import { useRef, useState } from "react";
import { useTranslation } from "react-i18next";
import { useQuery } from "@tanstack/react-query";
import { fetchEvents, fetchOccupancy, type LedgerEvent, type Occupancy } from "./api.js";
import { qk } from "./lib/query.js";
import { useLiveStore } from "./lib/live-store.js";
import { useShift } from "./lib/use-shift.js";
import { Panel } from "./ui/Panel.js";
import { StatusDot } from "./ui/StatusDot.js";
import { BoothPayModal } from "./BoothPayModal.js";
import { ActiveSessions } from "./ActiveSessions.js";

// The live operator booth view — the real-time heart of the console. Occupancy
// gauge + a streaming entry/exit/payment ticker. Query owns the initial load and
// the authoritative numbers; the WS-fed live store overlays real-time updates so
// the screen reacts the instant a car enters or exits. Dense, dark, glanceable.

/** Per-event-type display: i18n label key + accent colour for the ticker. */
const EVENT_STYLE: Record<string, { labelKey: string; color: string }> = {
  vehicle_entry: { labelKey: "booth.evtEntry", color: "text-term-green" },
  vehicle_exit: { labelKey: "booth.evtExit", color: "text-term-red" },
  payment: { labelKey: "booth.evtPay", color: "text-term-cyan" },
  void: { labelKey: "booth.evtVoid", color: "text-term-amber" },
  barrier_open_command: { labelKey: "booth.evtOpenCmd", color: "text-term-muted" },
  barrier_open_observed: { labelKey: "booth.evtOpenObserved", color: "text-term-muted" },
  shift_open: { labelKey: "booth.evtShiftOpen", color: "text-term-amber" },
  shift_z_report: { labelKey: "booth.evtShiftZ", color: "text-term-amber" },
  cash_movement: { labelKey: "booth.evtCashMovement", color: "text-term-cyan" },
  anomaly: { labelKey: "booth.evtAnomaly", color: "text-term-red" },
};

function hhmmss(iso: string): string {
  // Local time-of-day, terminal style. Defensive against a bad timestamp.
  const d = new Date(iso);
  return Number.isNaN(d.getTime()) ? "--:--:--" : d.toTimeString().slice(0, 8);
}

function OccupancyGauge({ occ }: { occ: Occupancy }) {
  const { t } = useTranslation();
  const pct = occ.capacity ? Math.min(100, Math.round((occ.count / occ.capacity) * 100)) : null;
  const barColor = occ.full ? "bg-term-red" : pct != null && pct >= 85 ? "bg-term-amber" : "bg-term-green";
  return (
    <div className="flex flex-col gap-3">
      <div className="flex items-end gap-4">
        <div className="text-6xl font-bold leading-none tabular-nums text-term-text">{occ.count}</div>
        <div className="pb-1 text-term-muted">
          <div className="text-[11px] uppercase tracking-wider">{t("booth.inside")}</div>
          <div className="text-sm tabular-nums">
            {occ.capacity == null ? t("booth.uncapped") : `${t("booth.of")} ${occ.capacity}`}
          </div>
        </div>
        <div className="ml-auto text-right">
          <div className="text-[11px] uppercase tracking-wider text-term-muted">{t("booth.free")}</div>
          <div className={`text-3xl font-bold tabular-nums ${occ.full ? "text-term-red" : "text-term-green"}`}>
            {occ.free == null ? "∞" : occ.free}
          </div>
        </div>
      </div>
      {pct != null && (
        <div className="h-2 w-full overflow-hidden rounded-term bg-term-panel-2">
          <div className={`h-full ${barColor} transition-[width] duration-300`} style={{ width: `${pct}%` }} />
        </div>
      )}
      {occ.full && (
        <div className="rounded-term border border-term-red px-2 py-1 text-center text-[11px] font-bold uppercase tracking-widest text-term-red">
          {t("booth.lotFull")}
        </div>
      )}
    </div>
  );
}

function EventRow({ e }: { e: LedgerEvent }) {
  const { t } = useTranslation();
  const style = EVENT_STYLE[e.type];
  const label = style ? t(style.labelKey) : e.type.toUpperCase();
  return (
    <div className="flex items-center gap-3 border-b border-term-border/50 py-1 text-[12px] tabular-nums">
      <span className="text-term-muted">{hhmmss(e.occurredAt)}</span>
      <span className={`w-20 shrink-0 font-semibold ${style?.color ?? "text-term-text"}`}>{label}</span>
      <span className="truncate text-term-text">{e.identity ?? "—"}</span>
      <span className="ml-auto text-term-muted">#{e.index}</span>
    </div>
  );
}

