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

from collections.abc import Callable
from typing import Any, Optional

import torch
from packaging import version
from torch.nn import Module
from torch.nn.parameter import Parameter

from vllm._ipex_ops import ipex_ops as ops
from vllm.model_executor.layers.fused_moe import (
    FusedMoEMethodBase,
    FusedMoeWeightScaleSupported,
)
from vllm.model_executor.layers.fused_moe.config import FusedMoEQuantConfig
from vllm.model_executor.layers.linear import (
    LinearBase,
    LinearMethodBase,
    UnquantizedLinearMethod,
)
from vllm.model_executor.layers.quantization import (
    QuantizationConfig,
    QuantizationMethods,
)
from vllm.model_executor.layers.quantization.awq import (
    AWQLinearMethod,
    is_layer_skipped_awq,
)
from vllm.model_executor.layers.quantization.fp8 import Fp8Config, Fp8LinearMethod
from vllm.model_executor.layers.quantization.gptq import GPTQLinearMethod
from vllm.model_executor.utils import set_weight_attrs
from vllm.platforms import current_platform

MIN_IPEX_VERSION = "2.6.0"


class IPEXConfig(QuantizationConfig):
    """INT8 quantization config class using IPEX for the CPU/XPU backend,
    including AWQ, GPTQ.
    """

    IPEX_QUANT_METHOD_MAP = {
        "awq": 1,
        "gptq": 0,
    }

    def __init__(
        self,
        method: str,
        weight_bits: int,
        group_size: int,
        modules_to_not_convert: list[str] | None = None,
        desc_act: bool | None = None,
        lm_head_quantized: bool | None = None,
    ) -> None:
        super().__init__()
        self.method = method
        self.weight_bits = weight_bits
        self.group_size = group_size
        self.modules_to_not_convert = modules_to_not_convert or []
        self.desc_act = desc_act
        self.lm_head_quantized = lm_head_quantized
        self.pack_factor = 32 // self.weight_bits

        if self.weight_bits not in [4]:
            raise ValueError(
                f"IPEX quantization supports weight bits [4], "
                f"but got {self.weight_bits}."
            )

        if self.method not in ["awq", "gptq"]:
            raise ValueError(
                f"IPEX quantization supports [awq, gptq], but got {self.method}."
            )

    def __repr__(self) -> str:
        return (
            f"IPEXConfig(method={self.method},"
            f"weight_bits={self.weight_bits}, "
            f"group_size={self.group_size})"
        )

    @classmethod
    def get_name(cls) -> QuantizationMethods:
        return "ipex"

    @classmethod
    def get_supported_act_dtypes(cls) -> list[torch.dtype]:
        return [torch.bfloat16, torch.float16]

    @classmethod
    def get_min_capability(cls) -> int:
        return -1

    @staticmethod
    def get_config_filenames() -> list[str]:
        return [
            "quant_config.json",
            "quantize_config.json",
        ]

    @classmethod
    def from_config(cls, config: dict[str, Any]) -> "IPEXConfig":
        method = cls.get_from_keys(config, ["quant_method"]).lower()
        if method == "awq":
            weight_bits = cls.get_from_keys(config, ["w_bit", "bits"])
            group_size = cls.get_from_keys(config, ["q_group_size", "group_size"])
            modules_to_not_convert = cls.get_from_keys_or(
                config, ["modules_to_not_convert"], None
            )
            return cls(
                method, weight_bits, group_size, modules_to_not_convert, False, False
            )
        # otherwise for gptq
        weight_bits = cls.get_from_keys(config, ["bits"])
        group_size = cls.get_from_keys(config, ["group_size"])
        lm_head_quantized = cls.get_from_keys_or(config, ["lm_head"], default=False)
        desc_act = cls.get_from_keys_or(config, ["desc_act"], default=False)
        return cls(method, weight_bits, group_size, [], desc_act, lm_head_quantized)

