/**
 * Auth Configuration Value Object
 * Validates and stores authentication configuration
 */

export interface PasswordConfig {
  minLength: number;
}

export interface SocialProviderConfig {
  enabled: boolean;
}

export interface GoogleAuthConfig extends SocialProviderConfig {
  webClientId?: string;
  iosClientId?: string;
  androidClientId?: string;
}

export interface AppleAuthConfig extends SocialProviderConfig {}

export interface SocialAuthConfig {
  google?: GoogleAuthConfig;
  apple?: AppleAuthConfig;
}

export type SocialAuthProvider = "google" | "apple";

export interface AuthConfig {
  password: PasswordConfig;
  social?: SocialAuthConfig;
}

export const DEFAULT_PASSWORD_CONFIG: PasswordConfig = { minLength: 6 };
export const DEFAULT_SOCIAL_CONFIG: SocialAuthConfig = {
  google: { enabled: false },
  apple: { enabled: false },
};
export const DEFAULT_AUTH_CONFIG: AuthConfig = {
  password: DEFAULT_PASSWORD_CONFIG,
  social: DEFAULT_SOCIAL_CONFIG,
};

class AuthConfigValidationError extends Error {
  constructor(message: string, public readonly field: string) {
    super(message);
    this.name = "AuthConfigValidationError";
  }
}

function validateAuthConfig(config: Partial<AuthConfig>): void {
  if (config.password) {
    if (typeof config.password.minLength !== "number") {
      throw new AuthConfigValidationError("Password minLength must be a number", "password.minLength");
    }
    if (config.password.minLength < 4) {
      throw new AuthConfigValidationError("Password minLength must be at least 4 characters", "password.minLength");
    }
    if (config.password.minLength > 128) {
      throw new AuthConfigValidationError("Password minLength must not exceed 128 characters", "password.minLength");
    }
  }

  if (config.social?.google?.enabled) {
    const googleConfig = config.social.google;
    if (!googleConfig.webClientId && !googleConfig.iosClientId && !googleConfig.androidClientId) {
      throw new AuthConfigValidationError("At least one Google client ID must be provided when Google Sign-In is enabled", "social.google");
    }
  }
}

export function sanitizeAuthConfig(config: Partial<AuthConfig> = {}): AuthConfig {
  validateAuthConfig(config);
  return {
    password: {
      minLength: config.password?.minLength ?? DEFAULT_PASSWORD_CONFIG.minLength,
    },
    social: {
      google: {
        enabled: config.social?.google?.enabled ?? DEFAULT_SOCIAL_CONFIG.google?.enabled ?? false,
        webClientId: config.social?.google?.webClientId,
        iosClientId: config.social?.google?.iosClientId,
        androidClientId: config.social?.google?.androidClientId,
      },
      apple: {
        enabled: config.social?.apple?.enabled ?? DEFAULT_SOCIAL_CONFIG.apple?.enabled ?? false,
      },
    },
  };
}