############################################################
# Hetzner Talos Kubernetes Cluster - Base Infrastructure
# Using custom Talos image created from ISO
############################################################

############################################################
# PROVIDERS CONFIGURATION
############################################################

provider "hcloud" {
  token = var.hcloud_token
}

############################################################
# DATA SOURCES
############################################################

# Use the custom Talos image created in aula-07
data "hcloud_image" "talos" {
  id = var.talos_image_id
}

############################################################
# RANDOM RESOURCES
############################################################

resource "random_string" "cluster_id" {
  length  = 6
  special = false
  lower   = true
  upper   = false
}

locals {
  cluster_name        = "talos-${random_string.cluster_id.result}"
  control_plane_count = var.enable_ha ? 3 : 1

  # Endpoint: LoadBalancer IP if enabled, otherwise Floating IP
  cluster_endpoint_ip = var.enable_loadbalancer ? hcloud_load_balancer.cluster[0].ipv4 : hcloud_floating_ip.control_plane[0].ip_address

  common_labels = {
    cluster     = local.cluster_name
    environment = var.environment
    managed_by  = "terraform"
  }
}

############################################################
# SSH KEY (for emergency access only)
############################################################

data "hcloud_ssh_keys" "all" {}

locals {
  ssh_key_normalized = trimspace(split(" ", var.ssh_public_key)[0] == "ssh-rsa" ?
    join(" ", slice(split(" ", var.ssh_public_key), 0, 2)) :
    var.ssh_public_key)

  ssh_key_matches = [
    for key in data.hcloud_ssh_keys.all.ssh_keys : key.id
    if key.public_key == local.ssh_key_normalized || key.public_key == var.ssh_public_key
  ]

  ssh_key_id = length(local.ssh_key_matches) > 0 ? local.ssh_key_matches[0] : hcloud_ssh_key.admin[0].id
}

resource "hcloud_ssh_key" "admin" {
  count      = length(local.ssh_key_matches) == 0 ? 1 : 0
  name       = "${local.cluster_name}-admin"
  public_key = var.ssh_public_key
  labels     = local.common_labels
}

############################################################
# NETWORK CONFIGURATION
############################################################

resource "hcloud_network" "cluster" {
  name     = "${local.cluster_name}-network"
  ip_range = "10.0.0.0/16"
  labels   = local.common_labels
}

resource "hcloud_network_subnet" "cluster" {
  type         = "cloud"
  network_id   = hcloud_network.cluster.id
  network_zone = "eu-central"
  ip_range     = "10.0.1.0/24"
}

############################################################
# FIREWALL CONFIGURATION
############################################################

resource "hcloud_firewall" "cluster" {
  name   = "${local.cluster_name}-firewall"
  labels = local.common_labels

  # Talos API access
  rule {
    direction = "in"
    protocol  = "tcp"
    port      = "50000"
    source_ips = ["0.0.0.0/0", "::/0"]
  }

  # Kubernetes API
  rule {
    direction = "in"
    protocol  = "tcp"
    port      = "6443"
    source_ips = ["0.0.0.0/0", "::/0"]
  }

  # Allow HTTP/HTTPS for Ingress
  rule {
    direction = "in"
    protocol  = "tcp"
    port      = "80"
    source_ips = ["0.0.0.0/0", "::/0"]
  }

  rule {
    direction = "in"
    protocol  = "tcp"
    port      = "443"
    source_ips = ["0.0.0.0/0", "::/0"]
  }

  # Allow NodePort range (for services)
  rule {
    direction = "in"
    protocol  = "tcp"
    port      = "30000-32767"
    source_ips = ["0.0.0.0/0", "::/0"]
  }

  # Allow VXLAN for Flannel CNI (private network only - secure)
  rule {
    direction  = "in"
    protocol   = "udp"
    port       = "4789"
    source_ips = ["10.0.0.0/8"]
  }

