prepare-release.yml

name: Prepare Release

# Creates a release PR from develop → main.
# Maintainers trigger this from Actions → Prepare Release → Run workflow.
# After reviewing, merge the PR — the "Finalize Release" workflow handles the rest.

on:
  workflow_dispatch:
    inputs:
      release_type:
        description: 'Release type (controls the pre-release label on main)'
        required: true
        type: choice
        options:
          - beta
          - rc
          - stable
        default: 'beta'
      version_override:
        description: 'Version override (optional, e.g., 2.0.0). Leave blank to let GitVersion calculate it.'
        required: false
        type: string

# Prevent two prepare-release runs from picking the same version number
concurrency:
  group: prepare-release
  cancel-in-progress: false

jobs:
  prepare-release:
    name: Create Release PR
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write

    steps:
      - name: Checkout develop
        uses: actions/checkout@v7
        with:
          ref: develop
          fetch-depth: 0
          token: ${{ secrets.RELEASE_PAT }}

      - name: Configure Git
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

      - name: Install GitVersion
        uses: gittools/actions/gitversion/setup@v4.7.0
        with:
          versionSpec: '6.x'

      - name: Determine Version
        uses: gittools/actions/gitversion/execute@v4.7.0
        with:
          useConfigFile: true
        id: gitversion

      - name: Compute release version
        id: version
        run: |
          if [ -n "${{ github.event.inputs.version_override }}" ]; then
            VERSION="${{ github.event.inputs.version_override }}"
          else
            VERSION="${{ steps.gitversion.outputs.MajorMinorPatch }}"
          fi

          RELEASE_TYPE="${{ github.event.inputs.release_type }}"

          if [ "$RELEASE_TYPE" = "stable" ]; then
            SEMVER="${VERSION}"
            TAG="v${VERSION}"
          else
            # Find the latest existing tag for this version + release type
            # and increment the pre-release number.
            # --sort=-v:refname gives correct numeric ordering (e.g., .9 before .10)
            LATEST_TAG=$(git tag -l "v${VERSION}-${RELEASE_TYPE}.*" --sort=-v:refname | head -1)

            if [ -z "$LATEST_TAG" ]; then
              NEXT_NUM=1
            else
              # Extract the trailing number: v2.0.0-beta.217 → 217
              CURRENT_NUM="${LATEST_TAG##*.}"
              NEXT_NUM=$((CURRENT_NUM + 1))
            fi

            SEMVER="${VERSION}-${RELEASE_TYPE}.${NEXT_NUM}"
            TAG="v${SEMVER}"
          fi

          echo "version=${VERSION}" >> $GITHUB_OUTPUT
          echo "semver=${SEMVER}" >> $GITHUB_OUTPUT
          echo "tag=${TAG}" >> $GITHUB_OUTPUT
          echo "release_type=${RELEASE_TYPE}" >> $GITHUB_OUTPUT

          echo "::notice::Computed version: ${SEMVER} (tag: ${TAG})"

      - name: Check for conflicts
        run: |
          TAG="${{ steps.version.outputs.tag }}"

          # Ensure tag does not already exist
          if git rev-parse "${TAG}" >/dev/null 2>&1; then
            echo "::error::Tag ${TAG} already exists."
            echo "::error::Choose a different version or delete the existing tag first."
            exit 1
          fi

          # Ensure no release branch or open PR already targets this version
          BRANCH="release/${TAG}"
          if git ls-remote --heads origin "${BRANCH}" | grep -q .; then
            echo "::error::Branch ${BRANCH} already exists on the remote."
            echo "::error::Delete it first or choose a different version."
            exit 1
          fi

      - name: Create release branch
        run: |
          BRANCH="release/${{ steps.version.outputs.tag }}"
          git checkout -b "$BRANCH"
          echo "branch=${BRANCH}" >> $GITHUB_OUTPUT
        id: branch

      - name: Update GitVersion.yml label for release type
        run: |
          RELEASE_TYPE="${{ steps.version.outputs.release_type }}"

          if [ "$RELEASE_TYPE" = "stable" ]; then
            NEW_LABEL="''"
          else
            NEW_LABEL="${RELEASE_TYPE}"
          fi

          # Update the label line that follows the main branch regex.
          sed -i "/regex: \^main/,/^  [a-z]/{s/^    label: .*/    label: ${NEW_LABEL}/}" GitVersion.yml

          echo "Updated GitVersion.yml main label to: '${NEW_LABEL}'"
          grep -A 5 "^  main:" GitVersion.yml

      - name: Commit label change
        run: |
          if git diff --quiet GitVersion.yml; then
            echo "No label change needed"
          else
            git add GitVersion.yml
            git commit -m "Set release label to '${{ steps.version.outputs.release_type }}' for ${{ steps.version.outputs.tag }}"
          fi

      - name: Push release branch
        run: |
          BRANCH="release/${{ steps.version.outputs.tag }}"
          git push origin "$BRANCH"

      - name: Create Pull Request
        env:
          GH_TOKEN: ${{ secrets.RELEASE_PAT }}
          SEMVER: ${{ steps.version.outputs.semver }}
          TAG: ${{ steps.version.outputs.tag }}
          RELEASE_TYPE: ${{ steps.version.outputs.release_type }}
        run: |
          BRANCH="release/${TAG}"

          if [ "$RELEASE_TYPE" = "stable" ]; then
            PRERELEASE_NOTE=""
          else
            PRERELEASE_NOTE="This is a **${RELEASE_TYPE}** pre-release."
          fi

          cat > /tmp/pr_body.md << EOF
          ## Release ${TAG}

          ${PRERELEASE_NOTE}

          **Version:** \`${SEMVER}\`
          **NuGet Package:** \`Terminal.Gui ${SEMVER}\`

          ### What happens when this PR is merged

          1. ✅ The **Finalize Release** workflow will automatically create tag \`${TAG}\`
          2. ✅ The **Publish** workflow will build and push to [NuGet.org](https://www.nuget.org/packages/Terminal.Gui)
          3. ✅ A **GitHub Release** will be created with auto-generated notes
          4. ✅ A **back-merge PR** from \`main\` → \`develop\` will be opened

          ### Checklist

          - [ ] CI passes on this PR
          - [ ] Version looks correct: \`${SEMVER}\`
          - [ ] Release notes reviewed (will be auto-generated on merge)
          EOF

          gh pr create \
            --base main \
            --head "$BRANCH" \
            --title "Release ${TAG}" \
            --body-file /tmp/pr_body.md

      - name: Summary
        run: |
          echo "## Release PR Created :rocket:" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "- **Version:** ${{ steps.version.outputs.semver }}" >> $GITHUB_STEP_SUMMARY
          echo "- **Tag:** ${{ steps.version.outputs.tag }}" >> $GITHUB_STEP_SUMMARY
          echo "- **Type:** ${{ steps.version.outputs.release_type }}" >> $GITHUB_STEP_SUMMARY
          echo "- **Branch:** release/${{ steps.version.outputs.tag }}" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "Review and merge the PR to trigger the release." >> $GITHUB_STEP_SUMMARY