1 files changed, 59 insertions, 0 deletions
diff --git a/packages/exchange-backoffice-ui/src/handlers/FormProvider.tsx b/packages/exchange-backoffice-ui/src/handlers/FormProvider.tsx
new file mode 100644
index 000000000..4019fbc89
--- /dev/null
+++ b/packages/exchange-backoffice-ui/src/handlers/FormProvider.tsx
@@ -0,0 +1,59 @@
+import { AbsoluteTime, TranslatedString } from "@gnu-taler/taler-util";
+import { ComponentChildren, VNode, createContext, h } from "preact";
+import { MutableRef, StateUpdater, useRef } from "preact/hooks";
+
+export interface FormType<T> {
+  value: MutableRef<Partial<T>>;
+  initialValue?: Partial<T>;
+  onUpdate?: StateUpdater<T>;
+  computeFormState?: (v: T) => FormState<T>;
+}
+
+//@ts-ignore
+export const FormContext = createContext<FormType<any>>({});
+
+export type FormState<T> = {
+  [field in keyof T]?: T[field] extends AbsoluteTime
+    ? Partial<InputFieldState>
+    : T[field] extends Array<infer P>
+    ? Partial<InputArrayFieldState<P>>
+    : T[field] extends object
+    ? FormState<T[field]>
+    : Partial<InputFieldState>;
+};
+
+export interface InputFieldState {
+  /* should show the error */
+  error?: TranslatedString;
+  /* should not allow to edit */
+  readonly: boolean;
+  /* should show as disable */
+  disabled: boolean;
+  /* should not show */
+  hidden: boolean;
+}
+
+export interface InputArrayFieldState<T> extends InputFieldState {
+  elements: FormState<T>[];
+}
+
+export function FormProvider<T>({
+  children,
+  initialValue,
+  onUpdate,
+  computeFormState,
+}: {
+  initialValue?: Partial<T>;
+  onUpdate?: (v: Partial<T>) => void;
+  computeFormState?: (v: T) => FormState<T>;
+  children: ComponentChildren;
+}): VNode {
+  const value = useRef(initialValue ?? {});
+  return (
+    <FormContext.Provider
+      value={{ initialValue, value, onUpdate, computeFormState }}
+    >
+      <form>{children}</form>
+    </FormContext.Provider>
+  );
+}