import uuid
from decimal import Decimal
from typing import List, Optional
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.models.entities import MarketModel, OrderModel, MarketStatus
from app.domains.ledger.service import LedgerService

class MarketService:
    """预测市场领域服务"""

    def __init__(self, session: AsyncSession):
        self.session = session

    async def list_markets(self, category: Optional[str] = None, status: Optional[str] = None) -> List[MarketModel]:
        stmt = select(MarketModel)
        if category:
            stmt = stmt.where(MarketModel.category == category)
        if status:
            stmt = stmt.where(MarketModel.status == status)
        stmt = stmt.order_by(MarketModel.created_at.desc())
        result = await self.session.execute(stmt)
        return list(result.scalars().all())

    async def get_market(self, market_address: str) -> Optional[MarketModel]:
        stmt = select(MarketModel).where(MarketModel.market_address == market_address.lower())
        result = await self.session.execute(stmt)
        return result.scalar_one_or_none()

class TradingService:
    """交易撮合与下单领域服务"""

    def __init__(self, session: AsyncSession):
        self.session = session
        self.ledger_service = LedgerService(session)

    async def place_order(
        self,
        user_address: str,
        market_address: str,
        outcome_index: int,
        side: str,
        amount: Decimal,
        price: Optional[Decimal] = None
    ) -> OrderModel:
        """执行下单流程"""
        order_id = str(uuid.uuid4())
        fee = amount * Decimal("0.006") # 0.6% protocol fee

        # 1. 记账并扣款/冻结
        await self.ledger_service.record_trade(
            address=user_address,
            market_address=market_address,
            order_id=order_id,
            side=side,
            amount=amount,
            fee=fee
        )

        # 2. 生成订单记录
        order = OrderModel(
            order_id=order_id,
            market_address=market_address.lower(),
            user_address=user_address.lower(),
            side=side,
            outcome_index=outcome_index,
            amount=amount,
            price=price,
            status="FILLED",
            filled_amount=amount,
            fee=fee
        )
        self.session.add(order)
        await self.session.flush()
        return order