import { BadRequestException, Injectable, Logger } from "@nestjs/common";
// eslint-disable-next-line import/no-named-as-default
import dayjs from "dayjs";
// eslint-disable-next-line import/no-named-as-default
import Decimal from "decimal.js";
import { Between, DataSource, QueryRunner } from "typeorm";

import { AuthMessage, DiscountMessage, InvoiceMessage, UserMessage, WalletMessage } from "../../../common/enums/message.enum";
import { RequestOtpDto } from "../../auth/DTO/request-otp.dto";
import { VerifyOtpDto } from "../../auth/DTO/verify-otp.dto";
import { DiscountRepository } from "../../discounts/repositories/discount.repository";
import { UsageDiscountRepository } from "../../discounts/repositories/usage-discount.repository";
import { SubscriptionPlan } from "../../subscriptions/entities/subscription.entity";
import { UsersService } from "../../users/providers/users.service";
import { OTPService } from "../../utils/providers/otp.service";
import { PaginationUtils } from "../../utils/providers/pagination.utils";
import { SmsService } from "../../utils/providers/sms.service";
import { Wallet } from "../../wallets/entities/wallet.entity";
import { WalletsService } from "../../wallets/providers/wallets.service";
import { ApplyDiscountDto } from "../DTO/apply-discount-invoice.dto";
import { CreateInvoiceDto } from "../DTO/create-invoice.dto";
import { InvoicesSearchQueryDto, UserInvoicesSearchQueryDto } from "../DTO/invoices-search-query.dto";
import { Invoice } from "../entities/invoice.entity";
import { InvoiceStatus } from "../enums/invoice-status.enum";
// import { InvoiceItemsRepository } from "../repositories/invoice-items.repository";
import { InvoicesRepository } from "../repositories/invoices.repository";

@Injectable()
export class InvoicesService {
  private readonly logger = new Logger(InvoicesService.name);

  constructor(
    private readonly invoiceRepository: InvoicesRepository,
    private readonly discountRepository: DiscountRepository,
    private readonly usageDiscountRepository: UsageDiscountRepository,
    private readonly usersService: UsersService,
    private readonly walletsService: WalletsService,
    private readonly otpService: OTPService,
    private readonly smsService: SmsService,
    private readonly dataSource: DataSource,
    // private readonly invoiceItemsRepository: InvoiceItemsRepository,
  ) {}

  ///********************************** */

  async createInvoiceAdmin(createDto: CreateInvoiceDto) {
    //
    const invoiceItems = createDto.items.map((item) => {
      return {
        name: item.name,
        count: item.count,
        unitPrice: item.unitPrice,
        discount: item.discount || 0,
        totalPrice: item.unitPrice * item.count - (item.unitPrice * item.count * item.discount) / 100,
      };
    });
    //
    const totalPrice = invoiceItems.reduce((sum, item) => new Decimal(item.totalPrice).add(sum), new Decimal(0));
    const tax = totalPrice.mul(0.1);
    //
    const dueDate = new Date();
    dueDate.setDate(dueDate.getDate() + 5);
    //
    const invoice = this.invoiceRepository.create({
      user: { id: createDto.userId },
      totalPrice: totalPrice.toNumber(),
      items: invoiceItems,
      tax: tax.toNumber(),
      dueDate,
    });
    //
    await this.invoiceRepository.save(invoice);
    //TODO: notify user

    return {
      message: InvoiceMessage.CREATED,
      invoice,
    };
  }

  //********************************** */

  async approveRequest(invoiceId: string, userId: string, requestOtpDto: RequestOtpDto) {
    const { phone } = requestOtpDto;
    const user = await this.usersService.findOneById(userId);
    if (!user) throw new BadRequestException(UserMessage.USER_NOT_FOUND);

    const invoice = await this.invoiceRepository.findOneBy({ id: invoiceId, user: { id: userId } });
    if (!invoice) throw new BadRequestException(InvoiceMessage.NOT_FOUND_BY_ID);

    if (invoice.status === InvoiceStatus.APPROVED) throw new BadRequestException(InvoiceMessage.ALREADY_APPROVED);
    if (invoice.status === InvoiceStatus.PAID) throw new BadRequestException(InvoiceMessage.INVOICE_ALREADY_PAID);
    if (dayjs().isAfter(invoice.dueDate)) throw new BadRequestException(InvoiceMessage.INVOICE_IS_OVERDUE);

