import { useState } from "react";
import { useTranslation } from "react-i18next";
import * as Dialog from "@radix-ui/react-dialog";
import { useQuery, useQueryClient } from "@tanstack/react-query";
import {
  boothExit,
  fetchSiteConfig,
  lookupSession,
  openShift,
  paySession,
  printReceipt,
  printVoucher,
  reopenBarrier,
  type SessionLookup,
} from "./api.js";
import { qk } from "./lib/query.js";
import { useShift } from "./lib/use-shift.js";
import { formatDuration, formatMoney, formatTime } from "./lib/format.js";
import { SnapshotStrip } from "./ui/SnapshotStrip.js";

// The booth pay/exit modal. Opened when the operator submits a ticket id. Shows the
// session (entry, exit=now, duration, total owed) + entry/exit snapshots, takes
// payment, then EITHER prints an exit voucher (customer self-exits at a distant
// exit) OR fires the exit immediately (booth at/near the exit) — controlled by a
// checkbox defaulting from site_config.exitVoucherDefault. See booth-exit-flow.md.

type Phase = "review" | "paying" | "finishing" | "done" | "error";

export function BoothPayModal({ identity, onClose }: { identity: string; onClose: () => void }) {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const session = useQuery({ queryKey: ["session", identity], queryFn: () => lookupSession(identity) });
  const config = useQuery({ queryKey: qk.siteConfig, queryFn: fetchSiteConfig });

  // A shift must be open (and mine) before any pay/exit/voucher action — the booth
  // money path is gated. The server enforces this too (409 no_shift); the modal
  // surfaces it up front and offers a one-click open. See wiki/concepts/shift.md.
  const { isOpen: shiftOpen, isMine: shiftMine, blockedByOther, heldBy } = useShift();
  const shiftReady = shiftOpen && shiftMine;

  const [tender, setTender] = useState<"cash" | "card">("cash");
  const [printVoucherChecked, setPrintVoucherChecked] = useState<boolean | null>(null);
  const [phase, setPhase] = useState<Phase>("review");
  const [error, setError] = useState<string | null>(null);
  const [result, setResult] = useState<string | null>(null);
  const [openingShift, setOpeningShift] = useState(false);
  const [reprinting, setReprinting] = useState(false);

  const s: SessionLookup | undefined = session.data;
  // Checkbox default comes from config the first time it loads; operator can toggle.
  const voucher = printVoucherChecked ?? config.data?.exitVoucherDefault ?? false;

  const alreadyPaid = s?.paidAt != null;
  const isSubscription = s?.subscription === true;
  // A subscription is prepaid: never charged. The only booth action is an audited
  // barrier open to ASSIST (faulty exit reader / lost card). Transient pay path is off.
  const canPay = shiftReady && s?.found && s.open && !alreadyPaid && !isSubscription;

  async function handleOpenBarrier() {
    if (!s) return;
    setError(null);
    setPhase("finishing");
    try {
      const r = await reopenBarrier(identity);
      setResult(r.opened ? t("pay.subBarrierOpened") : t("pay.paidExitRecorded", { reason: r.reason ?? t("booth.openManually") }));
      void qc.invalidateQueries({ queryKey: qk.events });
      void qc.invalidateQueries({ queryKey: qk.activeSessions });
      setPhase("done");
    } catch (e) {
      setError((e as Error).message);
      setPhase("error");
    }
  }

  async function handleOpenShift() {
    setOpeningShift(true);
    setError(null);
    try {
      await openShift();
      void qc.invalidateQueries({ queryKey: qk.shift });
      void qc.invalidateQueries({ queryKey: qk.events });
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setOpeningShift(false);
    }
  }

  async function handleReprintReceipt() {
    setReprinting(true);
    setError(null);
    try {
      const r = await printReceipt(identity);
      setResult(t("pay.receiptReprinted", { printer: r.printedBy }));
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setReprinting(false);
    }
  }

  async function handlePayAndExit() {
    if (!s) return;
    setError(null);
    try {
      // 1. Take payment (unless already paid — e.g. paid earlier at a kiosk).
      if (!alreadyPaid) {
        setPhase("paying");
        await paySession(identity, tender);
      }
      // 2. Voucher OR immediate exit.
      setPhase("finishing");
      if (voucher) {
        // The voucher slip carries the payment detail + barcode + grace.
        const r = await printVoucher(identity);
        setResult(t("pay.voucherPrinted", { printer: r.printedBy }));
      } else {
        const r = await boothExit(identity);
        // No voucher → auto-print a standalone payment receipt for transparency.
        // Best-effort: a printer fault must NOT block the exit that already happened;
        // the operator can reprint from the done screen.
        let receiptNote = "";
        try {
          await printReceipt(identity);
        } catch {
          receiptNote = ` ${t("pay.receiptPrintFailed")}`;
        }
        setResult(
          (r.opened
            ? t("pay.paidBarrierOpened")
            : t("pay.paidExitRecorded", { reason: r.reason ?? t("booth.openManually") })) +
            receiptNote,
        );
      }
      // Refresh the live views.
      void qc.invalidateQueries({ queryKey: qk.events });
      void qc.invalidateQueries({ queryKey: qk.occupancy });
      setPhase("done");
    } catch (e) {
      setError((e as Error).message);
      setPhase("error");
    }
  }

