import os
import base64
from dataclasses import dataclass
from typing import Optional


@dataclass
class Config:
    """Application configuration loaded from environment variables."""

    ssh_private_key: str
    uptime_kuma_url: str
    uptime_kuma_api_key: str
    claude_api_key: str
    dev_mode: bool = False

    @classmethod
    def from_env(cls) -> "Config":
        """Load configuration from environment variables."""
        ssh_key_b64 = os.environ.get("SSH_PRIVATE_KEY", "")

        # Decode base64 SSH key
        try:
            ssh_private_key = base64.b64decode(ssh_key_b64).decode("utf-8") if ssh_key_b64 else ""
        except Exception:
            ssh_private_key = ssh_key_b64  # Allow plain text for development

        return cls(
            ssh_private_key=ssh_private_key,
            uptime_kuma_url=os.environ.get("UPTIME_KUMA_URL", "http://localhost:3001"),
            uptime_kuma_api_key=os.environ.get("UPTIME_KUMA_API_KEY", ""),
            claude_api_key=os.environ.get("CLAUDE_API_KEY", ""),
            dev_mode=os.environ.get("DEV_MODE", "false").lower() == "true",
        )

    def validate(self) -> list[str]:
        """Validate configuration and return list of errors."""
        errors = []
        if not self.ssh_private_key:
            errors.append("SSH_PRIVATE_KEY is required")
        if not self.uptime_kuma_url:
            errors.append("UPTIME_KUMA_URL is required")
        if not self.uptime_kuma_api_key:
            errors.append("UPTIME_KUMA_API_KEY is required")
        if not self.claude_api_key:
            errors.append("CLAUDE_API_KEY is required")
        return errors


# Global config instance
_config: Optional[Config] = None


def get_config() -> Config:
    """Get the global configuration instance."""
    global _config
    if _config is None:
        _config = Config.from_env()
    return _config


def set_dev_mode(enabled: bool) -> None:
    """Update dev mode setting."""
    config = get_config()
    config.dev_mode = enabled