"""
EC2 Related Resource Scanners

Scans EC2 Instances (with EBS volumes, AMI info) and Elastic IPs.

Requirements:
    - 5.1: Scan EC2-related AWS services using boto3
"""

import boto3
from typing import List, Dict, Any
import logging

from app.scanners.base import ResourceData
from app.scanners.utils import retry_with_backoff

logger = logging.getLogger(__name__)


class EC2ServiceScanner:
    """Scanner for EC2-related AWS resources"""
    
    @staticmethod
    def _get_name_from_tags(tags: List[Dict[str, str]], default: str = '') -> str:
        """Extract Name tag value from tags list"""
        if not tags:
            return default
        for tag in tags:
            if tag.get('Key') == 'Name':
                return tag.get('Value', default)
        return default
    
    @staticmethod
    @retry_with_backoff()
    def scan_ec2_instances(session: boto3.Session, account_id: str, region: str) -> List[ResourceData]:
        """
        Scan EC2 Instances in the specified region.
        
        Attributes (vertical layout - one table per instance):
            Name, Instance ID, Instance Type, AZ, AMI,
            Public IP, Public DNS, Private IP, VPC ID, Subnet ID,
            Key, Security Groups, EBS Type, EBS Size, Encryption, Other Requirement
        """
        resources = []
        ec2_client = session.client('ec2')
        
        paginator = ec2_client.get_paginator('describe_instances')
        for page in paginator.paginate():
            for reservation in page.get('Reservations', []):
                for instance in reservation.get('Instances', []):
                    # Skip terminated instances
                    state = instance.get('State', {}).get('Name', '')
                    if state == 'terminated':
                        continue
                    
                    name = EC2ServiceScanner._get_name_from_tags(
                        instance.get('Tags', []), 
                        instance['InstanceId']
                    )
                    
                    # Get security groups
                    security_groups = []
                    for sg in instance.get('SecurityGroups', []):
                        security_groups.append(sg.get('GroupName', sg.get('GroupId', '')))
                    
                    # Get EBS volume info
                    ebs_type = ''
                    ebs_size = ''
                    ebs_encrypted = ''
                    
                    for block_device in instance.get('BlockDeviceMappings', []):
                        ebs = block_device.get('Ebs', {})
                        if ebs.get('VolumeId'):
                            # Get volume details
                            try:
                                vol_response = ec2_client.describe_volumes(
                                    VolumeIds=[ebs['VolumeId']]
                                )
                                if vol_response.get('Volumes'):
                                    volume = vol_response['Volumes'][0]
                                    ebs_type = volume.get('VolumeType', '')
                                    ebs_size = f"{volume.get('Size', '')} GB"
                                    ebs_encrypted = 'Yes' if volume.get('Encrypted') else 'No'
                            except Exception as e:
                                logger.warning(f"Failed to get volume details: {str(e)}")
                            break  # Only get first volume for simplicity
                    
                    resources.append(ResourceData(
                        account_id=account_id,
                        region=region,
                        service='ec2',
                        resource_type='Instance',
                        resource_id=instance['InstanceId'],
                        name=name,
                        attributes={
                            'Name': name,
                            'Instance ID': instance['InstanceId'],
                            'Instance Type': instance.get('InstanceType', ''),
                            'AZ': instance.get('Placement', {}).get('AvailabilityZone', ''),
                            'AMI': instance.get('ImageId', ''),
                            'Public IP': instance.get('PublicIpAddress', ''),
                            'Public DNS': instance.get('PublicDnsName', ''),
                            'Private IP': instance.get('PrivateIpAddress', ''),
                            'VPC ID': instance.get('VpcId', ''),
                            'Subnet ID': instance.get('SubnetId', ''),
                            'Key': instance.get('KeyName', ''),
                            'Security Groups': ', '.join(security_groups),
                            'EBS Type': ebs_type,
                            'EBS Size': ebs_size,
                            'Encryption': ebs_encrypted,
                            'Other Requirement': ''
                        }
                    ))
        
        return resources
    
    @staticmethod
    @retry_with_backoff()
    def scan_elastic_ips(session: boto3.Session, account_id: str, region: str) -> List[ResourceData]:
        """
        Scan Elastic IPs in the specified region.
        
        Attributes (horizontal layout): Name, Elastic IP
        """
        resources = []
        ec2_client = session.client('ec2')
        
        response = ec2_client.describe_addresses()
        for eip in response.get('Addresses', []):
            public_ip = eip.get('PublicIp', '')
            name = EC2ServiceScanner._get_name_from_tags(
                eip.get('Tags', []), 
                public_ip or eip.get('AllocationId', '')
            )
            
            resources.append(ResourceData(
                account_id=account_id,
                region=region,
                service='elastic_ip',
                resource_type='Elastic IP',
                resource_id=eip.get('AllocationId', public_ip),
                name=name,
                attributes={
                    'Name': name,
                    'Elastic IP': public_ip
                }
            ))
        
        return resources