from sqlalchemy import Column, Integer, String, Text, DateTime, JSON, ForeignKey, UniqueConstraint
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
from database import Base


class Post(Base):
    __tablename__ = "posts"

    id = Column(Integer, primary_key=True, index=True)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    title = Column(String(200), nullable=False)
    content = Column(Text, default="")
    post_type = Column(String(50), default="discussion")
    tags = Column(JSON, default=list)
    attachments = Column(JSON, default=list)
    views = Column(Integer, default=0)
    likes = Column(Integer, default=0)
    comments_count = Column(Integer, default=0)
    is_pinned = Column(Integer, default=0)
    created_at = Column(DateTime, server_default=func.now())
    updated_at = Column(DateTime, server_default=func.now(), onupdate=func.now())

    author = relationship("User", back_populates="posts")
    comments = relationship("Comment", back_populates="post", lazy="selectin", cascade="all, delete-orphan")
    favorites = relationship("PostFavorite", back_populates="post", lazy="selectin", cascade="all, delete-orphan")


class Comment(Base):
    __tablename__ = "comments"

    id = Column(Integer, primary_key=True, index=True)
    post_id = Column(Integer, ForeignKey("posts.id"), nullable=False)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    content = Column(Text, nullable=False)
    parent_id = Column(Integer, ForeignKey("comments.id"), nullable=True)
    likes = Column(Integer, default=0)
    created_at = Column(DateTime, server_default=func.now())

    post = relationship("Post", back_populates="comments")
    author = relationship("User")


class PostFavorite(Base):
    __tablename__ = "post_favorites"
    __table_args__ = (UniqueConstraint("user_id", "post_id", name="uq_post_favorite_user_post"),)

    id = Column(Integer, primary_key=True, index=True)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False, index=True)
    post_id = Column(Integer, ForeignKey("posts.id"), nullable=False, index=True)
    created_at = Column(DateTime, server_default=func.now())

    user = relationship("User")
    post = relationship("Post", back_populates="favorites")