import os
import subprocess
import warnings
from contextlib import ExitStack, contextmanager
from typing import Any


class EnvField:
    def __init__(self, default: Any):
        self.default = default
        # NOTE: we use None to indicate whether the value is set or not
        # If the value is manually set to None, we need mark it as _set_to_none.
        # Always use clear() to reset the value, which leads to the default fallback.
        self._set_to_none = False

    def __set_name__(self, owner, name):
        self.name = name

    def parse(self, value: str) -> Any:
        raise NotImplementedError()

    def get(self) -> Any:
        value = os.getenv(self.name)
        if self._set_to_none:
            assert value is None
            return None

        if value is None:
            return self.default

        try:
            return self.parse(value)
        except ValueError as e:
            warnings.warn(
                f'Invalid value for {self.name}: {e}, using default "{self.default}"'
            )
            return self.default

    def is_set(self):
        # NOTE: If None is manually set, it is considered as set.
        return self.name in os.environ or self._set_to_none

    def get_set_value_or(self, or_value: Any):
        # NOTE: Ugly usage, but only way to get custom default value.
        return self.get() if self.is_set() else or_value

    def set(self, value: Any):
        if value is None:
            self._set_to_none = True
            os.environ.pop(self.name, None)
        else:
            self._set_to_none = False
            os.environ[self.name] = str(value)

    @contextmanager
    def override(self, value: Any):
        backup_present = self.name in os.environ
        backup_value = os.environ.get(self.name)
        backup_set_to_none = self._set_to_none
        self.set(value)
        yield
        if backup_present:
            os.environ[self.name] = backup_value
        else:
            os.environ.pop(self.name, None)
        self._set_to_none = backup_set_to_none

    def clear(self):
        os.environ.pop(self.name, None)
        self._set_to_none = False

    @property
    def value(self):
        return self.get()


class EnvStr(EnvField):
    def parse(self, value: str) -> str:
        return value


class EnvBool(EnvField):
    def parse(self, value: str) -> bool:
        value = value.lower()
        if value in ["true", "1", "yes", "y"]:
            return True
        if value in ["false", "0", "no", "n"]:
            return False
        raise ValueError(f'"{value}" is not a valid boolean value')


class EnvInt(EnvField):
    def parse(self, value: str) -> int:
        try:
            return int(value)
        except ValueError:
            raise ValueError(f'"{value}" is not a valid integer value')


class EnvFloat(EnvField):
    def parse(self, value: str) -> float:
        try:
            return float(value)
        except ValueError:
            raise ValueError(f'"{value}" is not a valid float value')


class Envs:
    # fmt: off

    # Model & File Download
    SGLANG_USE_MODELSCOPE = EnvBool(False)

    # Test & Debug
    SGLANG_IS_IN_CI = EnvBool(False)
    SGLANG_IS_IN_CI_AMD = EnvBool(False)
    SGLANG_TEST_RETRACT = EnvBool(False)
    SGLANG_SET_CPU_AFFINITY = EnvBool(False)
    SGLANG_PROFILE_WITH_STACK = EnvBool(True)
    SGLANG_RECORD_STEP_TIME = EnvBool(False)
    SGLANG_GC_LOG = EnvBool(False)
    SGLANG_FORCE_SHUTDOWN = EnvBool(False)
    SGLANG_DEBUG_MEMORY_POOL = EnvBool(False)
    SGLANG_TEST_REQUEST_TIME_STATS = EnvBool(False)
    SGLANG_DISABLE_TP_MEMORY_INBALANCE_CHECK = EnvBool(False)
    SGLANG_DISABLE_REQUEST_LOGGING = EnvBool(False)
    SGLANG_SIMULATE_ACC_LEN = EnvFloat(-1)
    SGLANG_SIMULATE_ACC_METHOD = EnvStr("multinomial")
    SGLANG_TORCH_PROFILER_DIR = EnvStr("/tmp")

    # Scheduler: new token ratio hyperparameters
    SGLANG_INIT_NEW_TOKEN_RATIO = EnvFloat(0.7)
    SGLANG_MIN_NEW_TOKEN_RATIO_FACTOR = EnvFloat(0.14)
    SGLANG_NEW_TOKEN_RATIO_DECAY_STEPS = EnvInt(600)
    SGLANG_RETRACT_DECODE_STEPS = EnvInt(20)

