import { BadRequestException, Injectable, InternalServerErrorException, NotFoundException } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { In, IsNull, Repository } from 'typeorm';
import { createOrderDetailQuery } from '../../../utils/order/createOrderDetailQuery';
import { deriveOrderState } from '../../../utils/order/deriveOrderState';
import { deriveOrderTotals } from '../../../utils/order/deriveOrderTotals';
import { formatInvoicePaymentConfirmationStatus } from '../../../utils/invoice/formatInvoicePaymentConfirmationStatus';
import { resolveInvoiceStatusMessage } from '../../../utils/invoice/resolveInvoiceStatusMessage';
import { resolveInvoiceRequiredConfirmations } from '../../../utils/invoice/resolveInvoiceRequiredConfirmations';
import type { InvoiceState } from '../../../utils/invoice/types/InvoiceState';
import type { CryptoAtomicConverter } from '../../../types/CryptoAtomicConverter';
import { paymentMethodLabel } from '../../../consts/paymentMethodLabel';
import { resolveAtomicToCryptoConverter } from '../../../utils/payment/resolveAtomicToCryptoConverter';
import type { Invoice } from '../../payment/entities/Invoice';
import type { InvoicePayment } from '../../payment/entities/InvoicePayment';
import type { InvoiceExtended } from '../../payment/types/InvoiceExtended';
import type { InvoicePaymentExtended } from '../../payment/types/InvoicePaymentExtended';
import { InvoiceReason } from '../../payment/types/InvoiceReason';
import { InvoiceService } from '../../payment/services/InvoiceService';
import { DeliveryMode } from '../../product/types/DeliveryMode';
import { SetDeliveryCostDto } from '../dto/SetDeliveryCostDto';
import type { ListOrdersQueryDto } from '../dto/ListOrdersQueryDto';
import { Order } from '../entities/Order';
import { OrderLineManualFulfillment } from '../entities/OrderLineManualFulfillment';
import { ManualLineFulfillmentStatus } from '../types/ManualLineFulfillmentStatus';
import { EncryptionService } from '../../encryption/services/EncryptionService';
import { OrderAccessTokenService } from './OrderAccessTokenService';
import { OrderChatService } from './OrderChatService';
import type { OrderExtended } from '../types/OrderExtended';
import type { OrderListItem } from '../types/OrderListItem';
import type { PaginatedResponse } from '../../../types/PaginatedResponse';

@Injectable()
export class OrderService {
    constructor(
        @InjectRepository(Order)
        private readonly orderRepo: Repository<Order>,
        @InjectRepository(OrderLineManualFulfillment)
        private readonly manualFulfillmentRepo: Repository<OrderLineManualFulfillment>,
        private readonly orderChatService: OrderChatService,
        private readonly accessTokenService: OrderAccessTokenService,
        private readonly encryptionService: EncryptionService,
        private readonly invoiceService: InvoiceService
    ) {}

    async findIdByCheckoutSessionId(checkoutSessionId: string): Promise<string | null> {
        const order = await this.orderRepo.findOne({
            where: { checkoutSession: { id: checkoutSessionId } },
            select: { id: true }
        });

        return order?.id ?? null;
    }

    async findById(id: string): Promise<OrderExtended> {
        const orderDetailQuery = createOrderDetailQuery(this.orderRepo, id);

        const order = await orderDetailQuery.getOne();

        if (!order) {
            throw new NotFoundException('Order not found');
        }

        order.accessToken = this.accessTokenService.decryptStored(order.accessToken);

        this.encryptionService.decryptPlaintextFieldInPlace(order.messages, 'body');

        for (const line of order.lines ?? []) {
            this.encryptionService.decryptPlaintextFieldInPlace(line.autoFulfillmentItems, 'contentSnapshot');
        }

        return this.toOrderExtended(order);
    }

    /**
     * Paginate in two steps: entities first, then hydrate relations.
     *
     * Do not join one-to-many relations in the paginated query — LIMIT/skip apply to joined
     * rows, so a page of 20 items can return far fewer parents when each parent has
     * multiple children (one-to-many row multiplication).
     *
     * @see https://github.com/typeorm/typeorm/issues/11316#issuecomment-2074916139
     */
    async findAll({ page = 1, limit = 20 }: ListOrdersQueryDto): Promise<PaginatedResponse<OrderListItem>> {
        const [orders, total] = await this.orderRepo.findAndCount({
            order: { createdAt: 'DESC' },
            skip: (page - 1) * limit,
            take: limit
        });

        if (orders.length === 0) {
            return { items: [], total, page, limit };
        }

        const orderIds = orders.map(order => order.id);

        const ordersWithRelations = await this.orderRepo.find({
            where: { id: In(orderIds) },
            relations: [
                'checkoutInvoice',
                'checkoutInvoice.payments',
                'checkoutInvoice.moneroDetails',
                'checkoutInvoice.btcDetails',
                'shippingInvoice',
                'shippingInvoice.payments',
                'shippingInvoice.moneroDetails',
                'shippingInvoice.btcDetails',
                'lines',
                'lines.manualFulfillment',
                'discounts',
                'messages'
            ],
            order: { createdAt: 'DESC' }
        });

        return {
            items: ordersWithRelations.map(order => this.toOrderListItem(order)),
            total,
            page,
            limit
        };
    }

    private toOrderListItem(order: Order): OrderListItem {
        const fiatCurrency = order.checkoutInvoice?.fiatCurrency;

        if (!fiatCurrency) {
            throw new InternalServerErrorException('Order is missing checkout invoice fiat currency');
        }

