import json
from datetime import datetime

from sqlalchemy import String, Text, Integer, DateTime, Boolean, ForeignKey, func
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.db.base import Base


class Class_(Base):
    __tablename__ = "classes"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    name: Mapped[str] = mapped_column(String(100), nullable=False)
    cohort_year: Mapped[int] = mapped_column(Integer, nullable=False)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    invite_code: Mapped[str | None] = mapped_column(String(20), unique=True, nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), onupdate=func.now()
    )

    members: Mapped[list["User"]] = relationship("User", back_populates="class_")
    timelines: Mapped[list["Timeline"]] = relationship(
        "Timeline", back_populates="class_", cascade="all, delete-orphan"
    )
    schedules: Mapped[list["Schedule"]] = relationship(
        "Schedule", back_populates="class_", cascade="all, delete-orphan"
    )
    announcements: Mapped[list["Announcement"]] = relationship(
        "Announcement", back_populates="class_", cascade="all, delete-orphan"
    )
    resources: Mapped[list["Resource"]] = relationship(
        "Resource", back_populates="class_", cascade="all, delete-orphan"
    )
    roster: Mapped[list["StudentRoster"]] = relationship(
        "StudentRoster", back_populates="class_", cascade="all, delete-orphan"
    )


class User(Base):
    __tablename__ = "users"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    email: Mapped[str] = mapped_column(String(255), unique=True, nullable=False, index=True)
    password_hash: Mapped[str] = mapped_column(Text, nullable=False)
    name: Mapped[str] = mapped_column(String(100), nullable=False)
    student_id: Mapped[str | None] = mapped_column(String(50), nullable=True, unique=True)

    # role: super_admin | class_admin | student
    role: Mapped[str] = mapped_column(String(20), default="student", nullable=False)
    # status: pending | approved | rejected | disabled
    status: Mapped[str] = mapped_column(String(20), default="pending", nullable=False)

    class_id: Mapped[int | None] = mapped_column(
        Integer, ForeignKey("classes.id"), nullable=True
    )
    class_: Mapped["Class_ | None"] = relationship("Class_", back_populates="members")

    # Profile
    industry: Mapped[str | None] = mapped_column(String(100), nullable=True)
    company: Mapped[str | None] = mapped_column(String(100), nullable=True)
    position: Mapped[str | None] = mapped_column(String(100), nullable=True)
    skills_tags: Mapped[str | None] = mapped_column(Text, nullable=True)  # JSON array
    wechat_id: Mapped[str | None] = mapped_column(String(100), nullable=True)
    phone: Mapped[str | None] = mapped_column(String(20), nullable=True)
    avatar_url: Mapped[str | None] = mapped_column(Text, nullable=True)
    bio: Mapped[str | None] = mapped_column(Text, nullable=True)

    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), onupdate=func.now()
    )

    timeline_posts: Mapped[list["Timeline"]] = relationship(
        "Timeline", back_populates="author"
    )

    def get_skills_list(self) -> list[str]:
        if not self.skills_tags:
            return []
        try:
            return json.loads(self.skills_tags)
        except (json.JSONDecodeError, TypeError):
            return []

    def set_skills_list(self, tags: list[str]):
        self.skills_tags = json.dumps(tags, ensure_ascii=False) if tags else None


class Timeline(Base):
    __tablename__ = "timelines"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    class_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("classes.id"), nullable=False, index=True
    )
    author_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("users.id"), nullable=False
    )
    title: Mapped[str] = mapped_column(String(200), nullable=False)
    content: Mapped[str | None] = mapped_column(Text, nullable=True)
    image_urls: Mapped[str | None] = mapped_column(Text, nullable=True)  # JSON array
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), onupdate=func.now()
    )

    class_: Mapped["Class_"] = relationship("Class_", back_populates="timelines")
    author: Mapped["User"] = relationship("User", back_populates="timeline_posts")

    def get_image_urls_list(self) -> list[str]:
        if not self.image_urls:
            return []
        try:
            return json.loads(self.image_urls)
        except (json.JSONDecodeError, TypeError):
            return []

    def set_image_urls_list(self, urls: list[str]):
        self.image_urls = json.dumps(urls) if urls else None


class Schedule(Base):
    __tablename__ = "schedules"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    class_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("classes.id"), nullable=False, index=True
    )
    # type: course | deadline | activity
    type: Mapped[str] = mapped_column(String(20), nullable=False)
    title: Mapped[str] = mapped_column(String(200), nullable=False)
    start_time: Mapped[datetime] = mapped_column(DateTime, nullable=False)
    end_time: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
    location: Mapped[str | None] = mapped_column(String(200), nullable=True)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), onupdate=func.now()
    )

    class_: Mapped["Class_"] = relationship("Class_", back_populates="schedules")


class Announcement(Base):
    __tablename__ = "announcements"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    class_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("classes.id"), nullable=False, index=True
    )
    author_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("users.id"), nullable=False
    )
    title: Mapped[str] = mapped_column(String(200), nullable=False)
    content: Mapped[str | None] = mapped_column(Text, nullable=True)
    is_pinned: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, server_default=func.now(), onupdate=func.now()
    )

    class_: Mapped["Class_"] = relationship("Class_", back_populates="announcements")
    author: Mapped["User"] = relationship("User")


class Resource(Base):
    __tablename__ = "resources"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    class_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("classes.id"), nullable=False, index=True
    )
    uploader_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("users.id"), nullable=False
    )
    title: Mapped[str] = mapped_column(String(200), nullable=False)
    description: Mapped[str | None] = mapped_column(Text, nullable=True)
    file_url: Mapped[str] = mapped_column(Text, nullable=False)
    file_type: Mapped[str] = mapped_column(String(50), nullable=False)
    file_size: Mapped[int] = mapped_column(Integer, nullable=False)
    category: Mapped[str] = mapped_column(String(50), nullable=False)
    download_count: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())

    class_: Mapped["Class_"] = relationship("Class_", back_populates="resources")
    uploader: Mapped["User"] = relationship("User")


class Notification(Base):
    __tablename__ = "notifications"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    user_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("users.id"), nullable=False, index=True
    )
    type: Mapped[str] = mapped_column(String(50), nullable=False)
    title: Mapped[str] = mapped_column(String(200), nullable=False)
    content: Mapped[str | None] = mapped_column(Text, nullable=True)
    related_id: Mapped[int | None] = mapped_column(Integer, nullable=True)
    is_read: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())

    user: Mapped["User"] = relationship("User")


class StudentRoster(Base):
    __tablename__ = "student_rosters"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    class_id: Mapped[int] = mapped_column(
        Integer, ForeignKey("classes.id"), nullable=False, index=True
    )
    student_id: Mapped[str] = mapped_column(String(50), nullable=False)
    name: Mapped[str] = mapped_column(String(100), nullable=False)
    status: Mapped[str] = mapped_column(
        String(20), default="unregistered", nullable=False
    )
    user_id: Mapped[int | None] = mapped_column(
        Integer, ForeignKey("users.id"), nullable=True
    )
    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())

    class_: Mapped["Class_"] = relationship("Class_", back_populates="roster")
    user: Mapped["User | None"] = relationship("User")