name: Release

# Runs after a successful Deploy. When the top of CHANGELOG.md names a version
# that has no tag yet, this tags it, publishes a GitHub Release with the notes,
# and — for minor/major bumps only — invokes the release-notifier Lambda to
# announce it in Slack. Triggering on Deploy completion (not release:published /
# tag push) is deliberate: GITHUB_TOKEN-created events do not start downstream
# workflows, and gating on Deploy success means we never announce a version that
# is not actually live.
on:
  workflow_run:
    workflows: ["Deploy"]
    types: [completed]

permissions:
  contents: write # create the tag + GitHub Release
  id-token: write # OIDC to assume the notifier-invoke role

# Serialize so back-to-back releases announce in order (queued Deploys -> queued
# Releases), never overlapping.
concurrency:
  group: release-announce
  cancel-in-progress: false

jobs:
  release:
    if: ${{ github.event.workflow_run.conclusion == 'success' }}
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
        with:
          # The exact commit Deploy deployed — NOT the branch HEAD, which a later
          # merge may have already moved past.
          ref: ${{ github.event.workflow_run.head_sha }}
          fetch-depth: 0
          fetch-tags: true

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

      - name: Determine release
        id: rel
        run: |
          TOP=$(python scripts/changelog_cli.py top-version CHANGELOG.md)
          if [ -z "$TOP" ]; then
            echo "No version entry in CHANGELOG.md — nothing to release."
            echo "release=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          PREV=$(git tag -l 'v*' --sort=-v:refname | head -1)
          PREV="${PREV:-v0.0.0}"
          KIND=$(python scripts/changelog_cli.py bump-kind CHANGELOG.md "$PREV")

          TAG_EXISTS=false
          git rev-parse "v$TOP" >/dev/null 2>&1 && TAG_EXISTS=true
          RELEASE_EXISTS=false
          gh release view "v$TOP" >/dev/null 2>&1 && RELEASE_EXISTS=true

          echo "version=$TOP"        >> "$GITHUB_OUTPUT"
          echo "kind=$KIND"          >> "$GITHUB_OUTPUT"
          echo "tag_exists=$TAG_EXISTS"        >> "$GITHUB_OUTPUT"
          echo "release_exists=$RELEASE_EXISTS" >> "$GITHUB_OUTPUT"
          # "release" gates the rest: a clean bump whose Release isn't published yet.
          if [ "$KIND" != "none" ] && [ "$RELEASE_EXISTS" = "false" ]; then
            echo "release=true" >> "$GITHUB_OUTPUT"
          else
            echo "release=false" >> "$GITHUB_OUTPUT"
            echo "v$TOP: kind=$KIND release_exists=$RELEASE_EXISTS — no action."
          fi
        env:
          GH_TOKEN: ${{ github.token }}

      # Each artifact is created independently and idempotently so a re-run after
      # a mid-job failure can finish the release rather than skip it forever.
      - name: Create tag
        if: ${{ steps.rel.outputs.release == 'true' && steps.rel.outputs.tag_exists == 'false' }}
        run: |
          V="v${{ steps.rel.outputs.version }}"
          git tag -a "$V" -m "$V"
          git push origin "$V"

      - name: Build payload
        if: ${{ steps.rel.outputs.release == 'true' }}
        run: |
          python scripts/changelog_cli.py payload CHANGELOG.md "${{ steps.rel.outputs.version }}" > payload.json
          python -c "import json; print(json.load(open('payload.json'))['notes'])" > notes.md

      # Announce BEFORE publishing the Release: the Release is the durable "done"
      # marker, so announcing first keeps the step retryable. Minor/major only,
      # and only once the invoke-role variable has been bootstrapped (see README).
      - name: Configure AWS credentials
        if: ${{ steps.rel.outputs.release == 'true' && steps.rel.outputs.kind != 'patch' && vars.RELEASE_NOTIFY_INVOKE_ROLE_ARN != '' }}
        uses: aws-actions/configure-aws-credentials@v6
        with:
          role-to-assume: ${{ vars.RELEASE_NOTIFY_INVOKE_ROLE_ARN }}
          aws-region: us-east-1

      - name: Announce in Slack
        if: ${{ steps.rel.outputs.release == 'true' && steps.rel.outputs.kind != 'patch' && vars.RELEASE_NOTIFY_INVOKE_ROLE_ARN != '' }}
        run: |
          aws lambda invoke \
            --function-name afterhours-release-notifier \
            --cli-binary-format raw-in-base64-out \
            --payload file://payload.json \
            --output json response.json > invoke-meta.json
          # aws lambda invoke only emits a FunctionError key when the handler errored.
          if grep -q '"FunctionError"' invoke-meta.json; then
            echo "::error::release-notifier returned an error"; cat response.json; exit 1
          fi
          echo "Announced v${{ steps.rel.outputs.version }}."

      - name: Warn if announcement skipped (not bootstrapped)
        if: ${{ steps.rel.outputs.release == 'true' && steps.rel.outputs.kind != 'patch' && vars.RELEASE_NOTIFY_INVOKE_ROLE_ARN == '' }}
        run: echo "::warning::RELEASE_NOTIFY_INVOKE_ROLE_ARN is unset — tagged + released but did not announce. Set the repo variable from the stack output."

      - name: Publish GitHub Release
        if: ${{ steps.rel.outputs.release == 'true' }}
        run: |
          gh release create "v${{ steps.rel.outputs.version }}" \
            --title "v${{ steps.rel.outputs.version }}" \
            --notes-file notes.md \
            --target "${{ github.event.workflow_run.head_sha }}"
        env:
          GH_TOKEN: ${{ github.token }}