        const { checkoutInvoiceState, shippingInvoiceState, status } = deriveOrderState(order);

        const { totalFiat, grandTotalFiat } = deriveOrderTotals(order);

        const checkoutPaymentLabel = checkoutInvoiceState ? resolveInvoiceStatusMessage(checkoutInvoiceState) : null;
        const shippingPaymentLabel = shippingInvoiceState ? resolveInvoiceStatusMessage(shippingInvoiceState) : null;

        return {
            id: order.id,
            status,
            checkoutPaymentLabel,
            shippingPaymentLabel,
            totalFiat,
            grandTotalFiat,
            fiatCurrency,
            lineCount: order.lines?.length ?? 0,
            unreadMessageCount: this.orderChatService.countUnreadBuyerMessages(order),
            failureReason: order.failureReason,
            createdAt: order.createdAt,
            updatedAt: order.updatedAt
        };
    }

    private toOrderExtended(order: Order): OrderExtended {
        const fiatCurrency = order.checkoutInvoice?.fiatCurrency;

        if (!fiatCurrency) {
            throw new InternalServerErrorException('Order is missing checkout invoice fiat currency');
        }

        const state = deriveOrderState(order);
        const totals = deriveOrderTotals(order);

        const checkoutInvoice = order.checkoutInvoice
            ? this.toInvoiceExtended(order.checkoutInvoice, state.checkoutInvoiceState)
            : null;

        const shippingInvoice = order.shippingInvoice
            ? this.toInvoiceExtended(order.shippingInvoice, state.shippingInvoiceState)
            : null;

        return {
            ...order,
            state,
            totals,
            fiatCurrency,
            checkoutInvoice,
            shippingInvoice
        };
    }

    private toInvoiceExtended(invoice: Invoice, invoiceState: InvoiceState | null): InvoiceExtended {
        const requiredConfirmations = resolveInvoiceRequiredConfirmations(invoice);

        const statusLabel = invoiceState ? resolveInvoiceStatusMessage(invoiceState) : null;

        const convertAtomicToCrypto = resolveAtomicToCryptoConverter(invoice.paymentMethod);

        const expectedTotalCrypto = convertAtomicToCrypto(invoice.expectedTotalAtomic);

        const payments = (invoice.payments ?? []).map(payment =>
            this.toInvoicePaymentExtended(payment, requiredConfirmations, convertAtomicToCrypto)
        );

        return {
            ...invoice,
            statusLabel,
            paymentLabel: paymentMethodLabel[invoice.paymentMethod],
            expectedTotalCrypto,
            payments
        };
    }

    private toInvoicePaymentExtended(
        payment: InvoicePayment,
        requiredConfirmations: number,
        convertAtomicToCrypto: CryptoAtomicConverter
    ): InvoicePaymentExtended {
        const isConfirmed = payment.confirmations >= requiredConfirmations;

        const amountCrypto = convertAtomicToCrypto(payment.amountAtomic);

        const confirmationsLabel = formatInvoicePaymentConfirmationStatus({
            confirmations: payment.confirmations,
            requiredConfirmations,
            format: 'compact'
        });

        return {
            ...payment,
            amountCrypto,
            isConfirmed,
            confirmationsLabel
        };
    }

    async setDeliveryCost(orderId: string, { deliveryCost }: SetDeliveryCostDto): Promise<OrderExtended> {
        const order = await this.orderRepo.findOne({
            where: {
                id: orderId,
                failureReason: IsNull(),
                quotedAt: IsNull(),
                shippingInvoice: IsNull()
            },
            relations: ['lines', 'checkoutInvoice']
        });

        if (!order || !order.checkoutInvoice) {
            throw new NotFoundException('Order not found');
        }

        const hasManualLines = order.lines.some(line => line.deliveryMode === DeliveryMode.Manual);

        if (!hasManualLines) {
            throw new BadRequestException('Order does not require shipping');
        }

        const quotedAt = new Date();

        if (deliveryCost <= 0) {
            await this.orderRepo.update(orderId, { quotedAt });

            return this.findById(orderId);
        }

        const shippingInvoice = await this.invoiceService.issueInvoice({
            paymentMethod: order.checkoutInvoice.paymentMethod,
            reason: InvoiceReason.Shipping,
            contextId: orderId,
            amountFiat: deliveryCost
        });

        await this.orderRepo.update(orderId, {
            shippingInvoice: { id: shippingInvoice.id },
            quotedAt
        });

        return this.findById(orderId);
    }

    async fulfillManualLine(orderId: string, lineId: string): Promise<OrderExtended> {
        const order = await this.orderRepo.findOne({
            where: {
                id: orderId,
                failureReason: IsNull()
            },
            relations: ['lines', 'lines.manualFulfillment']
        });

        if (!order) {
            throw new NotFoundException('Order not found');
        }

        const line = order.lines?.find(item => item.id === lineId);

        if (!line) {
            throw new NotFoundException('Order line not found');
        }

        if (line.deliveryMode !== DeliveryMode.Manual) {
            throw new BadRequestException('Order line is not manually delivered');
        }

        if (!line.manualFulfillment) {
            throw new BadRequestException('Order line has no manual fulfillment record');
        }

        if (line.manualFulfillment.status === ManualLineFulfillmentStatus.Fulfilled) {
            throw new BadRequestException('Order line is already fulfilled');
        }

        await this.manualFulfillmentRepo.update(line.manualFulfillment.id, {
            status: ManualLineFulfillmentStatus.Fulfilled,
            fulfilledAt: new Date()
        });

        return this.findById(orderId);
    }
}