  return (
    <Dialog.Root open onOpenChange={(o) => !o && onClose()}>
      <Dialog.Portal>
        <Dialog.Overlay className="fixed inset-0 z-40 bg-black/70" />
        <Dialog.Content
          className="fixed left-1/2 top-1/2 z-50 w-[560px] max-w-[95vw] -translate-x-1/2 -translate-y-1/2 rounded-term border border-term-border bg-term-panel font-mono text-term-text shadow-2xl"
          aria-describedby={undefined}
        >
          <div className="flex items-center justify-between border-b border-term-border bg-term-panel-2 px-4 py-2">
            <Dialog.Title className="m-0 text-[12px] font-semibold uppercase tracking-wider text-term-amber">
              {isSubscription
                ? `${t("pay.subscription")} · ${s?.subscriptionHolder ?? t("subs.unnamed")}`
                : `${t("pay.ticket")} ${identity}`}
            </Dialog.Title>
            <Dialog.Close className="text-term-muted hover:text-term-text" aria-label={t("common.close")}>
              ✕
            </Dialog.Close>
          </div>

          <div className="flex flex-col gap-3 p-4">
            {/* Shift gate — block all actions until THIS operator has a shift open.
                Another operator's open shift can't be operated under (no shared
                till); only an "open mine" path when no shift is open at all. */}
            {!shiftReady && (
              <div className="rounded-term border border-term-amber bg-term-amber/5 px-3 py-2">
                {blockedByOther ? (
                  <>
                    <div className="text-[12px] font-semibold uppercase tracking-wider text-term-amber">
                      {t("shift.gateOtherTitle")}
                    </div>
                    <div className="mt-1 text-[12px] text-term-text">
                      {t("shift.gateOtherBody", { operator: heldBy ?? "?" })}
                    </div>
                  </>
                ) : (
                  <>
                    <div className="text-[12px] font-semibold uppercase tracking-wider text-term-amber">
                      {t("shift.gateTitle")}
                    </div>
                    <div className="mt-1 text-[12px] text-term-text">{t("shift.gateBody")}</div>
                    <button
                      type="button"
                      onClick={handleOpenShift}
                      disabled={openingShift}
                      className="mt-2 rounded-term border border-term-green bg-term-green/10 px-3 py-1 text-[12px] font-semibold uppercase tracking-wider text-term-green disabled:opacity-50"
                    >
                      {openingShift ? t("shift.opening") : t("shift.openNow")}
                    </button>
                  </>
                )}
              </div>
            )}

            {session.isLoading && <div className="text-term-muted">{t("pay.lookingUp")}</div>}

            {s && !s.found && (
              <div className="rounded-term border border-term-red px-3 py-2 text-term-red">
                {t("pay.noSessionFound")}
              </div>
            )}

            {s && s.found && !s.open && (
              <div className="rounded-term border border-term-amber px-3 py-2 text-term-amber">
                {t("pay.alreadyClosed", { time: formatTime(s.exitedAt) })}
              </div>
            )}

            {s && s.found && s.open && (
              <>
                {/* Session figures */}
                <div className="grid grid-cols-2 gap-x-6 gap-y-1 tabular-nums">
                  <Row label={t("pay.entry")} value={formatTime(s.enteredAt)} />
                  <Row label={t("pay.now")} value={formatTime(new Date().toISOString())} />
                  <Row
                    label={t("pay.duration")}
                    value={s.enteredAt ? formatDuration(s.enteredAt, new Date().toISOString()) : "—"}
                  />
                  <Row
                    label={t("pay.statusLabel")}
                    value={isSubscription ? t("pay.subscription") : alreadyPaid ? t("pay.paid") : t("pay.unpaid")}
                    valueClass={isSubscription ? "text-term-cyan" : alreadyPaid ? "text-term-green" : "text-term-amber"}
                  />
                </div>

                {/* Total — a subscription is prepaid (no amount); show a badge. */}
                <div className="flex items-end justify-between rounded-term bg-term-panel-2 px-3 py-2">
                  <span className="text-[11px] uppercase tracking-wider text-term-muted">
                    {isSubscription ? t("pay.plan") : t("pay.total")}
                  </span>
                  <span className="text-3xl font-bold text-term-cyan">
                    {isSubscription
                      ? t("pay.prepaid")
                      : s.amountMinor != null && s.currency
                        ? formatMoney(s.amountMinor, s.currency)
                        : alreadyPaid
                          ? t("booth.badgePaid")
                          : t("pay.noTariff")}
                  </span>
                </div>

