import { useState } from "react";
import { useTranslation } from "react-i18next";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { RotateCcw, Save, Send } from "lucide-react";
import { api, type ConfigItem, type SystemConfigData } from "../lib/api";
import { notify } from "../lib/notifications";
import Tooltip from "./Tooltip";

// Admin Configuration page: edit DB-overridable operational settings (registry-driven from
// the backend — adding a key there makes it appear here automatically). Group order is fixed
// where known so logically related settings (e.g. Email/SMTP) stay together.
const GROUP_ORDER = ["email"];

export default function ConfigPanel() {
  const { t } = useTranslation();
  const qc = useQueryClient();
  const q = useQuery({ queryKey: ["admin-config"], queryFn: api.adminConfig });
  const data = q.data;

  const apply = (fresh: SystemConfigData) => qc.setQueryData(["admin-config"], fresh);
  const save = useMutation({
    mutationFn: ({ key, value }: { key: string; value: string | number | boolean }) =>
      api.setConfig(key, value),
    onSuccess: (fresh) => {
      apply(fresh);
      notify({ level: "success", message: t("config.saved") });
    },
    onError: () => notify({ level: "error", message: t("config.saveFailed") }),
  });
  const reset = useMutation({
    mutationFn: (key: string) => api.resetConfig(key),
    onSuccess: (fresh) => {
      apply(fresh);
      notify({ level: "success", message: t("config.resetDone") });
    },
    onError: () => notify({ level: "error", message: t("config.saveFailed") }),
  });
  const testEmail = useMutation({
    mutationFn: () => api.testEmail(),
    onSuccess: (r) => notify({ level: "success", message: t("config.testSent", { to: r.to }) }),
    onError: () => notify({ level: "error", message: t("config.testFailed") }),
  });

  const busy = save.isPending || reset.isPending;

  if (q.isLoading || !data) {
    return <div className="p-4 max-w-3xl mx-auto text-muted">{t("config.loading")}</div>;
  }

  const groupKeys = Object.keys(data.groups).sort(
    (a, b) => (GROUP_ORDER.indexOf(a) + 1 || 99) - (GROUP_ORDER.indexOf(b) + 1 || 99)
  );

  return (
    <div className="p-4 max-w-3xl w-full mx-auto">
      <p className="text-xs text-muted mb-4 leading-relaxed">{t("config.intro")}</p>

      {groupKeys.map((g) => (
        <div key={g} className="glass rounded-2xl p-4 mb-4">
          <div className="text-xs uppercase tracking-wide text-muted mb-3">
            {t(`config.groups.${g}`, g)}
          </div>
          <div className="divide-y divide-border/60">
            {data.groups[g].map((item) => (
              <Field
                key={`${item.key}:${item.is_set}:${String(item.value ?? "")}`}
                item={item}
                secretsManageable={data.secrets_manageable}
                busy={busy}
                onSave={(value) => save.mutate({ key: item.key, value })}
                onReset={() => reset.mutate(item.key)}
              />
            ))}
          </div>

          {g === "email" && (
            <div className="mt-3 pt-3 border-t border-border/60">
              <Tooltip hint={t("config.testEmailHint")}>
                <button
                  onClick={() => testEmail.mutate()}
                  disabled={testEmail.isPending}
                  className="glass-card glass-hover inline-flex items-center gap-2 px-3 py-2 rounded-xl text-sm disabled:opacity-50 transition"
                >
                  <Send className={`w-4 h-4 ${testEmail.isPending ? "animate-pulse" : ""}`} />
                  {t("config.testEmail")}
                </button>
              </Tooltip>
            </div>
          )}
        </div>
      ))}
    </div>
  );
}

function Field({
  item,
  secretsManageable,
  busy,
  onSave,
  onReset,
}: {
  item: ConfigItem;
  secretsManageable: boolean;
  busy: boolean;
  onSave: (value: string | number) => void;
  onReset: () => void;
}) {
  const { t } = useTranslation();
  const isNum = item.type === "int";
  const [draft, setDraft] = useState<string>(item.secret ? "" : String(item.value ?? ""));

  const secretDisabled = item.secret && !secretsManageable;
  // Status line for secrets (never reveal the value): stored override / env value / unset.
  const secretStatus = item.is_set
    ? t("config.secretSet")
    : item.default_is_set
      ? t("config.secretEnv")
      : t("config.secretUnset");

  const canSave = item.secret ? draft.trim().length > 0 && !secretDisabled : true;

  return (
    <div className="flex items-start justify-between gap-3 py-3">
      <div className="min-w-0 flex-1">
        <div className="text-sm font-medium">{t(`config.fields.${item.key}.label`, item.key)}</div>
        <p className="text-xs text-muted leading-relaxed mt-0.5">
          {t(`config.fields.${item.key}.hint`, "")}
        </p>
        {item.secret ? (
          <p className="text-[11px] text-muted mt-1">
            {secretDisabled ? t("config.secretsDisabled") : secretStatus}
          </p>
        ) : (
          <p className="text-[11px] text-muted mt-1">
            {item.is_set ? t("config.overridden") : t("config.usingDefault")}
          </p>
        )}
      </div>

      <div className="flex flex-col items-end gap-1.5 shrink-0">
        <input
          type={item.secret ? "password" : isNum ? "number" : "text"}
          value={draft}
          disabled={secretDisabled}
          onChange={(e) => setDraft(e.target.value)}
          min={isNum && item.min != null ? item.min : undefined}
          max={isNum && item.max != null ? item.max : undefined}
          placeholder={item.secret ? "••••••••" : String(item.default ?? "")}
          className="w-52 bg-card border border-border rounded-xl px-3 py-1.5 text-sm outline-none focus:border-accent disabled:opacity-50"
        />
        <div className="flex items-center gap-1.5">
          {item.is_set && (
            <Tooltip hint={t("config.resetHint")}>
              <button
                onClick={onReset}
                disabled={busy}
                className="glass-card glass-hover inline-flex items-center gap-1 px-2.5 py-1.5 rounded-lg text-xs disabled:opacity-50 transition"
              >
                <RotateCcw className="w-3.5 h-3.5" />
                {t("config.reset")}
              </button>
            </Tooltip>
          )}
          <button
            onClick={() => onSave(isNum ? Number(draft) : draft)}
            disabled={busy || !canSave}
            className="inline-flex items-center gap-1 px-2.5 py-1.5 rounded-lg text-xs bg-accent text-accent-fg font-medium disabled:opacity-40 transition"
          >
            <Save className="w-3.5 h-3.5" />
            {t("config.save")}
          </button>
        </div>
      </div>
    </div>
  );
}