import { Injectable } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { Query } from "../entities/query.entity";
import { Repository } from "typeorm";
import { Vm } from "../../vm/vm.class";
import { VModule } from "../../vm/module.class";
import { DatabasePlugin } from "src/vm/plugins/database.plugin";

@Injectable()
export class QueryExecuterService {
  constructor(
    @InjectRepository(Query)
    private readonly queryRepository: Repository<Query>
  ) {}

  async runQuery(token: string, queryData: any) {
    const query = await this.queryRepository.findOne({
      where: { id: token },
    });

    if (!query) {
      throw new Error("Query not found");
    }

    const vm = await this.createVm(query);
    const result = await vm.runScript(query.source, queryData);

    return { message: "Query executed", result, query: queryData };
  }

  private async createVm(query: Query) {
    if (query.modules === undefined) {
      query.modules = [];
    }

    if (query.plugins === undefined) {
      query.plugins = [];
    }

    const vm = new Vm({
      memoryLimit: 128,
      modules: query.modules.map((module) => {
        return new VModule(module.name, module.sourcePath);
      }),
      plugins: query.plugins.map((plugin) => {
        switch (plugin.class) {
          case "DATABASE": {
            const config = JSON.parse(plugin.config);
            return DatabasePlugin.init(plugin.name, config);
          }
          default:
            throw new Error(`Unknown plugin class: ${plugin.class}`);
        }
      }),
    });

    return await vm.init();
  }
}