# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
import pytest
import torch

from tests.kernels.moe.utils import make_test_quant_config
from tests.kernels.quantization.nvfp4_utils import (
    FLOAT4_E2M1_MAX,
    FLOAT8_E4M3_MAX,
    dequantize_nvfp4_to_dtype,
)
from tests.kernels.utils import torch_moe
from vllm import _custom_ops as ops
from vllm.config import ParallelConfig, VllmConfig, set_current_vllm_config
from vllm.model_executor.layers.fused_moe import fused_topk
from vllm.model_executor.layers.fused_moe.config import (
    FusedMoEConfig,
    FusedMoEParallelConfig,
    RoutingMethodType,
)
from vllm.model_executor.layers.fused_moe.flashinfer_cutlass_moe import (
    FlashInferExperts,
    is_valid_flashinfer_cutlass_fused_moe,
)
from vllm.model_executor.layers.fused_moe.modular_kernel import FusedMoEModularKernel
from vllm.model_executor.layers.fused_moe.prepare_finalize import (
    MoEPrepareAndFinalizeNoEP,
)
from vllm.platforms import current_platform
from vllm.utils.flashinfer import has_flashinfer_cutlass_fused_moe
from vllm.utils.torch_utils import set_random_seed

if not has_flashinfer_cutlass_fused_moe() or not current_platform.has_device_capability(
    100
):
    pytest.skip(
        "Requires flashinfer_cutlass_fused_moe and nvfp4 support",
        allow_module_level=True,
    )

MNK_FACTORS = [
    (2, 1024, 1024),
    (2, 3072, 1024),
    (2, 3072, 1536),
    (64, 1024, 1536),
    (64, 3072, 1024),
    (64, 2048, 1536),
    (224, 1024, 1024),
    (224, 1024, 1536),
]


@pytest.mark.parametrize("m,n,k", MNK_FACTORS)
@pytest.mark.parametrize("e", [40, 64, 256])
@pytest.mark.parametrize("topk", [1, 6, 8])
@pytest.mark.parametrize("dtype", [torch.bfloat16])
@pytest.mark.parametrize("activation", ["silu_and_mul", "relu2"])
@torch.inference_mode()
def test_flashinfer_fp4_moe_no_graph(
    m: int,
    n: int,
    k: int,
    e: int,
    topk: int,
    dtype: torch.dtype,
    activation: str,
    workspace_init,
):
    set_random_seed(7)
    with set_current_vllm_config(
        VllmConfig(parallel_config=ParallelConfig(pipeline_parallel_size=1))
    ):
        a = torch.randn((m, k), device="cuda", dtype=dtype) / 10

        quant_blocksize = 16
        is_gated_act = activation == "silu_and_mul"

        w1_q, w2_q, quant_config = make_test_quant_config(
            e,
            n,
            k,
            in_dtype=dtype,
            quant_dtype="nvfp4",
            block_shape=None,
            per_act_token_quant=False,
            make_gate=is_gated_act,
        )

        score = torch.randn((m, e), device="cuda", dtype=dtype)
        topk_weights, topk_ids, _ = fused_topk(a, score, topk, renormalize=False)

        assert is_valid_flashinfer_cutlass_fused_moe(a, w1_q, w2_q)

        moe_config = FusedMoEConfig(
            num_experts=e,
            experts_per_token=topk,
            hidden_dim=k,
            intermediate_size_per_partition=n,
            num_local_experts=e,
            activation=activation,
            device="cuda",
            moe_parallel_config=FusedMoEParallelConfig.make_no_parallel(),
            in_dtype=dtype,
            is_act_and_mul=is_gated_act,
            routing_method=RoutingMethodType.TopK,
        )

        flashinfer_experts = FusedMoEModularKernel(
            MoEPrepareAndFinalizeNoEP(
                defer_input_quant=FlashInferExperts.expects_unquantized_inputs(
                    moe_config=moe_config,
                    quant_config=quant_config,
                )
            ),
            FlashInferExperts(moe_config=moe_config, quant_config=quant_config),
        )

        fi_activation = {"silu_and_mul": "silu", "relu2": "relu2_no_mul"}[activation]

        flashinfer_output = flashinfer_experts(
            hidden_states=a,
            w1=w1_q,
            w2=w2_q,
            topk_weights=topk_weights,
            topk_ids=topk_ids,
            activation=fi_activation,
        )

        # Reference check:
        a_global_scale = (
            (FLOAT8_E4M3_MAX * FLOAT4_E2M1_MAX) / torch.amax(a.flatten(), dim=-1)
        ).to(torch.float32)
        a_fp4, a_scale_interleaved = ops.scaled_fp4_quant(a, a_global_scale)
        _, m_k = a_fp4.shape
        a_in_dtype = dequantize_nvfp4_to_dtype(
            a_fp4,
            a_scale_interleaved,
            a_global_scale,
            dtype=a.dtype,
            device=a.device,
            block_size=quant_blocksize,
        )

        w1_d = torch.empty(
            (e, (2 if is_gated_act else 1) * n, k), device="cuda", dtype=dtype
        )
        w2_d = torch.empty((e, k, n), device="cuda", dtype=dtype)

        for idx in range(0, e):
            w1_d[idx] = dequantize_nvfp4_to_dtype(
                w1_q[idx],
                quant_config.w1_scale[idx],
                (1 / quant_config.g1_alphas[idx]),
                dtype=dtype,
                device=w1_q.device,
                block_size=quant_blocksize,
            )
            w2_d[idx] = dequantize_nvfp4_to_dtype(
                w2_q[idx],
                quant_config.w2_scale[idx],
                (1 / quant_config.g2_alphas[idx]),
                dtype=dtype,
                device=w2_q.device,
                block_size=quant_blocksize,
            )

        torch_output = torch_moe(
            a_in_dtype, w1_d, w2_d, score, topk, activation=activation
        )

        torch.testing.assert_close(
            torch_output, flashinfer_output, atol=1e-1, rtol=1e-1
        )


if __name__ == "__main__":
    test_flashinfer_fp4_moe_no_graph((2, 1024, 1024), 40, 1, torch.half)