# main.tf — dedicated NAT network + 3 cloud-init'd VMs, each with a thin OS disk
# (backed by the cloud image) and a blank thin Longhorn data disk (Phase 1 T-1.1).
#
# Node lifecycle stage 1 ("Create") per docs/02. cloud-init (infra/cloud-init/)
# does stage 2 ("Baseline"); Ansible (infra/ansible/) does stage 3 ("Cluster-join").

locals {
  # 1 GiB in bytes; libvirt volume sizes are bytes.
  gib = 1073741824

  # Per-node identity/addressing, indexed 0..node_count-1.
  nodes = [
    for i in range(var.node_count) : {
      name     = "${var.node_name_prefix}${i + 1}"
      ip       = var.node_ips[i]
      fqdn     = "${var.node_name_prefix}${i + 1}.${var.node_domain}"
      is_first = i == 0
    }
  ]
}

# --- dedicated NAT network (10.73.0.0/24, gw .1) ---------------------------
# DHCP is OFF: nodes get static IPs from cloud-init network-config, so the
# reserved VIP range (.240-.250) can never be leased to something else.
resource "libvirt_network" "k3s_dev" {
  name      = var.network_name
  mode      = "nat"
  addresses = [var.network_cidr]
  autostart = true

  dhcp {
    enabled = false
  }

  dns {
    enabled    = true
    local_only = true
  }
}

# --- base OS volume (downloaded/copied once, shared as a backing file) ------
resource "libvirt_volume" "base" {
  name   = "${var.cluster_name}-base.qcow2"
  pool   = var.pool_name
  source = var.image_source
  format = "qcow2"
}

# --- per-node OS disk: thin qcow2 backed by the base image ------------------
resource "libvirt_volume" "os" {
  count          = var.node_count
  name           = "${local.nodes[count.index].name}-os.qcow2"
  pool           = var.pool_name
  base_volume_id = libvirt_volume.base.id
  size           = var.os_disk_gib * local.gib
  format         = "qcow2"
}

# --- per-node data disk: blank thin qcow2 for Longhorn ----------------------
resource "libvirt_volume" "data" {
  count  = var.node_count
  name   = "${local.nodes[count.index].name}-data.qcow2"
  pool   = var.pool_name
  size   = var.data_disk_gib * local.gib
  format = "qcow2"
}

# --- cloud-init seed (user-data + meta-data + static network-config) --------
# Templates live in the sibling infra/cloud-init/ subtree (T-1.2).
resource "libvirt_cloudinit_disk" "seed" {
  count = var.node_count
  name  = "${local.nodes[count.index].name}-seed.iso"
  pool  = var.pool_name

  user_data = templatefile("${path.module}/../cloud-init/user-data.yaml.tftpl", {
    hostname           = local.nodes[count.index].name
    fqdn               = local.nodes[count.index].fqdn
    username           = var.login_user
    ssh_authorized_key = var.ssh_authorized_key
  })

  meta_data = templatefile("${path.module}/../cloud-init/meta-data.yaml.tftpl", {
    hostname = local.nodes[count.index].name
    fqdn     = local.nodes[count.index].fqdn
  })

  network_config = templatefile("${path.module}/../cloud-init/network-config.yaml.tftpl", {
    ip      = local.nodes[count.index].ip
    prefix  = var.network_prefix
    gateway = var.network_gateway
  })
}

# --- the VMs ----------------------------------------------------------------
resource "libvirt_domain" "node" {
  count  = var.node_count
  name   = local.nodes[count.index].name
  memory = var.memory_mib
  vcpu   = var.vcpu

  # host-passthrough so nested virt is available for KubeVirt in Phase 5.
  cpu {
    mode = var.cpu_mode
  }

  # qemu-guest-agent is installed by cloud-init; lets tofu read the lease/agent.
  qemu_agent = true

  cloudinit = libvirt_cloudinit_disk.seed[count.index].id

  # IP + hostname come from cloud-init (DHCP is off on this network), so we do NOT
  # set addresses/hostname here — the provider couples those to DHCP reservations.
  network_interface {
    network_id     = libvirt_network.k3s_dev.id
    wait_for_lease = false
  }

  # OS disk first (vda, boot), Longhorn data disk second (vdb).
  disk {
    volume_id = libvirt_volume.os[count.index].id
  }

  disk {
    volume_id = libvirt_volume.data[count.index].id
  }

  console {
    type        = "pty"
    target_port = "0"
    target_type = "serial"
  }

  console {
    type        = "pty"
    target_port = "1"
    target_type = "virtio"
  }

  graphics {
    type        = "spice"
    listen_type = "address"
    autoport    = true
  }
}