import { Fragment, useState } from "react";
import { useTranslation } from "react-i18next";
import { useQuery, useQueryClient } from "@tanstack/react-query";
import { closeShift, fetchShiftReport, openShift, type TillId } from "./api.js";
import { CARD_PAYMENTS_ENABLED } from "./lib/features.js";
import { qk } from "./lib/query.js";
import { useShift } from "./lib/use-shift.js";
import { Modal } from "./ui/Modal.js";
import { Spinner } from "./ui/Spinner.js";

/**
 * Shift control for ONE TILL — the till's single-open shift expressed as one button:
 *  - no shift open       → "Open shift" (enabled; opens this operator's shift on the till)
 *  - my shift open       → "Close shift" (enabled; signs + prints the Z-report)
 *  - another's shift open → disabled, labelled with who holds it (you can neither
 *    open yours nor close theirs until they hand over).
 * The header renders it for the booth; the wash desk renders it for the carwash till
 * (its labels then name the till, so the two are never confused). On open/close it
 * invalidates the shift status, the per-shift log, and occupancy.
 * See wiki/concepts/shift.md "Tills".
 */
export function ShiftButton({ till = "booth" }: { till?: TillId }) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const { status, isOpen, isMine, blockedByOther, heldBy } = useShift(till);
  // The till's `shift` guard (booth shift:create / wash carwash:cash). A role that may
  // only LOOK sees the state text, never the button; the server refuses the same.
  const canWork = status?.canWork ?? false;
  const [busy, setBusy] = useState(false);
  const [err, setErr] = useState<string | null>(null);
  // Closing a shift signs the Z-report and is irreversible, so the button never
  // closes directly (a stray click would end the shift) — it opens a confirm modal that
  // shows the live X-report first. Opening a shift has no such risk → immediate.
  const [confirmingClose, setConfirmingClose] = useState(false);

  function onClick() {
    if (isMine) {
      setConfirmingClose(true);
    } else {
      void act("open");
    }
  }

  async function act(kind: "open" | "close") {
    setBusy(true);
    setErr(null);
    try {
      if (kind === "open") await openShift(till);
      else await closeShift(till);
      // The shift boundary moves: refresh status, the per-shift log window, drawer.
      void qc.invalidateQueries({ queryKey: qk.shift });
      void qc.invalidateQueries({ queryKey: ["shifts"] });
      void qc.invalidateQueries({ queryKey: ["drawer"] });
      void qc.invalidateQueries({ queryKey: qk.events });
      void qc.invalidateQueries({ queryKey: qk.occupancy });
    } catch (e) {
      setErr((e as Error).message);
    } finally {
      setBusy(false);
    }
  }

  // The booth keeps its historical wording; any other till names itself.
  const tillName = t(`till.${till}`);
  const label = blockedByOther
    ? till === "booth"
      ? t("shift.headerHeldByShort", { operator: heldBy ?? "?" })
      : t("shift.tillHeldByShort", { till: tillName, operator: heldBy ?? "?" })
    : isMine
      ? till === "booth"
        ? t("shift.headerClose")
        : t("shift.tillClose", { till: tillName })
      : till === "booth"
        ? t("shift.headerOpen")
        : t("shift.tillOpen", { till: tillName });
  const tone = blockedByOther
    ? "border-term-border text-term-muted opacity-60 cursor-not-allowed"
    : isMine
      ? "border-term-red text-term-red hover:bg-term-red/10"
      : "border-term-green text-term-green hover:bg-term-green/10";

  return (
    <div className="flex items-center gap-1">
      {canWork && (
      <button
        type="button"
        disabled={busy || blockedByOther}
        title={blockedByOther ? t("shift.headerHeldBy", { operator: heldBy ?? "?" }) : undefined}
        onClick={onClick}
        className={`rounded-term border px-2 py-0.5 text-[0.6875rem] font-semibold uppercase tracking-wider disabled:opacity-60 ${tone}`}
      >
        {busy ? (
          <span className="inline-flex items-center gap-1.5">
            <Spinner /> {isMine ? t("shift.ending") : t("shift.opening")}
          </span>
        ) : (
          label
        )}
      </button>
      )}
      {!canWork && isOpen && (
        <span className="text-[0.625rem] uppercase tracking-wider text-term-muted">
          {till === "booth" ? t("shift.headerHeldByShort", { operator: heldBy ?? "?" }) : t("shift.tillHeldByShort", { till: tillName, operator: heldBy ?? "?" })}
        </span>
      )}
      {!isOpen && (
        <span className="text-[0.625rem] uppercase tracking-wider text-term-amber">
          {till === "booth" ? t("shift.headerNoShift") : t("shift.tillNoShift", { till: tillName })}
        </span>
      )}
      {err && <span className="text-[0.625rem] text-term-red">{err}</span>}
      {confirmingClose && (
        <CloseShiftConfirm
          till={till}
          busy={busy}
          onCancel={() => setConfirmingClose(false)}
          onConfirm={async () => {
            await act("close");
            setConfirmingClose(false);
          }}
        />
      )}
    </div>
  );
}

