state.py

"""全局状态容器 — 单例模式，所有模块通过它读写数据"""

import json
import os
from models import Concept, Relation, QuizQuestion, QuizRecord
from datetime import date

STATE_FILE = os.path.join(os.path.dirname(__file__), "data", "state.json")


class AppState:
    """应用全局状态，单例"""
    _instance = None

    def __new__(cls):
        if cls._instance is None:
            cls._instance = super().__new__(cls)
            cls._instance._init()
        return cls._instance

    def _init(self):
        self.concepts: dict[str, Concept] = {}       # id → Concept
        self.relations: list[Relation] = []
        self.questions: dict[str, QuizQuestion] = {} # id → QuizQuestion
        self.records: list[QuizRecord] = []

    # ─── 写入 ───

    def add_concept(self, c: Concept):
        existing = self.concepts.get(c.id)
        if existing:
            existing.description = existing.description or c.description
            existing.category = existing.category or c.category
            existing.difficulty = c.difficulty or existing.difficulty
            existing.related_ids = list(set(existing.related_ids + c.related_ids))
        else:
            self.concepts[c.id] = c

    def add_relation(self, r: Relation):
        if not any(x.src_id == r.src_id and x.dst_id == r.dst_id and x.rel_type == r.rel_type for x in self.relations):
            self.relations.append(r)
            src = self.concepts.get(r.src_id)
            dst = self.concepts.get(r.dst_id)
            if src and r.dst_id not in src.related_ids:
                src.related_ids.append(r.dst_id)
            if dst and r.src_id not in dst.related_ids:
                dst.related_ids.append(r.src_id)

    def add_question(self, q: QuizQuestion):
        self.questions[q.id] = q

    def add_record(self, r: QuizRecord):
        r.reviewed_at = date.today().isoformat()
        self.records.append(r)

    # ─── 查询 ───

    def get_concept_by_id(self, cid: str) -> Concept | None:
        return self.concepts.get(cid)

    def get_concept_by_name(self, name: str) -> Concept | None:
        for c in self.concepts.values():
            if c.name == name:
                return c
        return None

    def get_weak_concepts(self, top_n: int = 10) -> list[tuple[Concept, float]]:
        """返回正确率最低的概念 (concept, rate)"""
        stats: dict[str, list[bool]] = {}
        for r in self.records:
            for cid in r.concept_ids:
                stats.setdefault(cid, []).append(r.is_correct)
        result = []
        for cid, results in stats.items():
            concept = self.concepts.get(cid)
            if concept:
                rate = sum(results) / len(results)
                result.append((concept, rate))
        result.sort(key=lambda x: x[1])
        return result[:top_n]

    def get_due_reviews(self, target_date: str = "") -> list[tuple[QuizRecord, QuizQuestion]]:
        """获取到期待复习的题目"""
        if not target_date:
            target_date = date.today().isoformat()
        due = []
        for r in self.records:
            if r.next_review <= target_date and not r.is_correct:
                q = self.questions.get(r.question_id)
                if q:
                    due.append((r, q))
        return due

    def get_graph_data(self) -> dict:
        """返回 PyVis 格式的图数据"""
        nodes = []
        for c in self.concepts.values():
            nodes.append({
                "id": c.id, "label": c.name, "title": c.description,
                "group": c.category, "value": max(1, len(c.related_ids)),
                "difficulty": c.difficulty
            })
        edges = []
        for r in self.relations:
            edges.append({
                "from": r.src_id, "to": r.dst_id,
                "label": r.rel_type, "title": r.description
            })
        return {"nodes": nodes, "edges": edges}

    def get_stats(self) -> dict:
        """返回统计信息"""
        correct = sum(1 for r in self.records if r.is_correct)
        total = len(self.records)
        return {
            "concepts": len(self.concepts),
            "relations": len(self.relations),
            "questions": len(self.questions),
            "records": total,
            "accuracy": f"{correct/total*100:.1f}%" if total > 0 else "N/A"
        }

    # ─── 持久化 ───

    def save(self):
        data = {
            "concepts": [c.__dict__ for c in self.concepts.values()],
            "relations": [r.__dict__ for r in self.relations],
            "questions": [q.__dict__ for q in self.questions.values()],
            "records": [r.__dict__ for r in self.records],
        }
        os.makedirs(os.path.dirname(STATE_FILE), exist_ok=True)
        with open(STATE_FILE, "w", encoding="utf-8") as f:
            json.dump(data, f, ensure_ascii=False, indent=2)

    def load(self):
        if not os.path.exists(STATE_FILE):
            return
        with open(STATE_FILE, "r", encoding="utf-8") as f:
            data = json.load(f)
        self._init()
        for d in data.get("concepts", []):
            c = Concept(d["name"], d.get("description",""), d.get("category",""), d.get("source_file",""), d.get("difficulty",3), d.get("related_ids",[]))
            self.concepts[c.id] = c
        for d in data.get("relations", []):
            self.relations.append(Relation(d["src_id"], d["dst_id"], d.get("rel_type",""), d.get("description","")))
        for d in data.get("questions", []):
            q = QuizQuestion(d["question"], d["correct_answer"], d.get("explanation",""), d.get("concept_ids",[]), d.get("q_type","choice"), d.get("options",[]), d.get("difficulty",3))
            self.questions[q.id] = q
        for d in data.get("records", []):
            self.records.append(QuizRecord(**d))

    def clear(self):
        self._init()