# ==============================================================================
# Formeleon - Multi-tenant Form Generator
# Author: Björn Runden <br@runden.net>
# Module: services/exporter.py
# Description: Service for exporting form submissions.
# ==============================================================================

import csv
import json
import io
from typing import List, Dict, Any
from flask import Response
from models import Submission

class ExporterService:
    """Service to handle generating exports for submissions."""
    
    @classmethod
    def generate_csv_response(cls, submissions: List[Submission], filename: str = "export.csv") -> Response:
        """
        Generates a Flask Response containing a CSV stream of the given submissions.
        """
        # Determine all possible fields from the payloads
        all_keys = set()
        for sub in submissions:
            if isinstance(sub.payload, dict):
                all_keys.update(sub.payload.keys())
        
        fieldnames = ['ID', 'Date', 'Form', 'Status', 'reCAPTCHA'] + sorted(list(all_keys))
        
        si = io.StringIO()
        writer = csv.DictWriter(si, fieldnames=fieldnames)
        writer.writeheader()
        
        for sub in submissions:
            row = {
                'ID': sub.id,
                'Date': sub.created_at.strftime('%Y-%m-%d %H:%M:%S'),
                'Form': sub.form_config.name if sub.form_config else 'Unknown',
                'Status': sub.status.value,
                'reCAPTCHA': sub.recaptcha_score if sub.recaptcha_score is not None else ''
            }
            if isinstance(sub.payload, dict):
                row.update(sub.payload)
            writer.writerow(row)
            
        output = si.getvalue()
        
        return Response(
            output,
            mimetype="text/csv",
            headers={"Content-disposition": f"attachment; filename={filename}"}
        )

    @classmethod
    def generate_json_response(cls, submissions: List[Submission], filename: str = "export.json") -> Response:
        """
        Generates a Flask Response containing a JSON array of the given submissions.
        """
        data = []
        for sub in submissions:
            data.append({
                'id': sub.id,
                'date': sub.created_at.isoformat(),
                'form_name': sub.form_config.name if sub.form_config else None,
                'status': sub.status.value,
                'recaptcha_score': sub.recaptcha_score,
                'payload': sub.payload
            })
            
        return Response(
            json.dumps(data, indent=2),
            mimetype="application/json",
            headers={"Content-disposition": f"attachment; filename={filename}"}
        )