name: Check Source Text

# Source-hygiene + shell-script lint. Runs on drafts too - fast feedback.
#
# Checks:
#   * check-source-text.sh: trailing whitespace, hard tabs in C/H, CRLF,
#     BOM / non-ASCII.
#   * bash -n + shellcheck (warning level) on shell scripts.
#
# Scope:
#   * pull_request: only files changed in the PR (catches new violations
#     without failing on historical debt).
#   * push: scan the full tree (baseline guard on master).

on:
  push:
    branches: [ master, main ]
  pull_request:
    types: [opened, synchronize, reopened, ready_for_review]
    branches: [ master, main ]

concurrency:
  group: check-source-text-${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  check:
    runs-on: ubuntu-24.04
    timeout-minutes: 5
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install shellcheck
        uses: ./.github/actions/install-apt-deps
        with:
          packages: shellcheck

      - name: Collect files to check
        id: files
        run: |
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            BASE_SHA="${{ github.event.pull_request.base.sha }}"
            HEAD_SHA="${{ github.event.pull_request.head.sha }}"
            git diff --name-only --diff-filter=ACMR "$BASE_SHA" "$HEAD_SHA" \
              > changed.txt || true
            grep -E '\.sh$' changed.txt > changed-sh.txt || true
            echo "Files changed in PR:"
            cat changed.txt
            echo "Shell scripts changed:"
            cat changed-sh.txt
            echo "count=$(wc -l < changed.txt)"     >> "$GITHUB_OUTPUT"
            echo "sh_count=$(wc -l < changed-sh.txt)" >> "$GITHUB_OUTPUT"
          else
            : > changed.txt
            git ls-files '*.sh' > changed-sh.txt
            echo "count=0" >> "$GITHUB_OUTPUT"
            echo "sh_count=$(wc -l < changed-sh.txt)" >> "$GITHUB_OUTPUT"
          fi

      - name: Run check-source-text (PR changed files)
        if: github.event_name == 'pull_request' && steps.files.outputs.count != '0'
        run: |
          # shellcheck disable=SC2046
          ./.github/scripts/check-source-text.sh $(cat changed.txt)

      - name: Run check-source-text (full tree)
        if: github.event_name != 'pull_request'
        run: ./.github/scripts/check-source-text.sh

      - name: bash -n (syntax check)
        if: steps.files.outputs.sh_count != '0'
        run: |
          fail=0
          while IFS= read -r f; do
            [ -f "$f" ] || continue
            if ! bash -n "$f"; then
              echo "::error file=$f::bash -n syntax error"
              fail=1
            fi
          done < changed-sh.txt
          exit "$fail"

      - name: shellcheck (warning level)
        if: steps.files.outputs.sh_count != '0'
        run: |
          # Mirrors the internal multi-test check-shell-scripts subtest:
          #   --severity=warning
          #   -e SC2226,SC2166,SC2164,SC2046,SC2034,SC2188,SC2043
          # SC2226 (no ln destination), SC2166 ([ p -a q ]), SC2164 (cd ||),
          # SC2046 (word splitting), SC2034 (unused var), SC2188 (redirect
          # w/o command), SC2043 (loop runs once) - common in this codebase,
          # suppressed in the internal multi-test for the same reason.
          fail=0
          while IFS= read -r f; do
            [ -f "$f" ] || continue
            if ! shellcheck --severity=warning \
                            --exclude=SC2226,SC2166,SC2164,SC2046,SC2034,SC2188,SC2043 \
                            --format=gcc "$f"; then
              fail=1
            fi
          done < changed-sh.txt
          exit "$fail"