from __future__ import annotations

from datetime import datetime
from decimal import Decimal

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

from app.enums.credit_balance import CreditBalanceStatus, CreditScope
from app.models.base import Base, TimestampMixin


class UserCreditBalance(Base, TimestampMixin):
    __tablename__ = "user_credit_balances"
    __table_args__ = (
        CheckConstraint("grant_amount >= 0", name="ck_user_credit_balances_grant_nonnegative"),
        CheckConstraint("unspent_amount >= 0", name="ck_user_credit_balances_unspent_nonnegative"),
        CheckConstraint("consumed_amount >= 0", name="ck_user_credit_balances_consumed_nonnegative"),
        CheckConstraint("expired_amount >= 0", name="ck_user_credit_balances_expired_nonnegative"),
        CheckConstraint("revoked_amount >= 0", name="ck_user_credit_balances_revoked_nonnegative"),
        CheckConstraint(
            "grant_amount = unspent_amount + consumed_amount + expired_amount + revoked_amount",
            name="ck_user_credit_balances_amount_reconciled",
        ),
        CheckConstraint("expires_at > valid_from", name="ck_user_credit_balances_valid_window"),
        CheckConstraint(
            "(credit_scope = 'personal' AND team_id IS NULL) OR "
            "(credit_scope = 'team' AND team_id IS NOT NULL AND subscription_id IS NOT NULL "
            "AND subscription_period_id IS NOT NULL)",
            name="ck_user_credit_balances_scope_fields",
        ),
        Index(
            "ix_user_credit_balances_spendable",
            "user_id", "credit_scope", "credit_level_rank", "expires_at", "valid_from", "id",
            postgresql_where=text("unspent_amount > 0 AND revoked_at IS NULL"),
        ),
        Index(
            "ix_user_credit_balances_team_spendable",
            "team_id", "subscription_id", "subscription_period_id", "credit_level_rank", "expires_at", "id",
            postgresql_where=text("credit_scope = 'team' AND unspent_amount > 0 AND revoked_at IS NULL"),
        ),
        Index(
            "ix_user_credit_balances_expire_due",
            "expires_at", "id",
            postgresql_where=text(
                "unspent_amount > 0 AND expired_processed_at IS NULL AND revoked_at IS NULL"
            ),
        ),
        Index("ix_user_credit_balances_source", "source_type", "source_id"),
        Index("ix_user_credit_balances_payment", "payment_order_id"),
        Index("ix_user_credit_balances_subscription", "subscription_id", "subscription_period_id"),
        Index("uq_user_credit_balances_user_biz_key", "user_id", "biz_key", unique=True),
    )

    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,
        comment="资金所有人；团队积分为成交时队长",
    )
    credit_scope: Mapped[str] = mapped_column(
        String(16), nullable=False, default=CreditScope.PERSONAL.value,
        server_default=CreditScope.PERSONAL.value,
    )
    team_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("teams.id", ondelete="RESTRICT"), nullable=True
    )
    credit_level: Mapped[str] = mapped_column(String(32), nullable=False)
    credit_level_rank: Mapped[int] = mapped_column(nullable=False, default=20, server_default="20")

    source_type: Mapped[str] = mapped_column(String(48), nullable=False, index=True)
    source_id: Mapped[str | None] = mapped_column(String(64), nullable=True, index=True)
    product_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("credit_products.id", ondelete="SET NULL"), nullable=True
    )
    payment_order_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("payment_orders.id", ondelete="SET NULL"), nullable=True
    )
    subscription_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("user_credit_subscriptions.id", ondelete="SET NULL"), nullable=True
    )
    subscription_period_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("user_credit_subscription_periods.id", ondelete="SET NULL"), nullable=True
    )
    grant_record_id: Mapped[str | None] = mapped_column(
        String(32), ForeignKey("credit_records.id", ondelete="SET NULL"), nullable=True, index=True
    )

    grant_amount: Mapped[Decimal] = mapped_column(Numeric(20, 2), nullable=False)
    unspent_amount: Mapped[Decimal] = mapped_column(Numeric(20, 2), nullable=False)
    consumed_amount: Mapped[Decimal] = mapped_column(
        Numeric(20, 2), nullable=False, default=Decimal("0.00"), server_default="0"
    )
    expired_amount: Mapped[Decimal] = mapped_column(
        Numeric(20, 2), nullable=False, default=Decimal("0.00"), server_default="0"
    )
    revoked_amount: Mapped[Decimal] = mapped_column(
        Numeric(20, 2), nullable=False, default=Decimal("0.00"), server_default="0"
    )

    valid_from: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, index=True)
    expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, index=True)
    status: Mapped[str] = mapped_column(
        String(24), nullable=False, default=CreditBalanceStatus.ACTIVE.value,
        server_default=CreditBalanceStatus.ACTIVE.value,
    )
    expired_processed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    revoked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    biz_key: Mapped[str] = mapped_column(String(180), nullable=False)
    metadata_json: Mapped[dict | None] = mapped_column(JSON, nullable=True)