import { assert, assertEquals } from "./test_util.ts";

let isCI: boolean;
try {
  isCI = (Deno.env.get("CI")?.length ?? 0) > 0;
} catch {
  isCI = true;
}

// Skip these tests on linux CI, because the vulkan emulator is not good enough
// yet, and skip on macOS CI because these do not have virtual GPUs.
const isLinuxOrMacCI =
  (Deno.build.os === "linux" || Deno.build.os === "darwin") && isCI;
// Skip these tests in WSL because it doesn't have good GPU support.
const isWsl = await checkIsWsl();

Deno.test({
  permissions: { read: true, env: true },
  ignore: isWsl || isLinuxOrMacCI,
}, async function webgpuComputePass() {
  const adapter = await navigator.gpu.requestAdapter();
  assert(adapter);

  const numbers = [1, 4, 3, 295];

  const device = await adapter.requestDevice();
  assert(device);

  const shaderCode = await Deno.readTextFile(
    "cli/tests/testdata/webgpu/computepass_shader.wgsl",
  );

  const shaderModule = device.createShaderModule({
    code: shaderCode,
  });

  const size = new Uint32Array(numbers).byteLength;

  const stagingBuffer = device.createBuffer({
    size: size,
    usage: GPUBufferUsage.MAP_READ | GPUBufferUsage.COPY_DST,
  });

  const storageBuffer = device.createBuffer({
    label: "Storage Buffer",
    size: size,
    usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST |
      GPUBufferUsage.COPY_SRC,
    mappedAtCreation: true,
  });

  const buf = new Uint32Array(storageBuffer.getMappedRange());

  buf.set(numbers);

  storageBuffer.unmap();

  const computePipeline = device.createComputePipeline({
    layout: "auto",
    compute: {
      module: shaderModule,
      entryPoint: "main",
    },
  });
  const bindGroupLayout = computePipeline.getBindGroupLayout(0);

  const bindGroup = device.createBindGroup({
    layout: bindGroupLayout,
    entries: [
      {
        binding: 0,
        resource: {
          buffer: storageBuffer,
        },
      },
    ],
  });

  const encoder = device.createCommandEncoder();

  const computePass = encoder.beginComputePass();
  computePass.setPipeline(computePipeline);
  computePass.setBindGroup(0, bindGroup);
  computePass.insertDebugMarker("compute collatz iterations");
  computePass.dispatchWorkgroups(numbers.length);
  computePass.end();

  encoder.copyBufferToBuffer(storageBuffer, 0, stagingBuffer, 0, size);

  device.queue.submit([encoder.finish()]);

  await stagingBuffer.mapAsync(1);

  const data = stagingBuffer.getMappedRange();

  assertEquals(new Uint32Array(data), new Uint32Array([0, 2, 7, 55]));

  stagingBuffer.unmap();

  device.destroy();

  // TODO(lucacasonato): webgpu spec should add a explicit destroy method for
  // adapters.
  const resources = Object.keys(Deno.resources());
  Deno.close(Number(resources[resources.length - 1]));
});

Deno.test({
  permissions: { read: true, env: true },
  ignore: isWsl || isLinuxOrMacCI,
}, async function webgpuHelloTriangle() {
  const adapter = await navigator.gpu.requestAdapter();
  assert(adapter);

  const device = await adapter.requestDevice();
  assert(device);

  const shaderCode = await Deno.readTextFile(
    "cli/tests/testdata/webgpu/hellotriangle_shader.wgsl",
  );

  const shaderModule = device.createShaderModule({
    code: shaderCode,
  });

  const pipelineLayout = device.createPipelineLayout({
    bindGroupLayouts: [],
  });

  const renderPipeline = device.createRenderPipeline({
    layout: pipelineLayout,
    vertex: {
      module: shaderModule,
      entryPoint: "vs_main",
    },
    fragment: {
      module: shaderModule,
      entryPoint: "fs_main",
      targets: [
        {
          format: "rgba8unorm-srgb",
        },
      ],
    },
  });

  const dimensions = {
    width: 200,
    height: 200,
  };
  const unpaddedBytesPerRow = dimensions.width * 4;
  const align = 256;
  const paddedBytesPerRowPadding = (align - unpaddedBytesPerRow % align) %
    align;
  const paddedBytesPerRow = unpaddedBytesPerRow + paddedBytesPerRowPadding;

  const outputBuffer = device.createBuffer({
    label: "Capture",
    size: paddedBytesPerRow * dimensions.height,
    usage: GPUBufferUsage.MAP_READ | GPUBufferUsage.COPY_DST,
  });
  const texture = device.createTexture({
    label: "Capture",
    size: dimensions,
    format: "rgba8unorm-srgb",
    usage: GPUTextureUsage.RENDER_ATTACHMENT | GPUTextureUsage.COPY_SRC,
  });

  const encoder = device.createCommandEncoder();
  const view = texture.createView();
  const renderPass = encoder.beginRenderPass({
    colorAttachments: [
      {
        view,
        storeOp: "store",
        loadOp: "clear",
        clearValue: [0, 1, 0, 1],
      },
    ],
  });
  renderPass.setPipeline(renderPipeline);
  renderPass.draw(3, 1);
  renderPass.end();

  encoder.copyTextureToBuffer(
    {
      texture,
    },
    {
      buffer: outputBuffer,
      bytesPerRow: paddedBytesPerRow,
      rowsPerImage: 0,
    },
    dimensions,
  );

  const bundle = encoder.finish();
  device.queue.submit([bundle]);

  await outputBuffer.mapAsync(1);
  const data = new Uint8Array(outputBuffer.getMappedRange());

  assertEquals(
    data,
    await Deno.readFile("cli/tests/testdata/webgpu/hellotriangle.out"),
  );

  outputBuffer.unmap();

  device.destroy();

  // TODO(lucacasonato): webgpu spec should add a explicit destroy method for
  // adapters.
  const resources = Object.keys(Deno.resources());
  Deno.close(Number(resources[resources.length - 1]));
});

async function checkIsWsl() {
  return Deno.build.os === "linux" && await hasMicrosoftProcVersion();

  async function hasMicrosoftProcVersion() {
    // https://github.com/microsoft/WSL/issues/423#issuecomment-221627364
    try {
      const procVersion = await Deno.readTextFile("/proc/version");
      return /microsoft/i.test(procVersion);
    } catch {
      return false;
    }
  }
}