"""SQLAlchemy models for realtime messaging

Tables:
- tr_messages: Stores all messages sent in incident rooms
- tr_message_reactions: User reactions to messages (emoji)
- tr_message_edit_history: Audit trail for message edits

Note: All tables use 'tr_' prefix to avoid conflicts in shared database.
"""
from sqlalchemy import Column, Integer, String, Text, DateTime, Enum, ForeignKey, UniqueConstraint, Index, BigInteger, JSON
from sqlalchemy.orm import relationship
from datetime import datetime
import enum
import uuid
from app.core.database import Base


class MessageType(str, enum.Enum):
    """Types of messages in incident rooms"""
    TEXT = "text"
    IMAGE_REF = "image_ref"
    FILE_REF = "file_ref"
    SYSTEM = "system"
    INCIDENT_DATA = "incident_data"


class Message(Base):
    """Message model for incident room communications"""

    __tablename__ = "tr_messages"

    message_id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    room_id = Column(String(36), ForeignKey("tr_incident_rooms.room_id", ondelete="CASCADE"), nullable=False)
    sender_id = Column(String(255), nullable=False)  # User email/ID
    content = Column(Text, nullable=False)
    message_type = Column(Enum(MessageType), default=MessageType.TEXT, nullable=False)

    # Message metadata for structured data, file references, etc.
    message_metadata = Column(JSON)

    # @Mention tracking - stores array of mentioned user_ids
    mentions = Column(JSON, default=list)

    # Timestamps
    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
    edited_at = Column(DateTime)  # Last edit timestamp
    deleted_at = Column(DateTime)  # Soft delete timestamp

    # Sequence number for FIFO ordering within a room
    sequence_number = Column(BigInteger, nullable=False)

    # Relationships
    reactions = relationship("MessageReaction", back_populates="message", cascade="all, delete-orphan")
    edit_history = relationship("MessageEditHistory", back_populates="message", cascade="all, delete-orphan")

    # Indexes for common queries
    __table_args__ = (
        Index("ix_tr_messages_room_created", "room_id", "created_at"),
        Index("ix_tr_messages_room_sequence", "room_id", "sequence_number"),
        Index("ix_tr_messages_sender", "sender_id"),
    )


class MessageReaction(Base):
    """Message reaction model for emoji reactions"""

    __tablename__ = "tr_message_reactions"

    reaction_id = Column(Integer, primary_key=True, autoincrement=True)
    message_id = Column(String(36), ForeignKey("tr_messages.message_id", ondelete="CASCADE"), nullable=False)
    user_id = Column(String(255), nullable=False)  # User email/ID who reacted
    emoji = Column(String(10), nullable=False)  # Emoji character or code

    # Timestamp
    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)

    # Relationships
    message = relationship("Message", back_populates="reactions")

    # Constraints and indexes
    __table_args__ = (
        # Ensure unique reaction per user per message
        UniqueConstraint("message_id", "user_id", "emoji", name="uq_tr_message_reaction"),
        Index("ix_tr_message_reactions_message", "message_id"),
    )


class MessageEditHistory(Base):
    """Message edit history model for audit trail"""

    __tablename__ = "tr_message_edit_history"

    edit_id = Column(Integer, primary_key=True, autoincrement=True)
    message_id = Column(String(36), ForeignKey("tr_messages.message_id", ondelete="CASCADE"), nullable=False)
    original_content = Column(Text, nullable=False)  # Content before edit
    edited_by = Column(String(255), nullable=False)  # User who made the edit

    # Timestamp
    edited_at = Column(DateTime, default=datetime.utcnow, nullable=False)

    # Relationships
    message = relationship("Message", back_populates="edit_history")

    # Indexes
    __table_args__ = (
        Index("ix_tr_message_edit_history_message", "message_id", "edited_at"),
    )