"""大周天演化候选模型（契约字典 §12；self-evolution-design.md §11）。

演化候选是大周天（及未来镜界 / 反馈）产出的统一轻量演化增量载体；``type`` 区分
候选对象，``level``（L0-L4）决定半自动边界（见 [大周天演化候选落地设计]
../../docs/domain/core-domains.md §5）。``cycle_id`` 关联触发本次
的大周天循环，``resulting_target_id`` 记录派生后的下游资源 ID。
"""

from datetime import datetime

from sqlalchemy import Boolean, DateTime, Float, ForeignKey, String, Text
from sqlalchemy.orm import Mapped, mapped_column

from app.core.ids import new_evolution_candidate_id
from app.core.time import utc_now
from app.db.base import Base


class EvolutionCandidate(Base):
    """演化候选（统一表）。"""

    __tablename__ = "evolution_candidates"

    id: Mapped[str] = mapped_column(
        String(80), primary_key=True, default=new_evolution_candidate_id
    )
    character_id: Mapped[str] = mapped_column(String(80), ForeignKey("characters.id"), index=True)
    cycle_id: Mapped[str] = mapped_column(String(80), ForeignKey("big_cycles.id"), index=True)
    type: Mapped[str] = mapped_column(String(60), nullable=False)
    source: Mapped[str] = mapped_column(String(60), nullable=False, default="big_cycle")
    level: Mapped[str] = mapped_column(String(8), nullable=False, default="L4")
    scope: Mapped[str] = mapped_column(String(40), nullable=False, default="character_scope")
    title: Mapped[str] = mapped_column(String(200), nullable=False)
    proposal: Mapped[str] = mapped_column(Text, nullable=False)
    delta_json: Mapped[str] = mapped_column(Text, nullable=False, default="{}")
    evidence_ids_json: Mapped[str] = mapped_column(Text, nullable=False, default="[]")
    confidence: Mapped[float] = mapped_column(Float, nullable=False, default=0.5)
    benefit_score: Mapped[float] = mapped_column(Float, nullable=False, default=0.5)
    risk_score: Mapped[float] = mapped_column(Float, nullable=False, default=0.5)
    drift_score: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
    auto_apply_allowed: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
    status: Mapped[str] = mapped_column(String(40), nullable=False, default="pending", index=True)
    resulting_target_id: Mapped[str | None] = mapped_column(String(80))
    error_message: Mapped[str | None] = mapped_column(Text)
    reviewed_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
    reviewed_by: Mapped[str] = mapped_column(String(80), nullable=False, default="system")
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=utc_now)
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=utc_now, onupdate=utc_now
    )