import {
    ChannelService,
    EntityHydrator,
    ID,
    idsAreEqual,
    Injector,
    InternalServerError,
    isGraphQlErrorResult,
    Order,
    OrderLine,
    OrderSellerStrategy,
    OrderService,
    PaymentMethod,
    PaymentMethodService,
    PaymentService,
    RequestContext,
    SplitOrderContents,
    Surcharge,
    TransactionalConnection,
} from '@vendure/core';

import { CONNECTED_PAYMENT_METHOD_CODE, MULTIVENDOR_PLUGIN_OPTIONS } from '../constants';
import { MultivendorPluginOptions } from '../types';

declare module '@vendure/core/dist/entity/custom-entity-fields' {
    interface CustomSellerFields {
        connectedAccountId: string;
    }
}

export class MultivendorSellerStrategy implements OrderSellerStrategy {
    private entityHydrator: EntityHydrator;
    private channelService: ChannelService;
    private paymentService: PaymentService;
    private paymentMethodService: PaymentMethodService;
    private connection: TransactionalConnection;
    private orderService: OrderService;
    private options: MultivendorPluginOptions;

    init(injector: Injector) {
        this.entityHydrator = injector.get(EntityHydrator);
        this.channelService = injector.get(ChannelService);
        this.paymentService = injector.get(PaymentService);
        this.paymentMethodService = injector.get(PaymentMethodService);
        this.connection = injector.get(TransactionalConnection);
        this.orderService = injector.get(OrderService);
        this.options = injector.get(MULTIVENDOR_PLUGIN_OPTIONS);
    }

    async setOrderLineSellerChannel(ctx: RequestContext, orderLine: OrderLine) {
        await this.entityHydrator.hydrate(ctx, orderLine.productVariant, { relations: ['channels'] });
        const defaultChannel = await this.channelService.getDefaultChannel();

        // If a ProductVariant is assigned to exactly 2 Channels, then one is the default Channel
        // and the other is the seller's Channel.
        if (orderLine.productVariant.channels.length === 2) {
            const sellerChannel = orderLine.productVariant.channels.find(
                c => !idsAreEqual(c.id, defaultChannel.id),
            );
            if (sellerChannel) {
                return sellerChannel;
            }
        }
    }

    async splitOrder(ctx: RequestContext, order: Order): Promise<SplitOrderContents[]> {
        const partialOrders = new Map<ID, SplitOrderContents>();
        for (const line of order.lines) {
            const sellerChannelId = line.sellerChannelId;
            if (sellerChannelId) {
                let partialOrder = partialOrders.get(sellerChannelId);
                if (!partialOrder) {
                    partialOrder = {
                        channelId: sellerChannelId,
                        shippingLines: [],
                        lines: [],
                        state: 'ArrangingPayment',
                    };
                    partialOrders.set(sellerChannelId, partialOrder);
                }
                partialOrder.lines.push(line);
            }
        }

        for (const partialOrder of partialOrders.values()) {
            const shippingLineIds = new Set(partialOrder.lines.map(l => l.shippingLineId));
            partialOrder.shippingLines = order.shippingLines.filter(shippingLine =>
                shippingLineIds.has(shippingLine.id),
            );
        }

        return [...partialOrders.values()];
    }

    async afterSellerOrdersCreated(ctx: RequestContext, aggregateOrder: Order, sellerOrders: Order[]) {
        const paymentMethod = await this.connection.rawConnection.getRepository(PaymentMethod).findOne({
            where: {
                code: CONNECTED_PAYMENT_METHOD_CODE,
            },
        });
        if (!paymentMethod) {
            return;
        }
        const defaultChannel = await this.channelService.getDefaultChannel();
        for (const sellerOrder of sellerOrders) {
            const sellerChannel = sellerOrder.channels.find(c => !idsAreEqual(c.id, defaultChannel.id));
            if (!sellerChannel) {
                throw new InternalServerError(
                    `Could not determine Seller Channel for Order ${sellerOrder.code}`,
                );
            }
            sellerOrder.surcharges = [await this.createPlatformFeeSurcharge(ctx, sellerOrder)];
            await this.orderService.applyPriceAdjustments(ctx, sellerOrder);
            await this.entityHydrator.hydrate(ctx, sellerChannel, { relations: ['seller'] });
            const result = await this.orderService.addPaymentToOrder(ctx, sellerOrder.id, {
                method: paymentMethod.code,
                metadata: {
                    transfer_group: aggregateOrder.code,
                    connectedAccountId: sellerChannel.seller?.customFields.connectedAccountId,
                },
            });
            if (isGraphQlErrorResult(result)) {
                throw new InternalServerError(result.message);
            }
        }
    }

    private async createPlatformFeeSurcharge(ctx: RequestContext, sellerOrder: Order) {
        const platformFee = Math.round(sellerOrder.totalWithTax * -(this.options.platformFeePercent / 100));
        return this.connection.getRepository(ctx, Surcharge).save(
            new Surcharge({
                taxLines: [],
                sku: this.options.platformFeeSKU,
                description: 'Platform fee',
                listPrice: platformFee,
                listPriceIncludesTax: true,
                order: sellerOrder,
            }),
        );
    }
}