    if (invoice.status !== InvoiceStatus.PENDING) throw new BadRequestException(InvoiceMessage.INVOICE_CAN_NOT_APPROVED);

    const existCode = await this.otpService.checkExistOtp(phone, "LOGIN");
    if (existCode) {
      return {
        message: AuthMessage.OTP_ALREADY_SENT,
        ttlSecond: existCode,
      };
    }

    const otpCode = await this.otpService.generateAndSetInCache(phone, "LOGIN");
    //
    await this.smsService.sendSmsVerifyCode(phone, otpCode);
    this.logger.debug(`OTP sent to ${phone}: ${otpCode}`);

    return {
      message: AuthMessage.OTP_SENT,
      otpCode,
    };
  }

  //********************************** */

  async approveInvoiceByUser(invoiceId: string, userId: string, verifyOtpDto: VerifyOtpDto) {
    const { code, phone } = verifyOtpDto;

    const user = await this.checkUserVerifyCredentialWithPhone(phone, code, userId);
    if (!user) throw new BadRequestException(InvoiceMessage.INVOICE_CAN_NOT_APPROVED);

    const invoice = await this.invoiceRepository.findOneBy({ id: invoiceId, user: { id: userId } });
    if (!invoice) throw new BadRequestException(InvoiceMessage.NOT_FOUND_BY_ID);

    if (invoice.status === InvoiceStatus.APPROVED) throw new BadRequestException(InvoiceMessage.ALREADY_APPROVED);
    if (invoice.status === InvoiceStatus.PAID) throw new BadRequestException(InvoiceMessage.INVOICE_ALREADY_PAID);
    if (dayjs().isAfter(invoice.dueDate)) throw new BadRequestException(InvoiceMessage.INVOICE_IS_OVERDUE);

    if (invoice.status !== InvoiceStatus.PENDING) throw new BadRequestException(InvoiceMessage.INVOICE_CAN_NOT_APPROVED);

    invoice.status = InvoiceStatus.APPROVED;

    await this.invoiceRepository.save(invoice);

    return {
      message: InvoiceMessage.APPROVED,
      invoice,
    };
  }
  ///********************************** */

  async createInvoiceForSubscription(userId: string, plan: SubscriptionPlan, dueDate: Date, queryRunner: QueryRunner) {
    const invoiceItems = [
      { name: plan.service.name, count: 1, unitPrice: plan.price, discount: 0, subscriptionPlan: plan, totalPrice: plan.price },
    ];
    const invoice = queryRunner.manager.create(Invoice, {
      totalPrice: plan.price,
      user: { id: userId },
      status: InvoiceStatus.PAID,
      paidAt: new Date(),
      dueDate,
      items: invoiceItems,
    });
    //
    await queryRunner.manager.save(Invoice, invoice);
    return invoice;
  }

  ///********************************** */

  async getInvoices(queryDto: InvoicesSearchQueryDto) {
    const [invoices, count] = await this.invoiceRepository.getInvoicesForAdmin(queryDto);

    const usersWithInvoices = await this.invoiceRepository
      .createQueryBuilder("invoice")
      .leftJoinAndSelect("invoice.user", "user")
      .select(["user.id", "user.firstName", "user.lastName", "user.email"])
      .distinctOn(["user.id"])
      .getMany();

    return {
      users: usersWithInvoices.map((inv) => inv.user),
      invoices,
      count,
      paginate: true,
    };
  }

  //*********************************** */
  async getInvoiceById(invoiceId: string, isAdmin: boolean, userId: string) {
    let invoice: Invoice | null;

    if (isAdmin) {
      invoice = await this.invoiceRepository.findOne({
        where: { id: invoiceId },
        relations: { items: { subscriptionPlan: true }, user: true },
      });
    } else {
      invoice = await this.invoiceRepository.findOne({
        where: { id: invoiceId, user: { id: userId } },
        relations: { items: { subscriptionPlan: true } },
      });
    }

    if (!invoice) throw new BadRequestException(InvoiceMessage.NOT_FOUND_BY_ID);

    return {
      invoice,
    };
  }

  //*********************************** */

  async getUserInvoices(queryDto: UserInvoicesSearchQueryDto, userId: string) {
    const { limit, skip } = PaginationUtils(queryDto);

    const queryBuilder = this.invoiceRepository.createQueryBuilder("invoice");

