"""
Auto Scaling and ELB Resource Scanners

Scans Auto Scaling Groups (with Launch Templates), Load Balancers (ALB, NLB, CLB),
and Target Groups.

Requirements:
    - 5.1: Scan Auto Scaling and ELB 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 ELBServiceScanner:
    """Scanner for Auto Scaling and ELB 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_autoscaling_groups(session: boto3.Session, account_id: str, region: str) -> List[ResourceData]:
        """
        Scan Auto Scaling Groups in the specified region.
        
        Attributes (vertical layout - one table per ASG):
            Name, Launch Template, AMI, Instance type, Key, Target Groups,
            Desired, Min, Max, Scaling Policy
        """
        resources = []
        asg_client = session.client('autoscaling')
        ec2_client = session.client('ec2')
        
        paginator = asg_client.get_paginator('describe_auto_scaling_groups')
        for page in paginator.paginate():
            for asg in page.get('AutoScalingGroups', []):
                name = asg.get('AutoScalingGroupName', '')
                
                # Get Launch Template info
                launch_template_name = ''
                ami = ''
                instance_type = ''
                key_name = ''
                
                # Check for Launch Template
                lt = asg.get('LaunchTemplate')
                if lt:
                    launch_template_name = lt.get('LaunchTemplateName', lt.get('LaunchTemplateId', ''))
                    # Get Launch Template details
                    try:
                        lt_response = ec2_client.describe_launch_template_versions(
                            LaunchTemplateId=lt.get('LaunchTemplateId', ''),
                            Versions=[lt.get('Version', '$Latest')]
                        )
                        if lt_response.get('LaunchTemplateVersions'):
                            lt_data = lt_response['LaunchTemplateVersions'][0].get('LaunchTemplateData', {})
                            ami = lt_data.get('ImageId', '')
                            instance_type = lt_data.get('InstanceType', '')
                            key_name = lt_data.get('KeyName', '')
                    except Exception as e:
                        logger.warning(f"Failed to get launch template details: {str(e)}")
                
                # Check for Mixed Instances Policy
                mip = asg.get('MixedInstancesPolicy')
                if mip:
                    lt_spec = mip.get('LaunchTemplate', {}).get('LaunchTemplateSpecification', {})
                    if lt_spec:
                        launch_template_name = lt_spec.get('LaunchTemplateName', lt_spec.get('LaunchTemplateId', ''))
                
                # Check for Launch Configuration (legacy)
                lc_name = asg.get('LaunchConfigurationName')
                if lc_name and not launch_template_name:
                    launch_template_name = f"LC: {lc_name}"
                    try:
                        lc_response = asg_client.describe_launch_configurations(
                            LaunchConfigurationNames=[lc_name]
                        )
                        if lc_response.get('LaunchConfigurations'):
                            lc = lc_response['LaunchConfigurations'][0]
                            ami = lc.get('ImageId', '')
                            instance_type = lc.get('InstanceType', '')
                            key_name = lc.get('KeyName', '')
                    except Exception as e:
                        logger.warning(f"Failed to get launch configuration details: {str(e)}")
                
                # Get Target Groups
                target_groups = []
                for tg_arn in asg.get('TargetGroupARNs', []):
                    # Extract target group name from ARN
                    tg_name = tg_arn.split('/')[-2] if '/' in tg_arn else tg_arn
                    target_groups.append(tg_name)
                
                # Get Scaling Policies
                scaling_policies = []
                try:
                    policy_response = asg_client.describe_policies(
                        AutoScalingGroupName=name
                    )
                    for policy in policy_response.get('ScalingPolicies', []):
                        scaling_policies.append(policy.get('PolicyName', ''))
                except Exception as e:
                    logger.warning(f"Failed to get scaling policies: {str(e)}")
                
                resources.append(ResourceData(
                    account_id=account_id,
                    region=region,
                    service='autoscaling',
                    resource_type='Auto Scaling Group',
                    resource_id=asg.get('AutoScalingGroupARN', name),
                    name=name,
                    attributes={
                        'Name': name,
                        'Launch Template': launch_template_name,
                        'AMI': ami,
                        'Instance type': instance_type,
                        'Key': key_name,
                        'Target Groups': ', '.join(target_groups) if target_groups else 'N/A',
                        'Desired': str(asg.get('DesiredCapacity', 0)),
                        'Min': str(asg.get('MinSize', 0)),
                        'Max': str(asg.get('MaxSize', 0)),
                        'Scaling Policy': ', '.join(scaling_policies) if scaling_policies else 'N/A'
                    }
                ))
        
        return resources
    
    @staticmethod
    @retry_with_backoff()
    def scan_load_balancers(session: boto3.Session, account_id: str, region: str) -> List[ResourceData]:
        """
        Scan Load Balancers (ALB, NLB, CLB) in the specified region.
        
