"""ORM 模型：知识点、题目、练习记录、错题与每日完成状态。"""
from __future__ import annotations

from datetime import date, datetime

from sqlalchemy import (
    Boolean,
    Date,
    Float,
    ForeignKey,
    Integer,
    String,
    Text,
    UniqueConstraint,
    DateTime,
)
from sqlalchemy.orm import Mapped, mapped_column

from database import Base


class User(Base):
    __tablename__ = "users"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    username: Mapped[str] = mapped_column(String(64), unique=True, index=True)
    password_hash: Mapped[str] = mapped_column(Text)
    display_name: Mapped[str] = mapped_column(String(64), default="")
    active: Mapped[bool] = mapped_column(Boolean, default=True)
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)


class Role(Base):
    __tablename__ = "roles"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    code: Mapped[str] = mapped_column(String(32), unique=True)
    name: Mapped[str] = mapped_column(String(64))
    description: Mapped[str] = mapped_column(Text, default="")


class Permission(Base):
    __tablename__ = "permissions"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    code: Mapped[str] = mapped_column(String(64), unique=True)
    name: Mapped[str] = mapped_column(String(64))
    group: Mapped[str] = mapped_column(String(32), default="system")


class UserRole(Base):
    __tablename__ = "user_roles"
    __table_args__ = (UniqueConstraint("user_id", "role_id"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    user_id: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    role_id: Mapped[int] = mapped_column(
        ForeignKey("roles.id", ondelete="CASCADE"), index=True
    )


class RolePermission(Base):
    __tablename__ = "role_permissions"
    __table_args__ = (UniqueConstraint("role_id", "permission_id"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    role_id: Mapped[int] = mapped_column(
        ForeignKey("roles.id", ondelete="CASCADE"), index=True
    )
    permission_id: Mapped[int] = mapped_column(
        ForeignKey("permissions.id", ondelete="CASCADE"), index=True
    )


class Knowledge(Base):
    """全局知识点（同一知识点可被多个章节复用，用关系表关联）。"""

    __tablename__ = "knowledge"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    name: Mapped[str] = mapped_column(String(64), unique=True)
    domain: Mapped[str] = mapped_column(String(16), default="初等")  # 初等 / 高等
    category: Mapped[str] = mapped_column(String(64), default="")
    description: Mapped[str] = mapped_column(Text, default="")


class KnowledgeRelation(Base):
    """知识点间关系，支持未来知识图谱（前置/包含/相关等）。"""

    __tablename__ = "knowledge_relations"
    __table_args__ = (
        UniqueConstraint("source_id", "target_id", "relation_type"),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    source_id: Mapped[int] = mapped_column(
        ForeignKey("knowledge.id", ondelete="CASCADE"), index=True
    )
    target_id: Mapped[int] = mapped_column(
        ForeignKey("knowledge.id", ondelete="CASCADE"), index=True
    )
    relation_type: Mapped[str] = mapped_column(
        String(16), default="前置"
    )  # 前置 / 包含 / 相关


class KnowledgeResource(Base):
    """知识点对外资源链接（视频 / 在线课程 / 电子教材）。

    教材与章节不在此登记：章节通过 ChapterKnowledge 反向引用知识点，
    知识点详情据此反查“哪本书的哪一章讲了它”。
    """

    __tablename__ = "knowledge_resources"
    __table_args__ = (UniqueConstraint("knowledge_id", "kind", "url"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    knowledge_id: Mapped[int] = mapped_column(
        ForeignKey("knowledge.id", ondelete="CASCADE"), index=True
    )
    kind: Mapped[str] = mapped_column(String(16), default="video")  # video | book
    title: Mapped[str] = mapped_column(String(128), default="")
    url: Mapped[str] = mapped_column(String(256), default="")
    textbook_id: Mapped[int | None] = mapped_column(
        ForeignKey("textbooks.id", ondelete="CASCADE"),
        nullable=True,
    )
    course_id: Mapped[int | None] = mapped_column(
        ForeignKey("courses.id", ondelete="CASCADE"),
        nullable=True,
    )
    position: Mapped[int] = mapped_column(Integer, default=0)


class ChapterKnowledge(Base):
    __tablename__ = "chapter_knowledge"
    __table_args__ = (UniqueConstraint("chapter_id", "knowledge_id"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    chapter_id: Mapped[int] = mapped_column(
        ForeignKey("chapters.id", ondelete="CASCADE"), index=True
    )
    knowledge_id: Mapped[int] = mapped_column(
        ForeignKey("knowledge.id", ondelete="CASCADE"), index=True
    )


class QuestionKnowledge(Base):
    __tablename__ = "question_knowledge"
    __table_args__ = (UniqueConstraint("question_id", "knowledge_id"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    question_id: Mapped[int] = mapped_column(
        ForeignKey("questions.id", ondelete="CASCADE"), index=True
    )
    knowledge_id: Mapped[int] = mapped_column(
        ForeignKey("knowledge.id", ondelete="CASCADE"), index=True
    )


class UserKnowledge(Base):
    """用户对某全局知识点的掌握度（知识点经章节/题目引用，不靠名称匹配）。"""

