"""
Database Models - SQLAlchemy ORM
"""

from sqlalchemy import Column, Integer, String, Text, Boolean, DateTime, ForeignKey, Enum, Table
from sqlalchemy.orm import relationship, declarative_base
from sqlalchemy.sql import func
from datetime import datetime
import enum

Base = declarative_base()

# Association tables for many-to-many relationships
channel_members = Table(
    'channel_members',
    Base.metadata,
    Column('channel_id', Integer, ForeignKey('channels.id', ondelete='CASCADE'), primary_key=True),
    Column('user_id', Integer, ForeignKey('users.id', ondelete='CASCADE'), primary_key=True),
    Column('joined_at', DateTime, default=func.now())
)

class UserRole(str, enum.Enum):
    ENGINEER = "engineer"
    BD = "bd"
    ADMIN = "admin"
    EXEC = "exec"

class ChannelType(str, enum.Enum):
    PUBLIC = "public"
    PRIVATE = "private"

class User(Base):
    __tablename__ = "users"
    
    id = Column(Integer, primary_key=True, index=True)
    email = Column(String(255), unique=True, index=True, nullable=False)
    name = Column(String(255), nullable=False)
    password_hash = Column(String(255), nullable=False)
    role = Column(Enum(UserRole), default=UserRole.ENGINEER, nullable=False)
    is_active = Column(Boolean, default=True, nullable=False)
    is_online = Column(Boolean, default=False, nullable=False)
    last_seen = Column(DateTime, default=func.now())
    created_at = Column(DateTime, default=func.now())
    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())
    
    # Relationships
    messages = relationship("Message", back_populates="user", cascade="all, delete-orphan")
    sent_dms = relationship("DirectMessage", foreign_keys="DirectMessage.sender_id", back_populates="sender")
    received_dms = relationship("DirectMessage", foreign_keys="DirectMessage.recipient_id", back_populates="recipient")
    channels = relationship("Channel", secondary=channel_members, back_populates="members")
    files = relationship("File", back_populates="uploaded_by_user")
    
    def __repr__(self):
        return f"<User {self.email}>"

class Channel(Base):
    __tablename__ = "channels"
    
    id = Column(Integer, primary_key=True, index=True)
    name = Column(String(100), unique=True, index=True, nullable=False)
    description = Column(Text)
    type = Column(Enum(ChannelType), default=ChannelType.PUBLIC, nullable=False)
    created_by = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'))
    created_at = Column(DateTime, default=func.now())
    
    # Relationships
    messages = relationship("Message", back_populates="channel", cascade="all, delete-orphan")
    members = relationship("User", secondary=channel_members, back_populates="channels")
    
    def __repr__(self):
        return f"<Channel #{self.name}>"

class Message(Base):
    __tablename__ = "messages"
    
    id = Column(Integer, primary_key=True, index=True)
    channel_id = Column(Integer, ForeignKey('channels.id', ondelete='CASCADE'), nullable=False)
    user_id = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'), nullable=True)  # NULL if AI
    content = Column(Text, nullable=False)
    is_ai_message = Column(Boolean, default=False, nullable=False)
    reply_to_message_id = Column(Integer, ForeignKey('messages.id', ondelete='SET NULL'), nullable=True)
    created_at = Column(DateTime, default=func.now())
    edited_at = Column(DateTime, nullable=True)
    
    # Relationships
    channel = relationship("Channel", back_populates="messages")
    user = relationship("User", back_populates="messages")
    replies = relationship("Message", remote_side=[id], backref="parent_message")
    artifacts = relationship("Artifact", back_populates="message", cascade="all, delete-orphan")
    
    def __repr__(self):
        return f"<Message {self.id} in #{self.channel.name if self.channel else 'Unknown'}>"

class DirectMessage(Base):
    __tablename__ = "direct_messages"
    
    id = Column(Integer, primary_key=True, index=True)
    sender_id = Column(Integer, ForeignKey('users.id', ondelete='CASCADE'), nullable=False)
    recipient_id = Column(Integer, ForeignKey('users.id', ondelete='CASCADE'), nullable=False)
    content = Column(Text, nullable=False)
    is_ai_message = Column(Boolean, default=False, nullable=False)
    read_at = Column(DateTime, nullable=True)
    created_at = Column(DateTime, default=func.now())
    edited_at = Column(DateTime, nullable=True)
    
    # Relationships
    sender = relationship("User", foreign_keys=[sender_id], back_populates="sent_dms")
    recipient = relationship("User", foreign_keys=[recipient_id], back_populates="received_dms")
    
    def __repr__(self):
        return f"<DM from {self.sender_id} to {self.recipient_id}>"

class File(Base):
    __tablename__ = "files"
    
    id = Column(Integer, primary_key=True, index=True)
    filename = Column(String(255), nullable=False)
    original_filename = Column(String(255), nullable=False)
    file_path = Column(String(500), nullable=False)
    file_size = Column(Integer, nullable=False)  # bytes
    mime_type = Column(String(100), nullable=False)
    uploaded_by = Column(Integer, ForeignKey('users.id', ondelete='SET NULL'))
    channel_id = Column(Integer, ForeignKey('channels.id', ondelete='CASCADE'), nullable=True)
    created_at = Column(DateTime, default=func.now())
    
    # Relationships
    uploaded_by_user = relationship("User", back_populates="files")
    
    def __repr__(self):
        return f"<File {self.original_filename}>"

class Artifact(Base):
    __tablename__ = "artifacts"
    
    id = Column(Integer, primary_key=True, index=True)
    message_id = Column(Integer, ForeignKey('messages.id', ondelete='CASCADE'), nullable=False)
    filename = Column(String(255), nullable=False)
    file_path = Column(String(500), nullable=False)
    file_type = Column(String(50), nullable=False)  # pdf, csv, docx, etc.
    created_at = Column(DateTime, default=func.now())
    
    # Relationships
    message = relationship("Message", back_populates="artifacts")
    
    def __repr__(self):
        return f"<Artifact {self.filename}>"