name: Lint

on:
  pull_request:
    branches: [master]
  workflow_dispatch:

# Diff-only enforcement: clang-format and clang-tidy run only on lines changed
# in the PR. Existing files keep their current style until they're edited.
# See .clang-format and .clang-tidy for the rule sets.

jobs:
  clang-format-diff:
    runs-on: ubuntu-22.04
    steps:
      - uses: actions/checkout@v4
        with:
          # Need merge-base with target branch to compute the diff.
          fetch-depth: 0

      - name: Install clang-format
        run: |
          sudo apt-get update
          sudo apt-get install -y clang-format-15
          sudo ln -sf /usr/bin/clang-format-15 /usr/local/bin/clang-format

      - name: Check format on changed lines
        run: |
          BASE_SHA=$(git merge-base origin/${{ github.base_ref }} HEAD)
          echo "Comparing against merge-base: $BASE_SHA"

          # git-clang-format prints a diff if any changed line violates style.
          # --diff exits non-zero when reformatting would change something.
          OUTPUT=$(git clang-format --diff "$BASE_SHA" -- '*.cpp' '*.h' '*.hpp' '*.cc' || true)

          if [ -z "$OUTPUT" ] || [ "$OUTPUT" = "no modified files to format" ] || [ "$OUTPUT" = "clang-format did not modify any files" ]; then
            echo "clang-format: clean"
            exit 0
          fi

          echo "::error::clang-format wants to change the following on lines you touched."
          echo "Run \`git clang-format $BASE_SHA\` locally and commit the result."
          echo "$OUTPUT"
          exit 1

  clang-tidy-diff:
    runs-on: ubuntu-22.04
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
          submodules: recursive

      - name: Install dependencies + clang-tidy
        run: |
          sudo apt-get update
          sudo apt-get install -y build-essential cmake ninja-build clang-tidy-15 \
            libboost-all-dev libssl-dev libdb++-dev libleveldb-dev \
            libevent-dev libminiupnpc-dev zlib1g-dev \
            libsnappy-dev liblz4-dev libzstd-dev libsqlite3-dev
          sudo ln -sf /usr/bin/clang-tidy-15 /usr/local/bin/clang-tidy

      - name: Build RocksDB from source
        # Ubuntu 22.04's librocksdb-dev is 6.11.4 which CMakeLists.txt now
        # refuses to configure against (need >= 7.4 for XXH3 per-block
        # checksum). Build 8.9.1 from source — same version DNS2 ships —
        # into /usr/local so CMake's find_library picks it up first.
        run: sudo bash scripts/ci/build-rocksdb.sh

      - name: Configure (export compile_commands.json)
        run: |
          cmake -B build -G Ninja \
            -DCMAKE_BUILD_TYPE=Debug \
            -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
            -DBUILD_QT=OFF \
            -DBUILD_DAEMON=ON \
            -DBUILD_TESTS=ON \
            -DUSE_UPNP=OFF

      - name: Generate build artifacts that headers depend on
        # build.h, qt UI headers, etc. — clang-tidy needs them to parse sources.
        run: cmake --build build --target generate_build_info

      - name: Run clang-tidy on changed lines
        run: |
          BASE_SHA=$(git merge-base origin/${{ github.base_ref }} HEAD)
          echo "Comparing against merge-base: $BASE_SHA"

          # clang-tidy-diff.py ships with clang-tidy; runs tidy only on changed lines.
          DIFF_SCRIPT=$(dpkg -L clang-tidy-15 | grep clang-tidy-diff.py | head -1)
          if [ -z "$DIFF_SCRIPT" ]; then
            DIFF_SCRIPT=/usr/share/clang/clang-tidy-diff.py
          fi
          echo "Using: $DIFF_SCRIPT"

          # -p1 strips the leading "a/"/"b/" from git diff paths.
          # -path=build points clang-tidy at compile_commands.json.
          # -iregex restricts to project sources (not vendored).
          git diff -U0 "$BASE_SHA" -- 'src/*.cpp' 'src/*.h' \
            ':(exclude)src/json/nlohmann_json.hpp' \
            ':(exclude)src/leveldb/*' \
            ':(exclude)src/lz4/*' \
            ':(exclude)src/tor/tor-src/*' \
            | python3 "$DIFF_SCRIPT" -p1 -path build \
                -iregex '.*\.(cpp|cc|h|hpp)$' \
                -j$(nproc) || EXIT=$?

          # Warn-only initially. Flip this to `exit ${EXIT:-0}` once we're clean.
          exit 0