import { useParams } from "react-router";

import type { BrokerageOperation } from "@/entities/broker-operation";
import type { Portfolio } from "@/entities/portfolio";

import { useBrokerageOperations } from "@/entities/broker-operation";
import {
	type BrokerageAccount,
	useBrokerageAccounts,
} from "@/entities/brokerage-account";
import {
	type BrokerageEventsPreviewState,
	useBrokerageEvents,
} from "@/entities/brokerage-event";
import { type IncomeSummary, useIncomeSummary } from "@/entities/income";
import { formatShare, usePortfolio } from "@/entities/portfolio";
import { useStocks } from "@/entities/stock";
import { useScreenSync } from "@/features/tbank-connection";
import { apiErrorCode } from "@/shared/api";
import { formatMoney, instrumentLogoUrl } from "@/shared/lib";

const RECENT_EVENTS_LIMIT = 5;

type AccountPageContent = {
	account?: BrokerageAccount;
	accountId?: string;
	incomeSummary: AccountPageIncomeSummary;
	partial?: boolean;
	recentEvents: AccountPageRecentEvents;
	recentOperations: AccountPageRecentOperations;
	refreshError: boolean;
	refreshing: boolean;
	retry: () => Promise<unknown> | undefined;
	sourceError?: boolean;
};

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

type AccountPageIncomeSummary
	= | {
		lastSuccessfulAt?: null | string;
		refreshError?: boolean;
		stale?: boolean;
		state: "loaded";
		summary: IncomeSummary;
		to: string;
	}
	| { retry: () => Promise<unknown> | undefined; state: "error"; to: string }
	| { state: "empty"
		| "loading"
		| "partial"; to: string; };

type AccountPageLoadedViewModel = AccountPageContent & {
	portfolio: Portfolio;
	positionSections: AccountPagePositionSection[];
	state: "loaded";
};

type AccountPagePosition = Portfolio["positions"][number] & {
	instrumentTo?: string;
	logoSrc: null | string;
	returnText: null | string;
	returnTone?: AccountPageReturnTone;
	shareText: null | string;
};

type AccountPagePositionGroup = {
	key: string;
	positions: AccountPagePosition[];
};

type AccountPagePositionSection = {
	groups: AccountPagePositionGroup[];
	kind: PositionSectionKind;
};

type AccountPageRecentEvents = BrokerageEventsPreviewState;

type AccountPageRecentOperations
	= | {
		items: BrokerageOperation[];
		lastSuccessfulAt?: null | string;
		refreshError?: boolean;
		stale?: boolean;
		state: "loaded" | "partial";
		to: string;
	}
	| {
		state: "empty"
			| "error"
			| "loading";
		to: string;
	};

type AccountPageReturnTone = "negative" | "positive";

type AccountPageViewModel
	= | AccountPageEmptyViewModel
		| AccountPageLoadedViewModel
		| { code?: string; retry: () => Promise<unknown> | undefined; state: "error" }
		| { state: "loading" };

type PositionSectionKind = "bonds"
	| "other"
	| "stocks";

function groupPositions(
	positions: AccountPagePosition[],
): AccountPagePositionGroup[] {
	const groups = new Map<string, AccountPagePositionGroup>();

	for (const [index, position] of positions.entries()) {
		const identity = positionIdentity(position);
		const rowKey = JSON.stringify(["row", position.account?.id, index]);

		const key
			= identity && position.account
				? JSON.stringify([position.type, ...identity])
				: rowKey;

		const group = groups.get(key);

		if (
			group
			&& group.positions.every(
				item => item.account?.id !== position.account?.id,
			)
		) {
			group.positions.push(position);
		}
		else {
			const uniqueKey = group ? rowKey : key;
			groups.set(uniqueKey, { key: uniqueKey, positions: [position] });
		}
	}

