locals {
  server_node   = [for name, n in var.nodes : n if n.role == "server"][0]
  server_ip     = local.server_node.ip
  prefix_length = split("/", var.network_cidr)[1]
}

resource "libvirt_pool" "k3s" {
  name = var.storage_pool
  type = "dir"
  path = var.storage_pool_path
}

resource "libvirt_volume" "base" {
  name   = "k3s-base.qcow2"
  pool   = libvirt_pool.k3s.name
  source = var.base_image_url
  format = "qcow2"
}

# A dedicated, isolated NAT network so this project can't collide with
# anything else already using the host's default libvirt network. DHCP is
# off — every node gets a static IP via cloud-init instead.
resource "libvirt_network" "k3s" {
  name      = "k3s-homelab"
  mode      = "nat"
  domain    = "k3s.local"
  addresses = [var.network_cidr]

  dhcp {
    enabled = false
  }

  dns {
    enabled = true
  }
}

resource "libvirt_volume" "node" {
  for_each       = var.nodes
  name           = "${each.key}.qcow2"
  pool           = libvirt_pool.k3s.name
  base_volume_id = libvirt_volume.base.id
  size           = each.value.disk_gb * 1024 * 1024 * 1024
  format         = "qcow2"
}

resource "libvirt_cloudinit_disk" "node" {
  for_each = var.nodes
  name     = "${each.key}-cloudinit.iso"
  pool     = libvirt_pool.k3s.name

  user_data = templatefile("${path.module}/cloud-init/${each.value.role}.yaml.tpl", {
    hostname         = each.key
    ssh_public_key   = var.ssh_public_key
    k3s_token        = var.k3s_token
    server_ip        = local.server_ip
    k8s_api_hostname = var.k8s_api_hostname
  })

  network_config = templatefile("${path.module}/cloud-init/network-config.yaml.tpl", {
    ip            = each.value.ip
    prefix_length = local.prefix_length
    gateway       = var.gateway_ip
  })
}

resource "libvirt_domain" "node" {
  for_each = var.nodes
  name     = each.key
  vcpu     = each.value.vcpu
  memory   = each.value.memory

  cloudinit = libvirt_cloudinit_disk.node[each.key].id

  network_interface {
    network_id     = libvirt_network.k3s.id
    wait_for_lease = false
  }

  disk {
    volume_id = libvirt_volume.node[each.key].id
  }

  # Serial console only, no display — this box doesn't need a GUI hop for
  # a couple of small demo VMs.
  console {
    type        = "pty"
    target_type = "serial"
    target_port = "0"
  }

  # Terraform brings all VMs up in parallel; the agent cloud-init script
  # (cloud-init/agent.yaml.tpl) retries the join until the server's API is
  # reachable, so node boot order doesn't matter.
}