"""
this model is new to iteration 2. It defines the structure of form fields
that are linked using foreign key entity relationships to from templates,
in order to render these fields and templates dynamically in the ticket submission form page.
"""
# import relevant sql libraries
from enum import Enum
from sqlalchemy import (
    Column,
    Integer,
    String,
    Boolean,
    DateTime,
    ForeignKey,
    Index,
)
from sqlalchemy.orm import relationship
from sqlalchemy.sql import func
# import the declarative base from db_connect module
from ..db.db_connect import Base

# define enumerations for field input types
class FieldType(str, Enum):
    TEXT = "text"
    TEXTAREA = "textarea"
    NUMBER = "number"
    SELECT = "select"
    CHECKBOX = "checkbox"
    RADIO = "radio"
    EMAIL = "email"

# define the from field model
class FormField(Base):
    #define table name
    __tablename__ = "form_fields"
    # define attributes
    id = Column(Integer, primary_key=True, index=True)
    # apply a cascading delete function for when the parent template is deleted
    template_id = Column(Integer, ForeignKey("form_templates.id", ondelete="CASCADE"), nullable=False, index=True)
    question_text = Column(String(255), nullable=False)
    type = Column(String(32), nullable=False, default=FieldType.TEXT.value)
    required = Column(Boolean, nullable=False, default=False)
    position = Column(Integer, nullable=False, default=0)

    created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=False)
    
    __table_args__ = (
        Index("ix_form_fields_template_pos", "template_id", "position"),
    )

    template = relationship("FormTemplate", backref="fields", passive_deletes=True)

    def __repr__(self) -> str:
        return f"<FormField id={self.id} template_id={self.template_id} question={self.question_text!r} type={self.type!r} required={self.required} position={self.position} created_at={self.created_at} updated_at={self.updated_at}>"