---
# Pre-checks

- name: Fail if Postgres not enabled
  ansible.builtin.fail:
    msg: "Postgres via the matrix-postgres role is not enabled (`matrix_postgres_enabled`). Cannot use rust-synapse-compress-state."
  when: "not matrix_postgres_enabled | bool"


# Defaults

- name: Set matrix_synapse_rust_synapse_compress_state_find_rooms_command_wait_time, if not provided
  ansible.builtin.set_fact:
    matrix_synapse_rust_synapse_compress_state_find_rooms_command_wait_time: 1800
  when: "matrix_synapse_rust_synapse_compress_state_find_rooms_command_wait_time | default('') == ''"

- name: Set matrix_synapse_rust_synapse_compress_state_compress_room_time, if not provided
  ansible.builtin.set_fact:
    matrix_synapse_rust_synapse_compress_state_compress_room_time: 3600
  when: "matrix_synapse_rust_synapse_compress_state_compress_room_time | default('') == ''"

- name: Set matrix_synapse_rust_synapse_compress_state_psql_import_time, if not provided
  ansible.builtin.set_fact:
    matrix_synapse_rust_synapse_compress_state_psql_import_time: 3600
  when: "matrix_synapse_rust_synapse_compress_state_psql_import_time | default('') == ''"

- name: Set matrix_synapse_rust_synapse_compress_state_min_state_groups_required, if not provided
  ansible.builtin.set_fact:
    # The minimum number of state groups we're looking for before we consider a room eligible for compression.
    # Rooms with a smaller state groups count will not be compressed.
    matrix_synapse_rust_synapse_compress_state_min_state_groups_required: 100000
  when: "matrix_synapse_rust_synapse_compress_state_min_state_groups_required | default('') == ''"


# Actual compression work

- name: Ensure rust-synapse-compress-state paths exist
  ansible.builtin.file:
    path: "{{ matrix_synapse_rust_synapse_compress_state_base_path }}"
    state: directory
    mode: 0750
    owner: "{{ matrix_user_username }}"
    group: "{{ matrix_user_groupname }}"

- name: Ensure rust-synapse-compress-state image is pulled
  community.docker.docker_image:
    name: "{{ matrix_synapse_rust_synapse_compress_state_docker_image }}"
    source: "{{ 'pull' if ansible_version.major > 2 or ansible_version.minor > 7 else omit }}"
    force_source: "{{ matrix_synapse_rust_synapse_compress_state_docker_image_force_pull if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
    force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_synapse_rust_synapse_compress_state_docker_image_force_pull }}"
  register: result
  retries: "{{ devture_playbook_help_container_retries_count }}"
  delay: "{{ devture_playbook_help_container_retries_delay }}"
  until: result is not failed

- name: Generate rust-synapse-compress-state room find command
  ansible.builtin.set_fact:
    matrix_synapse_rust_synapse_compress_state_find_rooms_command: >-
      {{ devture_systemd_docker_base_host_command_docker }} run --rm --name matrix-rust-synapse-compress-state-find-rooms
      --user={{ matrix_user_uid }}:{{ matrix_user_gid }}
      --cap-drop=ALL
      --network={{ matrix_docker_network }}
      --env-file={{ matrix_postgres_base_path }}/env-postgres-psql
      {{ matrix_postgres_docker_image_latest }}
      psql -v ON_ERROR_STOP=1 -h matrix-postgres {{ matrix_synapse_database_database }} -c
      'SELECT array_to_json(array_agg(row_to_json (r))) FROM (SELECT room_id, count(*) AS count FROM state_groups_state GROUP BY room_id HAVING count(*) > {{ matrix_synapse_rust_synapse_compress_state_min_state_groups_required }} ORDER BY count DESC) r;'

- name: Find rooms eligible for compression with rust-synapse-compress-state
  ansible.builtin.command: "{{ matrix_synapse_rust_synapse_compress_state_find_rooms_command }}"
  async: "{{ matrix_synapse_rust_synapse_compress_state_find_rooms_command_wait_time }}"
  poll: 10
  register: matrix_synapse_rust_synapse_compress_state_find_rooms_command_result
  failed_when: not matrix_synapse_rust_synapse_compress_state_find_rooms_command_result.finished
  changed_when: false

# We expect the output to be like this:
#
# "stdout_lines": [
#     "                                                       array_to_json                                                        ",
#     "----------------------------------------------------------------------------------------------------------------------------",
#     " [{\"room_id\":\"!some-id\",\"count\":2461329},{\"room_id\":\"!another-id\",\"count\":512017}]",
#     "(1 row)"
# ]
#
# Row 3 (out of 4) contains the actual result.
#
# Row 3 contains a space when there's no result.

- when: "matrix_synapse_rust_synapse_compress_state_find_rooms_command_result.failed or matrix_synapse_rust_synapse_compress_state_find_rooms_command_result.stdout_lines | length != 4"
  block:
    - ansible.builtin.debug:
        var: "matrix_synapse_rust_synapse_compress_state_find_rooms_command_result"

    - name: Fail if room find result is not what we expect
      ansible.builtin.fail:
        msg: >-
          Expecting 4 lines in the "find rooms" result.

- when: "matrix_synapse_rust_synapse_compress_state_find_rooms_command_result.stdout_lines[2] != ' '"
  block:
    # matrix_synapse_rust_synapse_compress_state_eligible_rooms is a list
    # of dictionaries like this: {'room_id': '!some-id', 'count': 2461329}
    - ansible.builtin.set_fact:
        matrix_synapse_rust_synapse_compress_state_eligible_rooms: "{{ matrix_synapse_rust_synapse_compress_state_find_rooms_command_result.stdout_lines[2] | from_json }}"

    - name: Display rooms that will be compressed
      ansible.builtin.debug:
        msg: >-
          The following rooms contain more than {{ matrix_synapse_rust_synapse_compress_state_min_state_groups_required }} state group rows
          (configurable via `matrix_synapse_rust_synapse_compress_state_min_state_groups_required`)
          and will be compressed:
          {{ matrix_synapse_rust_synapse_compress_state_eligible_rooms }}

    - name: Compress room state
      ansible.builtin.include_tasks: "{{ role_path }}/tasks/rust-synapse-compress-state/compress_room.yml"
      with_items: "{{ matrix_synapse_rust_synapse_compress_state_eligible_rooms }}"
      loop_control:
        loop_var: room_details

- name: Show notice about lack of rooms to compress
  ansible.builtin.debug:
    msg: >-
      No rooms were found to contain more than {{ matrix_synapse_rust_synapse_compress_state_min_state_groups_required }} state group rows
      (configurable via `matrix_synapse_rust_synapse_compress_state_min_state_groups_required`),
      so there's nothing to compress.
  when: "matrix_synapse_rust_synapse_compress_state_find_rooms_command_result.stdout_lines[2] == ' '"
