/**
 * Pure helpers for the Vest client (lib/vest-class.ts) — parsing the gateway's
 * answers, naming accounts, Vest's trading day, market hours, volatility.
 *
 * Only Node built-ins are imported, so scripts/check-vest.mjs loads this file
 * directly (node --experimental-strip-types).
 */

import { createHash } from 'crypto';

/** A Vest login's primary wallet: 0x + 40 hex. The instance's saved Vest
 *  "credential" is this address — it says whose relayed session to trade. */
export function isVestWalletAddress(value: unknown): value is string {
    return typeof value === 'string' && /^0x[0-9a-fA-F]{40}$/.test(value.trim());
}

/** Stable numeric id for a Vest account uuid, in the same range as DXtrade's
 *  (dxAccountId) but keyed apart, so every numeric account table keeps
 *  working. */
export function vestAccountId(uuid: string): number {
    const digest = createHash('sha256').update(`vest|${uuid.toLowerCase()}`).digest();
    return 2 ** 50 + digest.readUIntBE(0, 6) * 16 + (digest[6] >> 4);
}

/** A decimal string or number from the gateway → a number (undefined when
 *  missing or not a number). */
export function num(raw: unknown): number | undefined {
    if (typeof raw === 'number') return Number.isFinite(raw) ? raw : undefined;
    if (typeof raw !== 'string' || raw.trim() === '') return undefined;
    const n = Number(raw);
    return Number.isFinite(n) ? n : undefined;
}

/** Epoch ms from the gateway's epoch ms, epoch seconds or ISO strings; NaN
 *  when unreadable. */
export function toMs(raw: unknown): number {
    if (typeof raw === 'number' && Number.isFinite(raw)) return raw < 1e11 ? raw * 1000 : raw;
    if (typeof raw === 'string' && raw.trim() !== '') {
        const n = Number(raw);
        if (Number.isFinite(n)) return n < 1e11 ? n * 1000 : n;
        const t = Date.parse(raw);
        return Number.isFinite(t) ? t : NaN;
    }
    return NaN;
}

/** `value` on a decimal grid, as the gateway wants it: a plain string with at
 *  most `decimals` places, trailing zeros trimmed (never exponent notation). */
export function formatDecimal(value: number, decimals: number): string {
    const d = Math.max(0, Math.min(18, Math.floor(decimals)));
    const fixed = value.toFixed(d);
    return d > 0 ? fixed.replace(/\.?0+$/, '') || '0' : fixed;
}

// ── Vest's trading day ──────────────────────────────────────────────────────

const ET_PARTS = new Intl.DateTimeFormat('en-US', {
    timeZone: 'America/New_York', hourCycle: 'h23',
    year: 'numeric', month: '2-digit', day: '2-digit', hour: '2-digit',
});

/** Vest's daily reset hour, America/New_York (its docs: 20:00 ET). */
export const VEST_RESET_HOUR_ET = 20;

/**
 * The trading day a moment belongs to, YYYY-MM-DD. Vest's day runs 20:00 ET
 * to 20:00 ET and is named for the date it ends on, like the CME session
 * that opens the evening before — so 21:00 ET on the 26th is the 27th's day.
 */
export function vestDayOf(ms: number): string {
    const parts = Object.fromEntries(ET_PARTS.formatToParts(new Date(ms)).map((p) => [p.type, p.value]));
    const date = `${parts.year}-${parts.month}-${parts.day}`;
    if (Number(parts.hour) < VEST_RESET_HOUR_ET) return date;
    const next = new Date(`${date}T12:00:00Z`);
    next.setUTCDate(next.getUTCDate() + 1);
    return next.toISOString().slice(0, 10);
}

/** The last 20:00 ET at or before `now`, epoch ms. 20:00 ET is 00:00 UTC
 *  in summer and 01:00 UTC in winter; whichever of those hours, on this or
 *  an earlier UTC day, reads as 20:00 in New York is the boundary. */
export function lastVestResetMs(now: number): number {
    const day = Date.UTC(new Date(now).getUTCFullYear(), new Date(now).getUTCMonth(), new Date(now).getUTCDate());
    for (let back = 0; back <= 2; back++) {
        for (const hour of [1, 0]) {
            const t = day - back * 86_400_000 + hour * 3_600_000;
            if (t > now) continue;
            const parts = Object.fromEntries(ET_PARTS.formatToParts(new Date(t)).map((p) => [p.type, p.value]));
            if (Number(parts.hour) === VEST_RESET_HOUR_ET) return t;
        }
    }
    return NaN;
}

