"use client";

import { useCallback, useEffect, useState } from "react";
import { authFetch, getApiBase } from "../lib/auth";
import { FEATURES, type Feature, type FeatureAccess } from "../lib/features";

type Account = { username: string; role: string; features: FeatureAccess };

export default function FeatureControls({ username, onSaved }: { username?: string; onSaved: () => void }) {
  const [accounts, setAccounts] = useState<Account[] | null>(null);
  const [changes, setChanges] = useState<Partial<FeatureAccess>>({});
  const [busy, setBusy] = useState(false);
  const [message, setMessage] = useState("");
  const [error, setError] = useState("");
  const load = useCallback(async () => {
    const response = await authFetch(
      `${getApiBase()}/admin/users/${username ? encodeURIComponent(username) : "summary"}`,
    );
    if (!response.ok) throw new Error("Could not load feature permissions.");
    const data = await response.json();
    setAccounts(username ? [data.user] : data.users.filter((user: Account) => user.role !== "admin"));
  }, [username]);
  useEffect(() => {
    void load().catch((err) => setError(err.message));
  }, [load]);
  const save = async () => {
    setBusy(true);
    setError("");
    setMessage("");
    try {
      const response = await authFetch(
        `${getApiBase()}/admin/users/${username ? `${encodeURIComponent(username)}/features` : "features/bulk"}`,
        {
          method: "PUT",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify(changes),
        },
      );
      if (!response.ok) throw new Error((await response.json()).detail || "Could not save permissions.");
      const result = await response.json();
      setChanges({});
      setMessage(username ? "Feature access saved." : `Feature access saved for ${result.updated} non-admin accounts.`);
      await load();
      onSaved();
    } catch (err) {
      setError(err instanceof Error ? err.message : "Could not save permissions.");
    } finally {
      setBusy(false);
    }
  };
  const admin = accounts?.some((account) => account.role === "admin");
  return (
    <section className="user-management-panel feature-controls">
      <h3>Feature access</h3>
      <p>
        {username
          ? "Choose which features this person can use in Magent."
          : "Apply feature access to every existing non-admin account, including users outside the current search. Only the checkboxes you change will be applied."}
      </p>
      <p>
        {admin
          ? "Administrators always have access to all features."
          : "Changes take effect on the next page or API request. These permissions control Magent access; linked services keep their own permissions."}
      </p>
      {!accounts && !error && <p>Loading permissions...</p>}
      {FEATURES.map(({ key, label, description }) => {
        const enabled = accounts?.filter((account) => account.features?.[key]).length ?? 0;
        const mixed = !!accounts?.length && enabled > 0 && enabled < accounts.length;
        const changed = Object.hasOwn(changes, key);
        return (
          <label key={key} className="feature-access-row">
            <input
              type="checkbox"
              ref={(input) => {
                if (input) input.indeterminate = !changed && mixed;
              }}
              checked={changes[key] ?? (!!accounts?.length && enabled === accounts.length)}
              disabled={busy || !accounts?.length || admin}
              onChange={(event) => setChanges((previous) => ({ ...previous, [key as Feature]: event.target.checked }))}
            />
            <span>
              <strong>{label}</strong>
              <small>{description}</small>
              {!username && (
                <small>
                  {enabled} of {accounts?.length ?? 0} enabled{mixed && !changed ? " · Mixed access" : ""}
                  {changed ? ` · Will ${changes[key] ? "enable" : "disable"} for everyone` : ""}
                </small>
              )}
            </span>
          </label>
        );
      })}
      {error && (
        <p className="error-banner" role="alert">
          {error}
        </p>
      )}
      {message && (
        <p className="status-banner" role="status">
          {message}
        </p>
      )}
      <div className="admin-inline-actions">
        <button type="button" disabled={busy || !Object.keys(changes).length} onClick={() => void save()}>
          {busy ? "Saving..." : username ? "Save feature access" : "Apply changed features to all users"}
        </button>
        <button
          type="button"
          className="ghost-button"
          disabled={busy || !Object.keys(changes).length}
          onClick={() => setChanges({})}
        >
          Reset changes
        </button>
      </div>
    </section>
  );
}