name: Bump build.func Revision

on:
  push:
    branches: [ main ]
    paths:
      - 'misc/*.func'
      - 'misc/*.sh'

jobs:
  bump-revision:
    runs-on: ubuntu-latest
    if: github.event.head_commit.author.name != 'github-actions[bot]'
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Detect misc changes
        id: changes
        run: |
          git diff --name-only HEAD^ HEAD > changed_files.txt
          echo "changed=$(cat changed_files.txt)" >> $GITHUB_OUTPUT

      - name: Bump Revision if needed
        if: contains(steps.changes.outputs.changed, 'misc/') && !contains(steps.changes.outputs.changed, 'misc/build.func')
        run: |
          REV_FILE=".build-revision"
          if [ ! -f "$REV_FILE" ]; then echo 0 > "$REV_FILE"; fi
          REV_NUM=$(($(cat $REV_FILE) + 1))
          echo $REV_NUM > $REV_FILE
          SHORT_SHA=$(git rev-parse --short HEAD)
          REV_STR="Revision: r${REV_NUM} (git-${SHORT_SHA})"
          sed -i "s/^# Revision:.*/# $REV_STR/" misc/build.func
          echo "REV_STR=$REV_STR" >> $GITHUB_ENV

      - name: Commit & push revision
        if: contains(steps.changes.outputs.changed, 'misc/') && !contains(steps.changes.outputs.changed, 'misc/build.func')
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"
          git add misc/build.func .build-revision
          git commit -m "chore: bump build.func to $REV_STR"
          git push