"use client";

import { useCallback, useEffect, useMemo, useState } from "react";
import { createClient } from "@/lib/supabase/client";
import { formatMessage } from "@/lib/i18n/shared";
import type { Profile, Role } from "@/lib/types";
import { useDict } from "@/components/i18n/LocaleProvider";

interface UserForm {
  id: string | null; // null = neuer Benutzer
  email: string;
  full_name: string;
  role: Role;
  password: string; // bei Bearbeitung optional (leer = unverändert)
  passwordRepeat: string;
}

const EMPTY_FORM: UserForm = {
  id: null,
  email: "",
  full_name: "",
  role: "staff",
  password: "",
  passwordRepeat: "",
};

export default function UserManager() {
  const supabase = useMemo(() => createClient(), []);
  const dict = useDict();
  const roleLabels: Record<Role, string> = {
    admin: dict.common.roleAdmin,
    staff: dict.common.roleStaff,
  };
  const [profiles, setProfiles] = useState<Profile[]>([]);
  const [me, setMe] = useState<string | null>(null);
  const [form, setForm] = useState<UserForm | null>(null);
  const [error, setError] = useState<string | null>(null);
  const [busy, setBusy] = useState(false);

  const load = useCallback(async () => {
    const [{ data: profileData, error: profileError }, { data: userData }] =
      await Promise.all([
        supabase.from("profiles").select("*").order("created_at"),
        supabase.auth.getUser(),
      ]);
    if (profileError)
      setError(formatMessage(dict.userManager.loadError, { message: profileError.message }));
    else setProfiles(profileData as Profile[]);
    setMe(userData.user?.id ?? null);
  }, [supabase, dict]);

  useEffect(() => {
    load();
  }, [load]);

  async function callApi(method: string, body: unknown): Promise<boolean> {
    setBusy(true);
    setError(null);
    try {
      const res = await fetch("/api/admin/users", {
        method,
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(body),
      });
      if (!res.ok) {
        const data = await res.json().catch(() => null);
        setError(data?.error ?? `Fehler (${res.status})`);
        return false;
      }
      return true;
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
      return false;
    } finally {
      setBusy(false);
    }
  }

  async function save(e: React.FormEvent) {
    e.preventDefault();
    if (!form) return;
    if (form.password && form.password !== form.passwordRepeat) {
      setError(dict.userManager.passwordMismatch);
      return;
    }
    const ok = form.id
      ? await callApi("PATCH", {
          id: form.id,
          full_name: form.full_name,
          role: form.role,
          password: form.password || undefined,
        })
      : await callApi("POST", {
          email: form.email,
          full_name: form.full_name,
          role: form.role,
          password: form.password,
        });
    if (ok) {
      setForm(null);
      await load();
    }
  }

  async function remove(profile: Profile) {
    if (
      !window.confirm(
        formatMessage(dict.userManager.confirmDelete, { email: profile.email })
      )
    )
      return;
    if (await callApi("DELETE", { id: profile.id })) await load();
  }

  return (
    <div className="max-w-3xl">
      <div className="flex items-center gap-3 mb-4">
        <h1 className="text-xl font-bold text-[var(--c-primary)] mr-auto">
          {dict.userManager.title}
        </h1>
        <button
          type="button"
          className="btn btn-add"
          onClick={() => setForm(EMPTY_FORM)}
        >
          {dict.userManager.newUser}
        </button>
      </div>

      {error && (
        <p className="mb-3 text-sm text-[var(--c-del)]" role="alert">
          {error}
        </p>
      )}

      {form && (
        <form onSubmit={save} className="card mb-4 space-y-3">
          <h2 className="font-semibold">
            {form.id ? dict.userManager.editUser : dict.userManager.newUser}
          </h2>
          {!form.id && (
            <div>
              <label className="label" htmlFor="user-email">
                {dict.common.email}
              </label>
              <input
                id="user-email"
                type="email"
                className="input"
                value={form.email}
                onChange={(e) => setForm({ ...form, email: e.target.value })}
                required
              />
            </div>
          )}
          <div>
            <label className="label" htmlFor="user-name">
              {dict.common.name}
            </label>
            <input
              id="user-name"
              className="input"
              value={form.full_name}
              onChange={(e) => setForm({ ...form, full_name: e.target.value })}
            />
          </div>
          <div className="max-w-60">
            <label className="label" htmlFor="user-role">
              {dict.common.role}
            </label>
            <select
              id="user-role"
              className="input"
              value={form.role}
              onChange={(e) =>
                setForm({ ...form, role: e.target.value as Role })
              }
            >
              <option value="staff">{dict.common.roleStaff}</option>
              <option value="admin">{dict.common.roleAdmin}</option>
            </select>
          </div>
          <div className="max-w-60">
            <label className="label" htmlFor="user-password">
              {form.id ? dict.userManager.newPasswordLabel : dict.common.password}
            </label>
            <input
              id="user-password"
              type="password"
              className="input"
              value={form.password}
              onChange={(e) => setForm({ ...form, password: e.target.value })}
              minLength={8}
              required={!form.id}
              autoComplete="new-password"
            />
          </div>
          <div className="max-w-60">
            <label className="label" htmlFor="user-password-repeat">
              {dict.userManager.repeatPasswordLabel}
            </label>
            <input
              id="user-password-repeat"
              type="password"
              className="input"
              value={form.passwordRepeat}
              onChange={(e) =>
                setForm({ ...form, passwordRepeat: e.target.value })
              }
              minLength={8}
              required={!form.id || !!form.password}
              autoComplete="new-password"
            />
          </div>
          <div className="flex gap-2">
            <button type="submit" className="btn btn-add" disabled={busy}>
              {dict.common.save}
            </button>
            <button
              type="button"
              className="btn btn-neutral"
              onClick={() => setForm(null)}
            >
              {dict.common.cancel}
            </button>
          </div>
        </form>
      )}

      <ul className="divide-y divide-gray-200 border border-gray-200 rounded-md bg-white">
        {profiles.map((p) => (
          <li key={p.id} className="flex items-center gap-3 px-4 py-2 text-sm">
            <span className="mr-auto">
              <span className="font-semibold">{p.full_name || p.email}</span>{" "}
              <span className="text-gray-500">
                – {p.email} – {roleLabels[p.role]}
              </span>
              {p.id === me && <span className="text-gray-400"> {dict.common.you}</span>}
            </span>
            <button
              type="button"
              className="btn btn-primary"
              onClick={() =>
                setForm({
                  id: p.id,
                  email: p.email,
                  full_name: p.full_name,
                  role: p.role,
                  password: "",
                  passwordRepeat: "",
                })
              }
            >
              {dict.common.edit}
            </button>
            {p.id !== me && (
              <button
                type="button"
                className="btn btn-del"
                onClick={() => remove(p)}
              >
                {dict.common.delete}
              </button>
            )}
          </li>
        ))}
      </ul>
    </div>
  );
}