name: "Detect relevant changes"
description: >-
  Classify the pull request's changed files with .circleci/scripts/classify_changes.sh
  and expose decision=run|skip for one category. backend means anything outside ui/,
  docs/ and markdown; ui means the dashboard sources alone. decision=skip lets callers
  short-circuit expensive steps while the job still completes successfully and satisfies
  its required status check, which a paths: filter cannot do because a workflow that
  never starts never reports. The file list comes from the pull request itself rather
  than from a git diff, because the checked-out merge ref is recomputed as the base
  branch advances and would otherwise attribute the base branch's own commits to the
  pull request. The decision defaults to run for any non pull_request event or whenever
  the changed set cannot be resolved, so jobs are never skipped when the classification
  is uncertain.

inputs:
  category:
    description: "Which classification to apply: backend, client or ui"
    required: false
    default: backend
  github-token:
    description: "Token used to list the pull request's files; needs pull-requests: read"
    required: false
    default: ${{ github.token }}

outputs:
  decision:
    description: "run when category-relevant files changed, otherwise skip"
    value: ${{ steps.classify.outputs.decision }}

runs:
  using: composite
  steps:
    - id: classify
      shell: bash
      env:
        GH_TOKEN: ${{ inputs.github-token }}
        CATEGORY: ${{ inputs.category }}
        REPO: ${{ github.repository }}
        PR_NUMBER: ${{ github.event.pull_request.number }}
        CHANGED_FILE_COUNT: ${{ github.event.pull_request.changed_files }}
      run: bash "${GITHUB_ACTION_PATH}/../../scripts/detect_changes.sh"