  # Allow all TCP traffic between cluster nodes (private network)
  rule {
    direction  = "in"
    protocol   = "tcp"
    port       = "any"
    source_ips = ["10.0.0.0/8"]
  }

  # Allow all UDP traffic between cluster nodes (private network)
  rule {
    direction  = "in"
    protocol   = "udp"
    port       = "any"
    source_ips = ["10.0.0.0/8"]
  }

  # Allow all outbound traffic
  rule {
    direction  = "out"
    protocol   = "tcp"
    port       = "any"
    destination_ips = ["0.0.0.0/0", "::/0"]
  }

  rule {
    direction  = "out"
    protocol   = "udp"
    port       = "any"
    destination_ips = ["0.0.0.0/0", "::/0"]
  }

  rule {
    direction  = "out"
    protocol   = "icmp"
    destination_ips = ["0.0.0.0/0", "::/0"]
  }
}

############################################################
# PLACEMENT GROUP (keep nodes close for low latency)
############################################################

resource "hcloud_placement_group" "cluster" {
  name   = "${local.cluster_name}-pg"
  type   = "spread"
  labels = local.common_labels
}

############################################################
# CONTROL PLANE NODES (HA with 3 CAX11 nodes)
############################################################

resource "hcloud_server" "control_plane" {
  count       = local.control_plane_count
  name        = "${local.cluster_name}-cp-${count.index}"
  server_type = "cax11"
  image       = data.hcloud_image.talos.id
  location    = "nbg1"  # CAX11 only available in Nuremberg
  ssh_keys    = [local.ssh_key_id]

  firewall_ids       = [hcloud_firewall.cluster.id]
  placement_group_id = hcloud_placement_group.cluster.id

  labels = merge(local.common_labels, {
    role = "control-plane"
    node = "cp-${count.index}"
    arch = "arm64"
  })

  public_net {
    ipv4_enabled = true
    ipv6_enabled = true
  }

  lifecycle {
    ignore_changes = [ssh_keys]
  }
}

resource "hcloud_server_network" "control_plane" {
  count      = local.control_plane_count
  server_id  = hcloud_server.control_plane[count.index].id
  network_id = hcloud_network.cluster.id
  ip         = "10.0.1.${10 + count.index}"
}

# Floating IP for stable control plane access (only if LoadBalancer is disabled)
resource "hcloud_floating_ip" "control_plane" {
  count         = var.enable_loadbalancer ? 0 : 1
  type          = "ipv4"
  name          = "${local.cluster_name}-cp-ip"
  home_location = "nbg1"
  labels        = local.common_labels
}

resource "hcloud_floating_ip_assignment" "control_plane" {
  count          = var.enable_loadbalancer ? 0 : 1
  floating_ip_id = hcloud_floating_ip.control_plane[0].id
  server_id      = hcloud_server.control_plane[0].id
}

############################################################
# LOAD BALANCER (for HA access to control plane and ingress)
############################################################

resource "hcloud_load_balancer" "cluster" {
  count              = var.enable_loadbalancer ? 1 : 0
  name               = "${local.cluster_name}-lb"
  load_balancer_type = "lb11"
  location           = "nbg1"
  labels             = local.common_labels
}

resource "hcloud_load_balancer_network" "cluster" {
  count            = var.enable_loadbalancer ? 1 : 0
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  network_id       = hcloud_network.cluster.id
  ip               = "10.0.1.2"

  depends_on = [hcloud_network_subnet.cluster]
}

# Kubernetes API (6443) -> Control Planes
resource "hcloud_load_balancer_service" "kubernetes_api" {
  count            = var.enable_loadbalancer ? 1 : 0
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  protocol         = "tcp"
  listen_port      = 6443
  destination_port = 6443

  health_check {
    protocol = "tcp"
    port     = 6443
    interval = 10
    timeout  = 5
    retries  = 3
  }
}

