Prisma Service

import {
  Injectable,
  OnModuleInit,
  OnModuleDestroy,
  Logger,
} from "@nestjs/common";
import { PrismaClient } from "@prisma/client";

@Injectable()
export class PrismaService
  extends PrismaClient
  implements OnModuleInit, OnModuleDestroy
{
  private readonly logger = new Logger(PrismaService.name);

  constructor() {
    super({
      log:
        process.env.NODE_ENV === "development"
          ? ["query", "info", "warn", "error"]
          : ["error"],
      errorFormat: "pretty",
    });
  }

  async onModuleInit() {
    try {
      await this.$connect();
      this.logger.log("Successfully connected to database");
    } catch (error) {
      this.logger.error("Failed to connect to database", error);
      throw error;
    }
  }

  async onModuleDestroy() {
    await this.$disconnect();
    this.logger.log("Disconnected from database");
  }

  async isHealthy(): Promise<boolean> {
    try {
      await this.$queryRaw`SELECT 1`;
      return true;
    } catch {
      return false;
    }
  }

  // Transaction helper with automatic retry
  async executeTransaction<T>(
    fn: (tx: Omit<PrismaClient, "$connect" | "$disconnect" | "$on" | "$transaction" | "$use" | "$extends">) => Promise<T>,
    maxRetries = 3
  ): Promise<T> {
    let retries = 0;

    while (retries < maxRetries) {
      try {
        return await this.$transaction(fn);
      } catch (error: any) {
        if (error.code === "P2034" && retries < maxRetries - 1) {
          retries++;
          this.logger.warn(`Transaction conflict, retrying (${retries}/${maxRetries})`);
          await new Promise((r) => setTimeout(r, 100 * retries));
          continue;
        }
        throw error;
      }
    }

    throw new Error("Transaction failed after max retries");
  }
}