Add the plan block as a conditional if statement

I am using terraform to deploy Linux VMs from the azure marketplace.

I have set a plan block in the linux module and declared the variables in my main.tf.

When running terraform plan/apply it works and builds the VM

I'm wondering how I would go about modifying my module and the main.tf to add the plan block as a conditional if statement.

I would like to use this module to build both non-azure marketplace & azure marketplace vms.

I wouldn't want a separate modules to do this.

module "vm-ansiblecontroller" {
  resource_group_name = module.rg-ansiblecontroller.resource_group_name
  location            = local.location
  linux_machine_name  = "linux-test1"
  tags                = var.tags

  nic_id = [module.vm-ansiblecontroller.nic_id]
  subnet_id = module.subnet-networkcore.subnet_id

  virtual_machine_size = "Standard_D2"

  admin_username       = "jpadmin"
  admin_ssh_public_key = file("~/.ssh/id_rsa.pub")

  source_image_publisher = "procomputers"
  source_image_offer     = "rocky-lnx-8-latest"
  source_image_sku       = "rocky-linux-8-latest"
  source_image_version   = "8.5.20220222"

  plan_name = "rocky-linux-8-latest"
  plan_product = "rocky-lnx-8-latest"
  plan_publisher = "procomputers"
  
  operating_system_disk_cache = "ReadWrite"
  operating_system_disk_type  = "Standard_LRS"

  ip_configuration_name         = "internal"
  private_ip_address_allocation = "Dynamic"

  public_ip_allocation_method = "Static"
  public_ip_sku               = "Standard"

   depends_on = [
    module.rg-networkcore,
    module.vnet-networkcore,
    module.subnet-networkcore
  ]
}

module "vm-jpdev" {
  resource_group_name = module.rg-jpdev-vm.resource_group_name
  location            = local.location
  linux_machine_name  = "linux-test2"
  tags                = var.tags

  nic_id = [module.vm-jpdev.nic_id]
  subnet_id = module.subnet-networkcore.subnet_id

  virtual_machine_size = "Standard_D2"

  admin_username       = "jpadmin"
  admin_ssh_public_key = file("~/.ssh/id_rsa.pub")

  source_image_publisher = "Canonical"
  source_image_offer     = "UbuntuServer"
  source_image_sku       = "16.04-LTS"
  source_image_version   = "latest"

  operating_system_disk_cache = "ReadWrite"
  operating_system_disk_type  = "Standard_LRS"

  ip_configuration_name         = "internal"
  private_ip_address_allocation = "Dynamic"

  public_ip_allocation_method = "Static"
  public_ip_sku               = "Standard"

}

modules/virtualmachine/linux/variables.tf

# VM Name
variable "linux_machine_name" {
  description = "Linux Virtual Machine Name - If left blank generated from metadata module"
  type        = string
  default     = ""
}

variable "resource_group_name" {
  description = "Resource group name"
  type        = string
}

variable "location" {
  description = "Azure region"
  type        = string
}

variable "tags" {
  description = "tags to be applied to resources"
  type        = map(string)
}

# VM Size
variable "virtual_machine_size" {
  description = "Instance size to be provisioned"
  type        = string
}

variable "admin_username" {
  description = "names to be applied to resources"
  type        = string
}

variable "admin_ssh_public_key" {
  description = "(Linux) Public SSH Key - Generated if left blank"
  type        = string
  default     = ""
  sensitive   = true
}

# Operating System
variable "source_image_publisher" {
  description = "Operating System Publisher"
  type        = string
}

variable "source_image_offer" {
  description = "Operating System Name"
  type        = string
}

variable "source_image_sku" {
  description = "Operating System SKU"
  type        = string
}

variable "source_image_version" {
  description = "Operating System Version"
  type        = string
  default     = "latest"
}

# Plan Block Variables
variable "plan_name" {
  description = "Plan Name"
  type        = string
}

variable "plan_product" {
  description = "Plan Product"
  type        = string
}

variable "plan_publisher" {
  description = "Plan Publisher"
  type        = string
}

# Operating System Disk
variable "operating_system_disk_cache" {
  description = "Type of caching to use on the OS disk - Options: None, ReadOnly or ReadWrite"
  type        = string
  default     = "ReadWrite"
}

variable "operating_system_disk_type" {
  description = "Type of storage account to use with the OS disk - Options: Standard_LRS, StandardSSD_LRS or Premium_LRS"
  type        = string
  default     = "StandardSSD_LRS"
}

variable "ip_configuration_name" {
  description = "ip configuration name"
  type        = string
  default     = ""
}

# Networking
variable "nic_id" {
  type        = list(string)
  description = "ID of the nic"
}

variable "subnet_id" {
  type        = string
  description = "ID of the subnet"
}

variable "private_ip_address_allocation" {
  type        = string
  description = "Private ip allocation method"
}

variable "public_ip_allocation_method" {
  type        = string
  description = "Public ip allocation method"
}

variable "public_ip_sku" {
  description = "SKU to be used with this public IP - Basic or Standard"
  type        = string
  default     = "Standard"
}

modules/virtualmachine/variables.tf

# Interface id
output "nic_id" {
  description = "ids of the vm nics provisoned."
  value = azurerm_network_interface.nic-linux.id

}