---
# Deploys, on Gitea. One way in, and only one:
#
#   - a human fills in the form under Actions > deploy > Run workflow, or the
#     same form is filled in over the API by another repository's job
#
# Nothing deploys on a push. That is the single most important property of this
# file: a merge to the default branch changes what *would* be deployed, and a
# person still decides when.
#
# Gitea has no `repository_dispatch`, so the two entry points GitHub gets collapse
# into one: the workflow dispatch API posts to *this* form.
#
#   POST /api/v1/repos/<owner>/<repo>/actions/workflows/deploy.yml/dispatches
#
# That is better than it sounds — the response can carry the run id, so a caller
# can follow the deploy it asked for, which `repository_dispatch` never allowed.
# See docs/triggering-deploys.md.
#
# The `options:` list has to be kept in step with ansible/playbooks/ by hand; a
# choice input cannot be populated dynamically on any platform. It is step 4 of
# skills/adding-a-stack/SKILL.md. Setup: docs/ci-gitea.md.
name: deploy

on:
  workflow_dispatch:
    inputs:
      stack:
        description: Which stack to act on
        required: true
        type: choice
        options:
          - site
          - reverse-proxy
          - banner
          - metrics
          - static-site
          - webapp
          - webapp-staging
      mode:
        description: check reports what would change; deploy does it
        required: true
        default: check
        type: choice
        options:
          - check
          - deploy
      pull:
        description: >-
          Image pull policy. always fetches newer images and enables per-stack
          update work (backups, migrations).
        required: true
        default: policy
        type: choice
        options:
          - policy
          - always
          - missing
          - never

# Two deploys of the same stack at once would race on the host. Concurrency
# syntax landed in Gitea 1.26; before that this block is ignored, and the only
# thing standing between you and a race is that both runs are started by hand.
concurrency:
  group: deploy-${{ github.event.inputs.stack }}
  cancel-in-progress: false

jobs:
  ansible:
    name: ${{ github.event.inputs.mode || 'check' }} ${{ github.event.inputs.stack }}
    # Change this label if the runner that picks up `ubuntu-latest` cannot reach
    # your hosts, and register a second runner carrying whatever you put here.
    # It has to be a literal: Gitea supports `runs-on: xyz` and `runs-on: [xyz]`
    # only, so GitHub's `${{ vars.DEPLOY_RUNNER || 'ubuntu-latest' }}` trick has
    # no equivalent. Do not name a label no runner carries — the job then queues
    # forever rather than failing.
    runs-on: ubuntu-latest
    # No `environment:` here. Gitea parses and ignores it, so writing one would
    # claim a protection that does not exist: there are no required reviewers and
    # no environment-scoped secrets. SSH_PRIVATE_KEY_B64 is an ordinary
    # repository (or organisation) secret, and what actually gates a deploy is
    # that dispatching a workflow needs write access to this repository. See
    # "What replaces environments" in docs/ci-gitea.md.
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-python@v5
        with:
          python-version: "3.12"

      # STACK, MODE and PULL reach a shell command, and over the dispatch API they
      # arrive from another repository. They go through the environment, never
      # through ${{ }} interpolation into a run: block — an expression is
      # substituted into the script *before* the shell sees it, so a crafted value
      # would be executed rather than compared. Validate, then use.
      #
      # `type: choice` is a UI constraint, not an API one. Do not read the
      # dropdown above as validation.
      - name: Validate the requested stack and pull policy
        env:
          # The `|| default` halves are not decoration. An input's declared
          # `default:` is applied by the dispatch *form*; a caller posting to the
          # API can leave the key out altogether, and a missing `mode` would then
          # be refused below rather than falling back to the safe value. `stack`
          # has no default on purpose — there is no safe guess for it.
          STACK: ${{ github.event.inputs.stack }}
          MODE: ${{ github.event.inputs.mode || 'check' }}
          PULL: ${{ github.event.inputs.pull || 'policy' }}
        run: |
          set -eu
          case "$STACK" in
            ''|*[!a-z0-9_-]*) echo "refusing STACK='$STACK'"; exit 1 ;;
          esac
          case "$MODE" in
            check|deploy) ;;
            *) echo "refusing MODE='$MODE'"; exit 1 ;;
          esac
          # An unchecked value can smuggle extra `-e` overrides onto the command
          # line (stack_dest, ansible_host) and redirect the deploy somewhere else
          # entirely.
          case "$PULL" in
            policy|always|missing|never) ;;
            *) echo "refusing PULL='$PULL'"; exit 1 ;;
          esac
          test -f "ansible/playbooks/${STACK}.yml" \
            || { echo "no playbook for '$STACK'"; exit 1; }
          {
            echo "STACK=$STACK"
            echo "MODE=$MODE"
            echo "PULL=$PULL"
          } >> "$GITHUB_ENV"

      - name: Install the pinned toolchain
        run: |
          set -eu
          scripts/check.sh --print-specs | head -1 | xargs -d '\n' pip install --quiet
          ansible-galaxy install -r ansible/requirements.yml

      # Two lines, not `export SSH_KEY_PATH="$(...)"`. export is a special builtin,
      # so the compound command reports *its* exit status and swallows the
      # script's — under `set -e` a loader failure goes unnoticed and the job dies
      # much later with a per-host "Permission denied (publickey)" instead of the
      # loader's own message saying which variable was missing.
      - name: Load the deploy key
        env:
          SSH_KEY_BACKEND: ci
          SSH_PRIVATE_KEY_B64: ${{ secrets.SSH_PRIVATE_KEY_B64 }}
        run: |
          set -eu
          SSH_KEY_PATH="$(scripts/load-ssh-key.sh)"
          echo "SSH_KEY_PATH=$SSH_KEY_PATH" >> "$GITHUB_ENV"

      - name: Run the playbook
        working-directory: ansible
        env:
          ANSIBLE_FORCE_COLOR: "1"
        run: |
          set -eu
          # An `if`, not `[ ... ] && extra=...`: when the test fails the AND-list
          # returns non-zero, and under `set -e` that ends the job right here with
          # no error message and a green-looking cancel.
          if [ "$MODE" = "check" ]; then
            set -- --check --diff
          else
            set --
          fi
          ansible-playbook "playbooks/${STACK}.yml" "$@" -e "pull=$PULL"