MoreTore/.github/workflows/update_release_branch.yaml

name: "Update FrogPilot Branch"
run-name: "Check scheduled FrogPilot release"

on:
  schedule:
    - cron: "0 11 * * 6"
      timezone: America/Phoenix

permissions:
  contents: write

env:
  BRANCH_RELEASE: ${{ vars.BRANCH_RELEASE || 'FrogPilot' }}
  BRANCH_PREVIOUS: ${{ vars.BRANCH_PREVIOUS || 'FrogPilot-Previous' }}
  BRANCH_STAGING: ${{ vars.BRANCH_STAGING || 'FrogPilot-Staging' }}
  TZ: America/Phoenix

concurrency:
  group: update-frogpilot-release

jobs:
  update_branch:
    name: "Promote the scheduled staging release"
    runs-on: ubuntu-latest
    timeout-minutes: 20
    steps:
      - name: "Checkout staging branch"
        uses: actions/checkout@v6
        with:
          fetch-depth: 0
          ref: ${{ env.BRANCH_STAGING }}

      - id: due
        name: "Check whether a release is due"
        run: |
          set -u

          if [[ ! -f ".github/update_date" ]]; then
            echo "No scheduled release marker found."
            echo "update_due=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          scheduled_date=$(tr -d "\r\n" < ".github/update_date")
          if ! parsed_date=$(TZ="$TZ" date -d "$scheduled_date" +%F 2>/dev/null); then
            echo "Invalid scheduled date in .github/update_date: $scheduled_date"
            exit 1
          fi

          today=$(TZ="$TZ" date +%F)
          if [[ "$parsed_date" != "$today" ]]; then
            echo "Scheduled release date is $parsed_date. Today in $TZ is $today."
            echo "update_due=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          echo "scheduled_date=$parsed_date" >> "$GITHUB_OUTPUT"
          echo "update_due=true" >> "$GITHUB_OUTPUT"

      - if: steps.due.outputs.update_due == 'true'
        name: "Configure git identity"
        run: |
          if [[ -z "${{ vars.GIT_NAME }}" || -z "${{ vars.GIT_EMAIL }}" ]]; then
            echo "Repository variables GIT_NAME and GIT_EMAIL must be set."
            exit 1
          fi

          git config user.name "${{ vars.GIT_NAME }}"
          git config user.email "${{ vars.GIT_EMAIL }}"
          git fetch origin "$BRANCH_RELEASE" "$BRANCH_PREVIOUS"

      - id: metadata
        if: steps.due.outputs.update_due == 'true'
        name: "Resolve anchor commit and compute release metadata"
        run: |
          set -u

          scheduled_date="${{ steps.due.outputs.scheduled_date }}"

          anchor_commit=HEAD
          while :; do
            subject=$(git log -1 --format=%s "$anchor_commit")

            if [[ "$subject" == "FrogPilot README" ]]; then
              break
            fi

            if ! git rev-parse "${anchor_commit}^" >/dev/null 2>&1; then
              echo "Unable to resolve the FrogPilot README commit on $BRANCH_STAGING."
              exit 1
            fi

            anchor_commit="${anchor_commit}^"
          done

          day=$(TZ="$TZ" date -d "$scheduled_date" +%-d)
          case "$day" in
            1|21|31) suffix="st" ;;
            2|22) suffix="nd" ;;
            3|23) suffix="rd" ;;
            *)      suffix="th" ;;
          esac

          month=$(TZ="$TZ" date -d "$scheduled_date" +%B)
          year=$(TZ="$TZ" date -d "$scheduled_date" +%Y)
          release_label="${month} ${day}${suffix}, ${year}"
          release_label_escaped=$(printf "%s" "$release_label" | sed -E "s/ /%20/g; s/,/%2C/g")

          echo "anchor_commit=$anchor_commit" >> "$GITHUB_OUTPUT"
          echo "previous_ref=$(git rev-parse "origin/$BRANCH_PREVIOUS")" >> "$GITHUB_OUTPUT"
          echo "release_label_escaped=$release_label_escaped" >> "$GITHUB_OUTPUT"
          echo "release_ref=$(git rev-parse "origin/$BRANCH_RELEASE")" >> "$GITHUB_OUTPUT"
          echo "release_timestamp=$(TZ="$TZ" date -d "$scheduled_date 12:00:00" +"%Y-%m-%dT%H:%M:%S %z")" >> "$GITHUB_OUTPUT"
          echo "root_commit=$(git rev-list --max-parents=0 HEAD)" >> "$GITHUB_OUTPUT"
          echo "staging_ref=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"

