import { useEffect, useState } from "react";
import { useTranslation } from "react-i18next";
import { fetchOccupancy, fetchSiteConfig, saveSiteConfig, type Occupancy, type SiteConfig } from "./api.js";

// Live occupancy + capacity + park metadata. Occupancy is shown to everyone (it's a
// fold over the signed ledger); capacity and the metadata fields are admin-editable.
// The FULL gate (refuse transient entry at capacity) is enforced server-side in the
// entry flow. Metadata (name, NIUS, address, contact) feeds the ticket header.
// See wiki/concepts/capacity-occupancy.md and wiki/concepts/site-metadata.md.

// The optional text fields, in display order. `labelKey`/`phKey` are i18n keys
// (resolved at render); only `address` is multiline.
const META_FIELDS: ReadonlyArray<{ key: keyof SiteConfig; labelKey: string; phKey?: string; multiline?: boolean }> = [
  { key: "parkName", labelKey: "site.fieldParkName", phKey: "site.fieldParkNamePh" },
  { key: "operatorName", labelKey: "site.fieldOperator", phKey: "site.fieldOperatorPh" },
  { key: "nius", labelKey: "site.fieldNius", phKey: "site.fieldNiusPh" },
  { key: "address", labelKey: "site.fieldAddress", multiline: true },
  { key: "phone", labelKey: "site.fieldPhone" },
  { key: "email", labelKey: "site.fieldEmail" },
];

export function SiteSettings({ canEdit }: { canEdit: boolean }) {
  const { t } = useTranslation();
  const [occ, setOcc] = useState<Occupancy | null>(null);
  const [capInput, setCapInput] = useState("");
  const [meta, setMeta] = useState<Record<string, string>>({});
  const [exitVoucherDefault, setExitVoucherDefault] = useState(false);
  const [reserveSubs, setReserveSubs] = useState(false);
  const [anprEntry, setAnprEntry] = useState(true);
  const [msg, setMsg] = useState<string | null>(null);

  function reload() {
    fetchOccupancy().then(setOcc).catch(() => {});
  }
  useEffect(() => {
    reload();
    fetchSiteConfig()
      .then((c) => {
        setCapInput(c.capacity == null ? "" : String(c.capacity));
        setExitVoucherDefault(c.exitVoucherDefault);
        setReserveSubs(c.reserveSubscriberSpots);
        setAnprEntry(c.anprEntryEnabled);
        const m: Record<string, string> = {};
        for (const { key } of META_FIELDS) m[key] = c[key] == null ? "" : String(c[key]);
        setMeta(m);
      })
      .catch(() => {});
  }, []);

  async function save() {
    setMsg(null);
    const raw = capInput.trim();
    const patch: Partial<SiteConfig> = {
      capacity: raw === "" ? null : Math.round(Number(raw)),
      exitVoucherDefault,
      reserveSubscriberSpots: reserveSubs,
      anprEntryEnabled: anprEntry,
    };
    // Send each metadata field; "" → null is applied server-side.
    for (const { key } of META_FIELDS) (patch as Record<string, string | null>)[key] = meta[key] ?? "";
    try {
      await saveSiteConfig(patch);
      reload();
      setMsg(t("site.saved"));
    } catch (e) {
      setMsg((e as Error).message);
    }
  }

  return (
    <section className="card mt-6 max-w-md p-4">
      <div className="flex flex-wrap items-center gap-1.5 text-[0.8125rem]">
        <strong className="uppercase tracking-wider text-term-muted">{t("site.occupancy")}</strong>
        {occ == null ? (
          <span className="text-term-muted">…</span>
        ) : (
          <>
            <span className="text-h5 font-semibold tabular-nums text-term-text">{occ.count}</span>
            <span className="tabular-nums text-term-muted">
              {occ.capacity != null ? `/ ${occ.capacity}` : t("site.noCapacitySet")}
            </span>
            {occ.capacity != null && (
              <span className="tabular-nums text-term-muted">· {occ.free} {t("site.free")}</span>
            )}
            {occ.full && <span className="font-semibold text-term-red">{t("site.full")}</span>}
            <button type="button" className="btn btn-ghost btn-sm" onClick={reload}>↻</button>
          </>
        )}
      </div>
      {canEdit && (
        <div className="mt-4 grid gap-3">
          <div className="field">
            <span className="label">{t("site.capacityLabel")}</span>
            <input className="input w-32" value={capInput} onChange={(e) => setCapInput(e.target.value)} placeholder={t("site.capacityPlaceholder")} />
          </div>
          <label className="flex items-center gap-2 text-[0.75rem] text-term-text">
            <input
              type="checkbox"
              className="accent-term-amber"
              checked={exitVoucherDefault}
              onChange={(e) => setExitVoucherDefault(e.target.checked)}
            />
            {t("site.printExitDefault")}
            <span className="hint">{t("site.printExitHint")}</span>
          </label>
          <label className="flex items-start gap-2 text-[0.75rem] text-term-text">
            <input
              type="checkbox"
              className="mt-0.5 accent-term-amber"
              checked={reserveSubs}
              onChange={(e) => setReserveSubs(e.target.checked)}
            />
            <span>
              {t("site.reserveSubs")}
              <span className="hint block">{t("site.reserveSubsHint")}</span>
            </span>
          </label>
          <label className="flex items-start gap-2 text-[0.75rem] text-term-text">
            <input
              type="checkbox"
              className="mt-0.5 accent-term-amber"
              checked={anprEntry}
              onChange={(e) => setAnprEntry(e.target.checked)}
            />
            <span>
              {t("site.anprEntry")}
              <span className="hint block">{t("site.anprEntryHint")}</span>
            </span>
          </label>
          <div className="border-t border-term-border pt-3 text-[0.6875rem] uppercase tracking-wider text-term-muted">
            {t("site.parkDetails")}
          </div>
          {META_FIELDS.map(({ key, labelKey, phKey, multiline }) => (
            <div key={key} className="field">
              <span className="label">{t(labelKey)}</span>
              {multiline ? (
                <textarea
                  className="textarea"
                  value={meta[key] ?? ""}
                  onChange={(e) => setMeta((m) => ({ ...m, [key]: e.target.value }))}
                  rows={2}
                  placeholder={phKey ? t(phKey) : undefined}
                />
              ) : (
                <input
                  className="input"
                  value={meta[key] ?? ""}
                  onChange={(e) => setMeta((m) => ({ ...m, [key]: e.target.value }))}
                  placeholder={phKey ? t(phKey) : undefined}
                />
              )}
            </div>
          ))}
          <div className="flex items-center gap-3">
            <button type="button" className="btn btn-primary btn-sm" onClick={save}>{t("site.save")}</button>
            {msg && <span className="text-[0.75rem] text-term-muted">{msg}</span>}
          </div>
        </div>
      )}
    </section>
  );
}