import uuid
from datetime import UTC, datetime

from sqlalchemy import Index

from app import db


class FileAttachment(db.Model):
    """Polymorphic file attachment model for Cards, Comments, and other entities"""

    __tablename__ = "file_attachments"

    id = db.Column(db.Integer, primary_key=True)
    uuid = db.Column(
        db.String(36), nullable=False, unique=True, default=lambda: str(uuid.uuid4())
    )
    filename = db.Column(db.String(255), nullable=False)
    original_name = db.Column(db.String(255), nullable=False)
    file_type = db.Column(db.String(50), nullable=False)  # 'image', 'pdf', 'document'
    mime_type = db.Column(db.String(100), nullable=False)
    file_size = db.Column(db.Integer, nullable=False)

    # MinIO storage information
    minio_bucket = db.Column(db.String(100), nullable=False)
    minio_object_name = db.Column(db.String(255), nullable=False, unique=True)

    # Thumbnail information (optional, for images)
    thumbnail_minio_object_name = db.Column(db.String(255))
    thumbnail_minio_bucket = db.Column(db.String(100))

    # Polymorphic relationship - can attach to different entity types
    attachable_type = db.Column(
        db.String(50), nullable=False
    )  # 'Card', 'Comment', 'Epic'
    attachable_id = db.Column(db.Integer, nullable=False)  # ID of the attached entity

    # Upload metadata
    uploaded_by = db.Column(
        db.Integer, db.ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    created_at = db.Column(db.DateTime, default=lambda: datetime.now(UTC))

    # Relationships
    uploader = db.relationship("User", backref="uploaded_files")

    # Indexes for efficient queries
    __table_args__ = (
        Index("ix_file_attachments_attachable", "attachable_type", "attachable_id"),
        Index("ix_file_attachments_user", "uploaded_by"),
        Index("ix_file_attachments_uuid", "uuid"),
    )

    def to_dict(self):
        """Convert file attachment to dictionary"""
        return {
            "id": self.id,
            "uuid": self.uuid,
            "filename": self.filename,
            "original_name": self.original_name,
            "file_type": self.file_type,
            "mime_type": self.mime_type,
            "file_size": self.file_size,
            "minio_bucket": self.minio_bucket,
            "minio_object_name": self.minio_object_name,
            "thumbnail_minio_object_name": self.thumbnail_minio_object_name,
            "thumbnail_minio_bucket": self.thumbnail_minio_bucket,
            "attachable_type": self.attachable_type,
            "attachable_id": self.attachable_id,
            "uploaded_by": self.uploaded_by,
            "created_at": self.created_at.isoformat() if self.created_at else None,
        }

    def __repr__(self):
        return f"<FileAttachment {self.original_name} ({self.file_type})>"