"""
Export Accounts Use Case - Exportiert Account-Daten in verschiedene Formate
"""

import logging
import csv
import json
from io import StringIO
from typing import List, Dict, Any, Optional
from datetime import datetime

logger = logging.getLogger("export_accounts_use_case")


class ExportAccountsUseCase:
    """
    Use Case für Account-Export.
    Exportiert Account-Daten in verschiedene Formate (CSV, JSON).
    """
    
    def __init__(self, db_manager):
        self.db_manager = db_manager
        
    def execute(self, 
                platform: Optional[str] = None,
                format: str = 'csv',
                include_passwords: bool = True) -> bytes:
        """
        Exportiert Account-Daten.
        
        Args:
            platform: Filter für spezifische Plattform (None = alle)
            format: Export-Format ('csv' oder 'json')
            include_passwords: Ob Passwörter inkludiert werden sollen
            
        Returns:
            Exportierte Daten als Bytes
        """
        # Hole Account-Daten
        if platform and platform.lower() not in ["all", ""]:
            accounts = self.db_manager.get_accounts_by_platform(platform.lower())
        else:
            accounts = self.db_manager.get_all_accounts()
            
        if not accounts:
            logger.warning(f"Keine Accounts gefunden für Export (platform: {platform})")
            return b""
        
        # Exportiere basierend auf Format
        if format.lower() == 'csv':
            result = self._export_csv(accounts, include_passwords)
        elif format.lower() == 'json':
            result = self._export_json(accounts, include_passwords)
        else:
            raise ValueError(f"Unsupported format: {format}")
            
        logger.info(f"Exported {len(accounts)} accounts as {format}")
        return result
    
    def _export_csv(self, accounts: List[Dict[str, Any]], include_passwords: bool) -> bytes:
        """
        Exportiert Accounts als CSV.
        
        Args:
            accounts: Liste der Account-Daten
            include_passwords: Ob Passwörter inkludiert werden sollen
            
        Returns:
            CSV-Daten als Bytes
        """
        output = StringIO()
        
        # Definiere Header basierend auf Passwort-Einstellung
        headers = [
            'Plattform',
            'Benutzername',
            'E-Mail',
            'Handynummer',
            'Name',
            'Geburtstag',
            'Erstellt am'
        ]
        
        if include_passwords:
            headers.insert(2, 'Passwort')
        
        writer = csv.DictWriter(output, fieldnames=headers)
        writer.writeheader()
        
        # Schreibe Account-Daten
        for account in accounts:
            row = {
                'Plattform': account.get('platform', ''),
                'Benutzername': account.get('username', ''),
                'E-Mail': account.get('email', ''),
                'Handynummer': account.get('phone', ''),
                'Name': account.get('full_name', ''),
                'Geburtstag': account.get('birthday', ''),
                'Erstellt am': account.get('created_at', '')
            }
            
            if include_passwords:
                row['Passwort'] = account.get('password', '')
            
            writer.writerow(row)
        
        return output.getvalue().encode('utf-8-sig')  # UTF-8 mit BOM für Excel
    
    def _export_json(self, accounts: List[Dict[str, Any]], include_passwords: bool) -> bytes:
        """
        Exportiert Accounts als JSON.
        
        Args:
            accounts: Liste der Account-Daten
            include_passwords: Ob Passwörter inkludiert werden sollen
            
        Returns:
            JSON-Daten als Bytes
        """
        export_data = {
            'export_date': datetime.now().isoformat(),
            'account_count': len(accounts),
            'accounts': []
        }
        
        for account in accounts:
            account_data = {
                'platform': account.get('platform', ''),
                'username': account.get('username', ''),
                'email': account.get('email', ''),
                'phone': account.get('phone', ''),
                'full_name': account.get('full_name', ''),
                'birthday': account.get('birthday', ''),
                'created_at': account.get('created_at', '')
            }
            
            if include_passwords:
                account_data['password'] = account.get('password', '')
            
            export_data['accounts'].append(account_data)
        
        return json.dumps(export_data, ensure_ascii=False, indent=2).encode('utf-8')
    
    def execute_with_accounts(self,
                            accounts: List[Dict[str, Any]],
                            format: str = 'csv',
                            include_passwords: bool = True) -> bytes:
        """
        Exportiert spezifische Account-Daten.
        
        Args:
            accounts: Liste der zu exportierenden Accounts
            format: Export-Format ('csv' oder 'json')
            include_passwords: Ob Passwörter inkludiert werden sollen
            
        Returns:
            Exportierte Daten als Bytes
        """
        if not accounts:
            logger.warning("Keine Accounts zum Export übergeben")
            return b""
        
        # Exportiere basierend auf Format
        if format.lower() == 'csv':
            result = self._export_csv(accounts, include_passwords)
        elif format.lower() == 'json':
            result = self._export_json(accounts, include_passwords)
        else:
            raise ValueError(f"Unsupported format: {format}")
            
        logger.info(f"Exported {len(accounts)} specific accounts as {format}")
        return result
    
    def get_export_filename(self, platform: Optional[str], format: str) -> str:
        """
        Generiert einen passenden Dateinamen für den Export.
        
        Args:
            platform: Plattform-Filter
            format: Export-Format
            
        Returns:
            Vorgeschlagener Dateiname
        """
        timestamp = datetime.now().strftime('%Y%m%d_%H%M%S')
        platform_str = platform.lower() if platform else 'alle'
        return f"accounts_{platform_str}_{timestamp}.{format}"