action.yml

name: pull-request-summary
description: GitHub Action that summarizes pull requests with AI (LLM)
author: remarkablemark

inputs:
  model:
    description: Language model name
    default: codellama
    required: false
  prompt:
    description: Input prompt before the PR diff
    default: 'Summarize the code diff concisely:'
    required: false
  token:
    description: GitHub token
    default: ${{ github.token }}
    required: false

runs:
  using: composite
  steps:
      - name: Setup ollama
        uses: ai-action/setup-ollama@v2

      - name: Checkout repository
        uses: actions/checkout@v6

      - name: Summarize pull request
        shell: bash
        run: |
          PROMPT=$(printf '%s\n%s' "$PROMPT" "$(gh pr diff $PR_NUMBER)")
          RESPONSE=$(ollama run $MODEL "$PROMPT" | sed 's/^/> /')
          BODY=$(gh pr view $PR_NUMBER --json body --jq .body)
          COMMENT_START='<!--pull-request-summary-start-->'
          COMMENT_END='<!--pull-request-summary-end-->'

          if [[ "$BODY" == *"$COMMENT_START"* ]]; then
            # delete between patterns (inclusive)
            BODY=$(echo "$BODY" | sed "/$COMMENT_START/,/$COMMENT_END/d")
          fi

          BODY=$(printf '%s\n\n%s\n\n> [!NOTE]\n%s\n\n%s\n' "$BODY" $COMMENT_START "$RESPONSE" $COMMENT_END)
          gh pr edit $PR_NUMBER --body "$BODY"
        env:
          GH_TOKEN: ${{ inputs.token }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          PROMPT: ${{ inputs.prompt }}
          MODEL: ${{ inputs.model }}

branding:
  icon: code
  color: gray-dark