name: Open / Update Version Bump PR

# Triggered when any PR merges to main touching src/ or debian/ (push),
# or when a bump:* label is added to the chore/version-bump PR (labeled).
# On push: recreates the branch from main and collects all commits since the
# last tag — no incremental accumulation, no rebase, no conflicts.
# On label change: checks out the existing branch and rewrites the changelog entry.

on:
  push:
    branches:
      - main
    paths:
      - 'src/**'
      - 'debian/**'
      - '!debian/changelog'
  pull_request:
    types:
      - labeled
    branches:
      - main

permissions:
  contents: write
  pull-requests: write

jobs:
  pr:
    runs-on: ubuntu-latest
    if: |
      (github.event_name == 'push' && github.actor != 'github-actions[bot]') ||
      (github.event_name == 'pull_request' &&
       github.event.pull_request.head.ref == 'chore/version-bump' &&
       startsWith(github.event.label.name, 'bump:'))

    steps:
      - uses: actions/checkout@v7
        with:
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Set up chore/version-bump branch
        run: |
          git config user.name  "github-actions[bot]"
          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"

          git fetch origin main

          # Collect all commits touching src/ since the last release tag (both paths need this)
          LAST_TAG=$(git describe --tags --abbrev=0 origin/main 2>/dev/null || true)
          if [[ -n "$LAST_TAG" ]]; then
            LOG=$(git log "${LAST_TAG}..origin/main" --oneline -- src/ | head -50)
          else
            LOG=$(git log origin/main --oneline -- src/ | head -50)
          fi
          echo "${LOG:-No src/ changes since last release.}" > /tmp/CHANGES.md

          if [[ "${{ github.event_name }}" == "push" ]]; then
            # Always recreate from main — avoids rebase conflicts after PR merge
            git checkout -b chore/version-bump origin/main
          else
            # Label change: check out the existing branch
            git fetch origin chore/version-bump
            git checkout chore/version-bump
          fi

      - name: Determine bump type
        id: bump_type
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          if [[ "${{ github.event_name }}" == "pull_request" ]]; then
            LABEL="${{ github.event.label.name }}"
          else
            # Use existing PR label if present, otherwise default to patch
            LABEL=$(gh pr list \
              --head "chore/version-bump" \
              --base main \
              --json labels \
              --jq '.[0].labels[].name' 2>/dev/null | grep '^bump:' | head -1 || echo "bump:patch")
          fi

          if [[ "$LABEL" == "bump:major" ]]; then
            echo "type=major" >> "$GITHUB_OUTPUT"
          elif [[ "$LABEL" == "bump:minor" ]]; then
            echo "type=minor" >> "$GITHUB_OUTPUT"
          else
            echo "type=patch" >> "$GITHUB_OUTPUT"
          fi

      - name: Compute new version
        id: version
        env:
          BUMP_TYPE: ${{ steps.bump_type.outputs.type }}
        run: |
          # Always base version on main's latest tag to avoid double-bumping on reruns
          CURRENT=$(git describe --tags --abbrev=0 origin/main 2>/dev/null | sed 's/^v//' \
            || git show origin/main:debian/changelog | grep -m1 '(' | sed 's/.*(\(.*\)).*/\1/')
          MAJOR=$(echo "$CURRENT" | cut -d. -f1)
          MINOR=$(echo "$CURRENT" | cut -d. -f2)
          PATCH=$(echo "$CURRENT" | cut -d. -f3)

          if [[ "$BUMP_TYPE" == "major" ]]; then
            NEW="$((MAJOR + 1)).0.0"
          elif [[ "$BUMP_TYPE" == "minor" ]]; then
            NEW="${MAJOR}.$((MINOR + 1)).0"
          else
            NEW="${MAJOR}.${MINOR}.$((PATCH + 1))"
          fi

          echo "Bumping $CURRENT → $NEW ($BUMP_TYPE)"
          echo "new=$NEW" >> "$GITHUB_OUTPUT"

      - name: Write debian/changelog
        env:
          NEW_VERSION: ${{ steps.version.outputs.new }}
        run: |
          LOG=$(cat /tmp/CHANGES.md 2>/dev/null || true)
          DATE=$(date -R)
          # Base on main's changelog so reruns always replace the previous bot entry cleanly
          MAIN_CHANGELOG=$(git show origin/main:debian/changelog)
          {
            echo "pve-mod ($NEW_VERSION) stable; urgency=low"
            echo ""
            while IFS= read -r line; do
              [[ -n "$line" ]] && echo "  * $line"
            done <<< "$LOG"
            [[ -z "$LOG" ]] && echo "  * Automated version bump."
            echo ""
            echo " -- github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>  $DATE"
            echo ""
            echo "$MAIN_CHANGELOG"
          } > debian/changelog
          git add debian/changelog
          git commit -m "chore: update changelog to v${NEW_VERSION}"
          git push --force origin chore/version-bump

      - name: Build PR body
        env:
          NEW_VERSION: ${{ steps.version.outputs.new }}
        run: |
          {
            echo "## Release v${NEW_VERSION}"
            echo ""
            cat /tmp/CHANGES.md 2>/dev/null || echo "No changes recorded."
            echo ""
            echo "---"
            echo "*Change label to \`bump:minor\` or \`bump:major\` before merging if needed.*"
            echo "*Merge this PR when ready to release.*"
          } > /tmp/pr-body.md

      - name: Create or update PR (push)
        if: github.event_name == 'push'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          BUMP_BRANCH="chore/version-bump"
          TITLE="chore: release next version"

          EXISTING=$(gh pr list \
            --head "$BUMP_BRANCH" \
            --base main \
            --json number --jq '.[0].number' 2>/dev/null || true)

          if [[ -n "$EXISTING" ]]; then
            gh pr edit "$EXISTING" --title "$TITLE" --body-file /tmp/pr-body.md
            echo "Updated PR #${EXISTING} (label unchanged)"
          else
            gh pr create \
              --title "$TITLE" \
              --body-file /tmp/pr-body.md \
              --base main \
              --head "$BUMP_BRANCH" \
              --label "bump:patch"
            echo "Opened new PR with label bump:patch"
          fi

      - name: Update PR body (label change)
        if: github.event_name == 'pull_request'
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
        run: |
          gh pr edit "$PR_NUMBER" --body-file /tmp/pr-body.md