import type {
	InvalidInputError,
	Price,
	ProductProjection,
	ProductVariant,
} from "@commercetools/platform-sdk";
import { CommercetoolsError } from "./exceptions.ts";
import type { Writable } from "./types.ts";

export type PriceSelector = {
	currency?: string;
	country?: string;
	customerGroup?: string;
	channel?: string;
};

/**
 * Apply the price selector on all the variants. The price selector is applied
 * on all the prices per variant and the first match per variant is stored in
 * the scopedPrice attribute
 */
export const applyPriceSelector = (
	products: ProductProjection[],
	selector: PriceSelector,
	noScopedPrice = false,
) => {
	validatePriceSelector(selector);

	for (const product of products) {
		// Get list of all variants (master + variants)
		const variants: Writable<ProductVariant>[] = [
			product.masterVariant,
			...(product.variants ?? []),
		].filter((x) => x !== undefined);

		for (const variant of variants) {
			const scopedPrices =
				variant.prices?.filter((p) => priceSelectorFilter(p, selector)) ?? [];

			if (scopedPrices.length > 0) {
				const price = scopedPrices[0];

				variant.price = scopedPrices[0];
				if (!noScopedPrice) {
					variant.scopedPriceDiscounted = false;
					variant.scopedPrice = {
						...price,
						currentValue: price.value,
					};
				}
			}
		}
	}
};

const validatePriceSelector = (selector: PriceSelector) => {
	if (
		(selector.country || selector.channel || selector.customerGroup) &&
		!selector.currency
	) {
		throw new CommercetoolsError<InvalidInputError>(
			{
				code: "InvalidInput",
				message:
					"The price selecting parameters country, channel and customerGroup " +
					"cannot be used without the currency.",
			},
			400,
		);
	}
};

/**
 * Return a boolean to indicate if the price matches the selector. Price
 * selection requires that if the selector or the price has a specific value
 * then it should match.
 */
export const priceSelectorFilter = (
	price: Price,
	selector: PriceSelector,
): boolean => {
	if (
		(selector.country || price.country) &&
		selector.country !== price.country
	) {
		return false;
	}

	if (
		(selector.currency || price.value.currencyCode) &&
		selector.currency !== price.value.currencyCode
	) {
		return false;
	}

	if (
		(selector.channel || price.channel?.id) &&
		selector.channel !== price.channel?.id
	) {
		return false;
	}

	if (
		(selector.customerGroup || price.customerGroup?.id) &&
		selector.customerGroup !== price.customerGroup?.id
	) {
		return false;
	}

	return true;
};