import base64

import attr
from attr.validators import instance_of

from .. import Task
from ..utilities.pyhocon import ConfigFactory, ConfigTree
from .auto_scaler import CloudDriver
from .cloud_driver import parse_tags

try:
    # noinspection PyPackageRequirements
    import boto3
    from botocore.exceptions import ClientError

    Task.add_requirements("boto3")
except ImportError as err:
    raise ImportError(
        "AwsAutoScaler requires 'boto3' package, it was not found\n"
        "install with: pip install boto3"
    ) from err

@attr.s
class AWSDriver(CloudDriver):
    """AWS Driver"""
    aws_access_key_id = attr.ib(validator=instance_of(str), default='')
    aws_secret_access_key = attr.ib(validator=instance_of(str), default='')
    aws_session_token = attr.ib(validator=instance_of(str), default='')
    aws_region = attr.ib(validator=instance_of(str), default='')
    use_credentials_chain = attr.ib(validator=instance_of(bool), default=False)
    use_iam_instance_profile = attr.ib(validator=instance_of(bool), default=False)
    iam_arn = attr.ib(validator=instance_of(str), default='')
    iam_name = attr.ib(validator=instance_of(str), default='')

    @classmethod
    def from_config(cls, config):
        obj = super().from_config(config)
        obj.aws_access_key_id = config['hyper_params'].get('cloud_credentials_key')
        obj.aws_secret_access_key = config['hyper_params'].get('cloud_credentials_secret')
        obj.aws_session_token = config['hyper_params'].get('cloud_credentials_token')
        obj.aws_region = config['hyper_params'].get('cloud_credentials_region')
        obj.use_credentials_chain = config['hyper_params'].get('use_credentials_chain', False)
        obj.use_iam_instance_profile = config['hyper_params'].get('use_iam_instance_profile', False)
        obj.iam_arn = config['hyper_params'].get('iam_arn')
        obj.iam_name = config['hyper_params'].get('iam_name')
        return obj

    def __attrs_post_init__(self):
        super().__attrs_post_init__()
        self.tags = parse_tags(self.tags)
        
    def spin_up_worker(self, resource_conf, worker_prefix, queue_name, task_id):
        # user_data script will automatically run when the instance is started. it will install the required packages
        # for clearml-agent, configure it using environment variables and run clearml-agent on the required queue
        # Config reference: https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2/client/run_instances.html
        user_data = self.gen_user_data(worker_prefix, queue_name, task_id, resource_conf.get("cpu_only", False))

        ec2 = boto3.client("ec2", **self.creds())
        launch_specification = ConfigFactory.from_dict(
            {
                "ImageId": resource_conf["ami_id"],
                "Monitoring": {'Enabled':bool(resource_conf.get('enable_monitoring', False))},
                "InstanceType": resource_conf["instance_type"],
            }
        )
        # handle EBS volumes (existing or new)
        # Ref: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/block-device-mapping-concepts.html
        if resource_conf.get("ebs_snapshot_id") and resource_conf.get("ebs_device_name"):
            launch_specification["BlockDeviceMappings"] = [
                {
                    "DeviceName": resource_conf["ebs_device_name"],
                    "Ebs": {
                        "SnapshotId": resource_conf["ebs_snapshot_id"]
                    }
                }
            ]
        elif resource_conf.get("ebs_device_name"):
            launch_specification["BlockDeviceMappings"] = [
                {
                    "DeviceName": resource_conf["ebs_device_name"],
                    "Ebs": {
                        "VolumeSize": resource_conf.get("ebs_volume_size", 80),
                        "VolumeType": resource_conf.get("ebs_volume_type", "gp3")
                    }
                }
            ]
            
        if resource_conf.get("subnet_id", None):
            launch_specification["SubnetId"] = resource_conf["subnet_id"]
        elif resource_conf.get("availability_zone", None):
            launch_specification["Placement"] = {"AvailabilityZone": resource_conf["availability_zone"]}
        else:
            raise Exception('subnet_id or availability_zone must to be specified in the config')
        if resource_conf.get("key_name", None):
            launch_specification["KeyName"] = resource_conf["key_name"]
        if resource_conf.get("security_group_ids", None):
            launch_specification["SecurityGroupIds"] = resource_conf[
                "security_group_ids"
            ]
        # Adding iam role - you can have Arn OR Name, not both, Arn getting priority
        if self.iam_arn:
            launch_specification["IamInstanceProfile"] = {
                'Arn': self.iam_arn,
            }
        elif self.iam_name:
            launch_specification["IamInstanceProfile"] = {
                'Name': self.iam_name
            }

        if resource_conf["is_spot"]:
            # Create a request for a spot instance in AWS
            encoded_user_data = base64.b64encode(user_data.encode("ascii")).decode(
                "ascii"
            )
            launch_specification["UserData"] = encoded_user_data
            ConfigTree.merge_configs(
                launch_specification, resource_conf.get("extra_configurations", {})
            )

            instances = ec2.request_spot_instances(
                LaunchSpecification=launch_specification
            )

            # Wait until spot request is fulfilled
            request_id = instances["SpotInstanceRequests"][0]["SpotInstanceRequestId"]
            waiter = ec2.get_waiter("spot_instance_request_fulfilled")
            waiter.wait(SpotInstanceRequestIds=[request_id])
            # Get the instance object for later use
            response = ec2.describe_spot_instance_requests(
                SpotInstanceRequestIds=[request_id]
            )
            instance_id = response["SpotInstanceRequests"][0]["InstanceId"]

        else:
            # Create a new EC2 instance
            launch_specification.update(
                MinCount=1,
                MaxCount=1,
                UserData=user_data,
                InstanceInitiatedShutdownBehavior="terminate",
            )
            ConfigTree.merge_configs(
                launch_specification, resource_conf.get("extra_configurations", {})
            )

            instances = ec2.run_instances(**launch_specification)

            # Get the instance object for later use
            instance_id = instances["Instances"][0]["InstanceId"]

        instance = boto3.resource("ec2", **self.creds()).Instance(instance_id)
        if resource_conf.get("tags"):
            instance.create_tags(
                Resources=[instance_id],
                Tags=[{"Key": key, "Value": val} for key, val in parse_tags(resource_conf.get("tags"))],
            )
        # Wait until instance is in running state
        instance.wait_until_running()
        return instance_id

    def spin_down_worker(self, instance_id):
        instance = boto3.resource("ec2", **self.creds()).Instance(instance_id)
        instance.terminate()

    def creds(self):
        creds = {
            'region_name': self.aws_region or None,
        }

        if not self.use_credentials_chain:
            creds.update({
                'aws_secret_access_key': self.aws_secret_access_key or None,
                'aws_access_key_id': self.aws_access_key_id or None,
                'aws_session_token': self.aws_session_token or None,
            })
        return creds

    def instance_id_command(self):
        return 'curl http://169.254.169.254/latest/meta-data/instance-id'

    def instance_type_key(self):
        return 'instance_type'

    def kind(self):
        return 'AWS'

    def console_log(self, instance_id):
        ec2 = boto3.client("ec2", **self.creds())
        try:
            out = ec2.get_console_output(InstanceId=instance_id)
            return out.get('Output', '')
        except ClientError as err:
            return 'error: cannot get logs for {}:\n{}'.format(instance_id, err)