    queryBuilder
      .andWhere("invoice.user.id = :userId", { userId: userId })
      .leftJoinAndSelect("invoice.items", "items")
      .leftJoinAndSelect("items.subscriptionPlan", "subscriptionPlan", "subscriptionPlan.id IS NOT NULL")
      .leftJoinAndSelect("subscriptionPlan.service", "service", "subscriptionPlan.id IS NOT NULL");

    if (queryDto.status) {
      queryBuilder.andWhere("invoice.status = :status", { status: queryDto.status });
    }

    queryBuilder.orderBy("invoice.createdAt", "DESC").skip(skip).take(limit);

    const [invoices, count] = await queryBuilder.getManyAndCount();

    return {
      invoices,
      count,
      paginate: true,
    };
  }

  //*********************************** */

  async payInvoice(invoiceId: string, userId: string) {
    const queryRunner = this.dataSource.createQueryRunner();
    await queryRunner.connect();
    await queryRunner.startTransaction();
    try {
      const user = await this.usersService.findOneByIdWithQueryRunner(userId, queryRunner);

      const invoice = await this.getPendingInvoiceByIdWithQueryRunner(invoiceId, user.id, queryRunner);

      if (invoice.status === InvoiceStatus.REJECTED) throw new BadRequestException(InvoiceMessage.INVOICE_IS_REJECTED);
      if (invoice.status === InvoiceStatus.EXPIRED) throw new BadRequestException(InvoiceMessage.INVOICE_IS_OVERDUE);
      if (invoice.status === InvoiceStatus.PAID) throw new BadRequestException(InvoiceMessage.INVOICE_ALREADY_PAID);
      if (invoice.status !== InvoiceStatus.APPROVED) throw new BadRequestException(InvoiceMessage.INVOICE_CAN_NOT_PAID);

      const userWallet = await this.walletsService.getWalletByUserId(user.id, queryRunner);

      if (new Decimal(userWallet.balance).lessThan(invoice.totalPrice)) throw new BadRequestException(WalletMessage.INSUFFICIENT_BALANCE);

      userWallet.balance = new Decimal(userWallet.balance).sub(invoice.totalPrice);

      await queryRunner.manager.save(Wallet, userWallet);

      await this.walletsService.createInvoiceTransaction(invoice.totalPrice, userWallet.id, queryRunner);

      invoice.status = InvoiceStatus.PAID;
      invoice.paidAt = new Date();

      await queryRunner.manager.save(Invoice, invoice);
      console.log(invoice);
      await queryRunner.commitTransaction();
      return {
        message: InvoiceMessage.INVOICE_PAID,
        invoice,
      };
    } catch (error) {
      await queryRunner.rollbackTransaction();
      throw error;
    } finally {
      await queryRunner.release();
    }
  }

  //*********************************** */

  async getPendingInvoiceByIdWithQueryRunner(invoiceId: string, userId: string, queryRunner: QueryRunner) {
    const invoice = await queryRunner.manager.findOneBy(Invoice, { user: { id: userId }, status: InvoiceStatus.PENDING, id: invoiceId });
    if (!invoice) throw new BadRequestException(InvoiceMessage.NOT_FOUND_BY_ID);
    return invoice;
  }

  //*********************************** */

  async applyDiscount(invoiceId: string, applyDiscountDto: ApplyDiscountDto, userId: string) {
    const invoice = await this.invoiceRepository.findOneBy({ id: invoiceId, status: InvoiceStatus.PENDING });
    if (!invoice) throw new BadRequestException(InvoiceMessage.NOT_FOUND_BY_ID);

    const discount = await this.discountRepository.findOne({
      where: { code: applyDiscountDto.discountCode, isActive: true },
      relations: ["subscriptionPlans", "users"],
    });
    if (!discount) {
      throw new BadRequestException(DiscountMessage.NOT_FOUND);
    }

    const hasUsedDiscount = await this.hasUserUsedDiscount(userId, discount.id);
    if (hasUsedDiscount) throw new BadRequestException(DiscountMessage.ALREADY_USED);

    if (discount.subscriptionPlans && discount.subscriptionPlans.length > 0) {
      const isApplicable = invoice.items.some((item) => {
        const subscriptionPlan = item.subscriptionPlan;
        if (!subscriptionPlan) return false;
        return discount.subscriptionPlans.some((plan) => plan.id === subscriptionPlan.id);
      });
      if (!isApplicable) {
        throw new BadRequestException(DiscountMessage.CAN_NOT_APPLICABLE);
      }
    }