    @classmethod
    def override_quantization_method(
        cls, hf_quant_cfg, user_quant
    ) -> QuantizationMethods | None:
        if not current_platform.is_cpu() and not current_platform.is_xpu():
            return None

        quant_method = hf_quant_cfg.get("quant_method", "").lower()

        if quant_method in ["awq", "gptq"]:
            return cls.get_name()

        return None

    def get_quant_method(
        self, layer: torch.nn.Module, prefix: str
    ) -> Optional["LinearMethodBase"]:
        if isinstance(layer, LinearBase):
            if self.method == "awq":
                if is_layer_skipped_awq(prefix, self.modules_to_not_convert):
                    return UnquantizedLinearMethod()
                return IPEXAWQLinearMethod(self)
            if self.method == "gptq":
                return IPEXGPTQLinearMethod(self)
        return None


class IPEXGPTQLinearMethod(GPTQLinearMethod):
    """GPTQ linear method using IPEX for the CPU/XPU backend."""

    def __init__(self, quant_config: IPEXConfig):
        self.quant_config = quant_config  # type: ignore

    def process_weights_after_loading(self, layer: torch.nn.Module) -> None:
        bias = layer.bias if not layer.skip_bias_add else None

        try:
            import intel_extension_for_pytorch as ipex

            if version.parse(ipex.__version__) < version.parse(MIN_IPEX_VERSION):
                raise ImportError(
                    "intel_extension_for_pytorch version is "
                    "wrong. Please install "
                    f"intel_extension_for_pytorch>={MIN_IPEX_VERSION}."
                )
        except ImportError as err:
            raise ImportError(
                "Please install "
                f"intel_extension_for_pytorch>={MIN_IPEX_VERSION} via "
                f"`pip install intel_extension_for_pytorch>={MIN_IPEX_VERSION}`"
                " to use IPEX-AWQ linear method."
            ) from err
        # Using the compute dtype (lowp_mode) as INT8 to leverage instructions
        # with better performance.
        lowp_mode = ipex.quantization.WoqLowpMode.INT8
        # The weight will be de-packed from INT4 to INT8.
        weight_dtype = ipex.quantization.WoqWeightDtype.INT4
        # The float activation will be quantized (dynamic, per-token) to INT8.
        act_quant_mode = ipex.quantization.WoqActQuantMode.PER_BATCH_IC_BLOCK

        qconfig = ipex.quantization.get_weight_only_quant_qconfig_mapping(
            weight_dtype=weight_dtype,
            lowp_mode=lowp_mode,
            act_quant_mode=act_quant_mode,
            group_size=self.quant_config.group_size,
        )
        layer.ipex_output_size = layer.qweight.shape[-1]
        g_idx = layer.g_idx if self.quant_config.desc_act else None
        layer.ipex_qlinear = (
            ipex.llm.quantization.woq_linear.IPEXWeightOnlyQuantizedLinear.from_weight(
                layer.qweight,
                layer.scales,
                layer.qzeros,
                layer.qweight.size(0),
                layer.ipex_output_size,
                qconfig=qconfig,
                g_idx=g_idx,
                bias=bias,
                group_size=self.quant_config.group_size,
                quant_method=IPEXConfig.IPEX_QUANT_METHOD_MAP["gptq"],
            )
        )

    def apply(
        self,
        layer: torch.nn.Module,
        x: torch.Tensor,
        bias: torch.Tensor | None = None,
    ) -> torch.Tensor:
        reshaped_x = x.reshape(-1, x.shape[-1])
        out = layer.ipex_qlinear(reshaped_x)
        return out.reshape(x.shape[:-1] + (layer.ipex_output_size,))


class IPEXAWQLinearMethod(AWQLinearMethod):
    """AWQ linear method using IPEX for the CPU/XPU backend."""

    def __init__(self, quant_config: IPEXConfig):
        self.quant_config = quant_config  # type: ignore

    def process_weights_after_loading(self, layer: torch.nn.Module) -> None:
        super().process_weights_after_loading(layer=layer)

        bias = layer.bias if not layer.skip_bias_add else None

        try:
            import intel_extension_for_pytorch as ipex

            if version.parse(ipex.__version__) < version.parse(MIN_IPEX_VERSION):
                raise ImportError(
                    "intel_extension_for_pytorch version is "
                    "wrong. Please install "
                    f"intel_extension_for_pytorch>={MIN_IPEX_VERSION}."
                )
        except ImportError as err:
            raise ImportError(
                "Please install "
                f"intel_extension_for_pytorch>={MIN_IPEX_VERSION} via "
                f"`pip install intel_extension_for_pytorch>={MIN_IPEX_VERSION}`"
                " to use IPEX-AWQ linear method."
            ) from err