    # Scheduler: others:
    SGLANG_EMPTY_CACHE_INTERVAL = EnvFloat(-1)  # in seconds. Set if you observe high memory accumulation over a long serving period.
    # Test: pd-disaggregation
    SGLANG_TEST_PD_DISAGG_BACKEND = EnvStr("mooncake")
    SGLANG_TEST_PD_DISAGG_DEVICES = EnvStr(None)

    # Model Parallel
    SGLANG_USE_MESSAGE_QUEUE_BROADCASTER = EnvBool(True)

    # Constrained Decoding
    SGLANG_DISABLE_OUTLINES_DISK_CACHE = EnvBool(True)
    SGLANG_GRAMMAR_TIMEOUT = EnvFloat(300)

    # Hi-Cache
    SGLANG_HICACHE_HF3FS_CONFIG_PATH = EnvStr(None)

    # Mooncake KV Transfer
    SGLANG_MOONCAKE_CUSTOM_MEM_POOL = EnvBool(False)
    ENABLE_ASCEND_TRANSFER_WITH_MOONCAKE = EnvBool(False)

    # AMD & ROCm
    SGLANG_USE_AITER = EnvBool(False)
    SGLANG_ROCM_FUSED_DECODE_MLA = EnvBool(False)

    # Quantization
    SGLANG_INT4_WEIGHT = EnvBool(False)
    SGLANG_CPU_QUANTIZATION = EnvBool(False)
    SGLANG_USE_DYNAMIC_MXFP4_LINEAR = EnvBool(False)
    SGLANG_FORCE_FP8_MARLIN = EnvBool(False)

    # Flashinfer
    SGLANG_IS_FLASHINFER_AVAILABLE = EnvBool(True)
    SGLANG_ENABLE_FLASHINFER_GEMM = EnvBool(False)
    SGLANG_FLASHINFER_WORKSPACE_SIZE = EnvInt(384 * 1024 * 1024)

    # Triton
    SGLANG_TRITON_DECODE_ATTN_STATIC_KV_SPLITS = EnvBool(False)

    # Torch Compile
    SGLANG_ENABLE_TORCH_COMPILE = EnvBool(False)

    # EPLB
    SGLANG_EXPERT_LOCATION_UPDATER_LOG_INPUT = EnvBool(False)
    SGLANG_EXPERT_LOCATION_UPDATER_CANARY = EnvBool(False)
    SGLANG_EXPERT_LOCATION_UPDATER_LOG_METRICS = EnvBool(False)
    SGLANG_LOG_EXPERT_LOCATION_METADATA = EnvBool(False)
    SGLANG_EXPERT_DISTRIBUTION_RECORDER_DIR = EnvStr("/tmp")

    # TBO
    SGLANG_TBO_DEBUG = EnvBool(False)

    # DeepGemm
    SGLANG_ENABLE_JIT_DEEPGEMM = EnvBool(True)
    SGLANG_JIT_DEEPGEMM_PRECOMPILE = EnvBool(True)
    SGLANG_JIT_DEEPGEMM_COMPILE_WORKERS = EnvInt(4)
    SGLANG_IN_DEEPGEMM_PRECOMPILE_STAGE = EnvBool(False)
    SGLANG_DG_CACHE_DIR = EnvStr(os.path.expanduser("~/.cache/deep_gemm"))
    SGLANG_DG_USE_NVRTC = EnvBool(False)
    SGLANG_USE_DEEPGEMM_BMM = EnvBool(False)

    # sgl-kernel
    SGLANG_SKIP_SGL_KERNEL_VERSION_CHECK = EnvBool(False)

    # vLLM dependencies (TODO: they have been deprecated, we can remove them safely)
    USE_VLLM_CUSTOM_ALLREDUCE = EnvBool(False)
    USE_VLLM_CUTLASS_W8A8_FP8_KERNEL = EnvBool(False)

