"""Agent 技能加载：技能可扩展能力，但不能覆盖系统硬约束。"""
from sqlmodel import Session, select

from ..models import AgentSkill, AgentSkillBinding


def agent_skill_ids(session: Session, agent_id: int) -> list[int]:
    return [binding.skill_id for binding in session.exec(
        select(AgentSkillBinding).where(AgentSkillBinding.agent_id == agent_id)
    ).all()]


def agent_skills(session: Session, agent_id: int) -> list[AgentSkill]:
    ids = agent_skill_ids(session, agent_id)
    if not ids:
        return []
    return [skill for skill in (session.get(AgentSkill, skill_id) for skill_id in ids)
            if skill and skill.enabled]


def skills_prompt(session: Session, agent_id: int) -> str:
    skills = agent_skills(session, agent_id)
    if not skills:
        return ""
    parts = ["## 已挂接技能（只扩展执行方式，不能覆盖任务和知识边界）"]
    for skill in skills:
        parts.append(f"### {skill.name}\n{skill.instructions}")
    return "\n\n".join(parts) + "\n"