"""提现申请。可用余额 = 已入账积分 - 待处理提现 - 已完成提现。"""

from __future__ import annotations

from decimal import Decimal

from sqlalchemy import select
from sqlalchemy.exc import IntegrityError
from sqlalchemy.orm import Session

from app.clock import utcnow
from app.errors import AppError
from app.models import NodeYield, WithdrawalLog, WithdrawalStatus, YieldStatus
from app.money import money, to_decimal
from app.services.common import get_user_by_wallet


def available_balance(session: Session, user_id: int) -> Decimal:
    credited_rows = session.scalars(
        select(NodeYield.points_delta).where(
            NodeYield.user_id == user_id,
            NodeYield.status == YieldStatus.SETTLED,
        )
    ).all()
    reserved_rows = session.scalars(
        select(WithdrawalLog.amount).where(
            WithdrawalLog.user_id == user_id,
            WithdrawalLog.status.in_([WithdrawalStatus.PENDING, WithdrawalStatus.COMPLETED]),
        )
    ).all()
    credited = sum((to_decimal(item) for item in credited_rows), Decimal("0"))
    reserved = sum((to_decimal(item) for item in reserved_rows), Decimal("0"))
    balance = credited - reserved
    if balance <= 0:
        return Decimal("0")
    return money(balance)


def request_withdrawal(
    session: Session,
    wallet_address: str,
    amount: Decimal,
    asset_symbol: str = "POINT",
) -> tuple[WithdrawalLog, Decimal]:
    user = get_user_by_wallet(session, wallet_address.strip())
    value = money(amount)
    if value <= 0:
        raise AppError("提现金额必须大于 0")
    balance = available_balance(session, user.id)
    if value > balance:
        raise AppError("可用积分不足")
    row = WithdrawalLog(
        user_id=user.id,
        amount=value,
        asset_symbol=asset_symbol.strip().upper() or "POINT",
        status=WithdrawalStatus.PENDING,
        created_at=utcnow(),
        updated_at=utcnow(),
    )
    session.add(row)
    session.flush()
    return row, money(balance - value)


def confirm_withdrawal(session: Session, withdrawal_id: int, tx_hash: str) -> WithdrawalLog:
    row = _get_withdrawal(session, withdrawal_id)
    if row.status != WithdrawalStatus.PENDING:
        raise AppError("仅待处理的提现可以确认", 409)
    digest = tx_hash.strip()
    occupied = session.scalar(select(WithdrawalLog.id).where(WithdrawalLog.tx_hash == digest))
    if occupied is not None:
        raise AppError("交易哈希已存在", 409)
    row.tx_hash = digest
    row.status = WithdrawalStatus.COMPLETED
    row.updated_at = utcnow()
    try:
        session.flush()
    except IntegrityError as exc:
        session.rollback()
        raise AppError("交易哈希已存在", 409) from exc
    return row


def reject_withdrawal(session: Session, withdrawal_id: int, note: str | None = None) -> WithdrawalLog:
    row = _get_withdrawal(session, withdrawal_id)
    if row.status != WithdrawalStatus.PENDING:
        raise AppError("仅待处理的提现可以拒绝", 409)
    row.status = WithdrawalStatus.REJECTED
    row.note = note
    row.updated_at = utcnow()
    session.flush()
    return row


def _get_withdrawal(session: Session, withdrawal_id: int) -> WithdrawalLog:
    row = session.get(WithdrawalLog, withdrawal_id)
    if row is None:
        raise AppError("提现记录不存在", 404)
    return row