- name: Define fully qualified domain name.
  set_fact:
    hostname_fqdn: "{{ vagrant_hostname }}"
  when: hostname_fqdn is undefined

- name: Define short hostname.
  set_fact:
    hostname_short: "{{ hostname_fqdn|regex_replace('^([^.]+).*$', '\\1') }}"
  when: hostname_short is undefined

- name: Add hostname to /etc/hosts.
  lineinfile:
    dest: /etc/hosts
    regexp: '.*\t{{ hostname_short }}$'
    line: "127.0.0.1\t{{ hostname_fqdn }}\t{{ hostname_short }}"
    state: present
    unsafe_writes: "{{ (ansible_virtualization_type == 'docker')|ternary('yes', 'no')|bool }}"

- name: Configure hostname.
  copy:
    content: "{{ (ansible_os_family == 'Debian') | ternary(hostname_short, hostname_fqdn) }}\n"
    dest: /etc/hostname
    unsafe_writes: "{{ (ansible_virtualization_type == 'docker')|ternary('yes', 'no')|bool }}"
  register: set_hostname

- name: Set the hostname for current session.
  shell: hostname --file /etc/hostname
  when: set_hostname.changed