import boto3
from datetime import datetime
from io import StringIO
import pandas as pd

class FeedbackSaverWithPandas:
    def __init__(self, aws_access_key_id, aws_secret_access_key):
        self.s3_client = boto3.client(
            's3',
            aws_access_key_id=aws_access_key_id,
            aws_secret_access_key=aws_secret_access_key
        )

    def save_feedback_to_s3(self, question, response, feedback, bucket_name, object_key):
        """Append new feedback data to existing CSV in an S3 bucket and save it back."""
        current_df = self._read_current_data_from_s3(bucket_name, object_key)
        new_df = pd.DataFrame([{
            "Date": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            "Question": question,
            "Response": response,
            "Feedback": feedback
        }])
        appended_data = pd.concat([current_df, new_df], ignore_index=True)
        self._write_data_to_s3(appended_data, bucket_name, object_key)

    def _read_current_data_from_s3(self, bucket, key):
        """Read existing CSV from S3 bucket into a pandas DataFrame."""
        try:
            csv_obj = self.s3_client.get_object(Bucket=bucket, Key=key)
            csv_string = csv_obj['Body'].read().decode('utf-8')
            return pd.read_csv(StringIO(csv_string))
        except self.s3_client.exceptions.NoSuchKey:
            # Return an empty DataFrame if the file does not exist
            return pd.DataFrame(columns=["Date", "Question", "Response", "Feedback"])

    def _write_data_to_s3(self, data_frame, bucket, key):
        """Write DataFrame back to S3 as a CSV."""
        csv_buffer = StringIO()
        data_frame.to_csv(csv_buffer, index=False)
        self.s3_client.put_object(Bucket=bucket, Key=key, Body=csv_buffer.getvalue().encode('utf-8'))