import { RedisNodeService } from "./../../redisManager/redisNode/redis.node.service";
import { Inject, 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 "src/vm/module.class";
import {
  QueryResponse,
  registeredModules,
  registeredPlugins,
} from "src/vm/vm.constants";
import { DatabaseManagerService } from "src/databaseManager/database/database.manager.service";
import { InjectQueue } from "@nestjs/bullmq";
import { QUEUE_NAMES } from "src/queue/constants";
import { Queue, QueueEvents } from "bullmq";
import { FunctionService } from "src/query/function/function.service";
import { SessionService } from "../session/session.service";
import { TLog } from "../logger/logger.types";

@Injectable()
export class QueryExecuterService {
  private queueEvents: QueueEvents;

  constructor(
    @InjectRepository(Query)
    readonly queryRepository: Repository<Query>,
    @Inject(FunctionService)
    private readonly functionService: FunctionService,
    readonly databaseManagerService: DatabaseManagerService,
    readonly redisNodeService: RedisNodeService,
    readonly sessionService: SessionService,
    @InjectQueue(QUEUE_NAMES.QUERY) private queryQueue: Queue
  ) {
    this.queueEvents = new QueueEvents(this.queryQueue.name);
  }

  parseImports(source: string): string[] {
    const importRegex =
      /import\s+(?:[\w*\s{},]*\s+from\s+)?["']([^"']+)["'];?/g;
    const imports: string[] = [];
    let match: RegExpExecArray | null;

    while ((match = importRegex.exec(source)) !== null) {
      imports.push(match[1]);
    }

    return imports;
  }

  clearImports(source: string): string {
    return source
      .replace(/import\s+(?:[\w*\s{},]*\s+from\s+)?["']([^"']+)["'];?/g, "")
      .trim();
  }

  async runQueryQueued(
    token: string,
    queryData: any,
    log: TLog,
    headers: Record<string, any> = {},
    cookies: Record<string, any> = {}
  ): Promise<QueryResponse> {
    const job = await this.queryQueue.add(
      `${new Date().getTime()}_${token}`,
      {
        token,
        queryData,
        headers,
        cookies,
        log,
      },
      {
        removeOnComplete: true,
        removeOnFail: true,
        attempts: 0,
      }
    );

    const result = await job.waitUntilFinished(this.queueEvents);
    return result;
  }

  async runQuery(
    token: string,
    queryData: any,
    headers: Record<string, any> = {},
    cookies: Record<string, any> = {},
    log: TLog = null
  ): Promise<QueryResponse> {
    const query = await this.queryRepository.findOne({
      where: { id: token },
      relations: ["project"],
    });

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

    const sessionId = cookies["x-session-id"] || null;

    if (!sessionId) {
      const session = await this.sessionService.create(query.project.id);
      cookies["x-session-id"] = session.sessionId;
    }

    const vm = await this.createVm(query, cookies["x-session-id"]);
    const result = await vm.runScript(
      this.clearImports(query.source),
      queryData,
      headers,
      log
    );

    if (!this.checkResponse(result)) {
      throw new Error(`Error initializing VM: ${JSON.stringify(result)}`);
    }

    if (!result?.cookies || !result?.cookies["x-session-id"]) {
      if (result.cookies === undefined) {
        result.cookies = {};
      }

      result.cookies["x-session-id"] = (
        await this.sessionService.get(cookies["x-session-id"], query.project.id)
      ).sessionId;
    }

    return result;
  }

  private async createVm(query: Query, sessionId: string = null) {
    const imports = this.parseImports(query.source);
    const importsParsed = imports.map((imp) => {
      const item = imp.split("/");

      return {
        type: item[0],
        name: item[1],
      };
    });

    const moduleNames = importsParsed.filter((imp) => imp.type === "module");
    const pluginNames = importsParsed.filter((imp) => imp.type === "plugin");
    const functionNames = importsParsed.filter(
      (imp) => imp.type === "function"
    );

    const functions = (
      await this.functionService.findByNames(
        query.project.id,
        functionNames.map((fn) => fn.name)
      )
    ).map((fn) => fn.source);

    const modules = moduleNames.map((mod) => {
      if (registeredModules[mod.name]) {
        return new VModule(mod.name, registeredModules[mod.name]);
      }

      throw new Error(`Module ${mod.name} not found`);
    });

    const plugins = [];
    for (const plugin of pluginNames) {
      if (!registeredPlugins[plugin.name]) {
        throw new Error(`Plugin ${plugin.name} not found`);
      }

      plugins.push(
        await registeredPlugins[plugin.name](this, query, sessionId)
      );
    }

    const vm = new Vm({
      memoryLimit: 128,
      timeLimit: BigInt(100e9),
      cpuTimeLimit: BigInt(5e9),
      modules: modules,
      plugins: plugins,
      functions: functions,
    });

    return await vm.init();
  }

  private checkResponse(obj: any): boolean {
    if (obj?.statusCode && obj.response && typeof obj.statusCode === "number") {
      return true;
    }

    return false;
  }

  async onModuleDestroy() {
    await this.queueEvents.close();
  }
}