import {
  ProductAttributesDataFragment,
  ProductVariantWebhookPayloadFragment,
} from "../../../generated/graphql";
import { isNotNil } from "../isNotNil";

type PartialChannelListing = {
  channel: {
    slug: string;
    currencyCode: string;
  };
};

export function channelListingToAlgoliaIndexId(
  channelListing: PartialChannelListing,
  indexNamePrefix: string | undefined
) {
  /**
   * Index name should not start with . (dot)
   */
  const normalizedPrefix = indexNamePrefix === "" ? undefined : indexNamePrefix;

  const nameSegments = [
    normalizedPrefix,
    channelListing.channel.slug,
    channelListing.channel.currencyCode,
    "products",
  ];

  return nameSegments.filter(isNotNil).join(".");
}

/**
 * Produces category tree in the format expected by hierarchical Algolia widgets, for example:
 *
 * {
 *  "lvl0": "Root Category",
 *  "lvl1": "Root Category > Subcategory"
 *  "lvl2": "Root Category > Subcategory > Sub-subcategory"
 * }
 * https://www.algolia.com/doc/guides/managing-results/refine-results/faceting/#hierarchical-facets
 */
export function categoryHierarchicalFacets({ product }: ProductVariantWebhookPayloadFragment) {
  const categoryParents = [
    product.category?.parent?.parent?.parent?.parent?.name,
    product.category?.parent?.parent?.parent?.name,
    product.category?.parent?.parent?.name,
    product.category?.parent?.name,
    product.category?.name,
  ].filter((category) => category?.length);

  const categoryLvlMapping: Record<string, string> = {};

  for (let i = 0; i < categoryParents.length; i += 1) {
    categoryLvlMapping[`lvl${i}`] = categoryParents.slice(0, i + 1).join(" > ");
  }

  return categoryLvlMapping;
}

export function formatMetadata({ product }: ProductVariantWebhookPayloadFragment) {
  return Object.fromEntries(product.metadata?.map(({ key, value }) => [key, value]) || []);
}

export type AlgoliaObject = ReturnType<typeof productAndVariantToAlgolia>;

/**
 *  Returns object with a key being attribute name and value of all attribute values
 *  separated by comma. If no value is selected, an empty string will be used instead.
 */
const mapSelectedAttributesToRecord = (attr: ProductAttributesDataFragment) => {
  if (!attr.attribute.name?.length) {
    return undefined;
  }

  const filteredValues = attr.values.filter((v) => !!v.name?.length);

  return {
    [attr.attribute.name]: filteredValues.map((v) => v.name).join(", ") || "",
  };
};

export function productAndVariantToAlgolia({
  variant,
  channel,
}: {
  variant: ProductVariantWebhookPayloadFragment;
  channel: string;
}) {
  const product = variant.product;
  const attributes = {
    ...product.attributes.reduce((acc, attr, idx) => {
      const preparedAttr = mapSelectedAttributesToRecord(attr);

      if (!preparedAttr) {
        return acc;
      }
      return {
        ...acc,
        ...preparedAttr,
      };
    }, {}),
    ...variant.attributes.reduce((acc, attr, idx) => {
      const preparedAttr = mapSelectedAttributesToRecord(attr);

      if (!preparedAttr) {
        return acc;
      }
      return {
        ...acc,
        ...preparedAttr,
      };
    }, {}),
  };

  const listing = variant.channelListings?.find((l) => l.channel.slug === channel);

  const document = {
    objectID: productAndVariantToObjectID(variant),
    productId: product.id,
    variantId: variant.id,
    name: `${product.name} - ${variant.name}`,
    productName: product.name,
    variantName: variant.name,
    attributes,
    description: product.description,
    slug: product.slug,
    thumbnail: product.thumbnail?.url,
    grossPrice: listing?.price?.amount,
    categories: categoryHierarchicalFacets(variant),
    collections: product.collections?.map((collection) => collection.name) || [],
    metadata: formatMetadata(variant),
  };

  return document;
}

export function productAndVariantToObjectID({
  product,
  ...variant
}: ProductVariantWebhookPayloadFragment) {
  return `${product.id}_${variant.id}`;
}