import { useEffectEvent } from "react";
import { useResource, resource } from "@assistant-ui/tap";
import type {
  Unstable_TriggerAdapter,
  Unstable_TriggerCategory,
  Unstable_TriggerItem,
} from "@assistant-ui/core";
import type { AssistantClient } from "@assistant-ui/store";
import { TriggerDetectionResource } from "./triggerDetectionResource";
import { TriggerKeyboardResource } from "./triggerKeyboardResource";
import { TriggerNavigationResource } from "./triggerNavigationResource";
import {
  TriggerSelectionResource,
  type SelectItemOverride,
  type TriggerBehavior,
} from "./triggerSelectionResource";
import type { TriggerMatcher } from "./detectTrigger";

export type { SelectItemOverride, TriggerBehavior };
export type { TriggerPopoverKeyEvent } from "./triggerKeyboardResource";

/** @deprecated Use `TriggerBehavior`. */
export type OnSelectBehavior = TriggerBehavior;

export type TriggerPopoverResourceOutput = {
  readonly open: boolean;
  readonly query: string;
  readonly activeCategoryId: string | null;
  readonly categories: readonly Unstable_TriggerCategory[];
  readonly items: readonly Unstable_TriggerItem[];
  readonly highlightedIndex: number;
  readonly isSearchMode: boolean;
  /** Whether the adapter is currently resolving items (async sources). */
  readonly isLoading: boolean;
  /** Stable ID prefix for generating accessible element IDs. */
  readonly popoverId: string;
  /** ID of the currently highlighted item (for aria-activedescendant). */
  readonly highlightedItemId: string | undefined;

  selectCategory(categoryId: string): void;
  goBack(): void;
  selectItem(item: Unstable_TriggerItem): void;
  close(): void;
  /** Move the highlight to an entry index (e.g. from pointer hover). Out-of-range values are ignored. */
  highlightIndex(index: number): void;
  handleKeyDown(e: {
    readonly key: string;
    readonly shiftKey: boolean;
    preventDefault(): void;
  }): boolean;

  setCursorPosition(pos: number): void;
  registerSelectItemOverride(fn: SelectItemOverride): () => void;
};

/** Composes detection, navigation, keyboard, and selection sub-resources. */
const useTriggerPopoverResource = ({
  adapter,
  text,
  triggerChar,
  matcher,
  behavior,
  aui,
  popoverId,
  isLoading,
}: {
  adapter: Unstable_TriggerAdapter | undefined;
  text: string;
  triggerChar: string;
  matcher: TriggerMatcher | undefined;
  behavior: TriggerBehavior | undefined;
  aui: AssistantClient;
  /** Stable ID for accessible element IDs (pass React's useId() from component layer). */
  popoverId: string;
  isLoading: boolean;
}): TriggerPopoverResourceOutput => {
  const detection = useResource(
    TriggerDetectionResource({ text, triggerChar, matcher }),
  );

  const open =
    detection.trigger !== null &&
    adapter !== undefined &&
    behavior !== undefined;

  const navigation = useResource(
    TriggerNavigationResource({
      adapter,
      query: detection.query,
      open,
    }),
  );

  const onSelected = useEffectEvent(() => {
    navigation.goBack();
  });

  const selection = useResource(
    TriggerSelectionResource({
      behavior,
      trigger: detection.trigger,
      aui,
      triggerChar,
      setCursorPosition: detection.setCursorPosition,
      onSelected,
    }),
  );

  const keyboard = useResource(
    TriggerKeyboardResource({
      navigableList: navigation.navigableList,
      isSearchMode: navigation.isSearchMode,
      activeCategoryId: navigation.activeCategoryId,
      query: detection.query,
      popoverId,
      open,
      selectItem: selection.selectItem,
      selectCategory: navigation.selectCategory,
      goBack: navigation.goBack,
      close: selection.close,
    }),
  );

  return {
    open,
    query: detection.query,
    activeCategoryId: navigation.activeCategoryId,
    categories: navigation.categories,
    items: navigation.items,
    highlightedIndex: keyboard.highlightedIndex,
    isSearchMode: navigation.isSearchMode,
    isLoading,
    popoverId,
    highlightedItemId: keyboard.highlightedItemId,
    selectCategory: navigation.selectCategory,
    goBack: navigation.goBack,
    selectItem: selection.selectItem,
    close: selection.close,
    highlightIndex: keyboard.highlightIndex,
    handleKeyDown: keyboard.handleKeyDown,
    setCursorPosition: detection.setCursorPosition,
    registerSelectItemOverride: selection.registerSelectItemOverride,
  };
};

export const TriggerPopoverResource = resource(useTriggerPopoverResource);