name: CI

on:
  pull_request:
  push:
    branches: [main]

permissions:
  contents: read

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - name: Shellcheck
        run: bash .github/scripts/shellcheck-all.sh
      - name: Install actionlint
        env:
          ACTIONLINT_VERSION: 1.7.12
        run: |
          curl -fsSLo actionlint.tar.gz \
            "https://github.com/rhysd/actionlint/releases/download/v${ACTIONLINT_VERSION}/actionlint_${ACTIONLINT_VERSION}_linux_amd64.tar.gz"
          tar -xzf actionlint.tar.gz actionlint
          sudo install actionlint /usr/local/bin/actionlint
      - name: Actionlint
        run: bash .github/scripts/actionlint-all.sh
      - name: Self-ref pin
        # The pin rules (issue #9; #1 D3): a stale CEREMONY_SELF_REF fails
        # CI here, not a consumer's release.
        run: bash .github/scripts/self-ref-check.sh
      - name: Tests
        env:
          # The npm-backed version_write case may skip locally when npm is
          # absent; in CI a skip must be a failure, or the case could
          # quietly stop running (issue #3's test contract).
          CEREMONY_REQUIRE_NPM: 1
        run: bash test/run.sh

  # The release exercise (issue #9's scratch caller) on every PR, so the
  # parse proof and the merge door's step-replay are standing, reviewable
  # evidence — not a dispatch someone must remember to run. PR-ONLY, and
  # the gate is load-bearing: this CI also runs on push to main, and a
  # workflow_call from THAT context would hand release.yml a genuine
  # push+refs/heads/main event — the merge door's exact gate — opening a
  # live door from CI. A pull_request event can never satisfy either
  # door's `if:`.
  release-exercise:
    if: github.event_name == 'pull_request'
    uses: ./.github/workflows/release-exercise.yml

  # The self-guards (issue #11): this repo eats exactly what it serves. The
  # three guard actions run against the REAL tree — VERSION, CHANGELOG.md,
  # drills/ — through the same `uses:` steps every consumer's CI carries.
  # These steps are also the composite-action wiring proof (issue #5's
  # acceptance criterion: action.yml resolving, $GITHUB_ACTION_PATH, the
  # relative lib sourcing) that action-exercise carried with scratch files
  # while this repo had no tree of its own to guard; the armed and
  # drill-recorded scratch steps moved here per the armed step's own
  # eviction note — the file backend hardcodes the VERSION name, so a
  # scratch write would SHADOW the real file, not sit beside it.
  self-guards:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          # The monotonic guard compares HEAD against the merge base; a
          # shallow checkout cannot resolve it, and in CI that is a hard
          # failure, not a skip (the action's description).
          fetch-depth: 0
      - uses: ./actions/changelog-armed
      - uses: ./actions/changelog-monotonic
      - uses: ./actions/drill-recorded

  # Exercises changelog-monotonic the way a consumer does, against a
  # CONSTRUCTED history. The self-guards job above runs the same action on
  # the real tree, but there its containment half is only as interesting as
  # the PR's own diff; this job commits a known base and an insert-above
  # edit on top, so a real, non-vacuous containment run is standing
  # evidence on every PR. (Armed and drill-recorded moved to self-guards —
  # the real tree now exercises them; monotonic stays because it reads no
  # version source, so it is immune to the VERSION-shadowing problem that
  # evicted the other two.)
  action-exercise:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Construct a scratch history for the monotonic guard
        # The monotonic guard's input is a DIFF, so its exercise needs
        # history, not just a file: commit a scratch changelog, mark that
        # commit as the fixture base, then commit an insert-above edit on
        # top — a real containment run, not just an action.yml parse. The
        # base ref is the in-job branch, passed explicitly, because this
        # job's shallow PR checkout carries no origin/main for the input's
        # default to resolve (consumers get that via fetch-depth: 0, per
        # the action's description). Scratch-named file so the real
        # CHANGELOG.md is never shadowed; the commits live only in this
        # job's checkout and are never pushed.
        run: |
          git config user.name ceremony-ci
          git config user.email ceremony-ci@users.noreply.github.com
          printf '# Changelog\n\n## Unreleased\n\n## 0.1.0 — 2026-07-01\n\n- Shipped entry.\n' > CHANGELOG.monotonic.scratch.md
          git add CHANGELOG.monotonic.scratch.md
          git commit -m 'fixture: monotonic base'
          git branch monotonic-fixture-base
          printf '# Changelog\n\n## Unreleased\n\n- Entry inserted above.\n\n## 0.1.0 — 2026-07-01\n\n- Shipped entry.\n' > CHANGELOG.monotonic.scratch.md
          git commit -am 'fixture: insert above'
      - uses: ./actions/changelog-monotonic
        with:
          changelog: CHANGELOG.monotonic.scratch.md
          base-ref: monotonic-fixture-base