EntityHelper.ts

import { inspect } from 'util';

import type { EntityManager } from '../EntityManager';
import type { AnyEntity, Dictionary, EntityMetadata, EntityProperty, IHydrator } from '../typings';
import { EntityTransformer } from '../serialization/EntityTransformer';
import { Reference } from './Reference';
import { Utils } from '../utils/Utils';
import { WrappedEntity } from './WrappedEntity';
import { ReferenceType } from '../enums';
import { helper } from './wrap';
import { EntityRepositoryType, OptionalProps, PrimaryKeyProp, PrimaryKeyType } from '../typings';

export class EntityHelper {

  static decorate<T extends object>(meta: EntityMetadata<T>, em: EntityManager): void {
    const fork = em.fork(); // use fork so we can access `EntityFactory`
    const serializedPrimaryKey = meta.props.find(p => p.serializedPrimaryKey);

    if (serializedPrimaryKey) {
      Object.defineProperty(meta.prototype, serializedPrimaryKey.name, {
        get(): string | null {
          return this._id ? em.getPlatform().normalizePrimaryKey<string>(this._id) : null;
        },
        set(id: string): void {
          this._id = id ? em.getPlatform().denormalizePrimaryKey(id) : null;
        },
      });
    }

    EntityHelper.defineBaseProperties(meta, meta.prototype, fork);

    if (!meta.embeddable && !meta.virtual) {
      EntityHelper.defineProperties(meta, fork);
    }

    const prototype = meta.prototype as Dictionary;

    if (!prototype.toJSON) { // toJSON can be overridden
      prototype.toJSON = function (this: T, ...args: any[]) {
        return EntityTransformer.toObject<T>(this, ...args.slice(meta.toJsonParams.length));
      };
    }
  }

  /**
   * As a performance optimization, we create entity state methods in a lazy manner. We first add
   * the `null` value to the prototype to reserve space in memory. Then we define a setter on the
   * prototype, that will be executed exactly once per entity instance. There we redefine given
   * property on the entity instance, so shadowing the prototype setter.
   */
  private static defineBaseProperties<T extends object>(meta: EntityMetadata<T>, prototype: T, em: EntityManager) {
    const helperParams = meta.embeddable || meta.virtual ? [] : [em.getComparator().getPkGetter(meta), em.getComparator().getPkSerializer(meta), em.getComparator().getPkGetterConverted(meta)];
    Object.defineProperties(prototype, {
      __entity: { value: !meta.embeddable },
      __meta: { value: meta },
      __platform: { value: em.getPlatform() },
      __factory: { value: em.getEntityFactory() },
      __helper: {
        get(): WrappedEntity<T, keyof T> {
          Object.defineProperty(this, '__helper', {
            value: new WrappedEntity(this, ...helperParams),
            enumerable: false,
          });

          return this.__helper;
        },
        configurable: true, // otherwise jest fails when trying to compare entities ¯\_(ツ)_/¯
      },
    });
  }

  /**
   * Defines getter and setter for every owning side of m:1 and 1:1 relation. This is then used for propagation of
   * changes to the inverse side of bi-directional relations. Rest of the properties are also defined this way to
   * achieve dirtiness, which is then used for fast checks whether we need to auto-flush because of managed entities.
   *
   * First defines a setter on the prototype, once called, actual get/set handlers are registered on the instance rather
   * than on its prototype. Thanks to this we still have those properties enumerable (e.g. part of `Object.keys(entity)`).
   */
  private static defineProperties<T>(meta: EntityMetadata<T>, em: EntityManager): void {
    const hydrator = em.config.getHydrator(em.getMetadata());
    Object
      .values<EntityProperty<T>>(meta.properties)
      .forEach(prop => {
        const isCollection = [ReferenceType.ONE_TO_MANY, ReferenceType.MANY_TO_MANY].includes(prop.reference);
        const isReference = [ReferenceType.ONE_TO_ONE, ReferenceType.MANY_TO_ONE].includes(prop.reference) && (prop.inversedBy || prop.mappedBy) && !prop.mapToPk;

        if (isReference) {
          return Object.defineProperty(meta.prototype, prop.name, {
            set(val: AnyEntity) {
              EntityHelper.defineReferenceProperty(meta, prop, this, hydrator);
              this[prop.name] = val;
            },
          });
        }

        if (prop.inherited || prop.primary || prop.persist === false || prop.trackChanges === false || prop.embedded || isCollection) {
          return;
        }

