from __future__ import annotations

from dataclasses import dataclass
from datetime import datetime

from app.enums.credit_record import CreditRecordChargeKind
from app.enums.llm_billing import LlmBillingLedgerState
from app.services.generation.billing_service import build_credit_biz_key


class LlmBillingConfigurationError(RuntimeError):
    """LLM 场景固定预扣配置无效。"""


class LlmBillingStateError(RuntimeError):
    """业务 attempt 的固定预扣状态不允许继续执行。"""


class LlmProviderPostprocessError(RuntimeError):
    """供应商请求已成功并返回用量，但响应内容或业务结构处理失败。"""

    def __init__(self, message: str, *, usage: dict | None = None) -> None:
        super().__init__(message)
        self.usage = dict(usage or {})


@dataclass(slots=True, frozen=True)
class LlmBillingPolicy:
    pre_deduct_credits: float
    valid: bool = True
    error: str | None = None
    policy_id: str | None = None
    version: int | None = None
    scene_name: str | None = None


@dataclass(slots=True)
class LlmBillingContext:
    user_id: str
    owner_type: str
    owner_id: str
    attempt_no: int
    charge_kind: str = CreditRecordChargeKind.TEXT_PROMPT.value
    billing_scene: str | None = None
    source_module: str | None = None
    source_project_id: str | None = None
    source_step_id: str | None = None
    source_step_code: str | None = None
    related_id: str | None = None
    description_prefix: str = "LLM"
    trace_id: str | None = None
    request_id: str | None = None
    celery_task_id: str | None = None
    provider: str | None = None
    model_name: str | None = None
    model_config_id: str | None = None
    model_parameters_snapshot: dict | None = None
    token_usage_id: str | None = None
    # 供应商响应成功事实先于审计落库设置。即使审计事务暂时失败，
    # 后续异常处理也不能把真实供应商成功覆盖成 provider failed。
    provider_call_succeeded: bool = False
    provider_usage_snapshot: dict | None = None
    request_time: datetime | None = None
    billing_execution_id: str | None = None
    current_call_attempt_id: str | None = None

    @property
    def pre_deduct_biz_key(self) -> str:
        return build_credit_biz_key(
            owner_type=self.owner_type,
            owner_id=self.owner_id,
            attempt_no=self.attempt_no,
            charge_kind=self.charge_kind,
            action="pre_deduct",
        )

    @property
    def refund_biz_key(self) -> str:
        return build_credit_biz_key(
            owner_type=self.owner_type,
            owner_id=self.owner_id,
            attempt_no=self.attempt_no,
            charge_kind=self.charge_kind,
            action="refund",
        )

    @property
    def billing_biz_key(self) -> str:
        return self.pre_deduct_biz_key


@dataclass(slots=True, frozen=True)
class LlmPreDeductResult:
    amount: float
    state: LlmBillingLedgerState
    created: bool = False
    record_id: str | None = None
    reason: str | None = None
    execution_id: str | None = None


@dataclass(slots=True, frozen=True)
class LlmPreDeductValidation:
    can_execute: bool
    amount: float
    state: LlmBillingLedgerState
    reason: str | None = None
    pre_deduct_record_id: str | None = None
    execution_id: str | None = None