import { type AuthProvider } from './cmap/auth/auth_provider';
import { GSSAPI } from './cmap/auth/gssapi';
import { type AuthMechanismProperties } from './cmap/auth/mongo_credentials';
import { MongoDBAWS } from './cmap/auth/mongodb_aws';
import { MongoDBOIDC, OIDC_WORKFLOWS, type Workflow } from './cmap/auth/mongodb_oidc';
import { AutomatedCallbackWorkflow } from './cmap/auth/mongodb_oidc/automated_callback_workflow';
import { HumanCallbackWorkflow } from './cmap/auth/mongodb_oidc/human_callback_workflow';
import { TokenCache } from './cmap/auth/mongodb_oidc/token_cache';
import { Plain } from './cmap/auth/plain';
import { AuthMechanism } from './cmap/auth/providers';
import { ScramSHA1, ScramSHA256 } from './cmap/auth/scram';
import { X509 } from './cmap/auth/x509';
import { MongoInvalidArgumentError } from './error';

/** @internal */
const AUTH_PROVIDERS = new Map<AuthMechanism | string, (workflow?: Workflow) => AuthProvider>([
  [AuthMechanism.MONGODB_AWS, () => new MongoDBAWS()],
  [
    AuthMechanism.MONGODB_CR,
    () => {
      throw new MongoInvalidArgumentError(
        'MONGODB-CR is no longer a supported auth mechanism in MongoDB 4.0+'
      );
    }
  ],
  [AuthMechanism.MONGODB_GSSAPI, () => new GSSAPI()],
  [AuthMechanism.MONGODB_OIDC, (workflow?: Workflow) => new MongoDBOIDC(workflow)],
  [AuthMechanism.MONGODB_PLAIN, () => new Plain()],
  [AuthMechanism.MONGODB_SCRAM_SHA1, () => new ScramSHA1()],
  [AuthMechanism.MONGODB_SCRAM_SHA256, () => new ScramSHA256()],
  [AuthMechanism.MONGODB_X509, () => new X509()]
]);

/**
 * Create a set of providers per client
 * to avoid sharing the provider's cache between different clients.
 * @internal
 */
export class MongoClientAuthProviders {
  private existingProviders: Map<AuthMechanism | string, AuthProvider> = new Map();

  /**
   * Get or create an authentication provider based on the provided mechanism.
   * We don't want to create all providers at once, as some providers may not be used.
   * @param name - The name of the provider to get or create.
   * @param credentials - The credentials.
   * @returns The provider.
   * @throws MongoInvalidArgumentError if the mechanism is not supported.
   * @internal
   */
  getOrCreateProvider(
    name: AuthMechanism | string,
    authMechanismProperties: AuthMechanismProperties
  ): AuthProvider {
    const authProvider = this.existingProviders.get(name);
    if (authProvider) {
      return authProvider;
    }

    const providerFunction = AUTH_PROVIDERS.get(name);
    if (!providerFunction) {
      throw new MongoInvalidArgumentError(`authMechanism ${name} not supported`);
    }

    let provider;
    if (name === AuthMechanism.MONGODB_OIDC) {
      provider = providerFunction(this.getWorkflow(authMechanismProperties));
    } else {
      provider = providerFunction();
    }

    this.existingProviders.set(name, provider);
    return provider;
  }

  /**
   * Gets either a device workflow or callback workflow.
   */
  getWorkflow(authMechanismProperties: AuthMechanismProperties): Workflow {
    if (authMechanismProperties.OIDC_HUMAN_CALLBACK) {
      return new HumanCallbackWorkflow(
        new TokenCache(),
        authMechanismProperties.OIDC_HUMAN_CALLBACK
      );
    } else if (authMechanismProperties.OIDC_CALLBACK) {
      return new AutomatedCallbackWorkflow(new TokenCache(), authMechanismProperties.OIDC_CALLBACK);
    } else {
      const environment = authMechanismProperties.ENVIRONMENT;
      const workflow = OIDC_WORKFLOWS.get(environment)?.();
      if (!workflow) {
        throw new MongoInvalidArgumentError(
          `Could not load workflow for environment ${authMechanismProperties.ENVIRONMENT}`
        );
      }
      return workflow;
    }
  }
}
