from typing import Dict, List, Optional

from vllm.config import (CacheConfig, DeviceConfig, LoRAConfig, ModelConfig,
                         ParallelConfig, SchedulerConfig, SpeculativeConfig,
                         VisionLanguageConfig)
from vllm.executor.executor_base import ExecutorAsyncBase, ExecutorBase
from vllm.logger import init_logger
from vllm.lora.request import LoRARequest
from vllm.sequence import SamplerOutput, SequenceGroupMetadata
from vllm.utils import (get_distributed_init_method, get_ip, get_open_port,
                        make_async)

logger = init_logger(__name__)


class GPUExecutor(ExecutorBase):

    def __init__(
        self,
        model_config: ModelConfig,
        cache_config: CacheConfig,
        parallel_config: ParallelConfig,
        scheduler_config: SchedulerConfig,
        device_config: DeviceConfig,
        lora_config: Optional[LoRAConfig],
        vision_language_config: Optional[VisionLanguageConfig],
        speculative_config: Optional[SpeculativeConfig],
    ) -> None:
        self.model_config = model_config
        self.cache_config = cache_config
        self.lora_config = lora_config
        self.parallel_config = parallel_config
        self.scheduler_config = scheduler_config
        self.device_config = device_config
        self.vision_language_config = vision_language_config

        assert (not speculative_config
                ), "Speculative decoding not yet supported for GPU backend"

        # Instantiate the worker and load the model to GPU.
        self._init_worker()

    def _init_worker(self):
        # Lazy import the Worker to avoid importing torch.cuda/xformers
        # before CUDA_VISIBLE_DEVICES is set in the Worker
        from vllm.worker.worker import Worker

        assert self.parallel_config.world_size == 1, (
            "GPUExecutor only supports single GPU.")

        distributed_init_method = get_distributed_init_method(
            get_ip(), get_open_port())
        self.driver_worker = Worker(
            model_config=self.model_config,
            parallel_config=self.parallel_config,
            scheduler_config=self.scheduler_config,
            device_config=self.device_config,
            cache_config=self.cache_config,
            local_rank=0,
            rank=0,
            distributed_init_method=distributed_init_method,
            lora_config=self.lora_config,
            vision_language_config=self.vision_language_config,
            is_driver_worker=True,
        )
        self.driver_worker.init_device()
        self.driver_worker.load_model()

    def determine_num_available_blocks(self) -> tuple[int, int]:
        """Determine the number of available KV blocks by invoking the
        underlying worker.
        """
        return self.driver_worker.determine_num_available_blocks()

    def initialize_cache(self, num_gpu_blocks: int, num_cpu_blocks) -> None:
        """Initialize the KV cache by invoking the underlying worker.
        """
        # NOTE: This is logged in the executor because there can be >1 worker
        # with other executors. We could log in the engine level, but work
        # remains to abstract away the device for non-GPU configurations.
        logger.info(f"# GPU blocks: {num_gpu_blocks}, "
                    f"# CPU blocks: {num_cpu_blocks}")

        self.driver_worker.initialize_cache(num_gpu_blocks, num_cpu_blocks)

    def execute_model(self,
                      seq_group_metadata_list: List[SequenceGroupMetadata],
                      blocks_to_swap_in: Dict[int, int],
                      blocks_to_swap_out: Dict[int, int],
                      blocks_to_copy: Dict[int, List[int]]) -> SamplerOutput:
        output = self.driver_worker.execute_model(
            seq_group_metadata_list=seq_group_metadata_list,
            blocks_to_swap_in=blocks_to_swap_in,
            blocks_to_swap_out=blocks_to_swap_out,
            blocks_to_copy=blocks_to_copy,
        )
        return output

    def add_lora(self, lora_request: LoRARequest) -> bool:
        assert lora_request.lora_int_id > 0, "lora_id must be greater than 0."
        return self.driver_worker.add_lora(lora_request)

    def remove_lora(self, lora_id: int) -> bool:
        assert lora_id > 0, "lora_id must be greater than 0."
        return self.driver_worker.remove_lora(lora_id)

    def list_loras(self) -> List[int]:
        return self.driver_worker.list_loras()

    def check_health(self) -> None:
        # GPUExecutor will always be healthy as long as
        # it's running.
        return


class GPUExecutorAsync(GPUExecutor, ExecutorAsyncBase):

    async def execute_model_async(
        self,
        seq_group_metadata_list: List[SequenceGroupMetadata],
        blocks_to_swap_in: Dict[int, int],
        blocks_to_swap_out: Dict[int, int],
        blocks_to_copy: Dict[int, List[int]],
    ) -> SamplerOutput:
        output = await make_async(self.driver_worker.execute_model)(
            seq_group_metadata_list=seq_group_metadata_list,
            blocks_to_swap_in=blocks_to_swap_in,
            blocks_to_swap_out=blocks_to_swap_out,
            blocks_to_copy=blocks_to_copy)
        return output

    async def check_health_async(self) -> None:
        # GPUExecutor will always be healthy as long as
        # it's running.
        return
