import { zodResolver } from "@hookform/resolvers/zod";
import { useEffect, useMemo, useState } from "react";
import { useForm } from "react-hook-form";
import { useParams, useSearchParams } from "react-router";

import { type IncomeAnalytics, useIncomeAnalytics } from "@/entities/income";
import { useScreenSync } from "@/features/tbank-connection";
import { isValidPeriod, moscowDate, useInitialAvailability } from "@/shared/lib";

import {
	type IncomeDisplayModel,
	toIncomeDisplayModel,
} from "../../model/display";
import { incomeFormSchema } from "../../model/income.schema";
import {
	formatDraftDate,
	type IncomeForm,
	type IncomePeriod,
	parseDraftDate,
} from "../../model/period";

const ISO_MONTH_LENGTH = 7;

type AccountIncomePageViewModel
	= | {
		analytics: IncomeAnalytics;
		display: IncomeDisplayModel;
		form: ReturnType<typeof useForm<IncomeForm>>;
		formRevision: string;
		onReset: () => void;
		onSubmit: (values: IncomeForm) => void;
		partial?: boolean;
		state: "loaded";
	}
	| {
		period: IncomePeriod;
		state: "error";
	}
	| { state: "loading" };

const useAccountIncomePageViewModel = (): AccountIncomePageViewModel => {
	const { accountId = "" } = useParams();
	const [searchParameters, setSearchParameters] = useSearchParams();

	const requested = useMemo(
		() => ({
			from: searchParameters.get("from") ?? "",
			to: searchParameters.get("to") ?? "",
		}),
		[searchParameters],
	);

	const period = useMemo(
		() => (isValidIncomePeriod(requested) ? requested : defaultPeriod()),
		[requested],
	);

	const form = useForm<IncomeForm>({
		defaultValues: draftPeriod(period),
		resolver: zodResolver(incomeFormSchema),
	});

	const [resetRevision, setResetRevision] = useState(0);
	const analytics = useIncomeAnalytics(accountId, period);

	useScreenSync(
		{ accountId, from: period.from, screen: "income", to: period.to },
		[analytics],
	);

	useEffect(() => {
		if (!isValidIncomePeriod(requested))
			setSearchParameters(period, { replace: true });
	}, [period, requested, setSearchParameters]);
	useEffect(() => {
		form.reset(draftPeriod(period));
	}, [accountId, form, period]);

	const availability = useInitialAvailability({
		hasContent: !!analytics.data,
		identity: `${accountId}:${period.from}:${period.to}`,
		isError: analytics.isError || analytics.meta?.lastAttempt.state === "failed",
		isFetching: analytics.isFetching,
	});

	if (availability === "loading" && analytics.isLoading)
		return { state: "loading" };

	if (!analytics.data)
		return availability === "unavailable"
			? { period, state: "error" }
			: { state: "loading" };

	const display = toIncomeDisplayModel(analytics.data);

	const onSubmit = (values: IncomeForm) => {
		const from = parseDraftDate(values.from);
		const to = parseDraftDate(values.to);
		if (from && to) setSearchParameters({ from, to });
	};

	const onReset = () => {
		const next = defaultPeriod();
		form.reset(draftPeriod(next));
		// Reset the open calendar along with the form.
		setResetRevision(revision => revision + 1);
		setSearchParameters(next, { replace: true });
	};

	return {
		analytics: analytics.data,
		display,
		form,
		formRevision: `${accountId}:${period.from}:${period.to}:${resetRevision}`,
		onReset,
		onSubmit,
		partial: analytics.meta?.completeness === "incomplete",
		state: "loaded",
	};
};

function defaultPeriod(): IncomePeriod {
	const today = moscowDate(new Date());

	return { from: `${today.slice(0, ISO_MONTH_LENGTH)}-01`, to: today };
}

function draftPeriod(period: IncomePeriod): IncomeForm {
	return { from: formatDraftDate(period.from), to: formatDraftDate(period.to) };
}

function isValidIncomePeriod(period: IncomePeriod): boolean {
	return isValidPeriod(period.from, period.to)
		&& period.to <= moscowDate(new Date());
}

export {
	type AccountIncomePageViewModel,
	useAccountIncomePageViewModel,
};