"use client";

import { useCallback, useEffect, useState } from "react";

import { DomainBericht } from "@/components/domain-bericht";
import { Icon } from "@/components/icons";
import { Modal } from "@/components/modal";
import {
  Badge,
  Button,
  Card,
  Checkbox,
  Field,
  Notice,
  TextInput,
} from "@/components/ui";
import { ApiError, apiJson } from "@/lib/api-client";
import type { Pruefbericht } from "@/lib/domain-check";

type Grant = { groupId: string; groupName: string; isDefault: boolean };

type AdminDomain = {
  id: string;
  hostname: string;
  label: string | null;
  isActive: boolean;
  codeCount: number;
  grants: Grant[];
};

type GroupOption = { id: string; name: string };

export function DomainAdmin({ baseUrlHostname }: { baseUrlHostname: string }) {
  const [domains, setDomains] = useState<AdminDomain[] | null>(null);
  const [groups, setGroups] = useState<GroupOption[]>([]);
  const [error, setError] = useState<string | null>(null);
  const [busy, setBusy] = useState<string | null>(null);

  const [creating, setCreating] = useState(false);
  const [form, setForm] = useState({ hostname: "", label: "" });
  const [formError, setFormError] = useState<string | null>(null);

  const [editing, setEditing] = useState<AdminDomain | null>(null);
  const [grants, setGrants] = useState<Grant[]>([]);
  const [grantError, setGrantError] = useState<string | null>(null);

  const [deleting, setDeleting] = useState<AdminDomain | null>(null);

  /** Prüfberichte je Domain — bleiben stehen, bis erneut geprüft wird. */
  const [reports, setReports] = useState<Record<string, Pruefbericht>>({});
  const [checking, setChecking] = useState<string | null>(null);

  const load = useCallback(async () => {
    try {
      const result = await apiJson<{
        domains: AdminDomain[];
        groups: GroupOption[];
      }>("/api/admin/domains");
      setDomains(result.domains);
      setGroups(result.groups);
      setError(null);
    } catch (caught) {
      setDomains([]);
      setError(
        caught instanceof ApiError
          ? caught.message
          : "Die Domains konnten nicht geladen werden.",
      );
    }
  }, []);

  useEffect(() => {
    // setState folgt erst nach dem await der Netzwerkantwort.
    // eslint-disable-next-line react-hooks/set-state-in-effect
    void load();
  }, [load]);

  const create = async () => {
    setFormError(null);
    try {
      await apiJson("/api/admin/domains", { method: "POST", json: form });
      setCreating(false);
      setForm({ hostname: "", label: "" });
      await load();
    } catch (caught) {
      setFormError(
        caught instanceof ApiError
          ? caught.message
          : "Die Domain konnte nicht angelegt werden.",
      );
    }
  };

  const patch = async (id: string, body: unknown, onDone?: () => void) => {
    setBusy(id);
    setError(null);
    try {
      await apiJson(`/api/admin/domains/${id}`, { method: "PATCH", json: body });
      await load();
      onDone?.();
      return true;
    } catch (caught) {
      const message =
        caught instanceof ApiError
          ? caught.message
          : "Die Änderung konnte nicht gespeichert werden.";
      if (onDone) setGrantError(message);
      else setError(message);
      return false;
    } finally {
      setBusy(null);
    }
  };

  const remove = async () => {
    if (!deleting) return;
    try {
      await apiJson(`/api/admin/domains/${deleting.id}`, { method: "DELETE" });
      setDeleting(null);
      await load();
    } catch (caught) {
      setError(
        caught instanceof ApiError
          ? caught.message
          : "Die Domain konnte nicht gelöscht werden.",
      );
      setDeleting(null);
    }
  };

  const check = async (domain: AdminDomain) => {
    setChecking(domain.id);
    setError(null);
    try {
      const { report } = await apiJson<{ report: Pruefbericht }>(
        `/api/admin/domains/${domain.id}/check`,
        { method: "POST" },
      );
      setReports((bisher) => ({ ...bisher, [domain.id]: report }));
    } catch (caught) {
      setError(
        caught instanceof ApiError
          ? caught.message
          : "Die Prüfung ließ sich nicht ausführen.",
      );
    } finally {
      setChecking(null);
    }
  };

  if (domains === null) {
    return <p className="text-sm text-slate-500">Domains werden geladen …</p>;
  }

  return (
    <div className="space-y-4">
      {error ? <Notice tone="error">{error}</Notice> : null}

