index.mts

import { MongoClient, MongoServerError } from "mongodb";

import { mappings } from "./config/mapping.mjs";
import { parseQuery } from "./utils/parser.mjs";
import { connect } from "./utils/database.mjs";
import { SqlToNoSqlType } from "./types/index.mjs";

export class SqlToNoSql {
  client: MongoClient | undefined;

  constructor(private config: SqlToNoSqlType) {}

  async run(query: string) {
    if (!query) {
      throw new Error("missing query!");
    }

    // // TODO: add better validation!
    // if ([";", "(", ")"].some((char) => query.includes(char))) {
    //   throw new Error("Invalid query, your query contains invalid characters!");
    // }

    const q = parseQuery(query);

    if (q.command === "select"){
      const filters: {
        [key: string]: {
          [operator: string]: string | number;
        };
      } = {};
  
      // Convert parsed filters to MongoDB query
      q.filters?.forEach((filter) => {
        const { column, operator, value } = filter;
  
        if (!filters[column]) {
          filters[column] = {
            [mappings["mongodb"]["operators"][operator]]: value,
          };
        }
      });
  
      const mongoQuery = {
        collection: q.table,
        [q.command]: mappings["mongodb"]["commands"][q.command],
        query: filters,
      };
  
      try {
        if (!this.client) {
          this.client = await connect(this.config.connection);
          await this.client.connect();
        }
  
        const db = this.client.db();
        const collection = db.collection(mongoQuery.collection);
  
        const data = await collection[mongoQuery[q.command]](
          mongoQuery.query,
        ).toArray();
  
        return data;
      } catch (err) {
        console.error(err);
        throw Error("Something went wrong!");
      }
    } else if (q.command === "create") {
      try {
        if (!this.client) {
          this.client = await connect(this.config.connection);
          await this.client.connect();
        }
  
        const db = this.client.db();
        const result = await db.createCollection(q.table);
        console.log("Mongo result", result);
        return result;
      } catch (err) {
        if (err instanceof MongoServerError) {
          if (err.codeName === 'NamespaceExists'){
            console.error("Collection already exists: " + q.table)
          }
        } else {
          throw Error("Something went wrong!");
        }
      }
    }
  }
}