import { FilterQuery, ObjectID } from 'mongodb';
import { DatabaseDriver } from './DatabaseDriver';
import { MongoConnection } from '../connections/MongoConnection';
import { EntityData, IEntityType, IPrimaryKey } from '../decorators';
import { QueryOrder } from '../query';
import { Utils } from '../utils';
import { MongoPlatform } from '../platforms/MongoPlatform';
import { QueryResult } from '../connections';

export class MongoDriver extends DatabaseDriver<MongoConnection> {

  protected readonly connection = new MongoConnection(this.config);
  protected readonly platform = new MongoPlatform();

  async find<T extends IEntityType<T>>(entityName: string, where: FilterQuery<T>, populate: string[], orderBy: Record<string, QueryOrder>, limit: number, offset: number): Promise<T[]> {
    where = this.renameFields(entityName, where);
    const res = await this.connection.find<T>(this.getCollectionName(entityName), where, orderBy, limit, offset);

    return res.map((r: T) => this.mapResult(r, this.metadata[entityName]));
  }

  async findOne<T extends IEntityType<T>>(entityName: string, where: FilterQuery<T> | IPrimaryKey, populate: string[] = [], orderBy: Record<string, QueryOrder> = {}): Promise<T | null> {
    if (Utils.isPrimaryKey(where)) {
      where = { _id: new ObjectID(where as string) };
    }

    where = this.renameFields(entityName, where) as FilterQuery<T>;
    const res = await this.connection.find<T>(this.getCollectionName(entityName), where, orderBy, 1);

    return this.mapResult(res[0], this.metadata[entityName]);
  }

  async count<T extends IEntityType<T>>(entityName: string, where: FilterQuery<T>): Promise<number> {
    where = this.renameFields(entityName, where);
    return this.connection.countDocuments<T>(this.getCollectionName(entityName), where);
  }

  async nativeInsert<T extends IEntityType<T>>(entityName: string, data: EntityData<T>): Promise<QueryResult> {
    data = this.renameFields(entityName, data);
    return this.connection.insertOne<EntityData<T>>(this.getCollectionName(entityName), data);
  }

  async nativeUpdate<T extends IEntityType<T>>(entityName: string, where: FilterQuery<T> | IPrimaryKey, data: EntityData<T>): Promise<QueryResult> {
    if (Utils.isPrimaryKey(where)) {
      where = { _id: new ObjectID(where as string) };
    }

    where = this.renameFields(entityName, where) as FilterQuery<T>;
    data = this.renameFields(entityName, data);

    return this.connection.updateMany<T>(this.getCollectionName(entityName), where, data);
  }

  async nativeDelete<T extends IEntityType<T>>(entityName: string, where: FilterQuery<T> | IPrimaryKey): Promise<QueryResult> {
    if (Utils.isPrimaryKey(where)) {
      where = { _id: new ObjectID(where as string) };
    }

    where = this.renameFields(entityName, where) as FilterQuery<T>;

    return this.connection.deleteMany<T>(this.getCollectionName(entityName), where);
  }

  async aggregate(entityName: string, pipeline: any[]): Promise<any[]> {
    return this.connection.aggregate(this.getCollectionName(entityName), pipeline);
  }

  private renameFields(entityName: string, data: any): any {
    data = Object.assign({}, data); // copy first
    Utils.renameKey(data, 'id', '_id');
    const meta = this.metadata[entityName];

    Object.keys(data).forEach(k => {
      if (meta && meta.properties[k]) {
        const prop = meta.properties[k];

        if (prop.fieldName) {
          Utils.renameKey(data, k, prop.fieldName);
        }
      }
    });

    return data;
  }

  private getCollectionName(entityName: string): string {
    return this.metadata[entityName] ? this.metadata[entityName].collection : entityName;
  }

}