/**
@license
Copyright (c) 2022 trading_peter
This program is available under Apache License Version 2.0
*/

const data = new Map();
const instancesPerKey = new Map();

/**
 * # Store
 *
 * A simple key value store.
 */
export const Store = function(superClass) {
  return class extends superClass {
    storeSubscribe(keys) {
      if (Array.isArray(keys) === false) {
        keys = [ keys ];
      }

      keys.forEach(key => {
        let targetProperty;
        if (typeof key === 'object') {
          targetProperty = key.targetProperty;
          key = key.key;
        }
        this._addInstance(this, key, targetProperty);
      });
    }

    storeUpdated(key, newValue, targetProperty) {
      this[targetProperty || key] = newValue;
    }

    storeWrite(key, value) {
      this._writeKey(key, value);
    }

    _addInstance(instance, key, targetProperty) {
      if (instancesPerKey.has(key) === false) {
        instancesPerKey.set(key, [ { instance, targetProperty } ]);
      } else {
        instancesPerKey.get(key).push({ instance, targetProperty });
      }

      if (data.has(key)) {
        this._notifyInstance(instance, key, data.get(key), targetProperty);
      }
    }

    _writeKey(key, value) {
      data.set(key, value);

      const instances = instancesPerKey.get(key);
      if (Array.isArray(instances)) {
        instances.forEach(entry => {
          this._notifyInstance(entry.instance, key, value, entry.targetProperty);
        });
      }
    }

    _notifyInstance(instance, key, value, targetProperty) {
      instance.storeUpdated(key, value, targetProperty);
    }
  };
}