        # Using the compute dtype (lowp_mode) as INT8 to leverage instructions
        # with better performance.
        lowp_mode = ipex.quantization.WoqLowpMode.INT8
        # The weight will be de-packed from INT4 to INT8.
        weight_dtype = ipex.quantization.WoqWeightDtype.INT4
        # The float activation will be quantized (dynamic, per-token) to INT8.
        act_quant_mode = ipex.quantization.WoqActQuantMode.PER_BATCH

        qconfig = ipex.quantization.get_weight_only_quant_qconfig_mapping(
            weight_dtype=weight_dtype,
            lowp_mode=lowp_mode,
            act_quant_mode=act_quant_mode,
            group_size=self.quant_config.group_size,
        )

        layer.ipex_output_size = layer.qweight.size(1) * self.quant_config.pack_factor
        layer.ipex_qlinear = (
            ipex.llm.quantization.woq_linear.IPEXWeightOnlyQuantizedLinear.from_weight(
                layer.qweight,
                layer.scales,
                layer.qzeros,
                layer.qweight.size(0),
                layer.ipex_output_size,
                qconfig=qconfig,
                bias=bias,
                group_size=self.quant_config.group_size,
                quant_method=IPEXConfig.IPEX_QUANT_METHOD_MAP["awq"],  # type: ignore
            )
        )

    def apply(
        self,
        layer: torch.nn.Module,
        x: torch.Tensor,
        bias: torch.Tensor | None = None,
    ) -> torch.Tensor:
        reshaped_x = x.reshape(-1, x.shape[-1])
        out = layer.ipex_qlinear(reshaped_x)
        return out.reshape(x.shape[:-1] + (layer.ipex_output_size,))


class XPUFp8LinearMethod(Fp8LinearMethod):
    def __init__(self, quant_config: Fp8Config):
        super().__init__(quant_config)

    def process_weights_after_loading(self, layer: Module) -> None:
        # If checkpoint not serialized fp8, quantize the weights.
        if not self.quant_config.is_checkpoint_fp8_serialized:
            qweight, weight_scale = ops.scaled_fp8_quant(layer.weight, scale=None)
            # Update the layer with the new values.
            layer.weight = Parameter(qweight, requires_grad=False)
            layer.weight_scale = Parameter(weight_scale, requires_grad=False)
            layer.input_scale = None

    def apply(
        self,
        layer: torch.nn.Module,
        x: torch.Tensor,
        bias: torch.Tensor | None = None,
    ) -> torch.Tensor:
        weight = layer.weight.data
        weight_scale = layer.weight_scale.data
        output = torch.ops.torch_ipex.fp8_gemm_w8a16(
            x, weight, True, weight_scale, bias
        )
        return output


class XPUFp8MoEMethod(FusedMoEMethodBase):
    def __init__(self, quant_config: Fp8Config, layer: torch.nn.Module):
        super().__init__(layer.moe_config)
        self.quant_config = quant_config

    def create_weights(
        self,
        layer: Module,
        num_experts: int,
        hidden_size: int,
        intermediate_size_per_partition: int,
        params_dtype: torch.dtype,
        **extra_weight_attrs,
    ):
        layer.intermediate_size_per_partition = intermediate_size_per_partition
        layer.hidden_size = hidden_size
        layer.num_experts = num_experts
        layer.orig_dtype = params_dtype
        layer.weight_block_size = None
        # WEIGHTS
        w13_weight = torch.nn.Parameter(
            torch.empty(
                num_experts,
                2 * intermediate_size_per_partition,
                hidden_size,
                dtype=params_dtype,
            ),
            requires_grad=False,
        )
        layer.register_parameter("w13_weight", w13_weight)
        set_weight_attrs(w13_weight, extra_weight_attrs)

        w2_weight = torch.nn.Parameter(
            torch.empty(
                num_experts,
                hidden_size,
                intermediate_size_per_partition,
                dtype=params_dtype,
            ),
            requires_grad=False,
        )
        layer.register_parameter("w2_weight", w2_weight)
        set_weight_attrs(w2_weight, extra_weight_attrs)

