feat: replace account page accordion with tabs and show open position result (#112)

src/pages/account/model/positions.ts

@@ -1,9 +1,11 @@
 import { formatShare, type Portfolio } from "@/entities/portfolio";
-import { formatMoney, instrumentLogoUrl } from "@/shared/lib";
+import { formatDecimal, formatMoney, instrumentLogoUrl } from "@/shared/lib";
 
 type AccountPagePosition = Portfolio["positions"][number] & {
 	instrumentTo?: string;
 	logoSrc: null | string;
+	returnPercent: null | string;
+	returnPercentText: null | string;
 	returnText: null | string;
 	returnTone?: AccountPageReturnTone;
 	shareText: null | string;
@@ -21,10 +23,73 @@ type AccountPagePositionSection = {
 
 type AccountPageReturnTone = "negative" | "positive";
 
+type Decimal = { scale: number; value: bigint };
+
+type Money = NonNullable<Portfolio["positions"][number]["absoluteReturn"]>;
+
 type PositionSectionKind = "bonds"
 	| "other"
 	| "stocks";
 
+const RADIX = 10n;
+const DECIMAL_PARTS = 2;
+const PERCENT_SCALE = 6;
+const DISPLAY_PERCENT_SCALE = 2;
+const PERCENT_FACTOR = 100n;
+const ROUNDING_FACTOR = 2n;
+
+function decimalFromString(value: string): Decimal {
+	const [whole = "0", fraction = ""] = value.split(".", DECIMAL_PARTS);
+
+	return { scale: fraction.length, value: BigInt(`${whole}${fraction}`) };
+}
+
+function decimalToString(decimal: Decimal): string {
+	const sign = decimal.value < 0n ? "-" : "";
+
+	const digits = (decimal.value < 0n ? -decimal.value : decimal.value)
+		.toString()
+		.padStart(decimal.scale + 1, "0");
+
+	const whole = decimal.scale
+		? digits.slice(0, -decimal.scale)
+		: digits;
+
+	let fraction = decimal.scale ? digits.slice(-decimal.scale) : "";
+
+	while (fraction.endsWith("0")) fraction = fraction.slice(0, -1);
+
+	const suffix = fraction ? `.${fraction}` : "";
+
+	return `${sign}${whole}${suffix}`;
+}
+
+function formatPositionReturnPercent(value: string): string {
+	const decimal = decimalFromString(value);
+	let rounded = decimal.value;
+
+	if (decimal.scale > DISPLAY_PERCENT_SCALE) {
+		const divisor = RADIX ** BigInt(decimal.scale - DISPLAY_PERCENT_SCALE);
+		const remainder = rounded % divisor;
+		const absoluteRemainder = remainder < 0n ? -remainder : remainder;
+		rounded /= divisor;
+
+		if (absoluteRemainder * ROUNDING_FACTOR >= divisor) {
+			rounded += decimal.value < 0n ? -1n : 1n;
+		}
+	}
+	else {
+		rounded *= RADIX ** BigInt(DISPLAY_PERCENT_SCALE - decimal.scale);
+	}
+
+	const sign = rounded > 0n ? "+" : "";
+
+	return `${sign}${decimalToString({
+		scale: DISPLAY_PERCENT_SCALE,
+		value: rounded,
+	})}`;
+}
+
 function groupPositions(
 	positions: AccountPagePosition[],
 ): AccountPagePositionGroup[] {
@@ -67,6 +132,53 @@ function positionIdentity(position: AccountPagePosition) {
 	return position.isin?.trim() ? ["isin", position.isin.trim()] : undefined;
 }
 
+function returnPercent(
+	position: Portfolio["positions"][number],
+): null | string {
+	const result = position.absoluteReturn;
+	const price = position.averagePurchasePrice;
+	if (!result || !price || result.currency !== price.currency) return null;
+
+	const quantity = decimalFromString(position.quantity);
+	const purchasePrice = decimalFromString(price.value);
+
+	const cost = {
+		scale: quantity.scale + purchasePrice.scale,
+		value: quantity.value * purchasePrice.value,
+	};
+
+	if (quantity.value <= 0n || cost.value <= 0n) return null;
+
+	const absoluteReturn = decimalFromString(result.value);
+
+	const numerator = absoluteReturn.value * PERCENT_FACTOR
+		* RADIX ** BigInt(cost.scale + PERCENT_SCALE);
+
+	const denominator = cost.value * RADIX ** BigInt(absoluteReturn.scale);
+	const remainder = numerator % denominator;
+
+	const isRoundsUp = (remainder < 0n ? -remainder : remainder) * ROUNDING_FACTOR
+		>= denominator;
+
+	const rounding = isRoundsUp ? 1n : 0n;
+	const signedRounding = numerator < 0n ? -rounding : rounding;
+	const rounded = numerator / denominator + signedRounding;
+
+	return decimalToString({ scale: PERCENT_SCALE, value: rounded });
+}
+
+function sumDecimals(values: Decimal[]): Decimal {
+	const scale = Math.max(...values.map(value => value.scale));
+
+	const sum = values.reduce(
+		(total, value) => total
+			+ value.value * RADIX ** BigInt(scale - value.scale),
+		0n,
+	);
+
+	return { scale, value: sum };
+}
+
 function toAccountPagePositionSections(
 	portfolio: Portfolio,
 ): AccountPagePositionSection[] {
@@ -111,6 +223,8 @@ function toPosition(
 	const returnPrefix
 		= isExpanded && returnValue !== null && returnValue > 0 ? "+" : "";
 
+	const percent = returnPercent(position);
+
 	return {
 		...position,
 		instrumentTo:
@@ -120,6 +234,10 @@ function toPosition(
 		logoSrc: isExpanded
 			? instrumentLogoUrl(position.logoName)
 			: null,
+		returnPercent: percent,
+		returnPercentText: percent
+			? `${formatDecimal(formatPositionReturnPercent(percent))} %`
+			: null,
 		returnText: position.absoluteReturn
 			? `${returnPrefix}${formatMoney(position.absoluteReturn)}`
 			: null,
@@ -162,9 +280,46 @@ function toSection(
 	};
 }
 
+function toUnrealizedReturns(
+	positions: Portfolio["positions"],
+): Money[] {
+	const totals = new Map<string, {
+		complete: boolean;
+		values: Decimal[];
+	}>();
+
+	for (const position of positions) {
+		const currencies = position.absoluteReturn
+			? [position.absoluteReturn.currency]
+			: [...new Set([
+					position.averagePurchasePrice?.currency,
+					position.currentValue?.currency,
+				].filter((currency): currency is string => !!currency))];
+
+		for (const currency of currencies) {
+			const total = totals.get(currency) ?? { complete: true, values: [] };
+
+			if (position.absoluteReturn) {
+				total.values.push(decimalFromString(position.absoluteReturn.value));
+			}
+			else {
+				total.complete = false;
+			}
+
+			totals.set(currency, total);
+		}
+	}
+
+	return [...totals].flatMap(([currency, total]) => total.complete
+		? [{ currency, value: decimalToString(sumDecimals(total.values)) }]
+		: []);
+}
+
 export {
 	type AccountPagePosition,
 	type AccountPagePositionGroup,
 	type AccountPagePositionSection,
+	formatPositionReturnPercent,
 	toAccountPagePositionSections,
+	toUnrealizedReturns,
 };