                {/* For a subscription, explain the only available action. */}
                {isSubscription && (
                  <div className="rounded-term border border-term-cyan/40 bg-term-cyan/5 px-3 py-2 text-[12px] text-term-text">
                    {t("pay.subAssistHint")}
                  </div>
                )}

                {/* Snapshots */}
                <SnapshotStrip identity={identity} />

                {phase !== "done" && !isSubscription && (
                  <>
                    {/* Tender */}
                    {canPay && (
                      <div className="flex items-center gap-2">
                        <span className="text-[11px] uppercase tracking-wider text-term-muted">{t("pay.tender")}</span>
                        {(["cash", "card"] as const).map((tn) => (
                          <button
                            key={tn}
                            type="button"
                            onClick={() => setTender(tn)}
                            className={`rounded-term border px-3 py-1 text-[12px] uppercase tracking-wider ${
                              tender === tn
                                ? "border-term-amber text-term-amber"
                                : "border-term-border text-term-muted hover:text-term-text"
                            }`}
                          >
                            {t(`pay.${tn}`)}
                          </button>
                        ))}
                      </div>
                    )}

                    {/* Voucher checkbox (default from site config) */}
                    <label className="flex items-center gap-2 text-[12px]">
                      <input
                        type="checkbox"
                        checked={voucher}
                        onChange={(e) => setPrintVoucherChecked(e.target.checked)}
                      />
                      {t("pay.printExitVoucher")}
                      <span className="text-term-muted">{t("pay.selfExitHint")}</span>
                    </label>
                  </>
                )}

                {error && <div className="rounded-term border border-term-red px-3 py-2 text-term-red">{error}</div>}
                {result && (
                  <div className="rounded-term border border-term-green px-3 py-2 text-term-green">{result}</div>
                )}

                {/* Actions */}
                <div className="flex justify-end gap-2 pt-1">
                  {phase === "done" ? (
                    <>
                      {/* Reprint the payment receipt (slip jammed / customer asks).
                          Only for a charged session — a subscription has no payment. */}
                      {!isSubscription && (
                        <button
                          type="button"
                          onClick={handleReprintReceipt}
                          disabled={reprinting}
                          className="rounded-term border border-term-border px-3 py-1.5 text-[12px] uppercase tracking-wider text-term-muted hover:text-term-text disabled:opacity-50"
                        >
                          {reprinting ? t("pay.reprinting") : t("pay.reprintReceipt")}
                        </button>
                      )}
                      <button
                        type="button"
                        onClick={onClose}
                        className="rounded-term border border-term-amber px-4 py-1.5 text-[12px] uppercase tracking-wider text-term-amber"
                      >
                        {t("common.close")}
                      </button>
                    </>
                  ) : (
                    <>
                      <button
                        type="button"
                        onClick={onClose}
                        className="rounded-term border border-term-border px-3 py-1.5 text-[12px] uppercase tracking-wider text-term-muted hover:text-term-text"
                      >
                        {t("common.cancel")}
                      </button>
                      {isSubscription ? (
                        // Prepaid — the only action is the audited barrier open (assist
                        // a faulty exit reader / missing card). Gated on an open shift.
                        <button
                          type="button"
                          onClick={handleOpenBarrier}
                          disabled={!shiftReady || phase === "finishing"}
                          className="rounded-term border border-term-cyan bg-term-cyan/10 px-4 py-1.5 text-[12px] font-semibold uppercase tracking-wider text-term-cyan disabled:opacity-50"
                        >
                          {phase === "finishing" ? t("pay.opening") : t("booth.openBarrier")}
                        </button>
                      ) : (
                        <button
                          type="button"
                          onClick={handlePayAndExit}
                          disabled={!shiftReady || phase === "paying" || phase === "finishing"}
                          className="rounded-term border border-term-green bg-term-green/10 px-4 py-1.5 text-[12px] font-semibold uppercase tracking-wider text-term-green disabled:opacity-50"
                        >
                          {phase === "paying"
                            ? t("pay.takingPayment")
                            : phase === "finishing"
                              ? voucher
                                ? t("pay.printingVoucher")
                                : t("pay.opening")
                              : alreadyPaid
                                ? voucher
                                  ? t("pay.printVoucher")
                                  : t("pay.openBarrier")
                                : voucher
                                  ? t("pay.payAndVoucher")
                                  : t("pay.payAndOpen")}
                        </button>
                      )}
                    </>
                  )}
                </div>
              </>
            )}
          </div>
        </Dialog.Content>
      </Dialog.Portal>
    </Dialog.Root>
  );
}

function Row({ label, value, valueClass = "" }: { label: string; value: string; valueClass?: string }) {
  return (
    <div className="flex items-baseline justify-between">
      <span className="text-[11px] uppercase tracking-wider text-term-muted">{label}</span>
      <span className={`text-sm ${valueClass}`}>{value}</span>
    </div>
  );
}