    USE_TRITON_W8A8_FP8_KERNEL = EnvBool(False)
    SGLANG_RETURN_ORIGINAL_LOGPROB = EnvBool(False)
    SGLANG_ALLOW_OVERWRITE_LONGER_CONTEXT_LEN = EnvBool(False)
    SGLANG_MOE_PADDING = EnvBool(False)
    SGLANG_CUTLASS_MOE = EnvBool(False)
    HF_HUB_DISABLE_XET = EnvBool(False)
    DISABLE_OPENAPI_DOC = EnvBool(False)
    SGLANG_ENABLE_TORCH_INFERENCE_MODE = EnvBool(False)
    SGLANG_IS_FIRST_RANK_ON_NODE = EnvBool(True)
    SGLANG_SUPPORT_CUTLASS_BLOCK_FP8 = EnvBool(False)
    SGLANG_SYNC_TOKEN_IDS_ACROSS_TP = EnvBool(False)
    SGLANG_ENABLE_COLOCATED_BATCH_GEN = EnvBool(False)

    # Deterministic inference
    SGLANG_ENABLE_DETERMINISTIC_INFERENCE = EnvBool(False)
    SGLANG_FLASHINFER_PREFILL_SPLIT_TILE_SIZE = EnvInt(4096)
    SGLANG_FLASHINFER_DECODE_SPLIT_TILE_SIZE = EnvInt(2048)
    SGLANG_TRITON_PREFILL_TRUNCATION_ALIGN_SIZE = EnvInt(4096)
    SGLANG_TRITON_DECODE_SPLIT_TILE_SIZE = EnvInt(256)

    # VLM
    SGLANG_IMAGE_MAX_PIXELS = EnvInt(16384 * 28 * 28)
    SGLANG_RESIZE_RESAMPLE = EnvStr("")

    # fmt: on


envs = Envs()


def _convert_SGL_to_SGLANG():
    for key, value in os.environ.items():
        if key.startswith("SGL_"):
            new_key = key.replace("SGL_", "SGLANG_", 1)
            warnings.warn(
                f"Environment variable {key} is deprecated, please use {new_key}"
            )
            os.environ[new_key] = value


_convert_SGL_to_SGLANG()


def example_with_exit_stack():
    # Use this style of context manager in unit test
    exit_stack = ExitStack()
    exit_stack.enter_context(envs.SGLANG_TEST_RETRACT.override(False))
    assert envs.SGLANG_TEST_RETRACT.value is False
    exit_stack.close()
    assert envs.SGLANG_TEST_RETRACT.value is None


def example_with_subprocess():
    command = ["python", "-c", "import os; print(os.getenv('SGLANG_TEST_RETRACT'))"]
    with envs.SGLANG_TEST_RETRACT.override(True):
        process = subprocess.Popen(
            command, stdout=subprocess.PIPE, stderr=subprocess.PIPE
        )
        process.wait()
        output = process.stdout.read().decode("utf-8").strip()
        assert output == "True"

    process = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    output = process.stdout.read().decode("utf-8").strip()
    assert output == "None"


def examples():
    # Example usage for envs
    envs.SGLANG_TEST_RETRACT.clear()
    assert envs.SGLANG_TEST_RETRACT.value is False

    envs.SGLANG_TEST_RETRACT.set(None)
    assert envs.SGLANG_TEST_RETRACT.is_set() and envs.SGLANG_TEST_RETRACT.value is None

    envs.SGLANG_TEST_RETRACT.clear()
    assert not envs.SGLANG_TEST_RETRACT.is_set()

    envs.SGLANG_TEST_RETRACT.set(True)
    assert envs.SGLANG_TEST_RETRACT.value is True

    with envs.SGLANG_TEST_RETRACT.override(None):
        assert (
            envs.SGLANG_TEST_RETRACT.is_set() and envs.SGLANG_TEST_RETRACT.value is None
        )

    assert envs.SGLANG_TEST_RETRACT.value is True

    envs.SGLANG_TEST_RETRACT.set(None)
    with envs.SGLANG_TEST_RETRACT.override(True):
        assert envs.SGLANG_TEST_RETRACT.value is True

    assert envs.SGLANG_TEST_RETRACT.is_set() and envs.SGLANG_TEST_RETRACT.value is None

    example_with_exit_stack()
    example_with_subprocess()


if __name__ == "__main__":
    examples()
