from __future__ import annotations

from datetime import datetime
from decimal import Decimal

from sqlalchemy import DateTime, ForeignKey, Index, JSON, Numeric, String
from sqlalchemy.orm import Mapped, mapped_column

from app.enums.llm_billing import LlmBillingExecutionStatus
from app.models.base import Base, TimestampMixin


class LlmBillingExecution(Base, TimestampMixin):
    __tablename__ = "llm_billing_executions"
    __table_args__ = (
        Index(
            "uq_llm_billing_executions_business_attempt",
            "user_id", "scene_code", "owner_type", "owner_id", "business_attempt_no",
            unique=True,
        ),
        Index("uq_llm_billing_executions_credit_record", "credit_record_id", unique=True),
        Index("ix_llm_billing_executions_status_time", "status", "created_at"),
    )

    id: Mapped[str] = mapped_column(String(32), primary_key=True)
    user_id: Mapped[str] = mapped_column(
        String(32), ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
    )
    scene_code: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
    scene_name_snapshot: Mapped[str] = mapped_column(String(128), nullable=False)
    owner_type: Mapped[str] = mapped_column(String(64), nullable=False)
    owner_id: Mapped[str] = mapped_column(String(64), nullable=False)
    business_attempt_no: Mapped[int] = mapped_column(nullable=False)

    model_config_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("model_configs.id", ondelete="SET NULL"), nullable=True
    )
    model_name_snapshot: Mapped[str | None] = mapped_column(String(128), nullable=True)
    provider_snapshot: Mapped[str | None] = mapped_column(String(64), nullable=True)
    model_parameters_snapshot: Mapped[dict | None] = mapped_column(JSON, nullable=True)

    billing_policy_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("llm_billing_policies.id", ondelete="SET NULL"), nullable=True
    )
    billing_policy_version: Mapped[int | None] = mapped_column(nullable=True)
    request_time: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
    pre_deduct_credits: Mapped[Decimal] = mapped_column(Numeric(20, 2), nullable=False)
    credit_record_id: Mapped[str] = mapped_column(
        String(32), ForeignKey("credit_records.id", ondelete="RESTRICT"), nullable=False
    )
    status: Mapped[str] = mapped_column(
        String(32), nullable=False, default=LlmBillingExecutionStatus.PRE_DEDUCTED.value,
        server_default=LlmBillingExecutionStatus.PRE_DEDUCTED.value,
    )

    total_call_count: Mapped[int] = mapped_column(nullable=False, default=0, server_default="0")
    successful_call_count: Mapped[int] = mapped_column(nullable=False, default=0, server_default="0")
    failed_call_count: Mapped[int] = mapped_column(nullable=False, default=0, server_default="0")
    total_input_tokens: Mapped[int] = mapped_column(nullable=False, default=0, server_default="0")
    total_output_tokens: Mapped[int] = mapped_column(nullable=False, default=0, server_default="0")
    total_tokens: Mapped[int] = mapped_column(nullable=False, default=0, server_default="0")

    refund_available_credits: Mapped[Decimal] = mapped_column(
        Numeric(20, 2), nullable=False, default=Decimal("0.00"), server_default="0"
    )
    refund_expired_credits: Mapped[Decimal] = mapped_column(
        Numeric(20, 2), nullable=False, default=Decimal("0.00"), server_default="0"
    )
    final_error_message: Mapped[str | None] = mapped_column(String(1000), nullable=True)
    completed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    refunded_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)