import { useState } from "react";
import { useTranslation } from "react-i18next";
import { useParams } from "react-router";

import type { Portfolio } from "@/entities/portfolio";
import type { InvestmentResourceMeta } from "@/shared/api";

import { useBrokerageOperations } from "@/entities/broker-operation";
import {
	type BrokerageAccount,
	useBrokerageAccounts,
} from "@/entities/brokerage-account";
import {
	useBrokerageEvents,
} from "@/entities/brokerage-event";
import { useIncomeSummary } from "@/entities/income";
import { usePortfolio } from "@/entities/portfolio";
import { useScreenSync } from "@/features/tbank-connection";
import { apiErrorCode, isBrokerageAccessLoss, readRetry } from "@/shared/api";
import { useInitialAvailability } from "@/shared/lib";

import {
	type Concentration,
	concentrationCurrencies,
	type ConcentrationLabels,
	type Slice,
	toConcentration,
} from "../../model/concentration";
import {
	type AccountPagePositionSection,
	toAccountPagePositionSections,
	toUnrealizedReturns,
} from "../../model/positions";
import {
	type AccountPageIncomeSummary,
	type AccountPageRecentEvents,
	type AccountPageRecentOperations,
	toIncomeSummary,
	toRecentEvents,
	toRecentOperations,
} from "../../model/previews";

type AccountPageContent = {
	account?: BrokerageAccount;
	accountId?: string;
	incomeSummary: AccountPageIncomeSummary;
	partial?: boolean;
	readRetry: AccountPageReadRetry;
	recentEvents: AccountPageRecentEvents;
	recentOperations: AccountPageRecentOperations;
	source?: InvestmentResourceMeta;
};

type AccountPageEmptyViewModel = AccountPageContent & {
	state: "empty";
};

type AccountPageLoadedViewModel = AccountPageContent & {
	concentration: Concentration | null;
	currency: null | string;
	onCurrencyChange: (currency: null | string) => void;
	onSliceChange: (slice: Slice) => void;
	onTabChange: (tab: null | string) => void;
	portfolio: Portfolio;
	positionSections: AccountPagePositionSection[];
	slice: Slice;
	state: "loaded";
	tab: string;
	unrealizedReturns: Portfolio["totalsByCurrency"];
};

type AccountPageReadRetry = ReturnType<typeof readRetry>;

type AccountPageViewModel
	= | AccountPageEmptyViewModel
		| AccountPageLoadedViewModel
		| { code?: string; readRetry: AccountPageReadRetry; state: "error" }
		| { state: "loading" };

function useAccountPageViewModel(): AccountPageViewModel {
	const { accountId } = useParams();
	const { t } = useTranslation();

	const [selection, setSelection] = useState<{
		accountId?: string;
		currency: null | string;
		slice: Slice;
		tab: string;
	}>({ accountId, currency: null, slice: "stocks", tab: "positions" });

	const current = selection.accountId === accountId
		? selection
		: {
				accountId, currency: null, slice: "stocks" as const, tab: "positions",
			};

	const updateSelection = (change: Partial<typeof selection>) =>
		setSelection({ ...current, ...change });

	const portfolio = usePortfolio(accountId);

	const operations = useBrokerageOperations(accountId, {
		limit: 5,
	});

	const events = useBrokerageEvents(accountId);
	const income = useIncomeSummary(accountId);
	const accounts = useBrokerageAccounts();

	useScreenSync({ accountId, screen: "account" }, [
		accounts,
		portfolio,
		operations,
		events,
		income,
	]);

	const code = apiErrorCode(portfolio.error);
	// The portfolio drives this screen; the retry repeats only its GET.
	const retry = readRetry([portfolio]);
	const isAccessFailure = isBrokerageAccessLoss(code);

	const availability = useInitialAvailability({
		hasContent: !!portfolio.data,
		identity: accountId ?? "account",
		isError: portfolio.isError || portfolio.meta?.lastAttempt.state === "failed",
		isFetching: portfolio.isFetching,
	});

	if (isAccessFailure)
		return { code, readRetry: retry, state: "error" as const };

	if (!portfolio.data)
		return availability === "unavailable"
			? { code, readRetry: retry, state: "error" as const }
			: { state: "loading" as const };

	const account = accounts.data?.find(item => item.id === accountId);
	const recentOperations = toRecentOperations(accountId, operations);
	const recentEvents = toRecentEvents(accountId, events);

	const incomeSummary = toIncomeSummary(accountId, income);

	if (
		portfolio.meta?.availability === "available"
		&& portfolio.data.positions.length === 0
		&& portfolio.data.cashBalances.length === 0
	)
		return {
			account,
			accountId,
			incomeSummary,
			readRetry: retry,
			recentEvents,
			recentOperations,
			source: portfolio.meta,
			state: "empty" as const,
		};

	const isPartial = portfolio.meta?.completeness === "incomplete";
	const currencies = concentrationCurrencies(portfolio.data);

	const currency = current.currency && currencies.includes(current.currency)
		? current.currency
		: currencies[0] ?? null;

	const labels: ConcentrationLabels = {
		missingIssuer: t("portfolio.concentration.missingIssuer"),
		missingSector: t("portfolio.concentration.missingSector"),
		other: t("portfolio.concentration.other"),
		sector: code => t(`stock.sectors.${code}`, { defaultValue: code }),
	};

	const concentration = accountId !== "all"
		&& current.tab === "concentration"
		? toConcentration(portfolio.data, current.slice, currency, labels)
		: null;

	return {
		account,
		accountId,
		concentration,
		currency,
		incomeSummary,
		onCurrencyChange: value => updateSelection({ currency: value }),
		onSliceChange: slice => updateSelection({ slice }),
		onTabChange: tab => updateSelection({ tab: tab ?? "positions" }),
		partial: isPartial,
		portfolio: portfolio.data,
		positionSections: toAccountPagePositionSections(portfolio.data),
		readRetry: retry,
		recentEvents,
		recentOperations,
		slice: current.slice,
		source: portfolio.meta,
		state: "loaded" as const,
		tab: current.tab,
		unrealizedReturns: toUnrealizedReturns(portfolio.data.positions),
	};
}

export { useAccountPageViewModel };