import { formsApi } from "../../../services/api";
import type { Form, FormField, FormWithSubmissionCount } from "../../../services/api/types";

export const DEFAULT_REGISTRATION_FORM_NAME = "Registration Form";

export const DEFAULT_REGISTRATION_FORM_FIELDS: FormField[] = [
  { label: "First name", type: "text", required: true, mapsTo: "firstName", isFixed: true },
  { label: "Last name", type: "text", required: true, mapsTo: "lastName", isFixed: true },
  { label: "Email", type: "email", required: true, mapsTo: "email", isFixed: true },
];

/** Registration form linked to the event, or null when the default template should be used. */
export async function resolveEventRegistrationForm(
  eventId: string,
  linkedFormId?: string | null,
): Promise<FormWithSubmissionCount | null> {
  const forms = await formsApi.listForEvent(eventId);
  const registrationForms = forms.filter((f) => f.type === "registration");

  const id = linkedFormId?.trim();
  if (id) {
    const linked = registrationForms.find((f) => f._id === id);
    if (linked) return linked;
    try {
      const form = await formsApi.get(id);
      if (form.type === "registration") {
        const count = registrationForms.find((f) => f._id === form._id)?.submissionCount ?? 0;
        return { ...form, submissionCount: count };
      }
    } catch {
      // fall through to first registration form or default
    }
  }

  return registrationForms[0] ?? null;
}

export function registrationFormDisplayName(form: Form | null): string {
  return form?.name?.trim() || DEFAULT_REGISTRATION_FORM_NAME;
}