---
# =============================================================================
# Node topology — soft affinity for workload placement (label-based, no taints)
# =============================================================================
# Active only in custom_inventory mode (multi-node). In localhost mode this
# is a no-op.
#
# Effect (SOFT AFFINITY - no hard enforcement):
#   - Control-plane nodes get label: workload-class=platform
#   - Worker nodes get label: workload-class=inference
#
# How pods are placed (via preferredDuringSchedulingIgnoredDuringExecution):
#   - Platform pods (Keycloak, PostgreSQL, Envoy, cert-manager):
#       Prefer workload-class=platform → land on control-plane
#   - Inference pods (vLLM, model serving):
#       Prefer workload-class=inference → land on workers
#
# Benefits:
#   - Resource isolation (platform vs inference workloads)
#   - NUMA optimization (workers dedicated to model serving)
#   - Control plane stability (masters not overloaded)
#   - Soft preferences allow flexibility (no hard failures)
#
# Idempotent: re-runs are safe; kubernetes.core.k8s overwrites in place.
# =============================================================================

- name: "node-topology | Skip — single-node"
  ansible.builtin.debug:
    msg: "Single-node inventory — node topology not applied."
  when: not (_k8s_needs_ssh | bool)

- name: "node-topology | Apply (multi-node)"
  when: _k8s_needs_ssh | bool
  block:

    - name: "node-topology | Discover worker nodes"
      kubernetes.core.k8s_info:
        api_version: v1
        kind: Node
      register: _topo_nodes

    # Build control-plane and worker node lists
    - name: "node-topology | Build control-plane list"
      vars:
        _cp_query: '[?type(metadata.labels."node-role.kubernetes.io/control-plane") != ''null''].metadata.name'
      ansible.builtin.set_fact:
        _topo_masters: "{{ _topo_nodes.resources | json_query(_cp_query) }}"

    - name: "node-topology | Build worker list"
      vars:
        _worker_query: '[?type(metadata.labels."node-role.kubernetes.io/control-plane") == ''null''].metadata.name'
      ansible.builtin.set_fact:
        _topo_workers: "{{ _topo_nodes.resources | json_query(_worker_query) }}"

    - name: "node-topology | Detected topology"
      ansible.builtin.debug:
        msg:
          - "Control-plane nodes ({{ _topo_masters | length }}): {{ _topo_masters | join(', ') }}"
          - "Worker nodes ({{ _topo_workers | length }}): {{ _topo_workers | join(', ') }}"

    - name: "node-topology | Skip — no workers found"
      ansible.builtin.debug:
        msg: "No worker nodes found (only control-plane present) — soft affinity disabled."
      when: _topo_workers | length == 0

    # Label control-plane nodes for platform workloads
    - name: "node-topology | Label control-plane nodes (workload-class=platform)"
      kubernetes.core.k8s:
        state: patched
        kind: Node
        name: "{{ item }}"
        definition:
          metadata:
            labels:
              workload-class: platform
      loop: "{{ _topo_masters }}"
      loop_control:
        label: "{{ item }}"
      when: _topo_masters | length > 0

    # Label worker nodes for inference workloads
    - name: "node-topology | Label worker nodes (workload-class=inference)"
      kubernetes.core.k8s:
        state: patched
        kind: Node
        name: "{{ item }}"
        definition:
          metadata:
            labels:
              workload-class: inference
      loop: "{{ _topo_workers }}"
      loop_control:
        label: "{{ item }}"
      when: _topo_workers | length > 0

    - name: "node-topology | Done (soft affinity enabled)"
      ansible.builtin.debug:
        msg:
          - "Node topology applied (soft affinity, no taints):"
          - "  Control-plane ({{ _topo_masters | length }}): label workload-class=platform"
          - "  Workers ({{ _topo_workers | length }}): label workload-class=inference"
          - ""
          - "Platform pods will prefer control-plane nodes."
          - "Inference pods will prefer worker nodes."
          - "Scheduler may override if resources are constrained."
      when: _topo_workers | length > 0