        Object.defineProperty(meta.prototype, prop.name, {
          set(val) {
            Object.defineProperty(this, prop.name, {
              get() {
                return this.__helper?.__data[prop.name];
              },
              set(val) {
                this.__helper.__data[prop.name] = val;
                this.__helper.__touched = true;
              },
              enumerable: true,
              configurable: true,
            });
            this.__helper.__data[prop.name] = val;
            this.__helper.__touched = true;
          },
        });
      });

    meta.prototype[inspect.custom] ??= function (this: T, depth: number) {
      const object = { ...this };
      // ensure we dont have internal symbols in the POJO
      [OptionalProps, EntityRepositoryType, PrimaryKeyType, PrimaryKeyProp].forEach(sym => delete object[sym]);
      const ret = inspect(object, { depth });
      let name = (this as object).constructor.name;

      const showEM = ['true', 't', '1'].includes(process.env.MIKRO_ORM_LOG_EM_ID?.toString().toLowerCase() ?? '');

      if (showEM) {
        if (helper(this).__em) {
          name += ` [managed by ${helper(this).__em.id}]`;
        } else {
          name += ` [not managed]`;
        }
      }

      // distinguish not initialized entities
      if (!helper(this).__initialized) {
        name = `(${name})`;
      }

      return ret === '[Object]' ? `[${name}]` : name + ' ' + ret;
    };
  }

  static defineReferenceProperty<T extends object>(meta: EntityMetadata<T>, prop: EntityProperty<T>, ref: T, hydrator: IHydrator): void {
    Object.defineProperty(ref, prop.name, {
      get() {
        return helper(ref).__data[prop.name];
      },
      set(val: AnyEntity | Reference<AnyEntity>) {
        const wrapped = helper(ref);
        const entity = Reference.unwrapReference(val ?? wrapped.__data[prop.name]);
        const old = Reference.unwrapReference(wrapped.__data[prop.name]);
        wrapped.__data[prop.name] = Reference.wrapReference(val as T, prop);

        // when propagation from inside hydration, we set the FK to the entity data immediately
        if (val && hydrator.isRunning() && wrapped.__originalEntityData && prop.owner) {
          wrapped.__originalEntityData[prop.name as string] = helper(wrapped.__data[prop.name]).getPrimaryKey(true);
        } else {
          wrapped.__touched = true;
        }

        EntityHelper.propagate(meta, entity, this, prop, Reference.unwrapReference(val), old);
      },
      enumerable: true,
      configurable: true,
    });
  }

  private static propagate<T extends object, O extends object>(meta: EntityMetadata<O>, entity: T, owner: O, prop: EntityProperty<O>, value?: T[keyof T & string], old?: object): void {
    const inverseProps = prop.targetMeta!.relations.filter(prop2 =>
      (prop2.inversedBy || prop2.mappedBy) === prop.name
      && (
        prop2.targetMeta!.abstract ?
          prop2.targetMeta!.root.className === meta.root.className :
          prop2.targetMeta!.className === meta.className
      ),
    );

    for (const prop2 of inverseProps) {
      const inverse = value?.[prop2.name as string];

      if (prop.reference === ReferenceType.MANY_TO_ONE && Utils.isCollection<O, T>(inverse) && inverse.isInitialized()) {
        inverse.add(owner);
      }

      if (prop.reference === ReferenceType.ONE_TO_ONE && entity && helper(entity).__initialized && Reference.unwrapReference(inverse) !== owner && value != null) {
        EntityHelper.propagateOneToOne(entity, owner, prop, prop2, value, old);
      }

      if (prop.reference === ReferenceType.ONE_TO_ONE && entity && helper(entity).__initialized && entity[prop2.name] != null && value == null) {
        EntityHelper.propagateOneToOne(entity, owner, prop, prop2, value, old);
      }
    }
  }

  private static propagateOneToOne<T extends object, O extends object>(entity: T, owner: O, prop: EntityProperty<O>, prop2: EntityProperty<T>, value?: T[keyof T & string], old?: T): void {
    helper(entity).__pk = helper(entity).getPrimaryKey()!;

    // the inverse side will be changed on the `value` too, so we need to clean-up and schedule orphan removal there too
    if (value?.[prop2.name as string] != null && value?.[prop2.name as string] !== entity) {
      const other = Reference.unwrapReference(value![prop2.name as string]);
      delete helper(other).__data[prop.name];

      if (prop2.orphanRemoval) {
        helper(other).__em?.getUnitOfWork().scheduleOrphanRemoval(other);
      }
    }

    if (value == null) {
      entity[prop2.name] = value as T[keyof T & string];
    } else if (prop2.mapToPk) {
      entity[prop2.name] = helper(owner).getPrimaryKey() as T[keyof T & string];
    } else {
      entity[prop2.name] = Reference.wrapReference(owner, prop) as T[keyof T & string];
    }

    if (old && prop.orphanRemoval) {
      helper(old).__em?.getUnitOfWork().scheduleOrphanRemoval(old);
    }

    if (old?.[prop2.name] != null) {
      delete helper(old).__data[prop2.name];
    }
  }

}