# Cut a release once a week, but only if there is something in it.
#
# It does nothing on a quiet week. A release with no commits in it is worse
# than no release: it moves `:latest` to an identical build, spends a version
# number, and mails everybody watching the repository about nothing.
#
# Unlike ihasmail, whose version is derived from the commit it builds, INBUXA
# Admin keeps its version in inbuxa-version.json. So this writes it: the bump
# is committed to main, and the tag names that commit. The commit is the
# release, which means the tree a tag points at always reports the version the
# tag claims -- something a tag placed beside an unbumped file cannot promise.
name: Weekly release

on:
  schedule:
    # Mondays, 09:37 UTC -- twenty minutes behind ihasmail-inbuxa's, twenty
    # ahead of the server's. Staggered rather than simultaneous so three
    # releases do not compete for runners, and so a bad Monday names one
    # repository instead of three. GitHub runs scheduled jobs best-effort and
    # can delay a run considerably, so the exact minute is not a promise; the
    # odd minute keeps it off the crowded top of the hour.
    #
    # Note also that GitHub disables scheduled workflows in a repository with
    # no activity for 60 days, which is worth checking for before assuming
    # this file is broken.
    - cron: "37 9 * * 1"
  workflow_dispatch:
    inputs:
      dry_run:
        description: "Work out what would be released, then stop"
        type: boolean
        default: false

# One at a time. Two overlapping runs would race to write the same version and
# create the same tag, and the loser fails noisily for a reason that has
# nothing to do with the code.
concurrency:
  group: weekly-release
  cancel-in-progress: false

jobs:
  check:
    runs-on: ubuntu-latest
    permissions:
      contents: read
    outputs:
      should_release: ${{ steps.decide.outputs.should_release }}
      version: ${{ steps.decide.outputs.version }}
      tag: ${{ steps.decide.outputs.tag }}
      previous: ${{ steps.decide.outputs.previous }}
      count: ${{ steps.decide.outputs.count }}
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          ref: main
          fetch-depth: 0
      - id: decide
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          set -euo pipefail

          # The newest published release, or empty on a repository that has
          # never had one -- in which case everything counts as new. Drafts are
          # excluded: an unpublished draft is not a release anybody has, so
          # counting from it would hide commits that have never shipped.
          previous="$(gh release list --limit 1 --exclude-drafts --json tagName --jq '.[0].tagName // ""')"
          # A tag named by a release is normally present after a full checkout,
          # but a release can outlive its tag. Falling back to the whole
          # history is the safe direction to be wrong in: it over-counts, which
          # cuts a release that was due anyway, where under-counting would skip
          # one that was.
          if [ -n "$previous" ] && git rev-parse -q --verify "refs/tags/${previous}" >/dev/null; then
            count="$(git rev-list --count "${previous}..HEAD")"
          else
            count="$(git rev-list --count HEAD)"
          fi

          # INBUXA's version is the date, as the rest of the family does it:
          # YYYY.M.D, unpadded. A second release on one day takes a `.N`
          # suffix, counting from 2, which is why this asks the tags rather
          # than assuming today is free.
          today="$(date -u +%Y.%-m.%-d)"
          version="$today"
          n=2
          while git rev-parse -q --verify "refs/tags/v${version}" >/dev/null; do
            version="${today}.${n}"
            n=$((n + 1))
          done

          should_release=true
          reason=""
          if [ "$count" -eq 0 ]; then
            should_release=false
            reason="no commits since ${previous}"
          fi

          {
            echo "should_release=$should_release"
            echo "version=$version"
            echo "tag=v${version}"
            echo "previous=$previous"
            echo "count=$count"
          } >> "$GITHUB_OUTPUT"

          # Written to the run summary so a skipped week reads as a decision
          # rather than as a workflow that quietly did nothing.
          {
            echo "### Weekly release"
            echo
            if [ "$should_release" = "true" ]; then
              echo "Releasing **v${version}** — ${count} commit(s) since ${previous:-the beginning}."
            else
              echo "Nothing to release: ${reason}."
            fi
          } >> "$GITHUB_STEP_SUMMARY"

  cut:
    needs: check
    if: needs.check.outputs.should_release == 'true' && !inputs.dry_run
    runs-on: ubuntu-latest
    permissions:
      contents: write
    outputs:
      sha: ${{ steps.bump.outputs.sha }}
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
        with:
          ref: main
          fetch-depth: 0
      - id: bump
        env:
          VERSION: ${{ needs.check.outputs.version }}
        run: |
          set -euo pipefail

          # Rewritten with a JSON parser rather than sed: the file is small and
          # the shape is known, but a version written into JSON by string
          # substitution is one stray quote away from a file nothing can read.
          node -e '
            const fs = require("fs");
            const f = "inbuxa-version.json";
            const j = JSON.parse(fs.readFileSync(f, "utf8"));
            j.version = process.env.VERSION;
            fs.writeFileSync(f, JSON.stringify(j, null, 2) + "\n");
          '

          git config user.name "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git add inbuxa-version.json
          git commit -m "Version ${VERSION}"
          git push origin HEAD:main

          echo "sha=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
      - env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          set -euo pipefail
          args=(--target "${{ steps.bump.outputs.sha }}"
                --title "INBUXA Admin ${{ needs.check.outputs.version }}"
                --generate-notes)
          # Bound the notes to what is actually new. Without a start tag the
          # generator reaches back to whatever it decides is previous, which on
          # a repository carrying older tag shapes -- this one still has the
          # inherited v1.0.x tags -- is not always the last release.
          if [ -n "${{ needs.check.outputs.previous }}" ]; then
            args+=(--notes-start-tag "${{ needs.check.outputs.previous }}")
          fi
          gh release create "${{ needs.check.outputs.tag }}" "${args[@]}"

  # Called rather than left to the `release` trigger on purpose: see the note
  # at the top of publish.yml. A release created with GITHUB_TOKEN raises no
  # event, so without this the tag would exist and no image would follow it.
  publish:
    needs: [check, cut]
    permissions:
      contents: read
      packages: write
    uses: ./.github/workflows/publish.yml
    with:
      ref: ${{ needs.cut.outputs.sha }}
      tag_latest: true