/**
 * Resolve the effective profit target and consistency for an account based on its withdrawal strategy.
 *
 * Mode A (targetSameEquity=true): the account must reach the same cumulative equity level.
 *   remainingProfit = priorProfit + totalWithdrawals (profit still in the account after payouts)
 *   effectiveProfitTarget = profitTarget − remainingProfit
 *
 * Mode B (withdrawalStages non-empty): Stage 1 (no withdrawals yet) uses base profitTarget/consistency.
 *   After the Nth withdrawal, use withdrawalStages[N-1]; last stage repeats.
 * Fallback: returns base profitTarget and consistency unchanged.
 */
export function resolveEffectiveConfig(
    profitTarget: number,
    consistency: number,
    minTradingDays: number,
    targetSameEquity: boolean,
    withdrawalStages: { profit: number; consistency: number; minTradingDays: number }[],
    priorProfit: number,
    fundTransactions: { date: string; amount: number }[]
): { profitTarget: number; consistency: number; minTradingDays: number } {
    if (targetSameEquity) {
        // Simple Mode A: effective target = profitTarget - equityProfit, computed in computeDailyTarget.
        // Since computeDailyTarget already compares (amount - accountSize) against profitTarget,
        // no adjustment needed here — just return the base values.
        return { profitTarget, consistency, minTradingDays };
    }
    if (withdrawalStages.length > 0) {
        const withdrawalCount = fundTransactions.filter((f) => f.amount < 0).length;
        if (withdrawalCount === 0) {
            return { profitTarget, consistency, minTradingDays }; // Stage 1 = base values
        }
        const idx = Math.min(withdrawalCount - 1, withdrawalStages.length - 1);
        const stage = withdrawalStages[idx];
        // Fall back to base minTradingDays when the stage doesn't specify one (0 or missing)
        return { profitTarget: stage.profit, consistency: stage.consistency, minTradingDays: stage.minTradingDays || minTradingDays };
    }
    return { profitTarget, consistency, minTradingDays };
}

/** @deprecated Use resolveEffectiveConfig instead */
export function resolveEffectiveProfitTarget(
    profitTarget: number,
    targetSameEquity: boolean,
    withdrawalStages: { profit: number; consistency: number; minTradingDays: number }[],
    priorProfit: number,
    fundTransactions: { date: string; amount: number }[]
): number {
    return resolveEffectiveConfig(profitTarget, 0, 0, targetSameEquity, withdrawalStages, priorProfit, fundTransactions).profitTarget;
}

/** Dollar-per-point value for common futures products. */
export const POINT_VALUES: { [symbol: string]: number } = {
    NQ: 20, MNQ: 2, ES: 50, MES: 5,
    YM: 5, MYM: 0.5, RTY: 50, M2K: 10,
    GC: 100, MGC: 10, SI: 50, CL: 1000,
    MCL: 100, NG: 10000, ZB: 1000, ZN: 1000,
    ZF: 1000, '6E': 125000, '6J': 12500000, '6B': 62500,
};

/**
 * Compute the next trading day's profit target for an account.
 *
 * Path 1 – No positive trading days yet:
 *   target = profitTarget × consistency
 *
 * Path 2 – At least one positive day exists:
 *   maxDay     = highest single-day P&L so far
 *   realTarget = maxDay / consistency  (the total profit at which maxDay ≤ consistency% of total)
 *   needed     = realTarget − totalProfit
 *
 *   if needed > maxDay  → target maxDay (still a long way from the real target; trade a normal day)
 *   else                → target needed (close to the real target; aim for exactly what's left)
 *
 * Min-day reservation (only when minDayPnL > 0):
 *   When there are still mandatory trading days remaining, today's target is capped so that
 *   enough profit is reserved for each future mandatory day to meet minDayPnL.
 *   Cap = (profitTarget - totalProfit) − (remainingDaysAfterToday × minDayPnL)
 *   Floor = minDayPnL (we must make at least this today)
 */
export function computeDailyTarget(
    profitTarget: number,
    consistency: number,
    dailyPnL: { date: string; pnl: number }[],
    minDayPnL: number,          // 0 = no minimum per day
    minTradingDays: number,     // 0 = no minimum trading days
    equityProfit: number | null | undefined // amount − accountSize. Null/undefined → skip (return null). 0 is valid.
): { amount: number; path: 'first_day' | 'normal_day' | 'reduced_day' } | null {
    // Don't run if we don't have a real account balance to compute against — 0 is valid.
    if (typeof equityProfit !== 'number' || !Number.isFinite(equityProfit)) {
        return null;
    }

    const qualifyingDays = minDayPnL === 0 ? dailyPnL : dailyPnL.filter((d) => d.pnl >= minDayPnL);
    const daysTraded = qualifyingDays.length;
    const effectiveMinDay = Math.max(0, minDayPnL);
    const tradingProfit = dailyPnL.reduce((s, d) => s + d.pnl, 0); // cycle-local trading profit

    // Shortfall to hit profitTarget (measured in equity terms — accounts for deposits/withdrawals)
    const equityShortfall = Math.max(0, profitTarget - equityProfit);

    // Shortfall to satisfy consistency rule: total trading profit must be ≥ maxDay / consistency,
    // otherwise the biggest day would exceed the consistency ratio.
    let consistencyShortfall = 0;
    if (consistency > 0 && consistency < 1 && qualifyingDays.length > 0) {
        const maxDay = Math.max(...qualifyingDays.map((d) => d.pnl));
        const realTarget = maxDay / consistency;
        consistencyShortfall = Math.max(0, realTarget - tradingProfit);
    }

    const remaining = Math.max(equityShortfall, consistencyShortfall);

    // 1. Both target and consistency already satisfied — coast on min-day if mandatory days remain.
    if (remaining <= 0) {
        const needsMoreDays = minTradingDays > daysTraded;
        return { amount: needsMoreDays ? effectiveMinDay : 0, path: 'reduced_day' };
    }

    // 2. Min-day reservation: future mandatory days each reserve minDayPnL.
    //    cappedByFuture = remaining profit available after reserving.
    const daysLeft = Math.max(1, minTradingDays - daysTraded); // includes today
    const futureReserve = (daysLeft - 1) * effectiveMinDay;
    const cappedByFuture = remaining - futureReserve;

    // 3. Consistency cap:
    //    - 0% or 100%: no constraint
    //    - Day 1 of cycle: max allowed = remaining × consistency
    //    - Day 2+ of cycle: max allowed = maxDay (keeps consistency ratio stable)
    let consistencyCap: number;
    let path: 'first_day' | 'normal_day' | 'reduced_day';

    if (consistency === 0 || consistency >= 1) {
        consistencyCap = Infinity;
        path = daysTraded === 0 ? 'first_day' : 'reduced_day';
    } else if (daysTraded === 0) {
        consistencyCap = remaining * consistency;
        path = 'first_day';
    } else {
        const maxDay = Math.max(...qualifyingDays.map((d) => d.pnl));
        consistencyCap = maxDay;
        path = 'normal_day';
    }

    // 4. Combine caps and apply min-day floor when mandatory days remain.
    const raw = Math.min(consistencyCap, cappedByFuture);
    const mustFloor = minTradingDays > daysTraded;
    const amount = mustFloor ? Math.max(effectiveMinDay, raw) : Math.max(0, raw);

    return { amount: Math.round(amount * 100) / 100, path };
}