"""掌握度引擎：状态分级、按全局知识点节点答题后更新。"""
from __future__ import annotations

from dataclasses import dataclass

from sqlalchemy.orm import Session

from models import Knowledge, UserKnowledge
from services.knowledge_service import ensure_knowledge, ensure_user_knowledge


MASTERY_DELTA = {
    "chapter": (5, 4),
    "legacy": (4, 3),
    "imported": (0, 0),
}


@dataclass
class KnowledgeView:
    id: int
    knowledge_id: int
    name: str
    mastery: int
    position: int
    domain: str
    category: str


def status_for(mastery: int) -> str:
    if mastery >= 85:
        return "已掌握"
    if mastery >= 75:
        return "基本掌握"
    if mastery >= 60:
        return "待加强"
    return "重点"


def action_for(mastery: int) -> str:
    if mastery < 60:
        return "优先强化"
    if mastery < 75:
        return "继续练习"
    return "保持复习"


def snapshot(db: Session, user_id: int) -> list[KnowledgeView]:
    rows = (
        db.query(UserKnowledge, Knowledge)
        .join(Knowledge, Knowledge.id == UserKnowledge.knowledge_id)
        .filter(UserKnowledge.user_id == user_id)
        .order_by(UserKnowledge.position.asc(), UserKnowledge.id.asc())
        .all()
    )
    return [
        KnowledgeView(
            id=user_knowledge.id,
            knowledge_id=knowledge.id,
            name=knowledge.name,
            mastery=user_knowledge.mastery,
            position=user_knowledge.position,
            domain=knowledge.domain,
            category=knowledge.category,
        )
        for user_knowledge, knowledge in rows
    ]


def apply_answers(
    db: Session,
    user_id: int,
    mode: str,
    answered: list[tuple[str, bool]],
) -> None:
    """按题目全量知识点逐点调整掌握度（答对加分、答错扣分，封顶 0-100）。"""
    plus, minus = MASTERY_DELTA.get(mode, (4, 3))
    for knowledge_name, is_correct in answered:
        knowledge = ensure_knowledge(db, knowledge_name)
        row = ensure_user_knowledge(db, user_id, knowledge)
        row.mastery = max(
            0, min(100, row.mastery + (plus if is_correct else -minus))
        )