import { byFillTime, fillsToTrades, startingNet, type Fill, type CarriedTrade } from './fill-trades';
import {
    loadOwnOrders, ownOrdersSince, loadFillTrades, saveFillTrades, deleteTrades, closeTradesUnseen,
    type FillTradeRow,
} from './db';

/**
 * Records the trades a futures platform's fills make (lib/fill-trades.ts) in
 * the trades table the dashboard lists, with who opened and closed each: the
 * bot when the fill's order is one it placed (own_orders), and how — its
 * stop, its take-profit, or a market close.
 *
 * Each pass hands over a window of fills (TopstepX: two days; Tradovate: the
 * session's) with the account's position now, and the window's trades are
 * rebuilt whole. A history and a position read a moment apart can disagree —
 * a fill landing between the two calls — and that pass would rebuild the
 * wrong trades, so a contract is written only when the position before its
 * window comes out the same two passes running.
 */

export interface ContractFills {
    /** As shown: "NQZ6". */
    symbol: string;
    /** Dollars per point per contract, for P&L the platform didn't give. */
    pointValue: number | null;
    fills: Fill[];
    /** Signed contracts held now. */
    currentNet: number;
}

/** The position before each window, last pass: prefix:account:symbol → net. */
const lastStart = new Map<string, number>();

export function recordFillTrades(prefix: string, account: { id: number; name: string }, contracts: ContractFills[]): void {
    let own: Map<string, string> | null = null;
    for (const c of contracts) {
        const fills = [...c.fills].sort(byFillTime);
        const startNet = startingNet(fills, c.currentNet);
        const key = `${prefix}:${account.id}:${c.symbol}`;
        const steady = lastStart.get(key) === startNet;
        lastStart.set(key, startNet);
        if (!steady) continue;

        const stored = loadFillTrades(account.id, prefix, c.symbol);
        const isOpen = (t: FillTradeRow) => t.closedAt === null && t.closeReason === null;
        const windowStart = fills.length > 0 ? fills[0].at : Infinity;

        if (fills.length === 0) {
            // Nothing in the window: an open trade stays open while the
            // position does, and is closed out of sight once it's gone.
            if (startNet === 0) closeTradesUnseen(stored.filter(isOpen).map((t) => t.positionId));
            continue;
        }

        const carryRow = stored
            .filter((t) => isOpen(t) && t.openedAt < windowStart)
            .sort((a, b) => b.openedAt - a.openedAt)[0];
        const carry: CarriedTrade | null = carryRow
            ? { id: carryRow.positionId, side: carryRow.side, quantity: carryRow.quantity, openPrice: carryRow.openPrice, fee: carryRow.fee, openedAt: carryRow.openedAt }
            : null;
        const trades = fillsToTrades(fills, { startNet, pointValue: c.pointValue, carry });

        own ??= loadOwnOrders(account.id);
        const since = ownOrdersSince();
        const rows: FillTradeRow[] = trades.map((t) => {
            const closeKind = t.closeOrderId === null ? undefined : own!.get(t.closeOrderId);
            const closed = t.closedAt !== null;
            return {
                positionId: t.carried ? t.id : `${prefix}:${t.id}`,
                accountId: account.id,
                accountName: account.name,
                symbol: c.symbol,
                side: t.side,
                quantity: t.quantity,
                openPrice: t.openPrice,
                closePrice: t.closePrice,
                pnl: t.pnl,
                fee: t.fee,
                openedAt: t.openedAt,
                closedAt: t.closedAt,
                closeReason: !closed ? null : closeKind === 'stop' ? 'stop_loss' : closeKind === 'limit' ? 'take_profit' : null,
                openedBy: t.carried ? null
                    : t.openOrderId !== null && own!.has(t.openOrderId) ? 'bot'
                        : t.openedAt >= since ? 'outside' : 'unknown',
                // A trade opened before own orders were noted had its exits
                // placed then too: whose close it was is unknown, not outside.
                closedBy: !closed || closeKind === 'stop' || closeKind === 'limit' ? null
                    : closeKind === 'market' ? 'bot'
                        : t.openedAt >= since ? 'outside' : 'unknown',
            };
        });
        saveFillTrades(rows);

        const ids = new Set(rows.map((r) => r.positionId));
        // Built last time off a window that has since moved under it.
        deleteTrades(stored.filter((t) => t.openedAt >= windowStart && !ids.has(t.positionId)).map((t) => t.positionId));
        // Open from before the window, and the window doesn't carry it on:
        // it closed somewhere the history no longer reaches.
        closeTradesUnseen(stored.filter((t) => isOpen(t) && t.openedAt < windowStart && !ids.has(t.positionId)).map((t) => t.positionId));
    }
}