import { deepGet, deepSet, Dict } from '@orbit/utils';
import { InitializedRecord, UninitializedRecord } from './record';

/**
 * Maintains a map between records' ids and keys.
 */
export class RecordKeyMap {
  private _idsToKeys!: Dict<Dict<string>>;
  private _keysToIds!: Dict<Dict<string>>;

  constructor() {
    this.reset();
  }

  /**
   * Resets the contents of the key map.
   */
  reset(): void {
    this._idsToKeys = {};
    this._keysToIds = {};
  }

  /**
   * Return a key value given a model type, key name, and id.
   */
  idToKey(type: string, keyName: string, idValue: string): string | undefined {
    return deepGet(this._idsToKeys, [type, keyName, idValue]);
  }

  /**
   * Return an id value given a model type, key name, and key value.
   */
  keyToId(type: string, keyName: string, keyValue: string): string | undefined {
    return deepGet(this._keysToIds, [type, keyName, keyValue]);
  }

  /**
   * Store the id and key values of a record in this key map.
   */
  pushRecord(record: InitializedRecord | UninitializedRecord): void {
    const { type, id, keys } = record;

    if (!keys || !id) {
      return;
    }

    Object.keys(keys).forEach((keyName) => {
      let keyValue = keys[keyName];
      if (keyValue) {
        deepSet(this._idsToKeys, [type, keyName, id], keyValue);
        deepSet(this._keysToIds, [type, keyName, keyValue], id);
      }
    });
  }

  /**
   * Given a record, find the cached id if it exists.
   */
  idFromKeys(type: string, keys: Dict<string>): string | undefined {
    for (let key of Object.keys(keys)) {
      let value = keys[key];
      if (value) {
        return this.keyToId(type, key, value);
      }
    }
  }
}