      <Notice tone="info">
        Eine Domain wirkt erst, wenn dein Reverse Proxy sie auf diese Anwendung
        weiterleitet. Die Weiterleitung erkennt sie am{" "}
        <code className="font-mono text-xs">Host</code>-Header und prüft ihn
        gegen diese Liste — ein unbekannter Hostname endet mit 404.
      </Notice>

      <div className="flex justify-end">
        <Button type="button" onClick={() => setCreating(true)}>
          Domain registrieren
        </Button>
      </div>

      {domains.map((domain) => (
        <Card key={domain.id}>
          <div className="flex flex-wrap items-start justify-between gap-3">
            <div className="min-w-0 flex-1">
              <div className="flex flex-wrap items-center gap-2">
                <h2 className="font-mono font-semibold text-slate-900">
                  {domain.hostname}
                </h2>
                {domain.hostname === baseUrlHostname ? (
                  <Badge tone="accent">aus BASE_URL</Badge>
                ) : null}
                {!domain.isActive ? (
                  <Badge tone="soon">abgeschaltet</Badge>
                ) : null}
                <Badge tone="neutral">
                  {domain.codeCount} {domain.codeCount === 1 ? "Code" : "Codes"}
                </Badge>
              </div>

              {domain.label ? (
                <p className="mt-1 text-sm text-slate-600">{domain.label}</p>
              ) : null}

              <p className="mt-2 text-sm text-slate-600">
                {domain.grants.length === 0
                  ? "Keiner Gruppe zugeteilt — niemand kann hier Codes anlegen."
                  : domain.grants
                      .map(
                        (grant) =>
                          `${grant.groupName}${grant.isDefault ? " (Voreinstellung)" : ""}`,
                      )
                      .join(" · ")}
              </p>

              <div className="mt-4 flex flex-wrap gap-2">
                <Button
                  type="button"
                  variant="secondary"
                  size="sm"
                  disabled={busy === domain.id}
                  onClick={() => {
                    setEditing(domain);
                    setGrants(domain.grants);
                    setGrantError(null);
                  }}
                >
                  <Icon name="pencil" className="size-3.5" />
                  Gruppen zuteilen
                </Button>
                <Button
                  type="button"
                  variant="secondary"
                  size="sm"
                  disabled={checking !== null}
                  onClick={() => void check(domain)}
                >
                  <Icon name="scan" className="size-3.5" />
                  {checking === domain.id ? "Prüft …" : "Prüfen"}
                </Button>
                <Button
                  type="button"
                  variant="secondary"
                  size="sm"
                  disabled={busy === domain.id}
                  onClick={() => void patch(domain.id, { isActive: !domain.isActive })}
                >
                  {domain.isActive ? "Abschalten" : "Einschalten"}
                </Button>
                <Button
                  type="button"
                  variant="ghost"
                  size="sm"
                  className="text-red-600 hover:bg-red-50"
                  disabled={busy === domain.id}
                  onClick={() => setDeleting(domain)}
                >
                  <Icon name="trash" className="size-3.5" />
                  Löschen
                </Button>
              </div>

              {reports[domain.id] ? (
                <DomainBericht bericht={reports[domain.id]} />
              ) : null}
            </div>
          </div>
        </Card>
      ))}

