/**
 * Form builder extension registry.
 * Extensions (e.g. welcome page from ivyforms-pro) register storage keys, defaults, and persistence rules.
 */

export type FormBuilderCanvasPlacement = 'prepend' | 'append'

export interface FormBuilderExtension {
  /** Stable extension id (e.g. welcomePage). */
  id: string
  /** Key on API payload / form extensionData map. */
  storageKey: string
  getDefaults: () => Record<string, unknown>
  normalize: (raw: Record<string, unknown> | null | undefined) => Record<string, unknown>
  /** When omitted, extension data is never auto-included on save. */
  isActiveForFormType?: (formType: string) => boolean
  /** Passed to ivyforms/form_builder/settings_panel_component filter context. */
  settingsPanelContext?: string
  /** When set, extension owns a builder canvas block at this placement (`id` is the selection id). */
  builderCanvas?: FormBuilderCanvasPlacement
}

const extensions: FormBuilderExtension[] = []

export function registerFormBuilderExtension(extension: FormBuilderExtension): void {
  if (extensions.some((e) => e.id === extension.id)) {
    return
  }
  extensions.push(extension)
}

export function getFormBuilderExtensions(): readonly FormBuilderExtension[] {
  return extensions
}

export function getFormBuilderExtension(id: string): FormBuilderExtension | undefined {
  return extensions.find((e) => e.id === id)
}