---
- name: Check unallocated disk space
  hosts: all
  become: true
  gather_facts: false

  tasks:

    - name: Get block device sizes
      command: lsblk -b -o NAME,SIZE,TYPE -dn
      register: lsblk_output

    - name: Parse lsblk output into structured facts
      set_fact:
        disks: "{{ disks | default({}) | combine({ item.split()[0]: item.split()[1]|int }) }}"
      loop: "{{ lsblk_output.stdout_lines }}"
      when: "'disk' in item"

    - name: Get partition sizes for each disk
      command: lsblk -b -o NAME,SIZE,TYPE -n
      register: partition_output

    - name: Initialize disk usage map
      set_fact:
        used_space: "{{ used_space | default({}) }}"

    - name: Sum partition sizes under each disk
      set_fact:
        used_space: >-
          {{
            used_space | combine({
              (item.0): (used_space[item.0]|default(0)) + (item.1.split()[1]|int)
            })
          }}
      with_nested:
        - "{{ disks.keys() | list }}"
        - "{{ partition_output.stdout_lines }}"
      when: item.1.startswith(item.0) and 'part' in item.1

    - name: Show disk usage summary
      debug:
        msg: >-
          Disk /dev/{{ item.key }}: Total {{ item.value|int // 1024**3 }} GB,
          Used {{ used_space[item.key]|default(0)|int // 1024**3 }} GB,
          Unallocated {{ (item.value|int - used_space[item.key]|default(0)|int) // 1024**3 }} GB
      loop: "{{ disks|dict2items }}"