import oca
import socket
import logging

from oca.pool import WrongNameError
from oca.exceptions import OpenNebulaException

from django.conf import settings
from django.utils.functional import cached_property

from utils.models import CustomUser
from .exceptions import KeyExistsError, UserExistsError, UserCredentialError

logger = logging.getLogger(__name__)


class OpenNebulaManager():
    """This class represents an opennebula manager."""

    def __init__(self, email=None, password=None):

        # Get oneadmin client
        self.oneadmin_client = self._get_opennebula_client(
            settings.OPENNEBULA_USERNAME,
            settings.OPENNEBULA_PASSWORD
        )

        # Get or create oppenebula user using given credentials
        try:
            self.opennebula_user = self._get_or_create_user(
                email,
                password
            )
            # If opennebula user was created/obtained, get his client
            self.client = self._get_opennebula_client(
                email,
                password
            )
        except:
            pass
    def _get_client(self, user):
        """Get a opennebula client object for a CustomUser object 
        
        Args:
            user (CustomUser): dynamicweb CustomUser object

        Returns:
            oca.Client: Opennebula client object

        Raise:
            ConnectionError: If the connection to the opennebula server can't be
                established 
        """
        return oca.Client("{0}:{1}".format(
            user.email,
            user.password),
            "{protocol}://{domain}:{port}{endpoint}".format(
                protocol=settings.OPENNEBULA_PROTOCOL,
                domain=settings.OPENNEBULA_DOMAIN,
                port=settings.OPENNEBULA_PORT,
                endpoint=settings.OPENNEBULA_ENDPOINT
        ))

    def _get_opennebula_client(self, username, password):
        return oca.Client("{0}:{1}".format(
            username,

            password),
            "{protocol}://{domain}:{port}{endpoint}".format(
                protocol=settings.OPENNEBULA_PROTOCOL,
                domain=settings.OPENNEBULA_DOMAIN,
                port=settings.OPENNEBULA_PORT,
                endpoint=settings.OPENNEBULA_ENDPOINT
        ))

    def _get_user(self, user):
        """Get the corresponding opennebula user for a CustomUser object 
        
        Args:
            user (CustomUser): dynamicweb CustomUser object

        Returns:
            oca.User: Opennebula user object

        Raise:
            WrongNameError: If no openebula user with this credentials exists
            ConnectionError: If the connection to the opennebula server can't be
                established 
        """
        user_pool = self._get_user_pool()
        return user_pool.get_by_name(user.email)

    def create_user(self, user: CustomUser):
        """Create a new opennebula user or a corresponding CustomUser object

        
        Args:
            user (CustomUser): dynamicweb CustomUser object

        Returns:
            int: Return the opennebula user id
            
        Raises:
            ConnectionError: If the connection to the opennebula server can't be
                established 
            UserExistsError: If a user with this credeintals already exits on the
                server
            UserCredentialError: If a user with this email exists but the
                password is worng

        """
        try:
            self._get_user(user)
            try: 
                self._get_client(self, user)
                logger.debug('User already exists')
                raise UserExistsError()
            except OpenNebulaException as err:
                logger.error('OpenNebulaException error: {0}'.format(err))
                logger.debug('User exists but password is wrong')
                raise UserCredentialError()

        except WrongNameError:
            user_id = self.oneadmin_client.call(oca.User.METHODS['allocate'],
                user.email, user.password, 'core')
            logger.debug('Created a user for CustomObject: {user} with user id = {u_id}',
                user=user,
                u_id=user_id
            )
            return user_id 
        except ConnectionRefusedError:
            logger.error('Could not connect to host: {host} via protocol {protocol}'.format(
                host=settings.OPENNEBULA_DOMAIN,
                protocol=settings.OPENNEBULA_PROTOCOL)
            )
            raise ConnectionRefusedError
        