        Attributes (vertical layout - one table per LB):
            Name, Type, DNS, Scheme, VPC, Availability Zones, Subnet, Security Groups
        """
        resources = []
        
        # Scan ALB/NLB using elbv2
        elbv2_client = session.client('elbv2')
        
        try:
            paginator = elbv2_client.get_paginator('describe_load_balancers')
            for page in paginator.paginate():
                for lb in page.get('LoadBalancers', []):
                    name = lb.get('LoadBalancerName', '')
                    lb_type = lb.get('Type', 'application')
                    
                    # Get availability zones and subnets
                    azs = []
                    subnets = []
                    for az_info in lb.get('AvailabilityZones', []):
                        azs.append(az_info.get('ZoneName', ''))
                        if az_info.get('SubnetId'):
                            subnets.append(az_info['SubnetId'])
                    
                    # Get security groups (only for ALB)
                    security_groups = lb.get('SecurityGroups', [])
                    
                    resources.append(ResourceData(
                        account_id=account_id,
                        region=region,
                        service='elb',
                        resource_type='Load Balancer',
                        resource_id=lb.get('LoadBalancerArn', name),
                        name=name,
                        attributes={
                            'Name': name,
                            'Type': lb_type.upper(),
                            'DNS': lb.get('DNSName', ''),
                            'Scheme': lb.get('Scheme', ''),
                            'VPC': lb.get('VpcId', ''),
                            'Availability Zones': ', '.join(azs),
                            'Subnet': ', '.join(subnets),
                            'Security Groups': ', '.join(security_groups) if security_groups else 'N/A'
                        }
                    ))
        except Exception as e:
            logger.warning(f"Failed to scan ALB/NLB: {str(e)}")
        
        # Scan Classic Load Balancers
        elb_client = session.client('elb')
        
        try:
            paginator = elb_client.get_paginator('describe_load_balancers')
            for page in paginator.paginate():
                for lb in page.get('LoadBalancerDescriptions', []):
                    name = lb.get('LoadBalancerName', '')
                    
                    resources.append(ResourceData(
                        account_id=account_id,
                        region=region,
                        service='elb',
                        resource_type='Load Balancer',
                        resource_id=name,
                        name=name,
                        attributes={
                            'Name': name,
                            'Type': 'CLASSIC',
                            'DNS': lb.get('DNSName', ''),
                            'Scheme': lb.get('Scheme', ''),
                            'VPC': lb.get('VPCId', ''),
                            'Availability Zones': ', '.join(lb.get('AvailabilityZones', [])),
                            'Subnet': ', '.join(lb.get('Subnets', [])),
                            'Security Groups': ', '.join(lb.get('SecurityGroups', []))
                        }
                    ))
        except Exception as e:
            logger.warning(f"Failed to scan Classic ELB: {str(e)}")
        
        return resources
    
    @staticmethod
    @retry_with_backoff()
    def scan_target_groups(session: boto3.Session, account_id: str, region: str) -> List[ResourceData]:
        """
        Scan Target Groups in the specified region.
        
        Attributes (vertical layout - one table per TG):
            Load Balancer, TG Name, Port, Protocol, Registered Instances, Health Check Path
        """
        resources = []
        elbv2_client = session.client('elbv2')
        
        try:
            paginator = elbv2_client.get_paginator('describe_target_groups')
            for page in paginator.paginate():
                for tg in page.get('TargetGroups', []):
                    name = tg.get('TargetGroupName', '')
                    tg_arn = tg.get('TargetGroupArn', '')
                    
                    # Get associated load balancers
                    lb_arns = tg.get('LoadBalancerArns', [])
                    lb_names = []
                    for lb_arn in lb_arns:
                        # Extract LB name from ARN
                        lb_name = lb_arn.split('/')[-2] if '/' in lb_arn else lb_arn
                        lb_names.append(lb_name)
                    
                    # Get registered targets
                    registered_instances = []
                    try:
                        targets_response = elbv2_client.describe_target_health(
                            TargetGroupArn=tg_arn
                        )
                        for target in targets_response.get('TargetHealthDescriptions', []):
                            target_id = target.get('Target', {}).get('Id', '')
                            if target_id:
                                registered_instances.append(target_id)
                    except Exception as e:
                        logger.warning(f"Failed to get target health: {str(e)}")
                    
                    resources.append(ResourceData(
                        account_id=account_id,
                        region=region,
                        service='target_group',
                        resource_type='Target Group',
                        resource_id=tg_arn,
                        name=name,
                        attributes={
                            'Load Balancer': ', '.join(lb_names) if lb_names else 'N/A',
                            'TG Name': name,
                            'Port': str(tg.get('Port', '')),
                            'Protocol': tg.get('Protocol', ''),
                            'Registered Instances': ', '.join(registered_instances) if registered_instances else 'None',
                            'Health Check Path': tg.get('HealthCheckPath', 'N/A')
                        }
                    ))
        except Exception as e:
            logger.warning(f"Failed to scan target groups: {str(e)}")
        
        return resources