export const description = `
Returns the atomically loaded the value pointed to by atomic_ptr. It does not modify the object.
`;

import { makeTestGroup } from '../../../../../../../common/framework/test_group.js';
import { keysOf } from '../../../../../../../common/util/data_tables.js';
import { GPUTest } from '../../../../../../gpu_test.js';

import { dispatchSizes, workgroupSizes, typedArrayCtor, kMapId } from './harness.js';

export const g = makeTestGroup(GPUTest);

g.test('load_storage')
  .specURL('https://www.w3.org/TR/WGSL/#atomic-load')
  .desc(
    `
AS is storage or workgroup
T is i32 or u32

fn atomicLoad(atomic_ptr: ptr<AS, atomic<T>, read_write>) -> T

`
  )
  .params(u =>
    u
      .combine('workgroupSize', workgroupSizes)
      .combine('dispatchSize', dispatchSizes)
      .combine('mapId', keysOf(kMapId))
      .combine('scalarType', ['u32', 'i32'])
  )
  .fn(t => {
    const numInvocations = t.params.workgroupSize * t.params.dispatchSize;
    const bufferNumElements = numInvocations;
    const scalarType = t.params.scalarType;
    const mapId = kMapId[t.params.mapId];

    const wgsl = `
      @group(0) @binding(0)
      var<storage, read_write> input : array<atomic<${scalarType}>>;

      @group(0) @binding(1)
      var<storage, read_write> output : array<${scalarType}>;

      @compute @workgroup_size(${t.params.workgroupSize})
      fn main(
          @builtin(global_invocation_id) global_invocation_id : vec3<u32>,
          ) {
        let id = ${scalarType}(global_invocation_id[0]);
        output[id] = atomicLoad(&input[id]);
      }
    `;

    const pipeline = t.device.createComputePipeline({
      layout: 'auto',
      compute: {
        module: t.device.createShaderModule({ code: wgsl }),
        entryPoint: 'main',
      },
    });

    const arrayType = typedArrayCtor(scalarType);

    // Create input buffer with values [map_id(0)..map_id(n)]
    const inputBuffer = t.device.createBuffer({
      size: bufferNumElements * arrayType.BYTES_PER_ELEMENT,
      usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_SRC,
      mappedAtCreation: true,
    });
    t.trackForCleanup(inputBuffer);
    const data = new arrayType(inputBuffer.getMappedRange());
    data.forEach((_, i) => (data[i] = mapId.f(i, numInvocations)));
    inputBuffer.unmap();

    const outputBuffer = t.device.createBuffer({
      size: bufferNumElements * arrayType.BYTES_PER_ELEMENT,
      usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_SRC,
    });
    t.trackForCleanup(outputBuffer);

    const bindGroup = t.device.createBindGroup({
      layout: pipeline.getBindGroupLayout(0),
      entries: [
        { binding: 0, resource: { buffer: inputBuffer } },
        { binding: 1, resource: { buffer: outputBuffer } },
      ],
    });

    // Run the shader.
    const encoder = t.device.createCommandEncoder();
    const pass = encoder.beginComputePass();
    pass.setPipeline(pipeline);
    pass.setBindGroup(0, bindGroup);
    pass.dispatchWorkgroups(t.params.dispatchSize);
    pass.end();
    t.queue.submit([encoder.finish()]);

    // Both input and output buffer should be the same now
    const expected = new (typedArrayCtor(t.params.scalarType))(bufferNumElements);
    expected.forEach((_, i) => (expected[i] = mapId.f(i, numInvocations)));
    t.expectGPUBufferValuesEqual(inputBuffer, expected);
    t.expectGPUBufferValuesEqual(outputBuffer, expected);
  });

g.test('load_workgroup')
  .specURL('https://www.w3.org/TR/WGSL/#atomic-load')
  .desc(
    `
AS is storage or workgroup
T is i32 or u32

fn atomicLoad(atomic_ptr: ptr<AS, atomic<T>, read_write>) -> T

`
  )
  .params(u =>
    u
      .combine('workgroupSize', workgroupSizes)
      .combine('dispatchSize', dispatchSizes)
      .combine('mapId', keysOf(kMapId))
      .combine('scalarType', ['u32', 'i32'])
  )
  .fn(t => {
    const numInvocations = t.params.workgroupSize;
    const wgNumElements = numInvocations;
    const scalarType = t.params.scalarType;
    const dispatchSize = t.params.dispatchSize;
    const mapId = kMapId[t.params.mapId];
    const extra = mapId.wgsl(numInvocations, t.params.scalarType); // Defines map_id()

    const wgsl =
      `
      var<workgroup> wg: array<atomic<${scalarType}>, ${wgNumElements}>;

      // Result of each workgroup is written to output[workgroup_id.x]
      @group(0) @binding(0)
      var<storage, read_write> output: array<${scalarType}, ${wgNumElements * dispatchSize}>;

      @compute @workgroup_size(${t.params.workgroupSize})
      fn main(
          @builtin(local_invocation_index) local_invocation_index: u32,
          @builtin(workgroup_id) workgroup_id : vec3<u32>
          ) {
        let id = ${scalarType}(local_invocation_index);
        let global_id = ${scalarType}(workgroup_id.x * ${wgNumElements} + local_invocation_index);

        // Initialize wg[id] with this invocations global id (mapped)
        atomicStore(&wg[id], map_id(global_id));
        workgroupBarrier();

        // Test atomic loading of value at wg[id] and store result in output[global_id]
        output[global_id] = atomicLoad(&wg[id]);
      }
      ` + extra;

    const pipeline = t.device.createComputePipeline({
      layout: 'auto',
      compute: {
        module: t.device.createShaderModule({ code: wgsl }),
        entryPoint: 'main',
      },
    });

    const arrayType = typedArrayCtor(scalarType);

    const outputBuffer = t.device.createBuffer({
      size: wgNumElements * dispatchSize * arrayType.BYTES_PER_ELEMENT,
      usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_SRC,
    });
    t.trackForCleanup(outputBuffer);

    const bindGroup = t.device.createBindGroup({
      layout: pipeline.getBindGroupLayout(0),
      entries: [{ binding: 0, resource: { buffer: outputBuffer } }],
    });

    // Run the shader.
    const encoder = t.device.createCommandEncoder();
    const pass = encoder.beginComputePass();
    pass.setPipeline(pipeline);
    pass.setBindGroup(0, bindGroup);
    pass.dispatchWorkgroups(dispatchSize);
    pass.end();
    t.queue.submit([encoder.finish()]);

    // Expected values should be map_id(0..n)
    const expected = new (typedArrayCtor(t.params.scalarType))(
      wgNumElements * t.params.dispatchSize
    );
    expected.forEach((_, i) => (expected[i] = mapId.f(i, numInvocations)));

    t.expectGPUBufferValuesEqual(outputBuffer, expected);
  });
