name: Track upstream branches

# The unattended lane. Packages marked "auto_merge": true follow a moving
# upstream branch (omarchy-dev and omarchy-settings-dev on quattro, omasnap-git
# on main) rather than tagged releases, so nothing in this repository changes
# when their source does. This workflow makes each new branch tip a commit pin
# in the recipe, which publish.yml then treats like any other version bump:
# the PR builds on the droplets, auto-merge lands it when `result` is green,
# and the merge publishes the artifacts. A tip that fails to build stays an
# unmerged red PR that the next tick supersedes.
#
# The PR and auto-merge use the PAT in PKGS_BOT_TOKEN so they trigger the
# build and publish workflows. The built-in GITHUB_TOKEN cannot drive this
# unattended chain. The PAT needs Contents: write and Pull requests: write
# on this repository, and its owner must be trusted by the build workflow.

on:
  schedule:
    # Every 2 hours, off the hour to dodge the scheduling backlog at :00
    - cron: '35 */2 * * *'
  workflow_dispatch:
    inputs:
      packages:
        description: 'Specific packages to track (space-separated, leave empty for every auto_merge package)'
        required: false
        default: ''

# One tracker at a time: two runs racing on auto/track-branches would each
# force-push their own pin over the other's.
concurrency:
  group: track-branches
  cancel-in-progress: false

jobs:
  track:
    runs-on: ubuntu-latest
    permissions:
      contents: read

    steps:
      - name: Require the tracking token
        env:
          PKGS_BOT_TOKEN: ${{ secrets.PKGS_BOT_TOKEN }}
        run: |
          if [[ -z "$PKGS_BOT_TOKEN" ]]; then
            echo "::error::Set PKGS_BOT_TOKEN to a PAT with Contents: write and Pull requests: write on this repository, owned by an account trusted to trigger builds."
            exit 1
          fi

      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          persist-credentials: false

      # Same container as the reviewed sync: vercmp decides whether a pin is
      # an upgrade with the comparator pacman uses on users' machines.
      - name: Pin tracked branches to their current tips
        id: sync
        run: |
          docker run --rm \
            -e PACKAGES="$PACKAGES" \
            -e UPSTREAM_GITHUB_TOKEN="$UPSTREAM_GITHUB_TOKEN" \
            -e HOST_UID="$(id -u)" \
            -e HOST_GID="$(id -g)" \
            -v "$PWD/bin:/workspace/bin:ro" \
            -v "$PWD/helpers:/workspace/helpers:ro" \
            -v "$PWD/pkgbuilds:/workspace/pkgbuilds" \
            -w /workspace \
            archlinux:base-devel bash -lc '
              set -euo pipefail

              pacman -Syu --noconfirm git jq python libarchive

              groupadd -g "$HOST_GID" runner
              useradd -m -u "$HOST_UID" -g "$HOST_GID" runner
              chown -R runner:runner /workspace/pkgbuilds

              if [[ -n "${PACKAGES:-}" ]]; then
                read -r -a package_args <<< "$PACKAGES"
                runuser -u runner -- ./bin/sync-upstream --lane auto-merge "${package_args[@]}"
              else
                runuser -u runner -- ./bin/sync-upstream --lane auto-merge
              fi
            '
        env:
          PACKAGES: ${{ github.event.inputs.packages }}
          UPSTREAM_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Check for changes
        if: ${{ !cancelled() && steps.sync.outcome != 'skipped' }}
        id: changes
        run: |
          if [ -z "$(git status --porcelain)" ]; then
            echo "has_changes=false" >> "$GITHUB_OUTPUT"
          else
            echo "has_changes=true" >> "$GITHUB_OUTPUT"
            git status --porcelain
            {
              echo "### Pinned"
              git diff --unified=0 -- 'pkgbuilds/*/PKGBUILD' | grep -E '^\+(pkgver|_commit)=' | sed 's/^+/- /'
            } >> "$GITHUB_STEP_SUMMARY"
          fi

      # The PR title names what moved, so the merged history reads like a
      # changelog: "Track upstream branches: omarchy-dev 4.0.0.r6520.g1a2b3c4, ...".
      - name: Describe the pins
        if: ${{ !cancelled() && steps.changes.outputs.has_changes == 'true' }}
        id: describe
        run: |
          title=$(git diff --unified=0 -- 'pkgbuilds/*/PKGBUILD' \
            | awk '/^\+\+\+ b\/pkgbuilds\//{split($2,p,"/"); pkg=p[3]} /^\+pkgver=/{sub(/^\+pkgver=/,""); printf "%s %s, ", pkg, $0}' \
            | sed 's/, $//')
          echo "title=Track upstream branches: ${title}" >> "$GITHUB_OUTPUT"

      - name: Open or update the tracking PR
        if: ${{ !cancelled() && steps.changes.outputs.has_changes == 'true' }}
        id: pr
        uses: peter-evans/create-pull-request@5f6978faf089d4d20b00c7766989d076bb2fc7f1 # v8.1.1
        with:
          token: ${{ secrets.PKGS_BOT_TOKEN }}
          commit-message: ${{ steps.describe.outputs.title }}
          title: ${{ steps.describe.outputs.title }}
          body: |
            Automated pin of packages that follow a moving upstream branch
            (`"auto_merge": true` in `.omarchy/package.json`). Each package's
            `_commit` now points at the branch tip. Fresh tips wait until
            their commit timestamp is at least `min_release_age` old.

            This PR auto-merges once the build checks pass. A failing build
            leaves it open; the next tracker run replaces it with the newer tip.
          branch: auto/track-branches
          delete-branch: true
          labels: automated

      # Auto-merge, not a direct merge: branch protection still has to see
      # `result`, `self-tests` and `build-isolation` green, and this lane
      # inherits every rule the reviewed lane has except the human.
      - name: Enable auto-merge
        if: ${{ !cancelled() && steps.pr.outputs.pull-request-number != '' }}
        env:
          GH_TOKEN: ${{ secrets.PKGS_BOT_TOKEN }}
          PR: ${{ steps.pr.outputs.pull-request-number }}
        run: |
          # Idempotent across re-runs of an updated PR: enabling twice errors.
          if [[ "$(gh pr view "$PR" -R "${{ github.repository }}" --json autoMergeRequest --jq '.autoMergeRequest != null')" == true ]]; then
            echo "auto-merge already enabled on #$PR"
            exit 0
          fi
          gh pr merge --auto --merge "$PR" -R "${{ github.repository }}"

      - name: Notify Basecamp on failure
        if: failure() && env.BASECAMP_CHATBOT_URL != ''
        env:
          BASECAMP_CHATBOT_URL: ${{ secrets.BASECAMP_CHATBOT_URL }}
        run: |
          curl -s -o /dev/null \
            -H "Content-Type: application/json" \
            -d "$(jq -n --arg content \
              "🔴 <strong>Branch tracking failed</strong><br><a href=\"${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}\">View run</a>" \
              '{content: $content}')" \
            "$BASECAMP_CHATBOT_URL"