/** Ticket entry: an HID barcode scanner types the id and presses Enter; a manual
 *  operator types it. Either way, submit opens the pay/exit modal for that id. The
 *  input auto-focuses and re-focuses after a scan so the scanner always lands here. */
function TicketInput({ onSubmit }: { onSubmit: (identity: string) => void }) {
  const { t } = useTranslation();
  const [value, setValue] = useState("");
  const ref = useRef<HTMLInputElement>(null);
  return (
    <form
      className="flex items-center gap-2"
      onSubmit={(e) => {
        e.preventDefault();
        const id = value.trim();
        if (id) {
          onSubmit(id);
          setValue("");
          ref.current?.focus();
        }
      }}
    >
      <input
        ref={ref}
        autoFocus
        value={value}
        onChange={(e) => setValue(e.target.value)}
        placeholder={t("booth.scanPlaceholder")}
        inputMode="numeric"
        className="flex-1 rounded-term border border-term-border bg-term-bg px-3 py-2 text-lg tabular-nums text-term-text placeholder:text-term-muted focus:border-term-amber"
      />
      <button
        type="submit"
        className="rounded-term border border-term-amber bg-term-amber/10 px-4 py-2 text-[12px] font-semibold uppercase tracking-wider text-term-amber"
      >
        {t("booth.open")}
      </button>
    </form>
  );
}

export function BoothScreen() {
  const { t } = useTranslation();
  // The site-wide shift drives the log scope: the feed shows ONLY the open shift's
  // window (per-shift logs, not all history). When no shift is open, the feed is
  // empty and the operator is prompted to open one.
  const { isOpen: shiftOpen, startedAt: shiftStart } = useShift();

  // Initial load via Query (also the fallback if the WS is briefly down). The events
  // query is scoped to the current shift's start so it never shows prior shifts.
  const occQuery = useQuery({ queryKey: qk.occupancy, queryFn: fetchOccupancy });
  const eventsQuery = useQuery({
    queryKey: [...qk.events, shiftStart ?? "none"],
    queryFn: () => fetchEvents(100, shiftStart ?? undefined),
    enabled: shiftOpen,
  });

  // The ticket currently open in the pay/exit modal (null = no modal).
  const [activeTicket, setActiveTicket] = useState<string | null>(null);

  // Live overlays from the WS store.
  const liveOcc = useLiveStore((s) => s.occupancy);
  const liveFeed = useLiveStore((s) => s.feed);

  // Prefer the live-pushed occupancy; fall back to the query.
  const occ = liveOcc ?? occQuery.data ?? null;

  // Merge: live events first (newest), then the queried history, de-duped by id —
  // then clip to the current shift window (the live store spans shifts; the feed
  // must not show events from before this shift's start). No shift → no feed.
  const seen = new Set(liveFeed.map((e) => e.id));
  const history = (eventsQuery.data?.events ?? []).filter((e) => !seen.has(e.id));
  const merged = [...liveFeed, ...history].slice(0, 200);
  const events =
    shiftOpen && shiftStart
      ? merged.filter((e) => e.occurredAt >= shiftStart)
      : [];

  return (
    <div className="grid h-full grid-cols-1 gap-3 lg:grid-cols-[minmax(320px,1fr)_2fr] lg:grid-rows-[auto_1fr]">
      {/* Ticket input spans both columns at the top — the operator's primary action. */}
      <div className="lg:col-span-2">
        <Panel title={t("booth.processTicket")}>
          <TicketInput onSubmit={setActiveTicket} />
        </Panel>
      </div>

      {/* Left column: occupancy gauge above the active-sessions list. */}
      <div className="flex min-h-0 flex-col gap-3">
        <Panel title={t("booth.occupancy")} right={<StatusDot />}>
          {occ ? (
            <OccupancyGauge occ={occ} />
          ) : (
            <div className="text-term-muted">{occQuery.isError ? t("booth.occUnavailable") : t("common.loading")}</div>
          )}
        </Panel>
        <div className="min-h-0 flex-1">
          <ActiveSessions onPick={setActiveTicket} />
        </div>
      </div>

      <Panel
        title={t("booth.liveFeed")}
        right={
          <span className="text-[10px] uppercase tracking-wider text-term-muted">
            {events.length} {t("booth.events")}
          </span>
        }
        className="min-h-0"
      >
        <div className="h-full overflow-y-auto pr-1">
          {!shiftOpen ? (
            <div className="text-term-amber">{t("shift.gateTitle")}</div>
          ) : events.length === 0 ? (
            <div className="text-term-muted">{eventsQuery.isLoading ? t("common.loading") : t("booth.noEventsYet")}</div>
          ) : (
            events.map((e) => <EventRow key={e.id} e={e} />)
          )}
        </div>
      </Panel>

      {activeTicket && <BoothPayModal identity={activeTicket} onClose={() => setActiveTicket(null)} />}
    </div>
  );
}