/** The next 20:00 ET after `now`, epoch ms (a day can be 23 or 25 hours). */
export function nextVestResetMs(now: number): number {
    for (let h = 1; h <= 26; h++) {
        const t = lastVestResetMs(now + h * 3_600_000);
        if (t > now) return t;
    }
    return NaN;
}

/**
 * What to do with an open position before the daily reset so the reset can't
 * breach it. At 20:00 ET Vest captures the realized balance (collateral in,
 * unrealized P&L out) and sets the day's floor to balance × (1 − rate); the
 * max-drawdown floor stays. A position whose loss allowance is wider than
 * that next-day room would breach the moment the reset lands, so its stop
 * comes in to where equity stays above the coming floor plus `reserve`, with
 * the exit fee paid:
 *   'none'  — its stop is already at least that tight;
 *   'stop'  — move (or place) the stop at `price`, on the tick grid, rounded
 *             toward the position's safe side;
 *   'close' — the mark is already past that price (with no room left by
 *             the account's other positions, it sits on the profit side),
 *             or no room and no mark to tell.
 */
export function resetSafeStop(o: {
    side: 'long' | 'short';
    quantity: number;
    openPrice: number;
    mark: number;
    /** Realized balance, collateral included — what the reset captures —
     *  less what the account's other positions may lose at their stops. */
    balance: number;
    /** The realized balance the floor is set from; default `balance`. */
    floorBalance?: number;
    dailyLossPct: number;
    maxDrawdownFloor: number | undefined;
    reserve: number;
    /** Taker fee as a fraction of notional. */
    exitFeeRate: number;
    currentStop: number | null;
    tick: number;
}): { action: 'none' } | { action: 'stop'; price: number } | { action: 'close' } {
    const floor = Math.max((o.floorBalance ?? o.balance) * (1 - o.dailyLossPct), o.maxDrawdownFloor ?? -Infinity);
    const exitFee = o.exitFeeRate * o.quantity * (Number.isFinite(o.mark) && o.mark > 0 ? o.mark : o.openPrice);
    const allowed = o.balance - floor - o.reserve - exitFee;
    if (!(o.quantity > 0)) return { action: 'close' };
    // No room to lose (the account's other positions took it): the stop must
    // lock in at least the shortfall — on the profit side of the entry,
    // which a position already that far up can still carry.
    if (!(allowed > 0) && !Number.isFinite(o.mark)) return { action: 'close' };
    const long = o.side === 'long';
    const raw = long ? o.openPrice - allowed / o.quantity : o.openPrice + allowed / o.quantity;
    const price = o.tick > 0
        ? (long ? Math.ceil(raw / o.tick - 1e-9) * o.tick : Math.floor(raw / o.tick + 1e-9) * o.tick)
        : raw;
    const rounded = Number(price.toFixed(10));
    if (o.currentStop !== null && (long ? o.currentStop >= rounded : o.currentStop <= rounded)) return { action: 'none' };
    if (Number.isFinite(o.mark) && (long ? o.mark <= rounded : o.mark >= rounded)) return { action: 'close' };
    return { action: 'stop', price: rounded };
}

// ── accounts ────────────────────────────────────────────────────────────────

export interface VestCapitalAccount {
    id: string;
    planId: string;
    planName: string;
    /** 'eval' | 'instant_funded' | … as the gateway names the product. */
    productType: string;
    /** 1-based stage; stages[stage-1] is the current one. */
    stage: number;
    stepsTotal: number;
    /** The current stage: 'eval' or 'funded'. */
    kind: string;
    status: number;
    attemptIndex: number;
    initialCapital: number;
    /** The current stage's profit target in dollars (0 = none). */
    profitTarget: number;
    targetEquity: number | undefined;
    maxDrawdownLimit: number | undefined;
    maxDailyLossPct: number;
    dailyResetBalance: number | undefined;
    dailyLossFloor: number | undefined;
    dailyResetAt: number;
    activatedAt: number;
    createdAt: number;
}

