import NCMB, { NCMBObject, NCMBRole, NCMBUser } from "../index";
import { JsonObject, NCMBRelationFormat } from "../types/Misc";

class NCMBRelation {
  static ncmb: NCMB;
  private relatedClass: string | null = null;
  private fields: JsonObject = {};
  private className: string | null = null;
  constructor(className: string) {
    this.className = className;
    switch (className) {
      case 'user':
        this.relatedClass = `/users`;
        break;
      case 'role':
        this.relatedClass = `/roles`;
        break;
      case 'installation':
        this.relatedClass = `/installations`;
        break;
      default:
        this.relatedClass = `/classes/${className}`;
    }
  }

  add(obj: NCMBObject | NCMBRole | NCMBUser | NCMBObject[] | NCMBRole[] | NCMBUser[]): NCMBRelation {
    if (!this.fields.objects) {
      this.fields = {
        __op: 'AddRelation',
        objects: []
      }
    }
    if (!Array.isArray(obj)) {
      obj = [obj];
    }
    obj.forEach(o => {
      if (o.className !== this.className) {
        throw new Error('Relation objects can be input just from instance of same class with first input.');
      }
      this.fields.objects.push(o);
    });
    return this;
  }

  remove(obj: NCMBObject | NCMBRole | NCMBUser | NCMBObject[] | NCMBRole[] | NCMBUser[]): NCMBRelation {
    if (!this.fields.objects) {
      this.fields = {
        __op: 'RemoveRelation',
        objects: []
      }
    }
    if (!Array.isArray(obj)) {
      obj = [obj];
    }
    obj.forEach(o => {
      if (o.className !== this.className) {
        throw new Error('Relation objects can be input just from instance of same class with first input.');
      }
      this.fields.objects.push(o);
    });
    return this;
  }

  toJSON(): NCMBRelationFormat {
    const json: NCMBRelationFormat = {
      __op: this.fields.__op,
      objects:  []
    };
    for (const obj of this.fields.objects) {
      obj as NCMBObject | NCMBUser | NCMBRole;
      json.objects.push(obj.toPointer());
    }
    return json;
  }
}

export default NCMBRelation;