import { EdgeConfigClient } from '@vercel/edge-config';
import type {
  DataKind,
  LDLogger,
  LDFeatureStore,
  LDFeatureStoreDataStorage,
  LDFeatureStoreItem,
  LDFeatureStoreKindData,
} from '@launchdarkly/js-server-sdk-common-edge';
import { noop } from '@launchdarkly/js-server-sdk-common-edge';

class VercelFeatureStore implements LDFeatureStore {
  private edgeConfig: EdgeConfigClient;

  private configKey: string;

  private logger: LDLogger;

  constructor(edgeConfig: EdgeConfigClient, sdkKey: string, logger: LDLogger) {
    this.edgeConfig = edgeConfig;
    this.configKey = `LD-Env-${sdkKey}`;
    this.logger = logger;
  }

  async get(
    kind: DataKind,
    flagKey: string,
    callback: (res: LDFeatureStoreItem | null) => void
  ): Promise<void> {
    this.logger.debug(`Requesting ${flagKey} from ${this.configKey}`);
    try {
      const config = await this.edgeConfig.get(this.configKey);
      if (config === null) {
        this.logger.error('Feature data not found in Edge Config.');
      }
      const kindKey = kind.namespace === 'features' ? 'flags' : kind.namespace;
      const item = config as LDFeatureStoreItem;
      callback(item[kindKey][flagKey]);
    } catch (err) {
      this.logger.error(err);
      callback(null);
    }
  }

  async all(kind: DataKind, callback: (res: LDFeatureStoreKindData) => void = noop): Promise<void> {
    const kindKey = kind.namespace === 'features' ? 'flags' : kind.namespace;
    this.logger.debug(`Requesting all ${kindKey} data from Edge Config.`);
    try {
      const config = await this.edgeConfig.get(this.configKey);
      if (config === null) {
        this.logger.error('Feature data not found in Edge Config.');
      }
      const item = config as LDFeatureStoreItem;
      callback(item[kindKey]);
    } catch (err) {
      this.logger.error(err);
      callback({});
    }
  }

  async initialized(callback: (isInitialized: boolean) => void = noop): Promise<void> {
    const config = await this.edgeConfig.get(this.configKey);
    const result = config !== null;
    this.logger.debug(`Is ${this.configKey} initialized? ${result}`);
    callback(result);
  }

  init(allData: LDFeatureStoreDataStorage, callback: () => void): void {
    callback();
  }

  getDescription(): string {
    return 'Vercel Edge Config';
  }

  // unused
  close = noop;

  delete = noop;

  upsert = noop;
}

export default VercelFeatureStore;