email_service.py

import os
import json
import requests
from io import StringIO
import csv
from datetime import datetime


class EmailService:
    """Email service using Resend API"""
    
    def __init__(self):
        self.api_key = os.environ.get('RESEND_API_KEY')
        self.base_url = 'https://api.resend.com'
        self.from_email = 'onboarding@resend.dev'  # Default Resend test email
    
    def send_data_report(self, to_email: str, data: list, metadata: dict, format_type: str = 'csv'):
        """Send data report via email with attachment"""
        if not self.api_key:
            raise ValueError("RESEND_API_KEY environment variable is required")
        
        try:
            # Prepare email content
            subject = f"Zambia Data Report - {metadata.get('source', 'Multiple Sources')}"
            
            # Create email body
            html_content = self._create_email_html(data, metadata)
            
            # Prepare attachment
            attachment = self._create_attachment(data, metadata, format_type)
            
            # Send email via Resend API
            response = requests.post(
                f"{self.base_url}/emails",
                headers={
                    'Authorization': f'Bearer {self.api_key}',
                    'Content-Type': 'application/json'
                },
                json={
                    'from': self.from_email,
                    'to': [to_email],
                    'subject': subject,
                    'html': html_content,
                    'attachments': [attachment] if attachment else []
                }
            )
            
            if response.status_code == 200:
                return {'success': True, 'message': 'Email sent successfully'}
            else:
                return {'success': False, 'error': f'Failed to send email: {response.text}'}
                
        except Exception as e:
            return {'success': False, 'error': str(e)}
    
    def _create_email_html(self, data: list, metadata: dict) -> str:
        """Create HTML email content"""
        total_records = len(data)
        source = metadata.get('source', 'Multiple Sources')
        data_type = metadata.get('data_type', 'Various')
        
        html = f"""
        <html>
        <head>
            <style>
                body {{ font-family: Arial, sans-serif; margin: 20px; }}
                .header {{ background-color: #f8f9fa; padding: 20px; border-radius: 5px; }}
                .summary {{ margin: 20px 0; }}
                .data-preview {{ margin: 20px 0; }}
                table {{ border-collapse: collapse; width: 100%; max-width: 600px; }}
                th, td {{ border: 1px solid #ddd; padding: 8px; text-align: left; }}
                th {{ background-color: #f2f2f2; }}
                .footer {{ margin-top: 30px; font-size: 12px; color: #666; }}
            </style>
        </head>
        <body>
            <div class="header">
                <h2>Zambia Data Collection Report</h2>
                <p>Generated on {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}</p>
            </div>
            
            <div class="summary">
                <h3>Report Summary</h3>
                <ul>
                    <li><strong>Data Source:</strong> {source}</li>
                    <li><strong>Data Type:</strong> {data_type}</li>
                    <li><strong>Total Records:</strong> {total_records}</li>
                </ul>
            </div>
            
            <div class="data-preview">
                <h3>Data Preview (First 5 Records)</h3>
                {self._create_data_table(data[:5])}
            </div>
            
            <div class="footer">
                <p>This report was generated by the Zambia Data Collection Tool.</p>
                <p>The complete dataset is attached to this email.</p>
            </div>
        </body>
        </html>
        """
        return html
    
    def _create_data_table(self, data: list) -> str:
        """Create HTML table from data"""
        if not data:
            return "<p>No data available</p>"
        
        # Get headers from first record
        headers = list(data[0].keys())
        
        table_html = "<table>"
        
        # Add headers
        table_html += "<tr>"
        for header in headers:
            table_html += f"<th>{header}</th>"
        table_html += "</tr>"
        
        # Add data rows
        for record in data:
            table_html += "<tr>"
            for header in headers:
                value = record.get(header, '')
                table_html += f"<td>{value}</td>"
            table_html += "</tr>"
        
        table_html += "</table>"
        return table_html
    
    def _create_attachment(self, data: list, metadata: dict, format_type: str) -> dict | None:
        """Create email attachment based on format"""
        if not data:
            return None
        
        timestamp = datetime.now().strftime('%Y%m%d_%H%M%S')
        source = metadata.get('source', 'zambia_data').replace(' ', '_').lower()
        
        if format_type == 'csv':
            # Create CSV content
            output = StringIO()
            if data:
                writer = csv.DictWriter(output, fieldnames=data[0].keys())
                writer.writeheader()
                writer.writerows(data)
            
            import base64
            return {
                'filename': f'{source}_{timestamp}.csv',
                'content': base64.b64encode(output.getvalue().encode('utf-8')).decode('utf-8'),
                'type': 'text/csv'
            }
        
        elif format_type == 'json':
            # Create JSON content
            json_data = {
                'metadata': metadata,
                'data': data,
                'generated_at': datetime.now().isoformat()
            }
            
            import base64
            return {
                'filename': f'{source}_{timestamp}.json',
                'content': base64.b64encode(json.dumps(json_data, indent=2).encode('utf-8')).decode('utf-8'),
                'type': 'application/json'
            }
        
        # Default to CSV if format not recognized
        return self._create_attachment(data, metadata, 'csv')