#api/models.py
from sqlalchemy import Column, Integer, String, ForeignKey, DateTime, Text
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
from api.database import Base

class User(Base):
    __tablename__ = "users"
    id = Column(Integer, primary_key=True, index=True)
    username = Column(String(50), unique=True, nullable=False)
    hashed_password = Column(String(255), nullable=False)
    conversations = relationship("Conversation", back_populates="user")
    documents = relationship("Document", back_populates="user")

class Conversation(Base):
    __tablename__ = "conversations"
    id = Column(Integer, primary_key=True, index=True)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    state = Column(Text)  # JSON-serialized AgentState

    messages = relationship("Message", back_populates="conversation", cascade="all, delete-orphan")
    document = relationship("Document", uselist=False, back_populates="conversation", cascade="all, delete-orphan")

    def __repr__(self):
        return f"<Conversation id={self.id} user_id={self.user_id}>"
    user = relationship("User", back_populates="conversations")

class Message(Base):
    __tablename__ = "messages"
    id = Column(Integer, primary_key=True, index=True)
    conversation_id = Column(Integer, ForeignKey("conversations.id"), nullable=False)
    sender = Column(String(20))  # "user" or "assistant"
    content = Column(Text, nullable=False)
    timestamp = Column(DateTime(timezone=True), server_default=func.now())
    conversation = relationship("Conversation", back_populates="messages")

class Document(Base):
    __tablename__ = "documents"
    id = Column(Integer, primary_key=True, index=True)
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
    conversation_id = Column(Integer, ForeignKey("conversations.id"), unique=True)
    doc_type = Column(String(100), nullable=False)
    content = Column(Text, nullable=False)
    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
    user = relationship("User", back_populates="documents")
    conversation = relationship("Conversation", back_populates="document")