---
- name: Apply Netplan configuration with automatic rollback on error
  block:
    - name: Deploy disable cloud-init message
      ansible.builtin.copy:
        dest: /etc/cloud/cloud-init.disabled
        src: cloud-init.disabled
        owner: root
        group: root
        mode: '0644'

    - name: Disable old netplan configuration files
      ansible.builtin.command:
        cmd: "mv {{ item }} {{ item }}.disabled"
        removes: "{{ item }}" # ファイルがない場合にエラーを発生させない
      loop:
        - /etc/netplan/00-installer-config.yaml
        - /etc/netplan/50-cloud-init.yaml

    - name: Fetch netplan configuration files
      ansible.builtin.fetch:
        src: /etc/netplan/10-ansible-netplan.yaml
        dest: "{{ fetch_dir }}/{{ inventory_hostname }}_10-ansible-netplan.yaml"
        flat: true
      ignore_errors: true

    - name: Deploy netplan configuration files
      ansible.builtin.copy:
        src: "{{ inventory_hostname }}/10-ansible-netplan.yaml"
        dest: /etc/netplan/10-ansible-netplan.yaml
        owner: root
        group: root
        mode: '0600'
      register: deploy_result

    - name: Validate netplan configuration syntax
      ansible.builtin.command: netplan generate
      when: deploy_result.changed
      changed_when: false

    - name: Confirm and permanently apply Netplan configuration
      ansible.builtin.command: netplan apply # tryしても即座に確定するためテストは不可能
      async: 3 # 通信ができなくなると処理が停止するため非同期で実行
      poll: 0
      when: deploy_result.changed

    - name: Verify SSH connectivity after configuration change
      ansible.builtin.wait_for:
        host: "{{ ansible_host }}"
        port: "{{ ansible_port | default(22) }}"
        state: started
        delay: 2
        timeout: 5
      delegate_to: localhost
      register: do_verify
      when: deploy_result.changed

  # 何らかの異常が発生した場合への対応
  rescue:
    - name: "[RESCUE] Re-enable disabled old Netplan files"
      ansible.builtin.copy:
        dest: /etc/netplan/10-ansible-netplan.yaml
        src: "{{ fetch_dir }}/{{ inventory_hostname }}_10-ansible-netplan.yaml"
        mode: '0600'
      when:
        - do_verify is undefined
        - deploy_result is defined
        - deploy_result.changed

    - name: "[RESCUE] Fail playbook execution with error notification"
      ansible.builtin.fail:
        msg: >-
          {{
            'SSH connection lost after netplan apply. Remote rollback is unavailable.'
            if do_verify is defined
            else 'Netplan configuration failed before apply and was safely rolled back.'
          }}