from .base_agent import BaseAgent
from ..aws_connector import AWSConnector
import time

class DMSAgent(BaseAgent):
    """
    An agent specialized in handling AWS Database Migration Service (DMS) tasks.
    """

    def execute(self, command: str, **kwargs):
        """
        Executes a given command related to DMS.
        """
        if command == 'smart_create_replication_task':
            task_name = kwargs.get('task_name', '')
            region = kwargs.get('region', '')
            print(f"You are about to smart-create a DMS replication task '{task_name}' in {region}.")
            confirm = input("This will create a replication instance, source/target endpoints, and a replication task. Are you sure you want to proceed? (yes/no): ")
            if confirm.lower() == 'yes':
                return self._smart_create_replication_task(**kwargs)
            else:
                return {"status": "cancelled", "message": "Smart Create DMS replication task command cancelled by user."}
        else:
            raise NotImplementedError(f"Command '{command}' is not supported by DMSAgent.")

    def _smart_create_replication_task(self, region: str, task_name: str, source_endpoint_id: str, target_endpoint_id: str, replication_instance_id: str = None, source_engine: str = 'mysql', target_engine: str = 'mysql', instance_class: str = 'dms.t3.medium', migration_type: str = 'full-load-and-cdc'):
        """
        Creates a DMS replication instance, source/target endpoints, and a replication task.
        This is a simplified version for demonstration.
        """
        print(f"DMSAgent: Smart creating replication task '{task_name}' in region {region}...")
        try:
            dms_client = AWSConnector.get_client('dms', region_name=region)

            # 1. Create Replication Instance (if not provided)
            if replication_instance_id is None:
                replication_instance_id = f'{task_name}-rep-instance'
                print(f"Creating replication instance '{replication_instance_id}'...")
                dms_client.create_replication_instance(
                    ReplicationInstanceIdentifier=replication_instance_id,
                    ReplicationInstanceClass=instance_class,
                    EngineVersion='3.4.5', # Example version
                    PubliclyAccessible=True, # For simplicity
                    AllocatedStorage=50,
                    Tags=[
                        {'Key': 'Name', 'Value': replication_instance_id}
                    ]
                )
                # Wait for instance to be available
                print("Waiting for replication instance to be available... (this may take several minutes)")
                waiter = dms_client.get_waiter('replication_instance_available')
                waiter.wait(Filters=[{'Name': 'replication-instance-id', 'Values': [replication_instance_id]}])
                print(f"Replication instance '{replication_instance_id}' is available.")
            else:
                print(f"Using existing replication instance: {replication_instance_id}")

            # 2. Create Source Endpoint (simplified - assumes basic connection info)
            # In a real scenario, you'd need more details like server name, port, username, password
            print(f"Creating source endpoint '{source_endpoint_id}'...")
            dms_client.create_endpoint(
                EndpointIdentifier=source_endpoint_id,
                EndpointType='source',
                EngineName=source_engine,
                ServerName='source-db.example.com', # Placeholder
                Port=3306, # Placeholder
                Username='dbuser', # Placeholder
                Password='dbpassword', # Placeholder
                SslMode='none',
                Tags=[
                    {'Key': 'Name', 'Value': source_endpoint_id}
                ]
            )
            print(f"Source endpoint '{source_endpoint_id}' created.")

            # 3. Create Target Endpoint (simplified)
            print(f"Creating target endpoint '{target_endpoint_id}'...")
            dms_client.create_endpoint(
                EndpointIdentifier=target_endpoint_id,
                EndpointType='target',
                EngineName=target_engine,
                ServerName='target-db.example.com', # Placeholder
                Port=3306, # Placeholder
                Username='dbuser', # Placeholder
                Password='dbpassword', # Placeholder
                SslMode='none',
                Tags=[
                    {'Key': 'Name', 'Value': target_endpoint_id}
                ]
            )
            print(f"Target endpoint '{target_endpoint_id}' created.")

            # 4. Create Replication Task
            print(f"Creating replication task '{task_name}'...")
            dms_client.create_replication_task(
                ReplicationTaskIdentifier=task_name,
                SourceEndpointArn=dms_client.describe_endpoints(Filters=[{'Name': 'endpoint-id', 'Values': [source_endpoint_id]}])['Endpoints'][0]['EndpointArn'],
                TargetEndpointArn=dms_client.describe_endpoints(Filters=[{'Name': 'endpoint-id', 'Values': [target_endpoint_id]}])['Endpoints'][0]['EndpointArn'],
                ReplicationInstanceArn=dms_client.describe_replication_instances(Filters=[{'Name': 'replication-instance-id', 'Values': [replication_instance_id]}])['ReplicationInstances'][0]['ReplicationInstanceArn'],
                MigrationType=migration_type,
                TableMappings='{"rules":[]}', # Empty table mappings for simplicity
                Tags=[
                    {'Key': 'Name', 'Value': task_name}
                ]
            )
            print(f"Replication task '{task_name}' created.")

            return {"status": "success", "message": f"DMS replication task '{task_name}' created successfully.", "replication_instance_id": replication_instance_id, "source_endpoint_id": source_endpoint_id, "target_endpoint_id": target_endpoint_id, "task_name": task_name}
        except Exception as e:
            print(f"Error during smart DMS replication task creation: {e}")
            return {"status": "error", "message": str(e)}