name: CI (On Pull-Request)
run-name: >-
  ${{ github.event_name }} / PR #${{ github.event.pull_request.number }} / ${{ github.event.action }} / ${{ github.event.pull_request.head.label }}

on:
  pull_request:
    types:
      - opened
      - synchronize
      - reopened
  pull_request_target:
    types:
      - opened
      - synchronize
      - reopened
      - ready_for_review

concurrency:
  # Keep only the newest run per PR and event type.
  # This avoids pull_request and pull_request_target cancelling each other.
  group: pr-ci-${{ github.repository }}-${{ github.event_name }}-pr-${{ github.event.pull_request.number }}
  cancel-in-progress: true

permissions:
  actions: read
  contents: read
  packages: write
  security-events: write

jobs:
  detect-pr-scope:
    name: 🔎 Detect PR scope
    if: ${{ github.event_name == 'pull_request' || github.event.pull_request.head.repo.full_name != github.repository }}
    runs-on: ubuntu-latest
    outputs:
      scope: ${{ steps.resolve.outputs.scope }}
      run_ci_orchestrator: ${{ steps.resolve.outputs.run_ci_orchestrator }}
    steps:
      - name: Checkout
        uses: actions/checkout@v6

      - name: Resolve PR scope
        id: resolve
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          REPOSITORY: ${{ github.repository }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
        run: ./scripts/meta/resolve/pr/scope.sh

  validate-pr-branch-prefix:
    name: 🧭 Validate PR branch prefix
    needs: detect-pr-scope
    if: ${{ github.event_name == 'pull_request' || github.event.pull_request.head.repo.full_name != github.repository }}
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v6

      - name: Validate branch prefix for detected scope
        env:
          PR_HEAD_REF: ${{ github.event.pull_request.head.ref }}
          PR_SCOPE: ${{ needs.detect-pr-scope.outputs.scope }}
        run: ./scripts/meta/resolve/pr/branch_prefix.sh

  pr-scope-gate:
    name: 🚦 Gate PR scope
    needs:
      - detect-pr-scope
      - validate-pr-branch-prefix
    if: ${{ needs.detect-pr-scope.outputs.run_ci_orchestrator == 'false' }}
    runs-on: ubuntu-latest
    steps:
      - name: Confirm lightweight PR scope
        shell: bash
        run: |
          set -euo pipefail
          echo "Lightweight PR scope '${{ needs.detect-pr-scope.outputs.scope }}' passed."

  ci-orchestrator:
    needs:
      - detect-pr-scope
      - validate-pr-branch-prefix
    if: ${{ github.event_name == 'pull_request' && needs.detect-pr-scope.outputs.run_ci_orchestrator == 'true' }}
    uses: ./.github/workflows/ci-orchestrator.yml
    with:
      distros: "arch debian ubuntu fedora centos"

  prepare-fork-merge-ref:
    needs:
      - detect-pr-scope
      - validate-pr-branch-prefix
    if: ${{ github.event_name == 'pull_request_target' && github.event.pull_request.head.repo.full_name != github.repository && needs.detect-pr-scope.outputs.run_ci_orchestrator == 'true' }}
    runs-on: ubuntu-latest
    outputs:
      checkout_ref: ${{ steps.out.outputs.checkout_ref }}
      image_tag: ${{ steps.out.outputs.image_tag }}
    steps:
      - name: Checkout
        uses: actions/checkout@v6

      - name: Resolve merge ref and image tag
        id: out
        env:
          PR_NUMBER: ${{ github.event.pull_request.number }}
          PR_MERGE_SHA: ${{ github.event.pull_request.merge_commit_sha || '' }}
        run: ./scripts/meta/resolve/pr/merge_ref.sh

  build-ci-images-fork:
    needs: prepare-fork-merge-ref
    uses: ./.github/workflows/build-ci-images.yml
    with:
      distros: "arch debian ubuntu fedora centos"
      checkout_ref: ${{ needs.prepare-fork-merge-ref.outputs.checkout_ref }}
      image_tag: ${{ needs.prepare-fork-merge-ref.outputs.image_tag }}
      concurrency_channel: pr-target-build-producer
    secrets: inherit

  images-mirror-missing-fork:
    needs: prepare-fork-merge-ref
    uses: ./.github/workflows/images-mirror-missing.yml
    with:
      repo_root: _pr_source
      source_repository: ${{ github.repository }}
      source_ref: ${{ needs.prepare-fork-merge-ref.outputs.checkout_ref }}
      source_path: _pr_source
      concurrency_channel: pr-target-mirror-producer
      concurrency_key: pr-${{ github.event.pull_request.number }}
    secrets: inherit