import { Inject, Injectable } from "@nestjs/common";
import { InjectRepository } from "@nestjs/typeorm";
import { Database } from "../entities/database.entity";
import { Repository } from "typeorm";
import { ProjectService } from "src/project/project.service";
import { DatabaseEncryptionService } from "../database.encryption.service";
import { DatabaseNodeService } from "../databaseNode/database.node.service";
import * as mysql from "mysql2/promise";

@Injectable()
export class DatabaseManagerService extends DatabaseEncryptionService {
  constructor(
    @InjectRepository(Database)
    private databaseRepository: Repository<Database>,
    @Inject(ProjectService)
    private readonly projectService: ProjectService,
    @Inject(DatabaseNodeService)
    private readonly databaseNodeService: DatabaseNodeService
  ) {
    super();
  }

  async findById(id: string): Promise<Database | null> {
    return this.databaseRepository.findOne({ where: { id } });
  }

  async runQuery(databaseId: string, query: string) {
    const database = await this.findById(databaseId);

    if (!database) {
      throw new Error("Database not found");
    }

    const dbConnection = await mysql.createConnection({
      host: database.node.host,
      port: database.node.port,
      user: database.c_username,
      password: this.decryptPassword(database.password),
      database: database.database,
      enableKeepAlive: true,
    });

    try {
      const [results] = await dbConnection.execute(query);
      return results;
    } finally {
      await dbConnection.end();
    }
  }

  async createDatabase(
    databaseNodeId: string,
    projectId: string
  ): Promise<Database> {
    const node = await this.databaseNodeService.findById(databaseNodeId);

    if (!node) {
      throw new Error("Database node not found");
    }

    const project = await this.projectService.findById(projectId);

    if (!project) {
      throw new Error("Project not found");
    }

    const c_username = `c_user_${Math.random().toString(36).substring(2, 8)}`;
    const q_username = `q_user_${Math.random().toString(36).substring(2, 8)}`;
    const databaseName = `db_${Math.random().toString(36).substring(2, 8)}`;
    const password = this.encryptPassword(
      Math.random().toString(36).substring(2, 10)
    );

    await this.databaseNodeService.initDatabase(
      {
        database: databaseName,
        c_username,
        q_username,
        password: this.decryptPassword(password),
      },
      databaseNodeId
    );

    const database = this.databaseRepository.create({
      q_username,
      c_username,
      database: databaseName,
      password,
      node,
      project,
    });

    return await this.databaseRepository.save(database);
  }
}