import { Fragment, h } from "preact";
import { FormProvider, FormProviderProps, FormState } from "./FormProvider.js";
import { RenderAllFieldsByUiConfig, UIFormField } from "./forms.js";
import { TranslatedString } from "@gnu-taler/taler-util";

/**
 * Flexible form uses a DoubleColumForm for design
 * and may have a dynamic properties defined by 
 * behavior function.
 */
export interface FlexibleForm<T extends object> {
  design: DoubleColumnForm;
  behavior?: (form: Partial<T>) => FormState<T>;
}

/**
 * Double column form
 * 
 * Form with sections, every sections have a title and may
 * have a description.
 * Every sections contain a set of fields.
 */
export type DoubleColumnForm = Array<DoubleColumnFormSection | undefined>;

export type DoubleColumnFormSection = {
  title: TranslatedString;
  description?: TranslatedString;
  fields: UIFormField[];
};

/**
 * Form Provider implementation that use FlexibleForm
 * to defined behavior and fields.
 */
export function DefaultForm<T extends object>({
  initial,
  onUpdate,
  form,
  onSubmit,
  children,
  readOnly,
}: Omit<FormProviderProps<T>, "computeFormState"> & { form: FlexibleForm<T> }) {
  return (
    <FormProvider
      initial={initial}
      onUpdate={onUpdate}
      onSubmit={onSubmit}
      readOnly={readOnly}
      computeFormState={form.behavior}
    >
      <div class="space-y-10 divide-y -mt-5 divide-gray-900/10">
        {form.design.map((section, i) => {
          if (!section) return <Fragment />;
          return (
            <div key={i} class="grid grid-cols-1 gap-x-8 gap-y-8 pt-5 md:grid-cols-3">
              <div class="px-4 sm:px-0">
                <h2 class="text-base font-semibold leading-7 text-gray-900">
                  {section.title}
                </h2>
                {section.description && (
                  <p class="mt-1 text-sm leading-6 text-gray-600">
                    {section.description}
                  </p>
                )}
              </div>
              <div class="bg-white shadow-sm ring-1 ring-gray-900/5 rounded-md md:col-span-2">
                <div class="p-3">
                  <div class="grid max-w-2xl grid-cols-1 gap-x-6 gap-y-8 sm:grid-cols-6">
                    <RenderAllFieldsByUiConfig
                      key={i}
                      fields={section.fields}
                    />
                  </div>
                </div>
              </div>
            </div>
          );
        })}
      </div>
      {children}
    </FormProvider>
  );
}
