import { Injectable } from '@nestjs/common';
import { DataSource, type EntityManager } from 'typeorm';
import { deriveInvoiceState } from '../../../utils/invoice/deriveInvoiceState';
import { NotificationService } from '../../notifications/services/NotificationService';
import { DeliveryMode } from '../../product/types/DeliveryMode';
import { CheckoutSession } from '../../storefrontCheckout/entities/CheckoutSession';
import { CheckoutSessionLine } from '../../storefrontCheckout/entities/CheckoutSessionLine';
import { Order } from '../entities/Order';
import { ManualLineFulfillmentStatus } from '../types/ManualLineFulfillmentStatus';
import { OrderFailureReason } from '../types/OrderFailureReason';
import type { PreparedStockClaim } from '../types/PreparedStockClaim';
import { isPreparedDigitalStockClaim, isPreparedManualStockClaim } from '../utils/isPreparedStockClaim';
import { OrderAccessTokenService } from './OrderAccessTokenService';
import { OrderClaimService } from './OrderClaimService';

@Injectable()
export class OrderCreationService {
    constructor(
        private readonly dataSource: DataSource,
        private readonly orderClaimService: OrderClaimService,
        private readonly accessTokenService: OrderAccessTokenService,
        private readonly notificationService: NotificationService
    ) {}

    async createFromPaidSession(sessionId: string): Promise<void> {
        const now = new Date();
        let createdOrderId: string | null = null;

        await this.dataSource.transaction(async manager => {
            const sessionRepo = manager.getRepository(CheckoutSession);
            const orderRepo = manager.getRepository(Order);

            const session = await sessionRepo
                .createQueryBuilder('session')
                .leftJoinAndSelect('session.lines', 'line')
                .leftJoinAndSelect('session.discounts', 'discount')
                .leftJoinAndSelect('session.invoice', 'invoice')
                .leftJoinAndSelect('invoice.moneroDetails', 'moneroDetails')
                .leftJoinAndSelect('invoice.btcDetails', 'btcDetails')
                .leftJoinAndSelect('invoice.payments', 'payment')
                .leftJoin('session.order', 'order')
                .where('session.id = :sessionId', { sessionId })
                .andWhere('session.cancelledAt IS NULL')
                .andWhere('order.id IS NULL')
                .andWhere('invoice.expiresAt > :now', { now })
                .setLock('pessimistic_write', undefined, ['session'])
                .getOne();

            if (!session || !session.invoice) {
                return;
            }

            const { isPaidSufficient } = deriveInvoiceState(session.invoice);

            if (!isPaidSufficient) {
                return;
            }

            const claimResult = await this.orderClaimService.claimFromSession(manager, session);

            const failureReason = claimResult.success ? null : claimResult.failureReason;
            const stockClaims = claimResult.success ? claimResult.stockClaims : [];

            const { lookup, encrypted } = this.accessTokenService.generate();

            const order = this.buildOrderFromSession(
                manager,
                session,
                {
                    accessTokenLookup: lookup,
                    accessToken: encrypted,
                    failureReason
                },
                stockClaims
            );

            await orderRepo.save(order);

            createdOrderId = order.id;
        });

        if (createdOrderId) {
            this.notificationService.sendNotification(createdOrderId, 'newOrder');
        }
    }

    private buildOrderFromSession(
        manager: EntityManager,
        session: CheckoutSession,
        {
            accessTokenLookup,
            accessToken,
            failureReason
        }: {
            accessTokenLookup: string;
            accessToken: string;
            failureReason: OrderFailureReason | null;
        },
        stockClaims: PreparedStockClaim[] = []
    ): Order {
        const orderRepo = manager.getRepository(Order);
        const stockClaimsByLineId = new Map(stockClaims.map(claim => [claim.checkoutSessionLineId, claim]));

        return orderRepo.create({
            accessTokenLookup,
            accessToken,
            failureReason,
            checkoutSession: { id: session.id },
            checkoutInvoice: { id: session.invoice.id },
            discounts: (session.discounts ?? []).map(discount => ({
                code: discount.code,
                amountFiat: discount.amountFiat
            })),
            lines: (session.lines ?? []).map(line => this.mapCheckoutLine(line, stockClaimsByLineId))
        });
    }

    private mapCheckoutLine(source: CheckoutSessionLine, stockClaimsByLineId: Map<string, PreparedStockClaim>) {
        const claim = stockClaimsByLineId.get(source.id);

        const isManualStockClaim =
            source.deliveryMode === DeliveryMode.Manual && claim && isPreparedManualStockClaim(claim);

        const isDigitalStockClaim =
            source.deliveryMode === DeliveryMode.Auto && claim && isPreparedDigitalStockClaim(claim);

        return {
            variantId: source.variantId,
            productId: source.productId,
            productTitle: source.productTitle,
            variantTitle: source.variantTitle,
            thumbnailUrl: source.thumbnailUrl,
            qty: source.qty,
            unitPriceFiat: source.unitPriceFiat,
            lineSubtotalFiat: source.lineSubtotalFiat,
            deliveryMode: source.deliveryMode,
            ...(isManualStockClaim
                ? {
                      manualFulfillment: {
                          status: ManualLineFulfillmentStatus.Pending
                      }
                  }
                : {}),
            ...(isDigitalStockClaim
                ? {
                      autoFulfillmentItems: claim.items.map((item, index) => ({
                          sortOrder: index,
                          contentSnapshot: item.content,
                          sourceDigitalStockItemId: item.id,
                          attachments: (item.attachments ?? []).map(attachment => ({
                              storageKey: attachment.storageKey,
                              sourceDigitalStockAttachmentId: attachment.id,
                              originalFilename: attachment.originalFilename,
                              mimeType: attachment.mimeType,
                              sizeBytes: attachment.sizeBytes
                          }))
                      }))
                  }
                : {})
        };
    }
}