name: PR

on:
  pull_request:
    paths:
      - .github/workflows/build.yml
      - .github/workflows/check.yml
      - .github/workflows/eval.yml
      - .github/workflows/lint.yml
      - .github/workflows/pr.yml
      - .github/workflows/labels.yml
      - .github/workflows/reviewers.yml # needs eval results from the same event type
  pull_request_target:

concurrency:
  group: pr-${{ github.workflow }}-${{ github.event_name }}-${{ github.event.pull_request.number || github.run_id }}
  cancel-in-progress: true

permissions: {}

jobs:
  prepare:
    runs-on: ubuntu-24.04-arm
    outputs:
      baseBranch: ${{ steps.branches.outputs.base }}
      headBranch: ${{ steps.branches.outputs.head }}
      mergedSha: ${{ steps.get-merge-commit.outputs.mergedSha }}
      targetSha: ${{ steps.get-merge-commit.outputs.targetSha }}
      systems: ${{ steps.systems.outputs.systems }}
    steps:
      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
        with:
          sparse-checkout: |
            .github/actions
            ci/supportedBranches.js
            ci/supportedSystems.json
      - name: Check if the PR can be merged and get the test merge commit
        uses: ./.github/actions/get-merge-commit
        id: get-merge-commit

      - name: Load supported systems
        id: systems
        run: |
          echo "systems=$(jq -c <ci/supportedSystems.json)" >> "$GITHUB_OUTPUT"

      - name: Determine branch type
        id: branches
        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
        with:
          script: |
            const { classify } = require('./ci/supportedBranches.js')
            const { base, head } = context.payload.pull_request

            const baseClassification = classify(base.ref)
            core.setOutput('base', baseClassification)
            core.info('base classification:', baseClassification)

            const headClassification =
              (base.repo.full_name == head.repo.full_name) ?
              classify(head.ref) :
              // PRs from forks are always considered WIP.
              { type: ['wip'] }
            core.setOutput('head', headClassification)
            core.info('head classification:', headClassification)

  check:
    name: Check
    needs: [prepare]
    uses: ./.github/workflows/check.yml
    permissions:
      # cherry-picks
      pull-requests: write
    with:
      baseBranch: ${{ needs.prepare.outputs.baseBranch }}
      headBranch: ${{ needs.prepare.outputs.headBranch }}

  lint:
    name: Lint
    needs: [prepare]
    uses: ./.github/workflows/lint.yml
    with:
      mergedSha: ${{ needs.prepare.outputs.mergedSha }}
      targetSha: ${{ needs.prepare.outputs.targetSha }}

  eval:
    name: Eval
    needs: [prepare]
    uses: ./.github/workflows/eval.yml
    permissions:
      # compare
      statuses: write
    secrets:
      OWNER_APP_PRIVATE_KEY: ${{ secrets.OWNER_APP_PRIVATE_KEY }}
    with:
      mergedSha: ${{ needs.prepare.outputs.mergedSha }}
      targetSha: ${{ needs.prepare.outputs.targetSha }}
      systems: ${{ needs.prepare.outputs.systems }}

  labels:
    name: Labels
    needs: [prepare, eval]
    uses: ./.github/workflows/labels.yml
    permissions:
      issues: write
      pull-requests: write
    secrets:
      NIXPKGS_CI_APP_PRIVATE_KEY: ${{ secrets.NIXPKGS_CI_APP_PRIVATE_KEY }}
    with:
      headBranch: ${{ needs.prepare.outputs.headBranch }}

  reviewers:
    name: Reviewers
    needs: [prepare, eval]
    if: |
      needs.prepare.outputs.targetSha &&
      !contains(fromJSON(needs.prepare.outputs.headBranch).type, 'development')
    uses: ./.github/workflows/reviewers.yml
    secrets:
      OWNER_APP_PRIVATE_KEY: ${{ secrets.OWNER_APP_PRIVATE_KEY }}

  build:
    name: Build
    needs: [prepare]
    uses: ./.github/workflows/build.yml
    secrets:
      CACHIX_AUTH_TOKEN: ${{ secrets.CACHIX_AUTH_TOKEN }}
    with:
      baseBranch: ${{ needs.prepare.outputs.baseBranch }}
      mergedSha: ${{ needs.prepare.outputs.mergedSha }}

  # This job's only purpose is to serve as a target for the "Required Status Checks" branch ruleset.
  # It "needs" all the jobs that should block merging a PR.
  # If they pass, it is skipped — which counts as "success" for purposes of the branch ruleset.
  # However, if any of them fail, this job will also fail — thus blocking the branch ruleset.
  no-pr-failures:
    # Modify this list to add or remove jobs from required status checks.
    needs:
      - check
      - lint
      - eval
      - build
    # WARNING:
    # Do NOT change the name of this job, otherwise the rule will not catch it anymore.
    # This would prevent all PRs from merging.
    name: no PR failures
    if: ${{ failure() }}
    runs-on: ubuntu-24.04-arm
    steps:
      - run: exit 1