/** One entry of GET /v3/capital/accounts/active; null when it isn't one. */
export function parseCapitalAccount(raw: unknown): VestCapitalAccount | null {
    const a = raw as Record<string, unknown>;
    if (!a || typeof a.id !== 'string') return null;
    const stages = Array.isArray(a.stages) ? (a.stages as Record<string, unknown>[]) : [];
    const stage = num(a.stage) ?? 1;
    const current = stages.find((s) => num(s.ordinal) === stage) ?? stages[stage - 1] ?? {};
    return {
        id: a.id,
        planId: typeof a.plan_id === 'string' ? a.plan_id : '',
        planName: typeof a.plan_name === 'string' ? a.plan_name : '',
        productType: typeof a.plan_product_type === 'string' ? a.plan_product_type : '',
        stage,
        stepsTotal: num(a.steps_total) ?? 0,
        kind: typeof current.kind === 'string' ? current.kind : '',
        status: num(a.status) ?? -1,
        attemptIndex: num(a.attempt_index) ?? 0,
        initialCapital: num(a.initial_capital) ?? 0,
        profitTarget: num(current.profit_target) ?? 0,
        targetEquity: num(a.target_equity),
        maxDrawdownLimit: num(a.max_drawdown_limit),
        maxDailyLossPct: num(a.max_daily_loss_pct) ?? 0,
        dailyResetBalance: num(a.daily_reset_balance),
        dailyLossFloor: num(a.daily_loss_floor),
        dailyResetAt: toMs(a.daily_reset_at),
        activatedAt: toMs(a.activated_at),
        createdAt: toMs(a.created_at),
    };
}

/** The capital account status every listed live account showed (2026-10-26).
 *  Anything else is treated as unable to trade until seen and named. */
export const VEST_STATUS_ACTIVE = 2;

const pct = (fraction: number) => Math.round(fraction * 1000) / 10;

/**
 * What the dashboard calls the account and what account-type prefixes match
 * against. Vest itself only says "Account 34", so the name carries the rules
 * that tell its types apart:
 *   V50K-E-D3-T10-34   evaluation, $50k, 3% daily loss, 10% target, attempt 34
 *   V50K-F-D3-34       the funded stage of an evaluation account
 *   V25K-I-7           instant funded (no daily loss limit, no target)
 * D0 = no daily loss limit. The target is the current stage's (a 2-Step's
 * second stage reads T5).
 */
export function vestAccountName(a: VestCapitalAccount): string {
    const size = a.initialCapital >= 1000 ? `${+(a.initialCapital / 1000).toFixed(1)}K` : `${Math.round(a.initialCapital)}`;
    const dll = `D${pct(a.maxDailyLossPct)}`;
    if (/instant/i.test(a.productType)) return `V${size}-I-${a.attemptIndex}`;
    if (a.kind === 'funded') return `V${size}-F-${dll}-${a.attemptIndex}`;
    const target = a.initialCapital > 0 && a.profitTarget > 0 ? `-T${pct(a.profitTarget / a.initialCapital)}` : '';
    return `V${size}-E-${dll}${target}-${a.attemptIndex}`;
}

// ── positions and orders ────────────────────────────────────────────────────

export interface VestLeg {
    id: string;
    triggerPrice: number;
    executionType: string;
    status: string;
}

export interface VestPosition {
    positionId: string;
    accountId: string;
    symbol: string;
    side: 'long' | 'short';
    quantity: number;
    openPrice: number;
    /** Margin the position holds out of the free balance. */
    collateral: number;
    leverage: number;
    openedAt: number;
    stopLosses: VestLeg[];
    takeProfits: VestLeg[];
}

function parseLegs(raw: unknown): VestLeg[] {
    if (!Array.isArray(raw)) return [];
    return raw.flatMap((l) => {
        const leg = l as Record<string, unknown>;
        const trigger = num(leg?.triggerPrice);
        if (typeof leg?.id !== 'string' || trigger === undefined) return [];
        return [{ id: leg.id, triggerPrice: trigger, executionType: String(leg.executionType ?? ''), status: String(leg.status ?? '') }];
    });
}

