# mapping on device memory, host memory and memory allocator

import logging
from typing import Optional

import torch

from sglang.srt.layers.radix_attention import RadixAttention
from sglang.srt.mem_cache.memory_pool import DSATokenToKVPool
from sglang.srt.utils import is_cuda, is_hip

logger = logging.getLogger(__name__)

# sgl_kernel.kvcacheio is only available in CUDA/ROCm sgl-kernel builds (not XPU/MPS/NPU/CPU).
_is_cuda = is_cuda()
_is_hip = is_hip()
if _is_cuda or _is_hip:
    from sgl_kernel.kvcacheio import transfer_kv_all_layer_mla
else:

    def transfer_kv_all_layer_mla(*args, **kwargs):
        raise RuntimeError(
            "HiSparse device KV transfer requires sgl_kernel.kvcacheio (CUDA/ROCm). "
            "It is not available on this backend."
        )


class HiSparseDSATokenToKVPool(DSATokenToKVPool):
    def __init__(
        self,
        size: int,
        page_size: int,
        kv_lora_rank: int,
        dtype: torch.dtype,
        qk_rope_head_dim: int,
        layer_num: int,
        device: str,
        index_head_dim: int,
        enable_memory_saver: bool,
        kv_cache_dim: int,
        start_layer: Optional[int] = None,
        end_layer: Optional[int] = None,
        host_to_device_ratio: int = 2,
    ):
        super().__init__(
            size=size,
            page_size=page_size,
            kv_lora_rank=kv_lora_rank,
            dtype=dtype,
            qk_rope_head_dim=qk_rope_head_dim,
            layer_num=layer_num,
            device=device,
            index_head_dim=index_head_dim,
            enable_memory_saver=enable_memory_saver,
            kv_cache_dim=kv_cache_dim,
            start_layer=start_layer,
            end_layer=end_layer,
            index_buf_size=size * host_to_device_ratio,
        )
        self.bytes_per_token = self.kv_cache_dim * self.dtype.itemsize

    def register_mapping(self, full_to_hisparse_device_index_mapping: torch.Tensor):
        self.full_to_hisparse_device_index_mapping = (
            full_to_hisparse_device_index_mapping
        )

    def translate_loc_to_hisparse_device(self, compressed_indices: torch.Tensor):
        return self.full_to_hisparse_device_index_mapping[compressed_indices]

    def _translate_loc_to_hisparse_device(self, compressed_indices: torch.Tensor):
        return self.full_to_hisparse_device_index_mapping[compressed_indices]

    def translate_loc_from_full_to_hisparse_device(self, full_indices: torch.Tensor):
        return self._translate_loc_to_hisparse_device(full_indices)

    def translate_loc_from_full_to_compressed(self, full_indices: torch.Tensor):
        return full_indices

    def set_kv_buffer(
        self,
        layer: RadixAttention,
        loc: torch.Tensor,
        cache_k: torch.Tensor,
        cache_v: torch.Tensor,
    ):
        loc = self.translate_loc_to_hisparse_device(loc)
        super().set_kv_buffer(layer, loc, cache_k, cache_v)

    def set_mla_kv_buffer(
        self,
        layer: RadixAttention,
        loc: torch.Tensor,
        cache_k_nope: torch.Tensor,
        cache_k_rope: torch.Tensor,
    ):
        loc = self.translate_loc_to_hisparse_device(loc)
        super().set_mla_kv_buffer(layer, loc, cache_k_nope, cache_k_rope)

    def get_mla_kv_buffer(
        self,
        layer: RadixAttention,
        loc: torch.Tensor,
        dst_dtype: Optional[torch.dtype] = None,
    ):
        loc = self.translate_loc_to_hisparse_device(loc)
        return super().get_mla_kv_buffer(layer, loc, dst_dtype)

    def transfer_values_on_device(self, dst_indices, src_indices):
        transfer_kv_all_layer_mla(
            src_layers=self.data_ptrs,
            dst_layers=self.data_ptrs,
            src_indices=src_indices,
            dst_indices=dst_indices,
            item_size=self.bytes_per_token,
            num_layers=self.layer_num,
        )

    def get_cpu_copy(self, indices, mamba_indices=None):
        raise NotImplementedError("HiSparseDevicePool does not support get_cpu_copy")

    def load_cpu_copy(self, kv_cache_cpu, indices, mamba_indices=None):
        raise NotImplementedError("HiSparseDevicePool does not support load_cpu_copy")