	// eslint-disable-next-line unicorn/prefer-iterator-to-array -- Production targets ES2023; Iterator helpers require a newer browser baseline.
	return [...groups.values()];
}

function positionIdentity(position: AccountPagePosition) {
	if (position.instrumentUid?.trim())
		return ["uid", position.instrumentUid.trim()];
	if (position.figi?.trim()) return ["figi", position.figi.trim()];

	return position.isin?.trim() ? ["isin", position.isin.trim()] : undefined;
}

function toAccountPagePositionSections(
	portfolio: Portfolio,
	instrumentDetails: Map<string, undefined
	| { slug: string }> = new Map(),
): AccountPagePositionSection[] {
	const denominators = new Map<string, number>();

	for (const position of portfolio.positions) {
		if (!position.currentValue) continue;
		const currency = position.currentValue.currency;
		denominators.set(
			currency,
			(denominators.get(currency) ?? 0) + Number(position.currentValue.value),
		);
	}

	const stocks = toSection(
		"stocks",
		portfolio,
		denominators,
		instrumentDetails,
	);

	const bonds = toSection("bonds", portfolio, denominators, instrumentDetails);
	const other = toSection("other", portfolio, denominators, instrumentDetails);

	return [stocks, bonds, other].filter(section => section.groups.length > 0);
}

function toIncomeSummary(
	accountId: string | undefined,
	income: ReturnType<typeof useIncomeSummary>,
): AccountPageIncomeSummary {
	const to = `/accounts/${accountId}/income`;
	if (!income.data && !income.isError && income.meta?.sync.state !== "failed")
		return { state: "loading", to };
	if (income.meta?.availability === "partial") return { state: "partial", to };
	if (!income.data && (income.isError || income.meta?.sync.state === "failed"))
		return { retry: () => income.refetch(), state: "error", to };
	if (!income.data?.totalsByCurrency.length) return { state: "empty", to };

	return {
		lastSuccessfulAt: income.meta?.lastSuccessfulAt,
		refreshError: income.isError || income.meta?.sync.state === "failed",
		stale: income.meta?.freshness === "stale",
		state: "loaded",
		summary: income.data,
		to,
	};
}

function toPosition(
	position: Portfolio["positions"][number],
	denominators: Map<string, number>,
	kind: PositionSectionKind,
	instrumentSlug?: string,
): AccountPagePosition {
	const isExpanded = kind !== "other";

	const returnValue = position.absoluteReturn
		? Number(position.absoluteReturn.value)
		: null; // eslint-disable-line unicorn/no-null -- Preserve the nullable domain value consumed by this view model.

	let returnTone: AccountPageReturnTone | undefined;
	if (returnValue !== null && returnValue !== 0)
		returnTone = returnValue > 0 ? "positive" : "negative";

	const returnPrefix
		= isExpanded && returnValue !== null && returnValue > 0 ? "+" : "";

	return {
		...position,
		instrumentTo:
			(kind === "stocks" || kind === "bonds") && position.instrumentUid
				? `/${kind}/${encodeURIComponent(instrumentSlug ?? position.instrumentUid)}`
				: undefined,
		logoSrc: isExpanded
			? instrumentLogoUrl(position.logoName)
			: null, // eslint-disable-line unicorn/no-null -- Preserve the nullable domain value consumed by this view model.
		returnText: position.absoluteReturn
			? `${returnPrefix}${formatMoney(position.absoluteReturn)}`
			: null, // eslint-disable-line unicorn/no-null -- Preserve the nullable domain value consumed by this view model.
		returnTone,
		shareText: position.currentValue?.currency
			? formatShare(position.currentValue, {
					currency: position.currentValue.currency,
					value: String(denominators.get(position.currentValue.currency) ?? 0),
				})
			: null, // eslint-disable-line unicorn/no-null -- Preserve the nullable domain value consumed by this view model.
	};
}