/** One entry of GET /v3/positions/opened; null when it isn't an open one. */
export function parsePosition(raw: unknown): VestPosition | null {
    const p = raw as Record<string, unknown>;
    const accountId = p?.accountId ?? p?.account_id;
    if (!p || typeof p.positionId !== 'string' || typeof accountId !== 'string' || typeof p.symbol !== 'string') return null;
    const quantity = Math.abs(num(p.quantity) ?? 0);
    if (!(quantity > 0)) return null;
    return {
        positionId: p.positionId,
        accountId,
        symbol: p.symbol,
        side: String(p.side).toLowerCase() === 'short' ? 'short' : 'long',
        quantity,
        openPrice: num(p.openPrice) ?? NaN,
        collateral: num(p.collateral) ?? 0,
        leverage: num(p.leverage) ?? 0,
        openedAt: toMs(p.openDate ?? p.createdAt),
        stopLosses: parseLegs(p.stopLosses),
        takeProfits: parseLegs(p.takeProfits),
    };
}

/**
 * One position from GET /v3/positions — Vest's position history, the app's
 * History tab: closed positions with how they ended (an open one has no
 * close yet). pnl is Vest's realized P&L before fees and funding.
 */
export interface VestTrade {
    positionId: string;
    symbol: string;
    side: 'long' | 'short';
    /** 0 when Vest doesn't say (a store keeps the size it already knows). */
    quantity: number;
    leverage: number | null;
    openPrice: number | null;
    closePrice: number | null;
    pnl: number | null;
    fee: number | null;
    funding: number | null;
    openedAt: number;
    closedAt: number | null;
    /** user_requested, stop_loss, take_profit, liquidation, auto_deleverage,
     *  temporary_leverage_limit, corporate_action. */
    closeReason: string | null;
}

export function parseHistoryPosition(raw: unknown): VestTrade | null {
    const p = raw as Record<string, unknown>;
    const id = p?.positionId ?? p?.position_id;
    if (!p || typeof id !== 'string' || typeof p.symbol !== 'string') return null;
    const openedAt = toMs(p.openDate ?? p.open_date ?? p.createdAt ?? p.created_at);
    if (!Number.isFinite(openedAt)) return null;
    const closedMs = toMs(p.closeDate ?? p.close_date);
    const closedAt = Number.isFinite(closedMs) && closedMs > 0 ? closedMs : null;
    const openPrice = num(p.openPrice ?? p.open_price);
    // An open position comes with a placeholder close price and a $0 P&L
    // (seen: 290.25 on an NDX short at 29,538.96): only a close has them.
    const closePrice = closedAt === null ? undefined : num(p.closePrice ?? p.close_price);
    const reason = p.closeReason ?? p.close_reason;
    return {
        positionId: id,
        symbol: p.symbol,
        side: String(p.side).toLowerCase() === 'short' ? 'short' : 'long',
        quantity: Math.abs(num(p.quantity) ?? 0),
        leverage: num(p.leverage) ?? null,
        openPrice: openPrice !== undefined && openPrice > 0 ? openPrice : null,
        closePrice: closePrice !== undefined && closePrice > 0 ? closePrice : null,
        pnl: closedAt === null ? null : num(p.pnl) ?? null,
        fee: num(p.fee) ?? null,
        funding: num(p.funding) ?? null,
        openedAt,
        closedAt,
        closeReason: typeof reason === 'string' && reason !== '' ? reason : null,
    };
}

/** Every string value in a JWT's payload, lower-case ([] when it isn't
 *  one). Used only to compare against account ids — never logged. */
export function jwtClaimStrings(token: string): string[] {
    const part = token.split('.')[1];
    if (!part) return [];
    let payload: unknown;
    try {
        payload = JSON.parse(Buffer.from(part.replace(/-/g, '+').replace(/_/g, '/'), 'base64').toString('utf8'));
    } catch {
        return [];
    }
    const out: string[] = [];
    const walk = (v: unknown, depth: number): void => {
        if (typeof v === 'string') out.push(v.toLowerCase());
        else if (v && typeof v === 'object' && depth < 4) for (const x of Object.values(v)) walk(x, depth + 1);
    };
    walk(payload, 0);
    return out;
}

/**
 * Whether a token the extension relayed is one Vest account's own token, not
 * the login's. The Vest app renews both through POST /v3/auth/refresh — the
 * login's every ~15 minutes, an account's while someone trades in it — and
 * an account's token sees only that account: /v3/capital/accounts/active
 * lists it alone, and /v3/accounts has no primary (wallet) account. The
 * login sees every account and its primary one.
 */
export function accountScopedToken(o: { capitalIds: string[]; hasPrimary: boolean; claims: string[] }): boolean {
    if (o.capitalIds.length > 1) return false;
    if (!o.hasPrimary) return true;
    return o.capitalIds.some((id) => o.claims.includes(id.toLowerCase()));
}