    __tablename__ = "user_knowledge"
    __table_args__ = (UniqueConstraint("user_id", "knowledge_id"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    user_id: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    knowledge_id: Mapped[int] = mapped_column(
        ForeignKey("knowledge.id", ondelete="CASCADE"), index=True
    )
    mastery: Mapped[int] = mapped_column(Integer, default=60)
    position: Mapped[int] = mapped_column(Integer, default=0)


class Textbook(Base):
    __tablename__ = "textbooks"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    name: Mapped[str] = mapped_column(String(128), unique=True)
    author: Mapped[str] = mapped_column(String(128), default="")
    publisher: Mapped[str] = mapped_column(String(128), default="")
    isbn: Mapped[str] = mapped_column(String(32), default="")
    edition: Mapped[str] = mapped_column(String(64), default="")
    grade: Mapped[str] = mapped_column(String(32), default="")
    link: Mapped[str] = mapped_column(String(256), default="")
    description: Mapped[str] = mapped_column(Text, default="")
    position: Mapped[int] = mapped_column(Integer, default=0)
    # 电子书：文件放在 data/ebooks/{textbook_id}/ 下，表里只存文件名与元信息
    ebook_file: Mapped[str] = mapped_column(String(256), default="")
    ebook_name: Mapped[str] = mapped_column(String(256), default="")  # 上传时的原始文件名
    ebook_format: Mapped[str] = mapped_column(String(8), default="")  # pdf | epub
    ebook_size: Mapped[int] = mapped_column(Integer, default=0)
    # 篇幅：PDF 页数 / EPUB 章节数，阅读器首次打开后回填真实值
    ebook_pages: Mapped[int] = mapped_column(Integer, default=0)
    ebook_uploaded_at: Mapped[datetime | None] = mapped_column(
        DateTime, nullable=True
    )


class Course(Base):
    """在线课程 / 视频课：只有外链，不带章节与电子书，因此与教材分表存放。"""

    __tablename__ = "courses"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    name: Mapped[str] = mapped_column(String(128), unique=True)
    provider: Mapped[str] = mapped_column(String(128), default="")  # 开课方
    url: Mapped[str] = mapped_column(String(256), default="")
    grade: Mapped[str] = mapped_column(String(32), default="")
    description: Mapped[str] = mapped_column(Text, default="")
    position: Mapped[int] = mapped_column(Integer, default=0)


class Chapter(Base):
    __tablename__ = "chapters"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    textbook_id: Mapped[int] = mapped_column(
        ForeignKey("textbooks.id", ondelete="CASCADE"), index=True
    )
    name: Mapped[str] = mapped_column(String(128))
    position: Mapped[int] = mapped_column(Integer, default=0)
    summary: Mapped[str] = mapped_column(Text, default="")
    # 章节在电子书里的起始定位：PDF 是页码，EPUB 是 spine 节序号；0 表示未设置
    ebook_page: Mapped[int] = mapped_column(Integer, default=0)


class Question(Base):
    __tablename__ = "questions"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    # 遗留字段：早期“专项练习 / 自适应题库”分类，已不再作为业务概念使用，
    # 仅为兼容旧数据库保留列。
    source: Mapped[str] = mapped_column(String(16), default="bank")
    stem: Mapped[str] = mapped_column(Text)
    options: Mapped[str] = mapped_column(Text)  # JSON 字符串
    correct_index: Mapped[int] = mapped_column(Integer)
    knowledge_name: Mapped[str] = mapped_column(String(64), index=True)
    explanation: Mapped[str] = mapped_column(Text, default="")
    chapter_id: Mapped[int | None] = mapped_column(
        ForeignKey("chapters.id", ondelete="SET NULL"),
        nullable=True,
        index=True,
    )
    difficulty: Mapped[int] = mapped_column(Integer, default=1)
    is_generated: Mapped[bool] = mapped_column(Boolean, default=False)
    used_count: Mapped[int] = mapped_column(Integer, default=0)


class AttemptSession(Base):
    __tablename__ = "attempt_sessions"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    user_id: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    mode: Mapped[str] = mapped_column(String(16))
    title: Mapped[str] = mapped_column(String(64))
    total: Mapped[int] = mapped_column(Integer)
    correct: Mapped[int] = mapped_column(Integer)
    chapter_id: Mapped[int | None] = mapped_column(
        ForeignKey("chapters.id", ondelete="SET NULL"),
        nullable=True,
        index=True,
    )
    happened_on: Mapped[date] = mapped_column(Date, default=date.today)


class AttemptItem(Base):
    """练习中的逐题作答明细（题目做快照保存，删除题库不影响历史记录）。"""

