import csv
import pandas as pd

class CSVtoJSONTransformer:
    def __init__(self, csv_reader):
        self.csv_reader = csv_reader
    
    def transform_to_json(self):
        df = pd.DataFrame(self.csv_reader)  # Convert csv_reader to DataFrame
        df["Author"] = df["Author"].replace({pd.NA: None})
        df["Comment Body"] = df["Comment Body"].replace({pd.NA: None})

        # Define an empty list to store the transformed data
        transformed_data = []

        # Group the DataFrame by the 'Subreddit' column
        grouped_df = df.groupby('Subreddit')

        # Iterate through each subreddit group
        for subreddit, group in grouped_df:
            subreddit_data = {
                "Subreddit": subreddit,
                "Posts": []
            }
            
            # Iterate through each row in the subreddit group
            for index, row in group.iterrows():
                post_title = row['Post Title']
                comment_body = row['Comment Body']
                timestamp = row['Timestamp']
                upvotes = row['Upvotes']
                ID = row['ID']
                author = row['Author']
                replies = row['Number of Replies']
                
                # Check if the post title already exists under the subreddit
                post_exists = False
                for post in subreddit_data["Posts"]:
                    if post['PostTitle'] == post_title:
                        post_exists = True
                        post['Comments'].append({
                            "CommentID": ID,
                            "Author": author,
                            "CommentBody": comment_body,
                            "Timestamp": timestamp,
                            "Upvotes": upvotes,
                            "NumberofReplies": replies
                        })
                        break
                
                # If the post title does not exist, create a new entry
                if not post_exists:
                    subreddit_data["Posts"].append({
                        "PostID": len(subreddit_data["Posts"]) + 1,
                        "PostTitle": post_title,
                        "Comments": [{
                            "CommentID": ID,
                            "Author": author,
                            "CommentBody": comment_body,
                            "Timestamp": timestamp,
                            "Upvotes": upvotes,
                            "NumberofReplies": replies
                        }]
                    })
            
            # Append the subreddit data to the transformed data list
            transformed_data.append(subreddit_data)

        return transformed_data