function toRecentEvents(
	accountId: string | undefined,
	events: ReturnType<typeof useBrokerageEvents>,
): AccountPageRecentEvents {
	const to = `/accounts/${accountId}/events`;
	if (!events.data && !events.isError && events.meta?.sync.state !== "failed")
		return { state: "loading", to };
	if (events.meta?.availability === "partial")
		return {
			items: events.data?.events.slice(0, RECENT_EVENTS_LIMIT) ?? [],
			state: "partial",
			to,
		};
	if (!events.data && (events.isError || events.meta?.sync.state === "failed"))
		return { state: "error", to };
	const items = events.data?.events.slice(0, RECENT_EVENTS_LIMIT) ?? [];
	if (items.length === 0) return { state: "empty", to };

	return {
		items,
		lastSuccessfulAt: events.meta?.lastSuccessfulAt,
		refreshError: events.isError || events.meta?.sync.state === "failed",
		stale: events.meta?.freshness === "stale",
		state: "loaded",
		to,
	};
}

function toRecentOperations(
	accountId: string | undefined,
	operations: ReturnType<typeof useBrokerageOperations>,
): AccountPageRecentOperations {
	const to = `/accounts/${accountId}/operations`;
	if (
		!operations.data
		&& !operations.isError
		&& operations.meta?.sync.state !== "failed"
	)
		return { state: "loading", to };
	if (operations.meta?.availability === "partial")
		return { items: operations.data?.items ?? [], state: "partial", to };
	if (
		!operations.data
		&& (operations.isError || operations.meta?.sync.state === "failed")
	)
		return { state: "error", to };
	if (!operations.data?.items.length) return { state: "empty", to };

	return {
		items: operations.data.items,
		lastSuccessfulAt: operations.meta?.lastSuccessfulAt,
		refreshError:
			operations.isError || operations.meta?.sync.state === "failed",
		stale: operations.meta?.freshness === "stale",
		state: "loaded",
		to,
	};
}

function toSection(
	kind: PositionSectionKind,
	portfolio: Portfolio,
	denominators: Map<string, number>,
	instrumentDetails: Map<string, undefined
	| { slug: string }>,
): AccountPagePositionSection {
	return {
		groups: groupPositions(
			portfolio.positions
				.filter((position) => {
					if (kind === "stocks") return position.type === "STOCK";

					return kind === "bonds"
						? position.type === "BOND"
						: position.type !== "STOCK"
							&& position.type !== "BOND"
							&& position.type !== "CURRENCY";
				})
				.map(position =>
					toPosition(
						position,
						denominators,
						kind,
						instrumentDetails.get(position.instrumentUid ?? "")?.slug,
					),
				),
		),
		kind,
	};
}

function useAccountPageViewModel(scopeId?: string): AccountPageViewModel {
	const { accountId: routeAccountId } = useParams();
	const accountId = scopeId ?? routeAccountId;
	const portfolio = usePortfolio(accountId);

	const stocks = useStocks(
		portfolio.data?.positions.flatMap(position =>
			position.type === "STOCK" && position.instrumentUid
				? [position.instrumentUid]
				: [],
		) ?? [],
	);

	const instrumentDetails = stocks;

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

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

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

	if (!portfolio.data) {
		if (portfolio.isError || portfolio.meta?.sync.state === "failed")
			return {
				code: apiErrorCode(portfolio.error),
				retry: sync.retry,
				state: "error" as const,
			};

		return { 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);

	const refresh = {
		partial: portfolio.meta?.availability === "partial",
		refreshError: portfolio.isError || sync.transportError || sync.sourceError,
		refreshing: portfolio.isFetching || sync.refreshing,
		retry: sync.retry,
		sourceError: sync.sourceError,
	};

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

	return {
		account,
		accountId,
		incomeSummary,
		portfolio: portfolio.data,
		positionSections: toAccountPagePositionSections(
			portfolio.data,
			instrumentDetails,
		),
		recentEvents,
		recentOperations,
		state: "loaded" as const,
		...refresh,
	};
}

export {
	type AccountPageIncomeSummary,
	type AccountPagePosition,
	type AccountPagePositionGroup,
	type AccountPagePositionSection,
	type AccountPageRecentEvents,
	type AccountPageRecentOperations,
	toAccountPagePositionSections,
	useAccountPageViewModel,
};