    def _get_or_create_user(self, email, password):
        try:
            user_pool = self._get_user_pool()
            opennebula_user = user_pool.get_by_name(email)
            return opennebula_user
        except WrongNameError as wrong_name_err:
            opennebula_user = self.oneadmin_client.call(oca.User.METHODS['allocate'], email,
                                                        password, 'core')
            logger.debug(
                "User {0} does not exist. Created the user. User id = {1}",
                email,
                opennebula_user
            )
            return opennebula_user
        except ConnectionRefusedError:
            logger.info('Could not connect to host: {host} via protocol {protocol}'.format(
                host=settings.OPENNEBULA_DOMAIN,
                protocol=settings.OPENNEBULA_PROTOCOL)
            )
            raise ConnectionRefusedError

    def _get_user_pool(self):
        try:
            user_pool = oca.UserPool(self.oneadmin_client)
            user_pool.info()
        except ConnectionRefusedError:
            logger.info('Could not connect to host: {host} via protocol {protocol}'.format(
                host=settings.OPENNEBULA_DOMAIN,
                protocol=settings.OPENNEBULA_PROTOCOL)
            )
            raise 
        return user_pool

    def _get_vm_pool(self):
        try:
            vm_pool = oca.VirtualMachinePool(self.client)
            vm_pool.info()
            return vm_pool
        except AttributeError:
            logger.info('Could not connect via client, using oneadmin instead')
            try:
                vm_pool = oca.VirtualMachinePool(self.oneadmin_client)
                vm_pool.info(filter=-2)
                return vm_pool
            except:
                raise ConnectionRefusedError

        except ConnectionRefusedError:
            logger.info('Could not connect to host: {host} via protocol {protocol}'.format(
                host=settings.OPENNEBULA_DOMAIN,
                protocol=settings.OPENNEBULA_PROTOCOL)
            )
            raise ConnectionRefusedError
        # For now we'll just handle all other errors as connection errors
        except:
            raise ConnectionRefusedError

    def get_vms(self):
        try:
            return self._get_vm_pool()
        except ConnectionRefusedError:
            raise ConnectionRefusedError

    def get_vm(self, vm_id):
        vm_id = int(vm_id)
        try:
            vm_pool = self._get_vm_pool()
            return vm_pool.get_by_id(vm_id)
        except:
            raise ConnectionRefusedError

    def create_template(self, name, cores, memory, disk_size, core_price, memory_price,
                        disk_size_price, ssh=''):
        """Create and add a new template to opennebula.
        :param name:      A string representation describing the template.
                          Used as label in view.
        :param cores:     Amount of virtual cpu cores for the VM.
        :param memory:  Amount of RAM for the VM (GB)
        :param disk_size:    Amount of disk space for VM (GB)
        :param core_price:     Price of virtual cpu for the VM per core.
        :param memory_price:  Price of RAM for the VM per GB
        :param disk_size_price:    Price of disk space for VM per GB
        :param ssh: User public ssh key
        """

        template_id = oca.VmTemplate.allocate(
            self.oneadmin_client,
            template_string_formatter.format(
                name=name,
                vcpu=cores,
                cpu=0.1 * cores,
                size=1024 * disk_size,
                memory=1024 * memory,
                # * 10 because we set cpu to *0.1
                cpu_cost=10 * core_price,
                memory_cost=memory_price,
                disk_cost=disk_size_price,
                ssh=ssh
            )
        )

    def create_vm(self, template_id, specs, ssh_key=None):

        template = self.get_template(template_id)
        vm_specs_formatter = """<TEMPLATE>
                                 <MEMORY>{memory}</MEMORY>
                                 <VCPU>{vcpu}</VCPU>
                                 <CPU>{cpu}</CPU>
                             """
        try:
            disk = template.template.disks[0]
            image_id = disk.image_id
            vm_specs = vm_specs_formatter.format(
                vcpu=int(specs['cpu']),
                cpu=0.1 * int(specs['cpu']),
                memory=1024 * int(specs['memory']),