    __tablename__ = "attempt_items"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    attempt_id: Mapped[int] = mapped_column(
        ForeignKey("attempt_sessions.id", ondelete="CASCADE"), index=True
    )
    user_id: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    question_index: Mapped[int] = mapped_column(Integer, default=1)
    question_id: Mapped[int | None] = mapped_column(
        ForeignKey("questions.id", ondelete="SET NULL"),
        nullable=True,
    )
    stem: Mapped[str] = mapped_column(Text)
    options: Mapped[str] = mapped_column(Text)  # JSON 字符串
    correct_index: Mapped[int] = mapped_column(Integer)
    selected: Mapped[int | None] = mapped_column(Integer, nullable=True)
    correct: Mapped[bool] = mapped_column(Boolean)
    knowledge_name: Mapped[str] = mapped_column(String(64), index=True)
    knowledge_names: Mapped[str] = mapped_column(Text, default="[]")
    explanation: Mapped[str] = mapped_column(Text, default="")


class ErrorEntry(Base):
    __tablename__ = "error_entries"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    user_id: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    source_label: Mapped[str] = mapped_column(String(64))
    knowledge_name: Mapped[str] = mapped_column(String(64), index=True)
    knowledge_names: Mapped[str] = mapped_column(Text, default="[]")
    diagnosis: Mapped[str] = mapped_column(Text)
    status: Mapped[str] = mapped_column(String(16), default="待复习")
    created_on: Mapped[date] = mapped_column(Date, default=date.today)
    attempt_id: Mapped[int | None] = mapped_column(
        ForeignKey("attempt_sessions.id", ondelete="SET NULL"),
        nullable=True,
    )
    question_id: Mapped[int | None] = mapped_column(
        ForeignKey("questions.id", ondelete="SET NULL"),
        nullable=True,
    )
    stem: Mapped[str] = mapped_column(Text, default="")
    options: Mapped[str] = mapped_column(Text, default="")  # JSON 字符串
    selected: Mapped[int | None] = mapped_column(Integer, nullable=True)
    correct_index: Mapped[int | None] = mapped_column(Integer, nullable=True)
    explanation: Mapped[str] = mapped_column(Text, default="")


class DailyCompletion(Base):
    __tablename__ = "daily_completions"
    __table_args__ = (UniqueConstraint("user_id", "done_on"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    user_id: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    chapter_id: Mapped[int | None] = mapped_column(
        ForeignKey("chapters.id", ondelete="SET NULL"), nullable=True, index=True
    )
    rating: Mapped[str] = mapped_column(String(16), default="")
    done_on: Mapped[date] = mapped_column(Date)


class LlmSetting(Base):
    __tablename__ = "llm_settings"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    name: Mapped[str] = mapped_column(String(128), default="")
    provider: Mapped[str] = mapped_column(String(32), default="openai")
    api_key: Mapped[str] = mapped_column(Text, default="")
    base_url: Mapped[str] = mapped_column(String(256), default="")
    model: Mapped[str] = mapped_column(String(64), default="")
    temperature: Mapped[float] = mapped_column(Float, default=0.3)
    max_tokens: Mapped[int | None] = mapped_column(Integer, nullable=True)
    is_default: Mapped[bool] = mapped_column(Boolean, default=False)
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)


class LlmTask(Base):
    """异步大模型任务：题目生成 / 章节生成，支持进度查询。"""

    __tablename__ = "llm_tasks"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    kind: Mapped[str] = mapped_column(String(32))  # generate_questions / generate_chapters
    status: Mapped[str] = mapped_column(String(16), default="pending")
    progress: Mapped[int] = mapped_column(Integer, default=0)
    message: Mapped[str] = mapped_column(Text, default="等待执行")
    params: Mapped[str] = mapped_column(Text, default="{}")
    result: Mapped[str] = mapped_column(Text, default="")
    created_by: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
    finished_at: Mapped[datetime | None] = mapped_column(
        DateTime, nullable=True
    )


class EbookProgress(Base):
    """阅读进度：PDF 记页码，EPUB 记 CFI，每人每本书一条。"""

    __tablename__ = "ebook_progress"
    __table_args__ = (UniqueConstraint("user_id", "textbook_id"),)

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    user_id: Mapped[int] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    textbook_id: Mapped[int] = mapped_column(
        ForeignKey("textbooks.id", ondelete="CASCADE"), index=True
    )
    locator: Mapped[str] = mapped_column(String(512), default="")  # EPUB CFI
    page: Mapped[int] = mapped_column(Integer, default=0)
    total: Mapped[int] = mapped_column(Integer, default=0)
    position: Mapped[float] = mapped_column(Float, default=0.0)  # 0~1
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow
    )