resource "random_pet" "prefix" {
  prefix = var.resource_group_name_prefix
  length = 1
}

# Resource Group
resource "azurerm_resource_group" "rg" {
  location = var.resource_group_location
  name     = "${random_pet.prefix.id}-rg"
}

# Virtual Network
resource "azurerm_virtual_network" "my_terraform_network" {
  name                = "${random_pet.prefix.id}-vnet"
  address_space       = ["10.0.0.0/16"]
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
}

# Subnet 1
resource "azurerm_subnet" "my_terraform_subnet_1" {
  name                 = "subnet-1"
  resource_group_name  = azurerm_resource_group.rg.name
  virtual_network_name = azurerm_virtual_network.my_terraform_network.name
  address_prefixes     = ["10.0.0.0/24"]
}

# Public IP address for NAT gateway
resource "azurerm_public_ip" "my_public_ip" {
  name                = "public-ip-nat"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  allocation_method   = "Static"
  sku                 = "Standard"
}

# NAT Gateway
resource "azurerm_nat_gateway" "my_nat_gateway" {
  name                = "nat-gateway"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
}

# Associate NAT Gateway with Public IP
resource "azurerm_nat_gateway_public_ip_association" "example" {
  nat_gateway_id       = azurerm_nat_gateway.my_nat_gateway.id
  public_ip_address_id = azurerm_public_ip.my_public_ip.id
}

# Associate NAT Gateway with Subnet
resource "azurerm_subnet_nat_gateway_association" "example" {
  subnet_id      = azurerm_subnet.my_terraform_subnet_1.id
  nat_gateway_id = azurerm_nat_gateway.my_nat_gateway.id
}

# Create public IP for virtual machine
resource "azurerm_public_ip" "my_public_ip_vm" {
  name                = "public-ip-vm"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  allocation_method   = "Static"
  sku                 = "Standard"
}

# Create Network Security Group and rule
resource "azurerm_network_security_group" "my_terraform_nsg" {
  name                = "nsg-1"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name

  security_rule {
    name                       = "SSH"
    priority                   = 1001
    direction                  = "Inbound"
    access                     = "Allow"
    protocol                   = "Tcp"
    source_port_range          = "*"
    destination_port_range     = "22"
    source_address_prefix      = "*"
    destination_address_prefix = "*"
  }
}

# Create network interface
resource "azurerm_network_interface" "my_terraform_nic" {
  name                = "nic-1"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name

  ip_configuration {
    name                          = "my_nic_configuration"
    subnet_id                     = azurerm_subnet.my_terraform_subnet_1.id
    private_ip_address_allocation = "Dynamic"
    public_ip_address_id          = azurerm_public_ip.my_public_ip_vm.id
  }
}

# Connect the security group to the network interface
resource "azurerm_network_interface_security_group_association" "example" {
  network_interface_id      = azurerm_network_interface.my_terraform_nic.id
  network_security_group_id = azurerm_network_security_group.my_terraform_nsg.id
}

# Generate random text for a unique storage account name
resource "random_id" "random_id" {
  keepers = {
    # Generate a new ID only when a new resource group is defined
    resource_group = azurerm_resource_group.rg.name
  }

  byte_length = 8
}

# Create storage account for boot diagnostics
resource "azurerm_storage_account" "my_storage_account" {
  name                     = "diag${random_id.random_id.hex}"
  location                 = azurerm_resource_group.rg.location
  resource_group_name      = azurerm_resource_group.rg.name
  account_tier             = "Standard"
  account_replication_type = "LRS"
}

# Create virtual machine
resource "azurerm_linux_virtual_machine" "my_terraform_vm" {
  name                  = "vm-1"
  location              = azurerm_resource_group.rg.location
  resource_group_name   = azurerm_resource_group.rg.name
  network_interface_ids = [azurerm_network_interface.my_terraform_nic.id]
  size                  = "Standard_DS1_v2"

  os_disk {
    name                 = "myOsDisk"
    caching              = "ReadWrite"
    storage_account_type = "Premium_LRS"
  }

  source_image_reference {
    publisher = "Canonical"
    offer     = "0001-com-ubuntu-server-jammy"
    sku       = "22_04-lts-gen2"
    version   = "latest"
  }

  computer_name  = "hostname"
  admin_username = var.username

  admin_ssh_key {
    username   = var.username
    public_key = jsondecode(azapi_resource_action.ssh_public_key_gen.output).publicKey
  }

  boot_diagnostics {
    storage_account_uri = azurerm_storage_account.my_storage_account.primary_blob_endpoint
  }
}

# Create SQL server name
resource "random_pet" "azurerm_mssql_server_name" {
  prefix = "sql"
}

# Random password for SQL server
resource "random_password" "admin_password" {
  count       = var.admin_password == null ? 1 : 0
  length      = 20
  special     = true
  min_numeric = 1
  min_upper   = 1
  min_lower   = 1
  min_special = 1
}

locals {
  admin_password = try(random_password.admin_password[0].result, var.admin_password)
}

# Create SQL server
resource "azurerm_mssql_server" "server" {
  name                         = random_pet.azurerm_mssql_server_name.id
  resource_group_name          = azurerm_resource_group.rg.name
  location                     = azurerm_resource_group.rg.location
  administrator_login          = var.admin_username
  administrator_login_password = local.admin_password
  version                      = "12.0"
}

# Create SQL database
resource "azurerm_mssql_database" "db" {
  name      = var.sql_db_name
  server_id = azurerm_mssql_server.server.id
}

# Create private endpoint for SQL server
resource "azurerm_private_endpoint" "my_terraform_endpoint" {
  name                = "private-endpoint-sql"
  location            = azurerm_resource_group.rg.location
  resource_group_name = azurerm_resource_group.rg.name
  subnet_id           = azurerm_subnet.my_terraform_subnet_1.id

  private_service_connection {
    name                           = "private-serviceconnection"
    private_connection_resource_id = azurerm_mssql_server.server.id
    subresource_names              = ["sqlServer"]
    is_manual_connection           = false
  }

  private_dns_zone_group {
    name                 = "dns-zone-group"
    private_dns_zone_ids = [azurerm_private_dns_zone.my_terraform_dns_zone.id]
  }
}

# Create private DNS zone
resource "azurerm_private_dns_zone" "my_terraform_dns_zone" {
  name                = "privatelink.database.windows.net"
  resource_group_name = azurerm_resource_group.rg.name
}

# Create virtual network link
resource "azurerm_private_dns_zone_virtual_network_link" "my_terraform_vnet_link" {
  name                  = "vnet-link"
  resource_group_name   = azurerm_resource_group.rg.name
  private_dns_zone_name = azurerm_private_dns_zone.my_terraform_dns_zone.name
  virtual_network_id    = azurerm_virtual_network.my_terraform_network.id
}