            )
            vm_specs += """<DISK>
                                  <TYPE>fs</TYPE>
                                  <SIZE>{size}</SIZE>
                                  <DEV_PREFIX>vd</DEV_PREFIX>
                                  <IMAGE_ID>{image_id}</IMAGE_ID>
                           </DISK>
                        """.format(size=1024 * int(specs['disk_size']),
                                   image_id=image_id)

        except:
            disk = template.template.disks[0]
            image = disk.image
            image_uname = disk.image_uname

            vm_specs = vm_specs_formatter.format(
                vcpu=int(specs['cpu']),
                cpu=0.1 * int(specs['cpu']),
                memory=1024 * int(specs['memory']),

            )
            vm_specs += """<DISK>
                                  <TYPE>fs</TYPE>
                                  <SIZE>{size}</SIZE>
                                  <DEV_PREFIX>vd</DEV_PREFIX>
                                  <IMAGE>{image}</IMAGE>
                                  <IMAGE_UNAME>{image_uname}</IMAGE_UNAME>
                           </DISK>
                        """.format(size=1024 * int(specs['disk_size']),
                                   image=image,
                                   image_uname=image_uname)
                        
                                
        if ssh_key:
            vm_specs += """<CONTEXT>
                    <SSH_PUBLIC_KEY>{ssh}</SSH_PUBLIC_KEY>
                    <NETWORK>YES</NETWORK>
                   </CONTEXT>
                              </TEMPLATE>
                """.format(ssh=ssh_key)
        vm_id = self.client.call(oca.VmTemplate.METHODS['instantiate'],
                                 template.id,
                                 '',
                                 True,
                                 vm_specs,
                                 False)

        self.oneadmin_client.call(
            oca.VirtualMachine.METHODS['action'],
            'release',
            vm_id
        )
        return vm_id

    def delete_vm(self, vm_id):
        TERMINATE_ACTION = 'terminate'
        vm_terminated = False
        try:
            self.oneadmin_client.call(
                oca.VirtualMachine.METHODS['action'],
                TERMINATE_ACTION,
                int(vm_id),
            )
            vm_terminated = True
        except socket.timeout as socket_err:
            logger.info("Socket timeout error: {0}".format(socket_err))
        except OpenNebulaException as opennebula_err:
            logger.info(
                "OpenNebulaException error: {0}".format(opennebula_err))
        except OSError as os_err:
            logger.info("OSError : {0}".format(os_err))
        except ValueError as value_err:
            logger.info("ValueError : {0}".format(value_err))

        return vm_terminated

    def _get_template_pool(self):
        try:
            template_pool = oca.VmTemplatePool(self.oneadmin_client)
            template_pool.info()
            return template_pool
        except ConnectionRefusedError:
            logger.info('Could not connect to host: {host} via protocol {protocol}'.format(
                host=settings.OPENNEBULA_DOMAIN,
                protocol=settings.OPENNEBULA_PROTOCOL)
            )
            raise ConnectionRefusedError
        except:
            raise ConnectionRefusedError

    def get_templates(self):
        try:
            public_templates = [
                template
                for template in self._get_template_pool()
                if 'public-' in template.name
            ]
            return public_templates
        except ConnectionRefusedError:
            raise ConnectionRefusedError
        except:
            raise ConnectionRefusedError

    def try_get_templates(self):
        try:
            return self.get_templates()
        except:
            return []

    def get_template(self, template_id):
        template_id = int(template_id)
        try:
            template_pool = self._get_template_pool()
            return template_pool.get_by_id(template_id)
        except:
            raise ConnectionRefusedError