# Talos API (50000) -> Control Planes
resource "hcloud_load_balancer_service" "talos_api" {
  count            = var.enable_loadbalancer ? 1 : 0
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  protocol         = "tcp"
  listen_port      = 50000
  destination_port = 50000

  health_check {
    protocol = "tcp"
    port     = 50000
    interval = 10
    timeout  = 5
    retries  = 3
  }
}

# HTTP (80) -> Workers (NGINX Ingress)
resource "hcloud_load_balancer_service" "http" {
  count            = var.enable_loadbalancer ? 1 : 0
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  protocol         = "tcp"
  listen_port      = 80
  destination_port = 80

  health_check {
    protocol = "tcp"
    port     = 80
    interval = 10
    timeout  = 5
    retries  = 3
  }
}

# HTTPS (443) -> Workers (NGINX Ingress)
resource "hcloud_load_balancer_service" "https" {
  count            = var.enable_loadbalancer ? 1 : 0
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  protocol         = "tcp"
  listen_port      = 443
  destination_port = 443

  health_check {
    protocol = "tcp"
    port     = 443
    interval = 10
    timeout  = 5
    retries  = 3
  }
}

# SSH (22) -> Workers (Gitea SSH)
resource "hcloud_load_balancer_service" "ssh" {
  count            = var.enable_loadbalancer ? 1 : 0
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  protocol         = "tcp"
  listen_port      = 22
  destination_port = 22

  health_check {
    protocol = "tcp"
    port     = 22
    interval = 10
    timeout  = 5
    retries  = 3
  }
}

# LB Targets: Control Planes (for 6443 and 50000)
resource "hcloud_load_balancer_target" "control_plane" {
  count            = var.enable_loadbalancer ? local.control_plane_count : 0
  type             = "server"
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  server_id        = hcloud_server.control_plane[count.index].id
  use_private_ip   = true

  depends_on = [hcloud_load_balancer_network.cluster]
}

# LB Targets: Workers (for 80, 443, and 22)
resource "hcloud_load_balancer_target" "worker" {
  count            = var.enable_loadbalancer ? 1 : 0
  type             = "server"
  load_balancer_id = hcloud_load_balancer.cluster[0].id
  server_id        = hcloud_server.worker[count.index].id
  use_private_ip   = true

  depends_on = [hcloud_load_balancer_network.cluster]
}

############################################################
# WORKER NODE (Single CAX11)
############################################################

resource "hcloud_server" "worker" {
  count       = 1
  name        = "${local.cluster_name}-worker-${count.index}"
  server_type = "cax11"
  image       = data.hcloud_image.talos.id
  location    = "nbg1"
  ssh_keys    = [local.ssh_key_id]

  firewall_ids       = [hcloud_firewall.cluster.id]
  placement_group_id = hcloud_placement_group.cluster.id

  labels = merge(local.common_labels, {
    role = "worker"
    node = "worker-${count.index}"
    arch = "arm64"
  })

  public_net {
    ipv4_enabled = true
    ipv6_enabled = true
  }

  lifecycle {
    ignore_changes = [ssh_keys]
  }
}

resource "hcloud_server_network" "worker" {
  count      = 1
  server_id  = hcloud_server.worker[count.index].id
  network_id = hcloud_network.cluster.id
  ip         = "10.0.1.${20 + count.index}"
}

############################################################
# TALOS CONFIGURATION
############################################################

# Generate Talos machine secrets
resource "talos_machine_secrets" "this" {
  talos_version = var.talos_version
}

# Generate Talos client configuration
data "talos_client_configuration" "this" {
  cluster_name         = local.cluster_name
  client_configuration = talos_machine_secrets.this.client_configuration
  endpoints            = [local.cluster_endpoint_ip]
}