/** Confirm-before-close modal for the shift button. Fetches the till's live X-report so
 *  the operator SEES their takings (split by source: tickets vs subscriptions) and the
 *  expected drawer before committing the irreversible Z-report. */
function CloseShiftConfirm({
  till,
  busy,
  onCancel,
  onConfirm,
}: {
  till: TillId;
  busy: boolean;
  onCancel: () => void;
  onConfirm: () => void;
}) {
  const { t } = useTranslation();
  const q = useQuery({ queryKey: ["shift", "xreport", "close-confirm", till], queryFn: () => fetchShiftReport(till) });
  const x = q.data;
  const cur = x?.currency ?? null;
  const fmt = (m: number) => `${(m / 100).toLocaleString()} ${cur ?? ""}`.trim();

  return (
    <Modal open onClose={onCancel} title={till === "booth" ? t("shift.endShift") : t("shift.tillClose", { till: t(`till.${till}`) })} width="max-w-md">
      <div className="text-[0.8125rem] tabular-nums">
        <p className="text-term-muted">{t("shift.endConfirm")}</p>
        {!x ? (
          <p className="mt-2 text-term-muted">{t("common.loading")}</p>
        ) : (
          <>
            <div className="mt-2 grid grid-cols-2 gap-x-6 gap-y-0.5">
              <ConfirmFigure label={t("shift.payments")} value={String(x.paymentCount)} />
              <span />
              {/* Split by source — only meaningful on the booth (a wash till has no
                  tickets or subscriptions; its takings are the bay payments). */}
              {till === "booth" && (
                <>
                  <ConfirmFigure label={t("shift.srcTickets")} value={fmt(x.ticketTotalMinor)} />
                  <ConfirmFigure label={t("shift.srcSubscriptions")} value={fmt(x.subscriptionTotalMinor)} />
                  {/* Module money that rode the ticket (a booth-paid wash) — only when any did. */}
                  {Object.entries(x.chargesByModuleMinor ?? {})
                    .filter(([, v]) => (v ?? 0) > 0)
                    .map(([m, v]) => (
                      <Fragment key={m}>
                        <ConfirmFigure label={t("shift.srcOnTicket", { module: t(`modules.name.${m}`) })} value={fmt(v ?? 0)} />
                        <span />
                      </Fragment>
                    ))}
                  {/* Abonime is the subscription TOTAL (sales + out-of-window). The 'jashtë orarit'
                      part is broken out below it; subscription SALES is not (it's the remainder). */}
                  <span />
                  <ConfirmFigure label={t("shift.srcSubWindow")} value={fmt(x.subscriptionWindowMinor)} sub />
                </>
              )}
            </div>
            <div className="mt-2 grid grid-cols-2 gap-x-6 gap-y-0.5 border-t border-term-border pt-2">
              <ConfirmFigure label={t("shift.cash")} value={fmt(x.cashTotalMinor)} />
              {CARD_PAYMENTS_ENABLED && <ConfirmFigure label={t("shift.card")} value={fmt(x.cardTotalMinor)} />}
              {/* Drawer math made explicit: opening float + cash taken = expected drawer. */}
              <ConfirmFigure label={t("shift.openingFloat")} value={fmt(x.openingFloatMinor)} />
              <span />
              <ConfirmFigure label={t("shift.expectedDrawer")} value={fmt(x.expectedDrawerMinor)} bold />
            </div>
          </>
        )}
        <div className="mt-3 flex justify-end gap-2">
          <button type="button" className="btn btn-sm" onClick={onCancel} disabled={busy}>
            {t("subs.cancel")}
          </button>
          <button type="button" className="btn btn-sm btn-danger" onClick={onConfirm} disabled={busy || !x}>
            {busy ? (
              <span className="inline-flex items-center gap-1.5">
                <Spinner /> {t("shift.ending")}
              </span>
            ) : (
              t("shift.endShift")
            )}
          </button>
        </div>
      </div>
    </Modal>
  );
}

function ConfirmFigure({ label, value, bold, sub }: { label: string; value: string; bold?: boolean; sub?: boolean }) {
  return (
    <div className={`flex items-baseline justify-between gap-2 ${sub ? "pl-3" : ""}`}>
      <span
        className={`whitespace-nowrap text-[0.6875rem] uppercase tracking-wider ${sub ? "text-term-muted/70" : "text-term-muted"}`}
      >
        {label}
      </span>
      {/* The money/number never splits across lines (e.g. "89,650 ALL"). */}
      <span className={`whitespace-nowrap ${bold ? "font-semibold text-term-text" : "text-term-text"}`}>{value}</span>
    </div>
  );
}