import os
from typing import Optional


class Config:
    """Application configuration management."""
    
    # API Configuration
    API_URL: str = "https://api.kleer.se/v1"
    DEFAULT_COMPANY_ID: str = "1336"
    API_KEY : str = "rjAXm8PM70kqTUt"  # To be set via environment variable

    # Date Formats
    CSV_DATE_FORMAT: str = '%m/%d/%Y'
    API_DATE_FORMAT: str = '%Y-%m-%d'
    XLSX_SHEET_NAME: str = "AGRESSO"
    
    # CSV Column Indices
    DATE_COL_INDEX: int = 5
    HOURS_COL_INDEX: int = 10
    
    # Business Rules
    MIN_HOURS_THRESHOLD: float = 0.2
    
    # Server Configuration
    SERVER_HOST: str = "0.0.0.0"
    SERVER_PORT: int = 8000
    
    # Environment Variables
    @staticmethod
    def get_api_key() -> Optional[str]:
        """Get Kleer API key from environment."""
        return os.getenv('KLEER_API_KEY',Config.API_KEY)
    
    @staticmethod
    def get_username() -> str:
        """Get username from environment with fallback."""
        return os.getenv('KLEER_USERNAME', 'Christopher Juhlin')
    
    @staticmethod
    def get_company_id() -> str:
        """Get company ID from environment with fallback."""
        return os.getenv('KLEER_COMPANY_ID', Config.DEFAULT_COMPANY_ID)
    
    @staticmethod
    def validate_config() -> None:
        """Validate required configuration is present."""
        if not Config.get_api_key():
            raise ValueError("KLEER_API_KEY environment variable is not set")