"""
Ticket Comment Model - Collaboration & Communication

Enables team collaboration on tickets with threaded discussions.
Supports internal comments (team only) and external comments (visible to client).
"""

from sqlalchemy import Column, String, ForeignKey, Boolean, TIMESTAMP, Text, CheckConstraint
from sqlalchemy.dialects.postgresql import UUID, JSONB, ARRAY
from sqlalchemy.orm import relationship
from datetime import datetime
import uuid

from app.core.database import Base


class TicketComment(Base):
    """
    Ticket Comment Model
    
    Threaded comments on tickets. Supports internal (team) and external (client-visible) 
    comments with mentions and attachments.
    
    Links to:
    - tickets (required) - which ticket this comment belongs to
    - users (commented by, edited by) - who created/edited comment
    - ticket_comments (parent) - for threaded discussions
    - documents (attachments) - optional file attachments
    """
    
    __tablename__ = "ticket_comments"
    
    # Primary Key
    id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
    
    # Foreign Keys
    ticket_id = Column(
        UUID(as_uuid=True),
        ForeignKey("tickets.id", ondelete="CASCADE"),
        nullable=False,
        index=True
    )
    user_id = Column(
        UUID(as_uuid=True),
        ForeignKey("users.id", ondelete="SET NULL"),
        nullable=True,  # Nullable: user may be deleted
        index=True
    )
    
    # Comment Content
    comment_text = Column(Text, nullable=False)
    
    # Comment Type & Visibility
    is_internal = Column(Boolean, default=True, nullable=False)  # TRUE = team only, FALSE = visible to client
    comment_type = Column(String(50), default='note', nullable=False)  # 'note', 'issue', 'resolution', 'question', 'update'
    
    # Threading (for replies)
    parent_comment_id = Column(
        UUID(as_uuid=True),
        ForeignKey("ticket_comments.id", ondelete="CASCADE"),
        nullable=True,
        index=True
    )
    
    # Mentions & notifications
    mentioned_user_ids = Column(ARRAY(UUID(as_uuid=True)), nullable=True)  # Array of user IDs mentioned in comment (e.g., @john)
    
    # Attachments (optional - links to documents)
    attachment_document_ids = Column(ARRAY(UUID(as_uuid=True)), nullable=True)  # Array of document IDs attached to comment
    
    # Edit Tracking
    is_edited = Column(Boolean, default=False, nullable=False)
    edited_at = Column(TIMESTAMP(timezone=True), nullable=True)
    edited_by_user_id = Column(
        UUID(as_uuid=True),
        ForeignKey("users.id", ondelete="SET NULL"),
        nullable=True
    )
    
    # Metadata
    additional_metadata = Column(
        JSONB,
        nullable=False,
        default={},
        server_default="{}"
    )
    
    # Timestamps
    created_at = Column(
        TIMESTAMP(timezone=True),
        nullable=False,
        default=datetime.utcnow,
        server_default="timezone('utc'::text, now())"
    )
    updated_at = Column(
        TIMESTAMP(timezone=True),
        nullable=False,
        default=datetime.utcnow,
        onupdate=datetime.utcnow,
        server_default="timezone('utc'::text, now())"
    )
    deleted_at = Column(TIMESTAMP(timezone=True), nullable=True)
    
    # Relationships
    ticket = relationship("Ticket", back_populates="comments")
    user = relationship("User", foreign_keys=[user_id])
    edited_by_user = relationship("User", foreign_keys=[edited_by_user_id])
    parent_comment = relationship("TicketComment", remote_side=[id], backref="replies")
    
    # Constraints
    __table_args__ = (
        CheckConstraint("LENGTH(TRIM(comment_text)) > 0", name='chk_comment_not_empty'),
    )
    
    def __repr__(self):
        return f"<TicketComment(id={self.id}, ticket_id={self.ticket_id}, is_internal={self.is_internal})>"
    
    def to_dict(self):
        """Convert comment to dictionary"""
        return {
            "id": str(self.id),
            "ticket_id": str(self.ticket_id),
            "user_id": str(self.user_id) if self.user_id else None,
            "comment_text": self.comment_text,
            "is_internal": self.is_internal,
            "comment_type": self.comment_type,
            "parent_comment_id": str(self.parent_comment_id) if self.parent_comment_id else None,
            "mentioned_user_ids": [str(uid) for uid in self.mentioned_user_ids] if self.mentioned_user_ids else [],
            "attachment_document_ids": [str(did) for did in self.attachment_document_ids] if self.attachment_document_ids else [],
            "is_edited": self.is_edited,
            "edited_at": self.edited_at.isoformat() if self.edited_at else None,
            "edited_by_user_id": str(self.edited_by_user_id) if self.edited_by_user_id else None,
            "additional_metadata": self.additional_metadata,
            "created_at": self.created_at.isoformat() if self.created_at else None,
            "updated_at": self.updated_at.isoformat() if self.updated_at else None,
        }