#
# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# This file is a part of the vllm-ascend project.
#

from dataclasses import dataclass, fields
from typing import Type, Union

from vllm.config import SchedulerConfig

MAX_INT = 2147483647


@dataclass
class AscendSchedulerConfig(SchedulerConfig):
    enable_chunked_prefill: bool = False
    max_long_partial_prefills: int = 1
    long_prefill_token_threshold: int = MAX_INT
    policy: str = "fcfs"
    scheduler_cls: Union[str, Type[object]] = (
        "vllm_npu.core.scheduler.AscendScheduler")
    enable_pd_transfer: bool = False
    decode_max_num_seqs: int = 0

    @classmethod
    def initialize_from_config(
        cls,
        vllm_scheduler_config: SchedulerConfig,
        ascend_scheduler_config,
    ):
        scheduler_config = {
            field.name: getattr(vllm_scheduler_config, field.name)
            for field in fields(vllm_scheduler_config) if field.init
        }
        # Override default values into original SchedulerConfig
        scheduler_config["enable_chunked_prefill"] = False
        scheduler_config["max_long_partial_prefills"] = None
        scheduler_config["long_prefill_token_threshold"] = None
        scheduler_config["policy"] = "fcfs"
        scheduler_config["scheduler_cls"] = (
            "vllm_npu.core.scheduler.AscendScheduler")
        scheduler_config["enable_pd_transfer"] = False
        scheduler_config["decode_max_num_seqs"] = 0
        # Override params in original SchedulerConfig with params in ascend_scheduler_config
        for k, _ in scheduler_config.items():
            if hasattr(ascend_scheduler_config, k):
                scheduler_config[k] = getattr(ascend_scheduler_config, k)
        return cls(**scheduler_config)

    def __post_init__(self) -> None:
        self.max_num_encoder_input_tokens = self.max_num_batched_tokens
        self.encoder_cache_size = self.max_num_batched_tokens
        self.chunked_prefill_enabled = self.enable_chunked_prefill
        if (self.max_num_batched_tokens < self.max_model_len
                and not self.chunked_prefill_enabled):
            raise ValueError(
                "Ascend scheduler is enabled without chunked prefill feature. "
                f"Argument max_num_batched_tokens ({self.max_num_batched_tokens}) is "
                f"smaller than max_model_len ({self.max_model_len}). "
                "This effectively limits the maximum sequence length to "
                "max_num_batched_tokens and makes vLLM reject longer "
                "sequences. Please increase max_num_batched_tokens or "
                "decrease max_model_len.")
        # concurrent partial prefills. Default is 1 meaning not enabled.
        if self.max_long_partial_prefills is None:
            self.max_long_partial_prefills = 1
            self.long_prefill_token_threshold = MAX_INT

        if self.long_prefill_token_threshold is None or \
            self.long_prefill_token_threshold <= 0:
            if self.max_model_len is None:
                self.long_prefill_token_threshold = MAX_INT
            else:
                self.long_prefill_token_threshold = \
                    max(1, int(self.max_model_len * 0.04))

        if self.max_long_partial_prefills < 0:
            raise ValueError(
                f"max_long_partial_prefills must be non-negative, but got "
                f"{self.max_long_partial_prefills}")
        if self.long_prefill_token_threshold < 0:
            raise ValueError(
                f"long_prefill_token_threshold must be non-negative, but got "
                f"{self.long_prefill_token_threshold}")

        if self.policy != "fcfs":
            raise NotImplementedError(
                f"currently AscendScheduler only supports fcfs policy, got {self.policy}"
            )
        if self.send_delta_data:
            raise NotImplementedError(
                "currently AscendScheduler doesn't support send_delta_data.")
        if getattr(self, "scheduler_delay_factor", 0) > 0:
            raise NotImplementedError(
                "currently AscendScheduler doesn't support scheduler_delay_factor."
            )