name: Detect Relevant Changes

on:
  workflow_call:
    inputs:
      area:
        description: Test area whose existing path scope should be evaluated
        required: true
        type: string
    outputs:
      relevant:
        description: Whether the caller's tests are relevant to this event
        value: ${{ jobs.detect.outputs.relevant }}

permissions:
  contents: read
  pull-requests: read

jobs:
  detect:
    runs-on: ubuntu-latest
    outputs:
      relevant: ${{ steps.changes.outputs.relevant }}
    steps:
      - name: Detect relevant changes
        id: changes
        uses: actions/github-script@v7
        env:
          AREA: ${{ inputs.area }}
        with:
          script: |
            if (context.eventName !== "pull_request") {
              core.info(`Running ${process.env.AREA} tests for ${context.eventName}.`);
              core.setOutput("relevant", "true");
              return;
            }

            const files = await github.paginate(github.rest.pulls.listFiles, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.payload.pull_request.number,
              per_page: 100,
            });
            const paths = files.flatMap((file) =>
              [file.filename, file.previous_filename].filter(Boolean),
            );

            const workflowChanged = (path, caller) =>
              path === ".github/workflows/detect-changes.yml" ||
              path === `.github/workflows/${caller}`;

            const matchers = {
              server: (path) =>
                workflowChanged(path, "server-test.yml") ||
                path.startsWith("server/"),
              kubernetes: (path) =>
                workflowChanged(path, "kubernetes-test.yml") ||
                (path.startsWith("kubernetes/") &&
                  !path.startsWith("kubernetes/docs/")),
              "real-e2e": (path) =>
                workflowChanged(path, "real-e2e.yml") ||
                path.startsWith("server/opensandbox_server/") ||
                path.startsWith("components/execd/") ||
                path.startsWith("components/egress/") ||
                path.startsWith("sdks/") ||
                path.startsWith("tests/"),
              egress: (path) =>
                workflowChanged(path, "egress-test.yaml.yml") ||
                path.startsWith("components/egress/") ||
                path.startsWith("components/internal/"),
              "kubernetes-mini-e2e": (path) =>
                workflowChanged(path, "kubernetes-nightly-build.yml") ||
                path === "scripts/python-k8s-e2e.sh" ||
                path === "scripts/python-k8s-e2e-ingress.sh" ||
                path === "scripts/common/kubernetes-e2e.sh" ||
                path.startsWith("kubernetes/charts/"),
              ingress: (path) =>
                workflowChanged(path, "ingress-test.yaml") ||
                path.startsWith("components/ingress/") ||
                path.startsWith("components/internal/"),
              execd: (path) =>
                workflowChanged(path, "execd-test.yml") ||
                path.startsWith("components/execd/") ||
                path.startsWith("components/internal/"),
              sdk: (path) =>
                workflowChanged(path, "sdk-tests.yml") ||
                path.startsWith("cli/") ||
                path.startsWith("sdks/") ||
                path.startsWith("specs/"),
            };

            const area = process.env.AREA;
            if (!Object.hasOwn(matchers, area)) {
              core.setFailed(`Unknown test area: ${area}`);
              return;
            }

            const relevant = paths.some(matchers[area]);
            core.info(`${area}: relevant=${relevant}; files=${files.length}`);
            core.setOutput("relevant", String(relevant));