app/models.py

import json
import csv
from io import StringIO

from pydantic import BaseModel, validator, ValidationError

class Card(BaseModel):
 question: str
 answer: str

class Message(BaseModel):
 role: str
 content: list[Card]

 @validator('content', pre=True)
 def parse_content(cls, v: str) -> 'Message':
 if isinstance(v, str):
 try:
 content_list = json.loads(v)
 return content_list
 except json.JSONDecodeError as e:
 raise ValueError(f"Error decoding 'content' JSON: {e}") from e
 return v

 def content_to_json(self) -> str:
 return json.dumps([card.dict() for card in self.content], indent=2)

 def content_to_csv(self) -> str:
 """
 Converts the content of the Message instance into a CSV string.
 """
 output = StringIO()
 # Step 2: Create a CSV writer - windows style is the default, so set Unix-style line endings
 writer = csv.writer(output, lineterminator='\n')
 writer.writerow(["Question", "Answer"])
 for card in self.content:
 writer.writerow([card.question, card.answer])
 csv_content = output.getvalue()
 output.close()
 return csv_content

class PydanticEncoder(json.JSONEncoder):
 def default(self, obj):
 if isinstance(obj, BaseModel):
 return obj.dict()
 return super().default(obj)

def parse_message(input_dict: dict[str, any]) -> Message:
 try:
 # Extract the role
 role: str = input_dict['role']

 # Parse the content
 content: str = input_dict['content']

 # If content is a string, try to parse it as JSON
 if isinstance(content, str):
 content = json.loads(content)

 # Create Card objects from the content
 cards = [Card(**item) for item in content]

 # Create and return the Message object
 return Message(role=role, content=cards)
 except json.JSONDecodeError as e:
 raise ValueError(f"Invalid JSON in content: {str(e)}")
 except ValidationError as e:
 raise ValueError(f"Validation error: {str(e)}")
 except KeyError as e:
 raise ValueError(f"Missing required key: {str(e)}")