      {/* --------------------------------------------------- Registrieren */}
      <Modal
        open={creating}
        title="Domain registrieren"
        onClose={() => setCreating(false)}
        footer={
          <>
            <Button type="button" variant="secondary" onClick={() => setCreating(false)}>
              Abbrechen
            </Button>
            <Button type="button" onClick={() => void create()}>
              Registrieren
            </Button>
          </>
        }
      >
        <div className="space-y-4">
          {formError ? <Notice tone="error">{formError}</Notice> : null}
          <Field
            label="Hostname"
            htmlFor="new-domain-host"
            hint="Ohne https:// und ohne Pfad — genau so, wie er im Browser steht."
          >
            <TextInput
              id="new-domain-host"
              className="font-mono"
              placeholder="qr.example.com"
              value={form.hostname}
              onChange={(event) =>
                setForm({ ...form, hostname: event.target.value })
              }
            />
          </Field>
          <Field label="Bezeichnung (optional)" htmlFor="new-domain-label">
            <TextInput
              id="new-domain-label"
              placeholder="Kundenprojekt Nord"
              value={form.label}
              onChange={(event) => setForm({ ...form, label: event.target.value })}
            />
          </Field>
        </div>
      </Modal>

      {/* ------------------------------------------------------- Zuteilung */}
      <Modal
        open={editing !== null}
        title={`Gruppen für ${editing?.hostname ?? ""}`}
        onClose={() => setEditing(null)}
        footer={
          <>
            <Button type="button" variant="secondary" onClick={() => setEditing(null)}>
              Abbrechen
            </Button>
            <Button
              type="button"
              disabled={busy === editing?.id}
              onClick={() =>
                editing &&
                void patch(
                  editing.id,
                  {
                    grants: grants.map((grant) => ({
                      groupId: grant.groupId,
                      isDefault: grant.isDefault,
                    })),
                  },
                  () => setEditing(null),
                )
              }
            >
              Speichern
            </Button>
          </>
        }
      >
        <div className="space-y-4">
          {grantError ? <Notice tone="error">{grantError}</Notice> : null}
          <p className="text-sm text-slate-600">
            Mehrere Gruppen dürfen dieselbe Domain nutzen. Die Voreinstellung
            bestimmt, welche Domain beim Anlegen eines Codes vorausgewählt ist.
          </p>

          <ul className="space-y-2">
            {groups.map((group) => {
              const grant = grants.find((entry) => entry.groupId === group.id);
              return (
                <li
                  key={group.id}
                  className="flex flex-wrap items-center gap-3 rounded-lg border border-slate-200 p-2.5"
                >
                  <Checkbox
                    id={`grant-${group.id}`}
                    label={group.name}
                    checked={Boolean(grant)}
                    onChange={(event) =>
                      setGrants((current) =>
                        event.target.checked
                          ? [
                              ...current,
                              {
                                groupId: group.id,
                                groupName: group.name,
                                isDefault: false,
                              },
                            ]
                          : current.filter((entry) => entry.groupId !== group.id),
                      )
                    }
                  />
                  {grant ? (
                    <label className="ml-auto flex items-center gap-1.5 text-xs text-slate-600">
                      <input
                        type="checkbox"
                        className="size-3.5 rounded border-slate-300 accent-indigo-600"
                        checked={grant.isDefault}
                        onChange={(event) =>
                          setGrants((current) =>
                            current.map((entry) =>
                              entry.groupId === group.id
                                ? { ...entry, isDefault: event.target.checked }
                                : entry,
                            ),
                          )
                        }
                      />
                      Voreinstellung
                    </label>
                  ) : null}
                </li>
              );
            })}
          </ul>
        </div>
      </Modal>

      {/* -------------------------------------------------------- Löschen */}
      <Modal
        open={deleting !== null}
        title="Domain löschen?"
        onClose={() => setDeleting(null)}
        footer={
          <>
            <Button type="button" variant="secondary" onClick={() => setDeleting(null)}>
              Abbrechen
            </Button>
            <Button type="button" variant="danger" onClick={() => void remove()}>
              Endgültig löschen
            </Button>
          </>
        }
      >
        {deleting ? (
          <p className="text-sm text-slate-600">
            <strong className="font-mono text-slate-900">
              {deleting.hostname}
            </strong>{" "}
            wird entfernt.
            {deleting.codeCount > 0
              ? ` Unter dieser Domain liegen noch ${deleting.codeCount} ${deleting.codeCount === 1 ? "Code" : "Codes"} — das Löschen wird deshalb abgelehnt. Schalte sie stattdessen ab.`
              : " Es liegen keine Codes darunter."}
          </p>
        ) : null}
      </Modal>
    </div>
  );
}