        # Allocate 2 scales for w1 and w3 respectively.
        # They will be combined to a single scale after weight loading.
        w13_weight_scale = torch.nn.Parameter(
            torch.ones(num_experts, 2, dtype=torch.float32), requires_grad=False
        )
        w2_weight_scale = torch.nn.Parameter(
            torch.ones(num_experts, dtype=torch.float32), requires_grad=False
        )
        layer.register_parameter("w13_weight_scale", w13_weight_scale)
        layer.register_parameter("w2_weight_scale", w2_weight_scale)

        extra_weight_attrs.update(
            {"quant_method": FusedMoeWeightScaleSupported.TENSOR.value}
        )
        # INPUT_SCALES
        layer.w13_input_scale = None
        layer.w2_input_scale = None

    def process_weights_after_loading(self, layer: Module) -> None:
        if not self.quant_config.is_checkpoint_fp8_serialized:
            fp8_dtype = current_platform.fp8_dtype()
            w13_weight = torch.empty_like(layer.w13_weight.data, dtype=fp8_dtype)
            w2_weight = torch.empty_like(layer.w2_weight.data, dtype=fp8_dtype)

            # Re-initialize w13_scale because we directly quantize
            # merged w13 weights and generate a single scaling factor.
            layer.w13_weight_scale = torch.nn.Parameter(
                torch.ones(
                    layer.local_num_experts,
                    dtype=torch.float32,
                    device=w13_weight.device,
                ),
                requires_grad=False,
            )
            for expert in range(layer.local_num_experts):
                w13_weight[expert, :, :], layer.w13_weight_scale[expert] = (
                    ops.scaled_fp8_quant(layer.w13_weight.data[expert, :, :])
                )
                w2_weight[expert, :, :], layer.w2_weight_scale[expert] = (
                    ops.scaled_fp8_quant(layer.w2_weight.data[expert, :, :])
                )
            layer.w13_weight = torch.nn.Parameter(w13_weight, requires_grad=False)
            layer.w2_weight = torch.nn.Parameter(w2_weight, requires_grad=False)
        import intel_extension_for_pytorch as ipex

        layer.ipex_fusion = ipex.llm.modules.GatedMLPMOE(
            layer.w13_weight,
            layer.w2_weight,
            w1_scale_inv=layer.w13_weight_scale,
            w2_scale_inv=layer.w2_weight_scale,
            a1_scale_inv=layer.w13_input_scale,
            a2_scale_inv=layer.w2_input_scale,
            use_prepack=True,
        )

    def get_fused_moe_quant_config(
        self, layer: torch.nn.Module
    ) -> FusedMoEQuantConfig | None:
        return None

    def apply(
        self,
        layer: torch.nn.Module,
        x: torch.Tensor,
        router_logits: torch.Tensor,
        top_k: int,
        renormalize: bool,
        use_grouped_topk: bool = False,
        topk_group: int | None = None,
        num_expert_group: int | None = None,
        global_num_experts: int = -1,
        expert_map: torch.Tensor | None = None,
        custom_routing_function: Callable | None = None,
        scoring_func: str = "softmax",
        routed_scaling_factor: float = 1.0,
        e_score_correction_bias: torch.Tensor | None = None,
        apply_router_weight_on_input: bool = False,
        activation: str = "silu",
        enable_eplb: bool = False,
        expert_load_view: torch.Tensor | None = None,
        logical_to_physical_map: torch.Tensor | None = None,
        logical_replica_count: torch.Tensor | None = None,
    ) -> torch.Tensor:
        return layer.ipex_fusion(
            x,
            use_grouped_topk,
            top_k,
            router_logits,
            renormalize,
            topk_group,
            num_expert_group,
            custom_routing_function=custom_routing_function,
        )