    if (discount.users && discount.users.length > 0) {
      if (!discount.users.some((user) => user.id === userId)) {
        throw new BadRequestException(DiscountMessage.CAN_NOT_APPLICABLE);
      }
    }

    const discountAmount =
      discount.calculationType === "PERCENTAGE"
        ? new Decimal(invoice.totalPrice).mul(discount.amount).div(100)
        : new Decimal(discount.amount);

    invoice.totalPrice = new Decimal(invoice.totalPrice).minus(discountAmount);
    await this.invoiceRepository.save(invoice);

    const usageDiscount = this.usageDiscountRepository.create({
      discount,
      users: [{ id: userId }],
      usageDate: new Date(),
    });

    await this.usageDiscountRepository.save(usageDiscount);

    return {
      message: InvoiceMessage.DISCOUNT_APPLIED,
      invoice,
    };
  }

  //*********************************** */

  async cancelDiscount(invoiceId: string, userId: string) {
    // Find the invoice by ID and ensure it is in a PENDING status
    const invoice = await this.invoiceRepository.findOneBy({ id: invoiceId, status: InvoiceStatus.PENDING });
    if (!invoice) throw new BadRequestException(InvoiceMessage.NOT_FOUND_BY_ID);

    // Find the usage discount associated with the user and invoice
    const usage = await this.usageDiscountRepository.findOne({
      where: {
        users: { id: userId },
        discount: { invoice: { id: invoice.id } },
      },
      relations: {
        discount: true,
        users: true,
      },
    });
    console.log(usage);
    if (!usage) throw new BadRequestException(DiscountMessage.NOT_FOUND);

    // Find the discount associated with the usage
    const discount = await this.discountRepository.findOneBy({ id: usage.discount.id });
    if (!discount) throw new BadRequestException(DiscountMessage.NOT_FOUND);

    // Calculate the discount amount to be removed from the invoice
    const discountAmount =
      discount.calculationType === "PERCENTAGE"
        ? new Decimal(invoice.totalPrice).mul(discount.amount).div(100)
        : new Decimal(discount.amount);

    // Update the invoice's total price by adding the discount amount (effectively removing the discount)
    invoice.totalPrice = new Decimal(invoice.totalPrice).add(discountAmount);
    await this.invoiceRepository.save(invoice);

    // Delete the usage discount record
    await this.usageDiscountRepository.delete(usage.id);

    return {
      message: InvoiceMessage.DISCOUNT_CANCELLED,
      invoice,
    };
  }

  //*********************************** */

  async getInvoicesCount() {
    const count = await this.invoiceRepository.count({
      where: {
        createdAt: Between(new Date(new Date().setHours(0, 0, 0, 0)), new Date(new Date().setHours(23, 59, 59, 999))),
      },
    });
    return count;
  }

  //*********************************** */

  private async hasUserUsedDiscount(userId: string, discountId: string): Promise<boolean> {
    const usage = await this.usageDiscountRepository.findOne({
      where: {
        users: {
          id: userId,
        },
        discount: {
          id: discountId,
        },
      },
    });
    return !!usage;
  }

  //*********************************** */

  private async checkUserVerifyCredentialWithPhone(phone: string, otpCode: string, userId: string) {
    //TODO: Change key from LOGIN to something else
    const isValid = await this.otpService.verifyOtp(phone, otpCode, "LOGIN");
    if (!isValid) throw new BadRequestException(AuthMessage.INVALID_OTP);

    await this.otpService.delOtpFormCache(phone, "LOGIN");

    const { user } = await this.usersService.findOneById(userId);
    if (!user) throw new BadRequestException(UserMessage.USER_NOT_FOUND);

    return user;
  }

  //*********************************** */

  // async calculateFinalPrice(invoiceId: string): Promise<Decimal> {
  //   const invoice = await this.invoiceRepository.findOneBy({ id: invoiceId });
  //   if (!invoice) throw new BadRequestException(InvoiceMessage.NOT_FOUND_BY_ID);

  //   let discountValue = new Decimal(0);
  //   if (invoice.discount) {
  //     if (invoice.discount.calculationType === "PERCENTAGE") {
  //       discountValue = invoice.totalPrice.mul(invoice.discount.amount).div(100);
  //     } else if (invoice.discount.calculationType === "FIXED") {
  //       discountValue = new Decimal(invoice.discount.amount);
  //     }
  //   }
  //   return invoice.totalPrice.minus(discountValue);
  // }
}