      - if: steps.due.outputs.update_due == 'true'
        name: "Rewrite README badge with release date"
        run: |
          set -u

          anchor_commit="${{ steps.metadata.outputs.anchor_commit }}"
          release_label_escaped="${{ steps.metadata.outputs.release_label_escaped }}"
          release_timestamp="${{ steps.metadata.outputs.release_timestamp }}"
          staging_ref="${{ steps.metadata.outputs.staging_ref }}"

          git switch --detach "$anchor_commit"
          sed -i -E "s|(Last%20Updated-)[^-)]*|\1${release_label_escaped}|g" README.md
          git add README.md

          if ! git diff --cached --quiet; then
            GIT_AUTHOR_DATE="$release_timestamp" \
            GIT_COMMITTER_DATE="$release_timestamp" \
            git commit --amend --no-edit --date="$release_timestamp"
          fi

          rewritten_anchor=$(git rev-parse HEAD)
          git switch -C release-rewrite "$staging_ref"
          if [[ "$staging_ref" == "$anchor_commit" ]]; then
            git reset --hard "$rewritten_anchor"
          else
            git rebase --onto "$rewritten_anchor" "$anchor_commit"
          fi

      - id: rewrite
        if: steps.due.outputs.update_due == 'true'
        name: "Rewrite all commit timestamps"
        run: |
          set -u

          release_timestamp="${{ steps.metadata.outputs.release_timestamp }}"
          root_commit="${{ steps.metadata.outputs.root_commit }}"

          rewrite_command="GIT_AUTHOR_DATE=\"$release_timestamp\" GIT_COMMITTER_DATE=\"$release_timestamp\" git commit --amend --no-edit --date=\"$release_timestamp\""
          if [[ "$(git rev-parse HEAD)" != "$root_commit" ]]; then
            GIT_SEQUENCE_EDITOR=: git rebase -i --exec "$rewrite_command" "$root_commit"
          fi

          echo "release_timestamp=$release_timestamp" >> "$GITHUB_OUTPUT"
          echo "staging_ref=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
          echo "release_ref=${{ steps.metadata.outputs.release_ref }}" >> "$GITHUB_OUTPUT"
          echo "previous_ref=${{ steps.metadata.outputs.previous_ref }}" >> "$GITHUB_OUTPUT"

      - if: steps.due.outputs.update_due == 'true'
        name: "Remove schedule marker and finalize release branch"
        run: |
          set -u

          git rm -f ".github/update_date"

          if git diff --cached --quiet; then
            echo "No schedule marker to remove."
            exit 1
          fi

          GIT_AUTHOR_DATE="${{ steps.rewrite.outputs.release_timestamp }}" \
          GIT_COMMITTER_DATE="${{ steps.rewrite.outputs.release_timestamp }}" \
          git commit --amend --no-edit --date="${{ steps.rewrite.outputs.release_timestamp }}"

      - if: steps.due.outputs.update_due == 'true'
        name: "Push release, backup, and staging branches"
        run: |
          git push \
            --force-with-lease="refs/heads/${{ env.BRANCH_PREVIOUS }}:${{ steps.rewrite.outputs.previous_ref }}" \
            origin "${{ steps.rewrite.outputs.release_ref }}:refs/heads/${{ env.BRANCH_PREVIOUS }}"

          git push \
            --force-with-lease="refs/heads/${{ env.BRANCH_RELEASE }}:${{ steps.rewrite.outputs.release_ref }}" \
            origin "HEAD:refs/heads/${{ env.BRANCH_RELEASE }}"

          git push \
            --force-with-lease="refs/heads/${{ env.BRANCH_STAGING }}:${{ steps.rewrite.outputs.staging_ref }}" \
            origin "HEAD:refs/heads/${{ env.BRANCH_STAGING }}"