import { Injectable } from '@nestjs/common';
import { AccessStore } from '../identity/access.store';
import type { Principal } from '../identity/identity.types';
import { AppError } from '../common/errors/app-error';

@Injectable()
export class CartStore {
  constructor(private readonly access: AccessStore) {}
  get(actor: Principal) {
    return this.access.mutate(actor, null, async (tx) => {
      const cart = await tx.cart.upsert({
        where: {
          userId_organizationId: {
            userId: actor.userId,
            organizationId: actor.organizationId,
          },
        },
        create: { userId: actor.userId, organizationId: actor.organizationId },
        update: {},
      });
      const lines = await tx.cartLine.findMany({
        where: { cartId: cart.id },
        orderBy: { id: 'asc' },
        select: {
          variantId: true,
          quantity: true,
          variant: {
            select: {
              name: true,
              sku: true,
              price: true,
              currency: true,
              active: true,
              product: { select: { name: true, status: true } },
            },
          },
        },
      });
      return { version: cart.version, lines };
    });
  }
  set(actor: Principal, variantId: string, version: number, quantity: number) {
    return this.access.mutate(actor, null, async (tx) => {
      const cart = await tx.cart.upsert({
        where: {
          userId_organizationId: {
            userId: actor.userId,
            organizationId: actor.organizationId,
          },
        },
        create: { userId: actor.userId, organizationId: actor.organizationId },
        update: {},
      });
      if (cart.version !== version) throw new AppError('CART_CHANGED');
      if (quantity === 0) {
        await tx.cartLine.deleteMany({ where: { cartId: cart.id, variantId } });
      } else {
        const variant = await tx.productVariant.findFirst({
          where: {
            id: variantId,
            organizationId: actor.organizationId,
            active: true,
            product: { status: 'PUBLISHED' },
          },
        });
        if (!variant) throw new AppError('CART_ITEM_UNAVAILABLE');
        const lines = await tx.cartLine.findMany({
          where: { cartId: cart.id },
          include: { variant: true },
        });
        if (lines.some((line) => line.variant.currency !== variant.currency))
          throw new AppError('CART_CURRENCY');
        if (
          lines.length >= 20 &&
          !lines.some((line) => line.variantId === variantId)
        )
          throw new AppError('CART_LIMIT');
        await tx.cartLine.upsert({
          where: { cartId_variantId: { cartId: cart.id, variantId } },
          create: {
            cartId: cart.id,
            organizationId: actor.organizationId,
            variantId,
            quantity,
          },
          update: { quantity },
        });
      }
      await tx.cart.update({
        where: { id: cart.id },
        data: { version: { increment: 1 } },
      });
      return { version: version + 1 };
    });
  }
}