# Control plane configuration
data "talos_machine_configuration" "control_plane" {
  count            = local.control_plane_count
  cluster_name     = local.cluster_name
  machine_type     = "controlplane"
  cluster_endpoint = "https://${local.cluster_endpoint_ip}:6443"
  machine_secrets  = talos_machine_secrets.this.machine_secrets
  talos_version    = var.talos_version

  config_patches = [
    templatefile("${path.module}/talos-patches/control-plane.yaml", {
      cluster_name = local.cluster_name
      node_name    = hcloud_server.control_plane[count.index].name
      is_ha        = var.enable_ha
      is_first_cp  = count.index == 0
      etcd_peers   = [for i in range(local.control_plane_count) : "10.0.1.${10 + i}"]
      floating_ip  = local.cluster_endpoint_ip
    })
  ]

  depends_on = [
    hcloud_server.control_plane,
    hcloud_load_balancer.cluster,
    hcloud_floating_ip_assignment.control_plane
  ]
}

# Worker configuration
data "talos_machine_configuration" "worker" {
  count            = 1
  cluster_name     = local.cluster_name
  machine_type     = "worker"
  cluster_endpoint = "https://${local.cluster_endpoint_ip}:6443"
  machine_secrets  = talos_machine_secrets.this.machine_secrets
  talos_version    = var.talos_version

  config_patches = [
    templatefile("${path.module}/talos-patches/worker.yaml", {
      cluster_name = local.cluster_name
      node_name    = hcloud_server.worker[count.index].name
    })
  ]

  depends_on = [
    hcloud_server.worker,
    hcloud_load_balancer.cluster,
    hcloud_floating_ip_assignment.control_plane
  ]
}

############################################################
# APPLY TALOS CONFIGURATION
############################################################

resource "talos_machine_configuration_apply" "control_plane" {
  count                       = local.control_plane_count
  client_configuration        = talos_machine_secrets.this.client_configuration
  machine_configuration_input = data.talos_machine_configuration.control_plane[count.index].machine_configuration
  endpoint                    = hcloud_server.control_plane[count.index].ipv4_address
  node                        = hcloud_server.control_plane[count.index].ipv4_address

  depends_on = [
    hcloud_server_network.control_plane,
    data.talos_machine_configuration.control_plane
  ]
}

resource "talos_machine_configuration_apply" "worker" {
  count                       = 1
  client_configuration        = talos_machine_secrets.this.client_configuration
  machine_configuration_input = data.talos_machine_configuration.worker[count.index].machine_configuration
  endpoint                    = hcloud_server.worker[count.index].ipv4_address
  node                        = hcloud_server.worker[count.index].ipv4_address

  depends_on = [
    hcloud_server_network.worker,
    data.talos_machine_configuration.worker,
    talos_machine_configuration_apply.control_plane
  ]
}

############################################################
# BOOTSTRAP KUBERNETES
############################################################

resource "talos_machine_bootstrap" "this" {
  client_configuration = talos_machine_secrets.this.client_configuration
  node                 = hcloud_server.control_plane[0].ipv4_address

  depends_on = [
    talos_machine_configuration_apply.control_plane,
    talos_machine_configuration_apply.worker
  ]
}

############################################################
# GET KUBECONFIG
############################################################

resource "talos_cluster_kubeconfig" "this" {
  client_configuration = talos_machine_secrets.this.client_configuration
  node                 = hcloud_server.control_plane[0].ipv4_address

  depends_on = [talos_machine_bootstrap.this]
}

############################################################
# SAVE CONFIGURATIONS
############################################################

resource "local_sensitive_file" "kubeconfig" {
  # Replace the internal hostname with the LB/Floating IP for external access
  content = replace(
    talos_cluster_kubeconfig.this.kubeconfig_raw,
    "https://${local.cluster_name}.local:6443",
    "https://${local.cluster_endpoint_ip}:6443"
  )
  filename = "${path.root}/kubeconfig"
}

resource "local_sensitive_file" "talosconfig" {
  content  = data.talos_client_configuration.this.talos_config
  filename = "${path.root}/talosconfig"
}