name: CI

on:
  pull_request:
    branches: [dev, main]
  push:
    branches: [dev, main]

jobs:
  engine:
    name: Engine (Linux, CPU)
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Build glm
        run: cd c && make glm
      - name: C test suite
        run: cd c && make test-c

  engine-cuda-syntax:
    name: CUDA syntax check
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Install CUDA toolkit (compiler only)
        uses: Jimver/cuda-toolkit@v0.2.19
        with:
          # v0.2.19's version table stops at 12.6.2 — 12.6.3 fails the install
          # step with "Version not available" before nvcc is ever reached.
          cuda: '12.6.2'
          method: network
          sub-packages: '["nvcc"]'
      - name: Compile backend_cuda.cu (syntax only, no GPU)
        run: |
          cd c
          # NOT `nvcc ... | head -40`: a pipeline exits with the status of its
          # LAST command, so head's 0 masked every nvcc error and the job could
          # only ever be green. A check that cannot fail is worse than no check —
          # it buys false confidence in the one file nothing else compiles.
          nvcc -O2 -std=c++17 -arch=sm_80 -c backend_cuda.cu -o /dev/null \
            -Xcompiler=-Wall,-Wextra
          echo "CUDA syntax check passed"

  windows-cuda-build:
    # The Windows CUDA path has no coverage anywhere: `engine-cuda-syntax` above
    # compiles with nvcc's *GCC* host on Linux, and check.yml's windows job is
    # MinGW/UCRT64 CPU-only by design (#140). But nvcc on Windows requires MSVC
    # as its host compiler — it does not accept MinGW — so `make cuda-dll` runs a
    # toolchain nothing else in CI touches. That gap is not theoretical: every
    # bug in #158 was a *build* failure on this path (MSVC rejects the GCC-style
    # -Xcompiler=-Wall,-Wextra with "D8021 invalid numeric argument '/Wextra'",
    # unresolvable CUDA_HOME/NVCC defaults, POSIX setenv in the kernel test), and
    # #314 was CUDA_HOME with spaces — the layout the CUDA installer ships by
    # default. Both classes are compile-time and need no GPU to catch.
    #
    # Build-only ON PURPOSE: GitHub's hosted runners have no NVIDIA device, so
    # this job proves the Windows+MSVC CUDA build stays buildable, NOT that the
    # kernels or the DLL loader behave on real silicon. That still needs hardware
    # (see #157). Claiming otherwise would be the false confidence the
    # engine-cuda-syntax comment above already warns about.
    name: CUDA build (Windows, MSVC host)
    # windows-2022, NOT windows-latest: the latest image now ships Visual Studio
    # 18 (MSVC 14.5x), and CUDA's crt/host_config.h hard-errors on any host newer
    # than VS 2022 ("Only the versions between 2017 and 2022 (inclusive) are
    # supported"). That is a real constraint for every CUDA user on Windows, not
    # a CI quirk — pinning tracks what the toolkit actually supports. Revisit when
    # a CUDA release accepts VS 18; -allow-unsupported-compiler would only mask it.
    runs-on: windows-2022
    steps:
      - uses: actions/checkout@v4
      - name: MSVC environment (puts cl.exe on PATH for nvcc -ccbin)
        uses: ilammy/msvc-dev-cmd@v1
      - name: Install CUDA toolkit (compiler only)
        uses: Jimver/cuda-toolkit@v0.2.19
        with:
          # Same pin as engine-cuda-syntax: v0.2.19's version table stops at
          # 12.6.2. This installs to the default "C:\Program Files\NVIDIA GPU
          # Computing Toolkit\..." path, so CUDA_HOME is space-bearing here —
          # which is exactly the #314 regression this job would have caught.
          cuda: '12.6.2'
          method: network
          # cudart as well as nvcc: unlike the Linux job (which only needs to
          # *compile* backend_cuda.cu), cuda-dll links it, and on Windows the
          # runtime headers/import lib ship as a separate installer component —
          # with '["nvcc"]' alone this fails at `#include <cuda_runtime.h>`.
          sub-packages: '["nvcc", "cudart"]'
      - uses: msys2/setup-msys2@v2
        with:
          msystem: UCRT64
          update: false
          # inherit: cl.exe (msvc-dev-cmd) and nvcc (cuda-toolkit) are added to
          # the *Windows* PATH by the steps above; without inheriting it the
          # recipe's `command -v` guards fail inside the MSYS2 shell.
          path-type: inherit
          install: >-
            make
            mingw-w64-ucrt-x86_64-gcc
      - name: make cuda-dll (nvcc + MSVC host)
        shell: msys2 {0}
        run: |
          cd c
          # CUDA_ARCH is pinned: the default is `native`, which asks the driver
          # what card is present — there is none here, so it must be explicit.
          # sm_80 matches engine-cuda-syntax and is supported by the 12.6 pin.
          make cuda-dll CUDA_ARCH=sm_80
          test -f coli_cuda.dll || { echo "cuda-dll reported success but produced no DLL" >&2; exit 1; }
          echo "coli_cuda.dll built (MSVC host)"
      - name: make glm CUDA_DLL=1 (host links backend_loader, not cudart)
        shell: msys2 {0}
        run: |
          cd c
          make glm CUDA_DLL=1
          test -f glm.exe || { echo "glm CUDA_DLL=1 reported success but produced no exe" >&2; exit 1; }
          echo "glm.exe built against the DLL loader"

  web:
    name: Web UI
    runs-on: ubuntu-latest
    defaults:
      run:
        working-directory: web
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '22'
          cache: npm
          cache-dependency-path: web/package-lock.json
      - run: npm ci
      - name: Build
        run: npm run build
      - name: Test
        run: npx vitest run

  python:
    name: Python tests
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: '3.12'
      - name: Python test suite
        run: cd c && python3 -m unittest discover -s tests -p 'test_*.py'