import { HttpException, HttpStatus, Injectable, Logger } from "@nestjs/common";
import { PaymentDataAccess } from "../../dataAccess/payment.dataAccess";
import mongoose, { Mongoose, startSession } from "mongoose";
import { PaymentGateway } from "../IPG/PaymentGateway";
import { UserDataAccess } from "../../dataAccess/user.dataAccess";
import { PurchaseDataAccess } from "../../dataAccess/purchase.dataAccess";
import { CourseDataAccess } from "../../dataAccess/course.dataAccess";
import { PaymentStatus } from "../../common/eNums/paymentStatus.enum";

@Injectable()
export class PaymentService {
  private readonly logger = new Logger(PaymentService.name);
  constructor(
    private readonly paymentDataAccess: PaymentDataAccess,
    private readonly paymentGateway: PaymentGateway,
    private readonly userDataAccess: UserDataAccess,
    private readonly purchaseDataAccess: PurchaseDataAccess,
    private readonly courseDataAccess: CourseDataAccess
  ) { }

  async createPayment(userId: string, courseId: string) {
    const session = await startSession();
    session.startTransaction();
    try {
      const user = await this.userDataAccess.findOne(userId);
      const course = await this.courseDataAccess.getOneCourse(courseId);
      if (!course) {
        throw new HttpException(
          {
            status: HttpStatus.BAD_REQUEST,
            error: 'دوره مورد نظر یافت نشد',
          },
          HttpStatus.BAD_REQUEST,
        );
      }
      const courseExists = user.courseIds.find(id => id.equals(courseId));
      if (courseExists) {
        throw new HttpException(
          {
            status: HttpStatus.BAD_REQUEST,
            error: 'شما قبلا این دوره را خریداری کرده اید',
          },
          HttpStatus.BAD_REQUEST,
        );
      }

      if (course.price === 0) {
        // Handle free course registration
        const transactionNumber = `FREE-${Date.now()}-${Math.floor(Math.random() * 10000)}`;
        const payment = await this.paymentDataAccess.createPayment(
          userId,
          0,
          courseId,
          transactionNumber,
          'FREE',
          session
        );

        await session.commitTransaction();

        await this.purchaseDataAccess.createPurchase(payment.userId.toString(), payment.courseId.toString(), payment._id.toString());

        payment.paymentStatus = PaymentStatus.Completed;
        await this.paymentDataAccess.updatePaymentStatus(payment._id.toString(), PaymentStatus.Completed);

        const registerCourse = await this.userDataAccess.registerCourse(payment.userId, payment.courseId);
        if (!registerCourse.success) {
          if (!payment) {
            throw new HttpException(
              {
                status: HttpStatus.BAD_REQUEST,
                error: 'درخواست خرید دوره با مشکل مواجه شد',
              },
              HttpStatus.BAD_REQUEST,
            );
          }
        }

        await session.commitTransaction();
        await session.endSession();

        return { success: true, payment: payment }
      }

      const paymentData = await this.paymentGateway.requestPayment({ amount: course.price, userId, callbackPath: "cart" });
      if (!paymentData) {
        throw new HttpException(
          {
            status: HttpStatus.BAD_REQUEST,
            error: 'درخواست خرید دوره با مشکل مواجه شد',
          },
          HttpStatus.BAD_REQUEST,
        );
      }
      const transactionNumber = `DLR-${Date.now()}-${Math.floor(Math.random() * 10000)}`;

      const payment = await this.paymentDataAccess.createPayment(
        userId,
        course.price,  //amount
        courseId,
        transactionNumber,
        paymentData.authority,
        session
      );
      await session.commitTransaction();
      await session.endSession();
      return { payment: payment, paymentData }
    } catch (error) {
      await session.abortTransaction();
      await session.endSession();
      this.logger.warn(error);
      return error;
    }
  }


  async verifyPayment(authority: string, status: string) {
    const paymentData = await this.paymentDataAccess.getPaymentByAuthority(authority);
    if (!paymentData) {
      throw new Error("payment not found");
    }
    const verifyData = await this.paymentGateway.verifyPayment({ authority, amount: paymentData.amount });
    console.log({verifyData})
    if (verifyData.code === 100 || verifyData.code === 101) {
      await this.purchaseDataAccess.createPurchase(paymentData.userId.toString(), paymentData.courseId.toString(), paymentData._id.toString());
      paymentData.paymentStatus = PaymentStatus.Completed;
      await paymentData.save();
      const registerCourse = await this.userDataAccess.registerCourse(paymentData.userId, paymentData.courseId);
      if (!registerCourse.success) {
        if (!paymentData) {
          throw new HttpException(
            {
              status: HttpStatus.BAD_REQUEST,
              error: 'درخواست خرید دوره با مشکل مواجه شد',
            },
            HttpStatus.BAD_REQUEST,
          );
        }
      }
      return { success: true, payment: paymentData, verifyData }
    }

  }


  async getPayments() {
    return this.paymentDataAccess.getPayments();
  }

  async getPaymentsByUser(userId: string) {
    return this.paymentDataAccess.getPaymentsByUserId(userId);
  }
}