#!/bin/bash

# Initialize counters for the summary report
TOTAL_AL2=0
TOTAL_NOT_AL2=0
TOTAL_UNKNOWN=0

# Get a list of all enabled regions
REGIONS=$(aws ec2 describe-regions --query "Regions[].RegionName" --output text)

for REGION in $REGIONS; do
    echo "--- Region: $REGION ---"
    
    # Get all instance IDs in the current region
    INSTANCES=$(aws ec2 describe-instances --region "$REGION" --query "Reservations[].Instances[].InstanceId" --output text)
    
    if [ -z "$INSTANCES" ]; then
        echo "no instance found"
        continue
    fi
    
    for INSTANCE_ID in $INSTANCES; do
        echo -n "Instance $INSTANCE_ID: "
        
        # Capture console output
        OUTPUT=$(aws ec2 get-console-output --region "$REGION" --instance-id "$INSTANCE_ID" --query "Output" --output text)
        
        if [ -z "$OUTPUT" ] || [ "$OUTPUT" == "None" ]; then
            echo "cannot determine (Empty output)"
            ((TOTAL_UNKNOWN++))
            continue
        fi

        # NESTED LOGIC: Handle Amazon Linux branding overlap
        if echo "$OUTPUT" | grep -qiE "Amazon Linux|\.amzn"; then
            
            # Sub-check: Is it actually AL2023?
            if echo "$OUTPUT" | grep -qiE "Amazon Linux 2023|\.amzn2023"; then
                echo "NOT running Amazon Linux 2 (Detected AL2023)"
                ((TOTAL_NOT_AL2++))
            
            # Sub-check: Confirm it is indeed AL2
            elif echo "$OUTPUT" | grep -qiE "Amazon Linux 2|\.amzn2\."; then
                echo "RUNNING Amazon Linux 2"
                ((TOTAL_AL2++))
            
            else
                echo "cannot determine (Generic Amazon Linux string)"
                ((TOTAL_UNKNOWN++))
            fi

        # Check for other known Operating Systems
        elif echo "$OUTPUT" | grep -qiE "Red Hat|Enterprise Linux|\.el[0-9]|Ubuntu|Debian|CentOS|Fedora|SLES|SUSE"; then
            echo "NOT running Amazon Linux 2"
            ((TOTAL_NOT_AL2++))
            
        # Fallback for everything else
        else
            echo "cannot determine the operating system"
            ((TOTAL_UNKNOWN++))
        fi
    done
done

# Output the final report
echo -e "\n"
echo "========================================"
echo "      AL2 EOL MIGRATION SUMMARY         "
echo "========================================"
echo "Total AL2 Instances (Action Required): $TOTAL_AL2"
echo "Total Non-AL2 Instances (Safe):        $TOTAL_NOT_AL2"
echo "Total Unknown (Needs Review):          $TOTAL_UNKNOWN"
echo "========================================"