    def create_template(self, name, cores, memory, disk_size, core_price, memory_price,
                        disk_size_price, ssh=''):
        """Create and add a new template to opennebula.
        :param name:      A string representation describing the template.
                          Used as label in view.
        :param cores:     Amount of virtual cpu cores for the VM.
        :param memory:  Amount of RAM for the VM (GB)
        :param disk_size:    Amount of disk space for VM (GB)
        :param core_price:     Price of virtual cpu for the VM per core.
        :param memory_price:  Price of RAM for the VM per GB
        :param disk_size_price:    Price of disk space for VM per GB
        :param ssh: User public ssh key
        """
        template_string_formatter = """<TEMPLATE>
                                        <NAME>{name}</NAME>
                                        <MEMORY>{memory}</MEMORY>
                                        <VCPU>{vcpu}</VCPU>
                                        <CPU>{cpu}</CPU>
                                        <DISK>
                                         <TYPE>fs</TYPE>
                                         <SIZE>{size}</SIZE>
                                         <DEV_PREFIX>vd</DEV_PREFIX>
                                        </DISK>
                                        <CPU_COST>{cpu_cost}</CPU_COST>
                                        <MEMORY_COST>{memory_cost}</MEMORY_COST>
                                        <DISK_COST>{disk_cost}</DISK_COST>
                                        <SSH_PUBLIC_KEY>{ssh}</SSH_PUBLIC_KEY>
                                       </TEMPLATE>
                                       """
        template_id = oca.VmTemplate.allocate(
            self.oneadmin_client,
            template_string_formatter.format(
                name=name,
                vcpu=cores,
                cpu=0.1 * cores,
                size=1024 * disk_size,
                memory=1024 * memory,
                # * 10 because we set cpu to *0.1
                cpu_cost=10 * core_price,
                memory_cost=memory_price,
                disk_cost=disk_size_price,
                ssh=ssh
            )
        )

        return template_id

    def delete_template(self, template_id):
        self.oneadmin_client.call(oca.VmTemplate.METHODS[
                                  'delete'], template_id, False)

    def change_user_password(self, new_password):
        self.oneadmin_client.call(
            oca.User.METHODS['passwd'],
            self.opennebula_user.id,
            new_password
        )

    def add_public_key(self, user, public_key='', merge=False):
        """ 

        Args: 
            user (CustomUser): Dynamicweb user 
            public_key (string): Public key to add to the user
            merge (bool): Optional if True the new public key replaces the old

        Raises:
            KeyExistsError: If replace is False and the user already has a
                public key 
            WrongNameError: If no openebula user with this credentials exists
            ConnectionError: If the connection to the opennebula server can't be
                established 

        Returns:
            True if public_key was added

        """
        # TODO: Check if we can remove this first try because we basically just
        # raise the possible Errors 
        try:
            open_user = self._get_user(user)
            try:
                old_key = open_user.template.ssh_public_key 
                if not merge:
                    raise KeyExistsError()
                public_key += '\n{key}'.format(key=old_key)

            except AttributeError:
                pass
            self.oneadmin_client.call('user.update', open_user.id,
                         '<CONTEXT><SSH_PUBLIC_KEY>{key}</SSH_PUBLIC_KEY></CONTEXT>'.format(key=public_key))
            return True
        except WrongNameError:
            raise

        except ConnectionError:
            raise

    def remove_public_key(self, user, public_key=''):
        """ 

        Args: 
            user (CustomUser): Dynamicweb user 
            public_key (string): Public key to be removed to the user

        Raises:
            KeyDoesNotExistsError: If replace is False and the user already has a
                public key 
            WrongNameError: If no openebula user with this credentials exists
            ConnectionError: If the connection to the opennebula server can't be
                established 

        Returns:
            True if public_key was removed

        """

        try:
            open_user = self._get_user(user)
            try:
                old_key = open_user.template.ssh_public_key 
                if public_key not in old_key:
                    raise KeyDoesNotExistsError()
                if '\n{}'.format(public_key) in old_key:
                    public_key = old_key.replace('\n{}'.format(public_key), '')
                else: 
                    public_key = old_key.replace(public_key, '')

            except AttributeError:
                raise KeyDoesNotExistsError()
                
            self.oneadmin_client.call('user.update', open_user.id,
                         '<CONTEXT><SSH_PUBLIC_KEY>{key}</SSH_PUBLIC_KEY></CONTEXT>'.format(key=public_key))
            return True
        except WrongNameError:
            raise

        except ConnectionError:
            raise