# Set the VM, image, and networking configuration
VM_NAME="langflow-dev"
IMAGE_FAMILY="debian-11"
IMAGE_PROJECT="debian-cloud"
BOOT_DISK_SIZE="100GB"
ZONE="us-central1-a"
REGION="us-central1"
VPC_NAME="default"
SUBNET_NAME="default"
SUBNET_RANGE="10.128.0.0/20"
NAT_GATEWAY_NAME="nat-gateway"
CLOUD_ROUTER_NAME="nat-client"

# Set the GCP project's compute region
gcloud config set compute/region $REGION

# Check if the VPC exists, and create it if not
vpc_exists=$(gcloud compute networks list --filter="name=$VPC_NAME" --format="value(name)")
if [[ -z "$vpc_exists" ]]; then
  gcloud compute networks create $VPC_NAME --subnet-mode=custom
fi

# Check if the subnet exists, and create it if not
subnet_exists=$(gcloud compute networks subnets list --filter="name=$SUBNET_NAME AND region=$REGION" --format="value(name)")
if [[ -z "$subnet_exists" ]]; then
  gcloud compute networks subnets create $SUBNET_NAME --network=$VPC_NAME --region=$REGION --range=$SUBNET_RANGE
fi

# Create a firewall rule to allow TCP port 7860 for all instances in the VPC
firewall_7860_exists=$(gcloud compute firewall-rules list --filter="name=allow-tcp-7860" --format="value(name)")
if [[ -z "$firewall_7860_exists" ]]; then
  gcloud compute firewall-rules create allow-tcp-7860 --network $VPC_NAME --allow tcp:7860 --source-ranges 0.0.0.0/0 --direction INGRESS
fi

# Create a firewall rule to allow IAP traffic
firewall_iap_exists=$(gcloud compute firewall-rules list --filter="name=allow-iap" --format="value(name)")
if [[ -z "$firewall_iap_exists" ]]; then
    gcloud compute firewall-rules create allow-iap --network $VPC_NAME --allow tcp:80,tcp:443,tcp:22,tcp:3389 --source-ranges 35.235.240.0/20 --direction INGRESS
fi

# Define the startup script as a multiline Bash here-doc
STARTUP_SCRIPT=$(cat <<'EOF'
#!/bin/bash

# Update and upgrade the system
apt -y update
apt -y upgrade

# Install Python 3 pip, Langflow, and Nginx
apt -y install python3-pip
pip install langflow
langflow --host 0.0.0.0 --port 7860
EOF
)

# Create a temporary file to store the startup script
tempfile=$(mktemp)
echo "$STARTUP_SCRIPT" > $tempfile

# Create the VM instance with the specified configuration and startup script
gcloud compute instances create $VM_NAME \
  --image-family $IMAGE_FAMILY \
  --image-project $IMAGE_PROJECT \
  --boot-disk-size $BOOT_DISK_SIZE \
  --machine-type=n1-standard-4 \
  --metadata-from-file startup-script=$tempfile \
  --zone $ZONE \
  --network $VPC_NAME \
  --subnet $SUBNET_NAME \
  --preemptible

# Remove the temporary file after the VM is created
rm $tempfile