/** Exit legs still waiting to trigger. */
export function awaitingLegs(p: VestPosition): VestLeg[] {
    return [...p.stopLosses, ...p.takeProfits].filter((l) => l.status === 'awaiting');
}

export interface VestOpenOrder {
    orderId: string;
    accountId: string;
    positionId: string | undefined;
    symbol: string;
    createdAt: number;
}

/** One entry of GET /v3/positions/opened-orders (snake or camel case). */
export function parseOpenOrder(raw: unknown): VestOpenOrder | null {
    const o = raw as Record<string, unknown>;
    const orderId = o?.order_id ?? o?.orderId ?? o?.id;
    const accountId = o?.account_id ?? o?.accountId;
    if (typeof orderId !== 'string' || typeof accountId !== 'string') return null;
    const positionId = o.position_id ?? o.positionId;
    return {
        orderId,
        accountId,
        positionId: typeof positionId === 'string' ? positionId : undefined,
        symbol: String(o.symbol ?? ''),
        createdAt: toMs(o.created_at ?? o.createdAt),
    };
}

/** Unrealized P&L of a position at `mark`. */
export function unrealizedPnl(p: Pick<VestPosition, 'side' | 'quantity' | 'openPrice'>, mark: number): number {
    if (!Number.isFinite(mark) || !Number.isFinite(p.openPrice)) return 0;
    return (p.side === 'long' ? 1 : -1) * p.quantity * (mark - p.openPrice);
}

// ── transactions ────────────────────────────────────────────────────────────

/**
 * The gateway's transaction types (its app's own enum, 2026-10-26). Trading
 * P&L is fees, realized P&L, funding and the adjustments that come with them;
 * funds are money moved in or out; the rest only moves margin between the
 * free balance and positions, and leaves the account's total alone.
 */
export const VEST_TXN = {
    DEPOSIT: 1, WITHDRAW: 2, OPEN_POSITION: 3, CLOSE_POSITION: 4, CORRECTION: 5, FILL_MARGIN: 6, MARGIN_RELEASE: 7,
    FEE: 8, REALIZED_PNL: 9, FUNDING: 10, LEVERAGE_RESERVE: 11, LEVERAGE_RELEASE: 12, ADD_COLLATERAL: 13,
    REMOVE_COLLATERAL: 14, ORDER_MARGIN_RESERVE: 15, ORDER_MARGIN_RELEASE: 16, LIQUIDATION_DEFICIT_COVERAGE: 17,
    CORPORATE_ACTION_CASH_ADJUSTMENT: 18, FUNDED_PROFIT_CREDIT: 19, AFFILIATE_PAYOUT_CREDIT: 20, COMPENSATION: 22,
    BALANCE_MIGRATION: 23,
} as const;

const TRADING_TXNS = new Set<number>([
    VEST_TXN.CORRECTION, VEST_TXN.FEE, VEST_TXN.REALIZED_PNL, VEST_TXN.FUNDING,
    VEST_TXN.LIQUIDATION_DEFICIT_COVERAGE, VEST_TXN.CORPORATE_ACTION_CASH_ADJUSTMENT,
]);
const FUND_TXNS = new Set<number>([
    VEST_TXN.DEPOSIT, VEST_TXN.WITHDRAW, VEST_TXN.FUNDED_PROFIT_CREDIT, VEST_TXN.AFFILIATE_PAYOUT_CREDIT,
    VEST_TXN.COMPENSATION, VEST_TXN.BALANCE_MIGRATION,
]);

export type VestTxnKind = 'trade' | 'fund' | 'margin';

export function txnKind(type: number): VestTxnKind {
    if (TRADING_TXNS.has(type)) return 'trade';
    if (FUND_TXNS.has(type)) return 'fund';
    return 'margin';
}

export interface VestTxn {
    /** action_id, else type|time|amount — what a page overlap dedupes on. */
    key: string;
    type: number;
    kind: VestTxnKind;
    /** Signed: what it did to the account's balance. */
    amount: number;
    time: number;
}

