"""SQLAlchemy 2.x ORM models,对应 DESIGN.md §7.4 schema。

5 张表:users / tasks / messages / runs / usage_events。
- users 本地形态固定 INSERT sentinel(`00000000-...`)
- messages.payload 用 jsonb,GIN 索引在 migration 里建
- runs / usage_events 在 B 阶段先建表,真正写入要等 D 阶段(HTTP /v1 + run 生命周期)
"""
from __future__ import annotations

from datetime import datetime
from decimal import Decimal
from typing import Any, Optional
from uuid import UUID, uuid4

from sqlalchemy import (
    BigInteger,
    DateTime,
    ForeignKey,
    Integer,
    Numeric,
    Text,
    UniqueConstraint,
    func,
)
from sqlalchemy.dialects.postgresql import JSONB, UUID as PG_UUID
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column


class Base(DeclarativeBase):
    pass


# 本地单用户 sentinel —— 所有本地 task 都 FK 到这一行
SENTINEL_USER_ID: UUID = UUID("00000000-0000-0000-0000-000000000000")


class User(Base):
    __tablename__ = "users"

    user_id: Mapped[UUID] = mapped_column(PG_UUID(as_uuid=True), primary_key=True, default=uuid4)
    email: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    oidc_subject: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    password_hash: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    plan: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )


class Task(Base):
    __tablename__ = "tasks"

    task_id: Mapped[UUID] = mapped_column(PG_UUID(as_uuid=True), primary_key=True, default=uuid4)
    user_id: Mapped[UUID] = mapped_column(
        PG_UUID(as_uuid=True), ForeignKey("users.user_id"), nullable=False
    )
    name: Mapped[str] = mapped_column(Text, nullable=False)
    working_dir: Mapped[str] = mapped_column(Text, nullable=False)
    skill: Mapped[str] = mapped_column(Text, nullable=False, default="")
    description: Mapped[str] = mapped_column(Text, nullable=False, default="")
    status: Mapped[str] = mapped_column(Text, nullable=False, default="active")
    model: Mapped[str] = mapped_column(Text, nullable=False, default="")
    model_profile: Mapped[str] = mapped_column(Text, nullable=False, default="")
    reasoning_effort: Mapped[str] = mapped_column(Text, nullable=False, default="")
    tokens_prompt: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    tokens_completion: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    cost_usd: Mapped[Decimal] = mapped_column(Numeric(12, 6), nullable=False, default=0)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=False
    )


class Message(Base):
    __tablename__ = "messages"
    __table_args__ = (UniqueConstraint("task_id", "idx", name="uq_messages_task_idx"),)

    message_id: Mapped[UUID] = mapped_column(PG_UUID(as_uuid=True), primary_key=True, default=uuid4)
    task_id: Mapped[UUID] = mapped_column(
        PG_UUID(as_uuid=True),
        ForeignKey("tasks.task_id", ondelete="CASCADE"),
        nullable=False,
    )
    idx: Mapped[int] = mapped_column(Integer, nullable=False)
    payload: Mapped[dict[str, Any]] = mapped_column(JSONB, nullable=False)
    tokens_in: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
    tokens_out: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )


class Run(Base):
    __tablename__ = "runs"

    run_id: Mapped[UUID] = mapped_column(PG_UUID(as_uuid=True), primary_key=True, default=uuid4)
    task_id: Mapped[UUID] = mapped_column(
        PG_UUID(as_uuid=True),
        ForeignKey("tasks.task_id", ondelete="CASCADE"),
        nullable=False,
    )
    status: Mapped[str] = mapped_column(Text, nullable=False, default="pending")
    started_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)
    finished_at: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)
    error: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    tokens_p: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    tokens_c: Mapped[int] = mapped_column(Integer, nullable=False, default=0)


class UsageEvent(Base):
    """append-only 审计。task_id / run_id 不 FK,task 硬删后审计仍存活(§7.4)。"""

    __tablename__ = "usage_events"

    id: Mapped[int] = mapped_column(BigInteger, primary_key=True, autoincrement=True)
    user_id: Mapped[UUID] = mapped_column(PG_UUID(as_uuid=True), nullable=False)
    task_id: Mapped[Optional[UUID]] = mapped_column(PG_UUID(as_uuid=True), nullable=True)
    run_id: Mapped[Optional[UUID]] = mapped_column(PG_UUID(as_uuid=True), nullable=True)
    kind: Mapped[str] = mapped_column(Text, nullable=False)
    value: Mapped[Decimal] = mapped_column(Numeric(20, 8), nullable=False)
    ts: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), server_default=func.now(), nullable=False
    )