name: Select E2E version matrix
description: >
  Emits the full version array or a reduced [min, max] array depending on whether
  the event's changed files match the given SDK-touching regex. Full matrix on
  workflow_dispatch and when any changed file matches the regex; min+max otherwise.

inputs:
  all-versions:
    required: true
    description: JSON array of all supported versions (e.g. '["3.10","3.14"]').
  match-regex:
    required: true
    description: POSIX extended regex; any changed file matching it forces the full matrix.
  github-token:
    required: true
    description: Token used to list PR/commit files via the GitHub API.

outputs:
  versions:
    description: JSON array of versions the caller should feed into its strategy matrix.
    value: ${{ steps.pick.outputs.versions }}

runs:
  using: composite
  steps:
    - id: pick
      shell: bash
      env:
        GH_TOKEN: ${{ inputs.github-token }}
        ALL: ${{ inputs.all-versions }}
        REGEX: ${{ inputs.match-regex }}
        REPO: ${{ github.repository }}
        EVENT: ${{ github.event_name }}
        PR_NUMBER: ${{ github.event.pull_request.number }}
        BEFORE: ${{ github.event.before }}
        SHA: ${{ github.sha }}
      run: |
        set -euo pipefail
        if [ "$EVENT" = "workflow_dispatch" ]; then
            echo "versions=$ALL" >> "$GITHUB_OUTPUT"
            exit 0
        fi
        if [ "$EVENT" = "pull_request" ]; then
            FILES=$(gh api --paginate "repos/$REPO/pulls/$PR_NUMBER/files" --jq '.[].filename')
        elif [ -n "$BEFORE" ] && [ "$BEFORE" != "0000000000000000000000000000000000000000" ]; then
            # Aggregate across the full push range so multi-commit pushes (rebase-merge, direct pushes)
            # don't miss SDK-touching files landed in non-tip commits.
            FILES=$(gh api "repos/$REPO/compare/$BEFORE...$SHA" --jq '.files[].filename')
        else
            # Branch creation / force-push: before is zero or missing; fall back to tip.
            FILES=$(gh api "repos/$REPO/commits/$SHA" --jq '.files[].filename')
        fi
        # Default to full matrix on empty file list so a degenerate API response
        # never silently under-tests.
        if [ -z "$FILES" ] || echo "$FILES" | grep -Eq "$REGEX"; then
            echo "versions=$ALL" >> "$GITHUB_OUTPUT"
        else
            echo "versions=$(echo "$ALL" | jq -c '[.[0], .[-1]]')" >> "$GITHUB_OUTPUT"
        fi