-server-10.0 "
                                 "mysql-server/root_password_again "
                                 "password {chars}\" | "
                                 "debconf-set-selections"
                                 .format(chars=chars),
                                 log=False)
        except CommandExecutionError as e:
            self.log.error("Failed to initialize MySQL package")

        # Write ~/.my.cnf configuration
        mysql_config = """
        [client]
        user = root
        password = {chars}
        """.format(chars=chars)
        config = configparser.ConfigParser()
        config.read_string(mysql_config)
        self.log.debug('Writting configuration into MySQL file')
        with open(os.path.expanduser("~")+'/.my.cnf', encoding='utf-8',
                  mode='w') as configfile:
            config.write(configfile)

    def _post_install_stack(self):
        """
        Defines activities done after installing mysql stack
        """
        pass

    def install_stack(self):
        """
        Install MYSQL stack
        """
        self.log.info("Installing MySQL stack, please wait...")
        self._pre_install_stack()
        super(EEMysqlStack, self).install_stack()
        self._post_install_stack()

    def remove_stack(self):
        """
        Remove MYSQL stack
        """
        self.log.info("Removing MySQL stack, please wait...")
        super(EEMysqlStack, self).remove_stack()

    def purge_stack(self):
        self.log.info("Purging MySQL stack, please wait...")
        super(EEMysqlStack, self).purge_stack()