name: 'Generate Release Notes'
description: 'Generate release notes for a given version'

inputs:
  version:
    description: 'The version being released'
    required: true
  head_ref:
    description: 'The commit SHA or reference of the head of the release branch'
    required: true
  prior_ref:
    description: 'The previous version to compare against'
    required: true

outputs:
  pr_body_file:
    description: 'Path to the generated PR body file'
    value: ${{ steps.generate.outputs.pr_body_file }}

runs:
  using: 'composite'
  steps:
    - name: Generate release notes
      id: generate
      shell: bash
      env:
        VERSION: ${{ inputs.version }}
        HEAD_REF: ${{ inputs.head_ref }}
        PRIOR_REF: ${{ inputs.prior_ref }}
        TEMPLATE_FILE: "${{ github.action_path }}/pr_body_template.txt"
      run: |
        git fetch origin "$HEAD_REF" "$PRIOR_REF"

        {
          sed -e "s/{{VERSION}}/${VERSION}/g" \
              -e "s/{{PRIOR_VERSION}}/${PRIOR_REF}/g" \
              "$TEMPLATE_FILE"
          git log --pretty=format:"- %s (%h)" --reverse ${PRIOR_REF}..${HEAD_REF}
          echo ""
          echo "---"
          echo "*This release PR was generated automatically.*"
        } > pr_body.txt

        echo "pr_body_file=pr_body.txt" >> $GITHUB_OUTPUT