import { useRef, useState } from "react";

import { apiClient } from "@/shared/api";

type Criteria = {
	countryOfRisk: string;
	currency: string;
	maxLot: string;
	query: string;
	realExchange: string;
	sector: string;
	shareType: string;
};

type ScreenerPage = Awaited<ReturnType<typeof readPage>>;

type StocksPageVm = ReturnType<typeof useStocksPageVm>;

const emptyCriteria: Criteria = {
	countryOfRisk: "",
	currency: "",
	maxLot: "",
	query: "",
	realExchange: "",
	sector: "",
	shareType: "",
};

async function createSearch(criteria: Criteria) {
	const { data } = await apiClient.POST("/api/v1/stocks/screener/search", {
		body: {
			...(criteria.countryOfRisk && { countryOfRisk: criteria.countryOfRisk }),
			...(criteria.currency && { currency: criteria.currency }),
			...(criteria.maxLot && { maxLot: Number(criteria.maxLot) }),
			...(criteria.query && { query: criteria.query }),
			...(criteria.realExchange && { realExchange: criteria.realExchange }),
			...(criteria.sector && { sector: criteria.sector }),
			...(criteria.shareType && { shareType: criteria.shareType }),
		},
	});

	if (!data) throw new Error("Stock screener search failed");

	return data;
}

async function readPage(searchId: string, page: number) {
	const { data } = await apiClient.GET(
		"/api/v1/stocks/screener/search/{searchId}",
		{ params: { path: { searchId }, query: { page } } },
	);

	if (!data) throw new Error("Stock screener page failed");

	return data;
}

function useStocksPageVm() {
	const [criteria, setCriteria] = useState(emptyCriteria);
	const [page, setPage] = useState<null | ScreenerPage>(null);
	const [pending, setPending] = useState(false);
	const [error, setError] = useState(false);
	const requestIdRef = useRef(0);

	const search = async () => {
		const currentRequestId = requestIdRef.current + 1;
		requestIdRef.current = currentRequestId;
		setPending(true);
		setError(false);

		try {
			const result = await createSearch(criteria);
			if (requestIdRef.current === currentRequestId) setPage(result);
		}
		catch {
			if (requestIdRef.current === currentRequestId) setError(true);
		}
		finally {
			if (requestIdRef.current === currentRequestId) setPending(false);
		}
	};

	const changePage = async (nextPage: number) => {
		if (!page) return;

		const currentRequestId = requestIdRef.current + 1;
		requestIdRef.current = currentRequestId;
		setPending(true);
		setError(false);

		try {
			const result = await readPage(page.searchId, nextPage);
			if (requestIdRef.current === currentRequestId) setPage(result);
		}
		catch {
			if (requestIdRef.current === currentRequestId) setError(true);
		}
		finally {
			if (requestIdRef.current === currentRequestId) setPending(false);
		}
	};

	return {
		changePage,
		criteria,
		error,
		items: page?.items ?? [],
		loading: pending,
		onCriteriaChange: (name: keyof Criteria, value: string) =>
			setCriteria(current => ({ ...current, [name]: value })),
		onPage: (nextPage: number) => void changePage(nextPage),
		onSearch: () => void search(),
		page: page?.page,
		resultTime: page?.asOf,
		// Test seam: settle the actual operation instead of the handler release.
		search,
		searched: page !== null,
		totalPages: page ? page.page + Number(page.hasNext) : 0,
	};
}

export { type Criteria, type StocksPageVm, useStocksPageVm };