terraform {
  required_providers {
    azurerm = {
      source  = "hashicorp/azurerm"
      version = "3.74.0"
    }
    random = {
      source  = "hashicorp/random"
      version = "3.6.0"
    }
    tls = {
      source  = "hashicorp/tls"
      version = "4.0.4"
    }
    cloudinit = {
      source  = "hashicorp/cloudinit"
      version = "2.3.2"
    }
  }
}

provider "azurerm" {
  use_oidc = true
  features {}
}

provider "tls" {}

resource "random_string" "suffix" {
  length  = 6
  special = false
}

resource "tls_private_key" "ssh_key" {
  algorithm = "RSA"
  rsa_bits  = 2048
}

data "cloudinit_config" "cloud_init" {
  base64_encode = true
  part {
    filename     = "cloud-init.yaml"
    content_type = "text/cloud-config"

    content = file("${path.module}/cloud-init.yaml")
  }
}

resource "azurerm_resource_group" "main" {
  name     = var.resource_group
  location = var.location
}

resource "azurerm_virtual_network" "main" {
  name                = "mini-${random_string.suffix.result}"
  address_space       = ["10.0.0.0/16"]
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
}

resource "azurerm_subnet" "main" {
  name                 = "mini-${random_string.suffix.result}"
  resource_group_name  = azurerm_resource_group.main.name
  virtual_network_name = azurerm_virtual_network.main.name
  address_prefixes     = ["10.0.2.0/24"]
}

resource "azurerm_public_ip" "main" {
  name                = "mini-${random_string.suffix.result}"
  location            = azurerm_resource_group.main.location
  resource_group_name = azurerm_resource_group.main.name
  allocation_method   = "Static"
  sku                 = "Standard"
}

resource "azurerm_network_interface" "main" {
  name                = "mini-${random_string.suffix.result}"
  resource_group_name = azurerm_resource_group.main.name
  location            = azurerm_resource_group.main.location

  ip_configuration {
    name                          = "main"
    subnet_id                     = azurerm_subnet.main.id
    private_ip_address_allocation = "Dynamic"
    public_ip_address_id          = azurerm_public_ip.main.id
  }
}

resource "azurerm_network_security_group" "ssh" {
  name                = "mini-${random_string.suffix.result}"
  resource_group_name = azurerm_resource_group.main.name
  location            = azurerm_resource_group.main.location

  security_rule {
    name                       = "ssh"
    priority                   = 100
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_port_range          = "*"
    destination_port_range     = "22"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }
}

resource "azurerm_subnet_network_security_group_association" "ssh" {
  subnet_id                 = azurerm_subnet.main.id
  network_security_group_id = azurerm_network_security_group.ssh.id
}

resource "azurerm_linux_virtual_machine" "main" {
  name                = "mini-${random_string.suffix.result}"
  resource_group_name = azurerm_resource_group.main.name
  location            = azurerm_resource_group.main.location

  # Standard_D8s_v5 provides nested virtualization support
  size = var.machine_type

  admin_username = "adminuser"

  admin_ssh_key {
    username   = "adminuser"
    public_key = tls_private_key.ssh_key.public_key_openssh
  }

  boot_diagnostics {

  }

  network_interface_ids = [
    azurerm_network_interface.main.id,
  ]

  source_image_reference {
    publisher = "Canonical"
    offer     = "0001-com-ubuntu-server-jammy-daily"
    sku       = "22_04-daily-lts"
    version   = "latest"
  }

  os_disk {
    storage_account_type = "Standard_LRS"
    caching              = "ReadWrite"
  }

  user_data = data.cloudinit_config.cloud_init.rendered
}