/** One entry of GET /v3/transactions; null when unreadable. A withdrawal is
 *  always negative and a deposit positive, whatever sign the gateway used. */
export function parseTxn(raw: unknown): VestTxn | null {
    const t = raw as Record<string, unknown>;
    const type = num(t?.transaction_type ?? t?.transactionType);
    const amount = num(t?.amount);
    const time = toMs(t?.created_at ?? t?.createdAt);
    if (type === undefined || amount === undefined || !Number.isFinite(time)) return null;
    const signed = type === VEST_TXN.WITHDRAW ? -Math.abs(amount) : type === VEST_TXN.DEPOSIT ? Math.abs(amount) : amount;
    const action = t.action_id ?? t.actionId;
    return {
        key: typeof action === 'string' || typeof action === 'number' ? `${action}|${type}` : `${type}|${time}|${amount}`,
        type,
        kind: txnKind(type),
        amount: signed,
        time,
    };
}

/** Daily trading P&L and fund rows by Vest day, from the account's
 *  transactions. */
export function bookTxns(txns: VestTxn[]): { daily: Map<string, { pnl: number; fees: number }>; funds: Map<string, number> } {
    const daily = new Map<string, { pnl: number; fees: number }>();
    const funds = new Map<string, number>();
    for (const t of txns) {
        const day = vestDayOf(t.time);
        if (t.kind === 'fund') {
            funds.set(day, (funds.get(day) ?? 0) + t.amount);
        } else if (t.kind === 'trade') {
            const e = daily.get(day) ?? { pnl: 0, fees: 0 };
            e.pnl += t.amount;
            if (t.type === VEST_TXN.FEE) e.fees += Math.abs(t.amount);
            daily.set(day, e);
        }
    }
    return { daily, funds };
}

// ── market data ─────────────────────────────────────────────────────────────

/** Fewest hourly returns a volatility is measured from. */
export const MIN_HOURLY_RETURNS = 24;

/**
 * σ of log returns per √hour from hourly klines ([openTime, o, h, l, close, …],
 * any order). Only returns between consecutive hours count: an index perp
 * closes for weekends and the daily maintenance hour, and a return across
 * such a gap is a gap, not an hour's move. null when too few are left.
 */
export function hourlyVolatility(klines: unknown[]): number | null {
    const rows = klines.flatMap((k) => {
        if (!Array.isArray(k)) return [];
        const t = num(k[0]);
        const close = num(k[4]);
        return t !== undefined && close !== undefined && close > 0 ? [{ t: toMs(t), close }] : [];
    }).sort((a, b) => a.t - b.t);
    const returns: number[] = [];
    for (let i = 1; i < rows.length; i++) {
        if (Math.abs(rows[i].t - rows[i - 1].t - 3_600_000) > 60_000) continue;
        returns.push(Math.log(rows[i].close / rows[i - 1].close));
    }
    if (returns.length < MIN_HOURLY_RETURNS) return null;
    const mean = returns.reduce((s, r) => s + r, 0) / returns.length;
    const variance = returns.reduce((s, r) => s + (r - mean) ** 2, 0) / (returns.length - 1);
    return Math.sqrt(variance);
}

/**
 * Whether the market-hours periods (GET /v4/market-hours/{assetId}) have the
 * symbol open for trading at `now`, and for how long yet. A symbol with no
 * periods at all (crypto: always open) reads as open with no end. A closure
 * (weekly, the daily maintenance hour) counts as closed even where the
 * gateway still says OPEN: no leg should start into one.
 */
export function marketOpen(periods: unknown, now: number): { open: boolean; closesAt: number | null } {
    if (!Array.isArray(periods) || periods.length === 0) return { open: true, closesAt: null };
    const list = periods.flatMap((p) => {
        const r = p as {
            fromMs?: unknown; toMs?: unknown;
            state?: { tradingStatus?: unknown; closure?: unknown; price?: { allow?: unknown } };
        };
        const from = num(r?.fromMs);
        const to = num(r?.toMs);
        if (from === undefined || to === undefined) return [];
        const closure = r.state?.closure;
        const open = r.state?.tradingStatus === 'OPEN' && r.state?.price?.allow !== false
            && (closure === undefined || closure === 'unspecified');
        return [{ from, to, open }];
    }).sort((a, b) => a.from - b.from);
    const i = list.findIndex((p) => p.from <= now && now < p.to);
    if (i < 0 || !list[i].open) return { open: false, closesAt: null };
    // Consecutive open periods (overnight → pre-market → regular …) are one stretch.
    let end = list[i].to;
    for (let j = i + 1; j < list.length && list[j].open && list[j].from <= end + 1; j++) end = list[j].to;
    return { open: true, closesAt: end };
}