import { SvelteComponentTyped } from "svelte";
import type { SvelteHTMLElements } from "svelte/elements";

export type MultiSelectItemText = string;

export type MultiSelectItem<Id = any> = {
  id: Id;
  text: MultiSelectItemText;
  /** Whether the item is disabled */
  disabled?: boolean;
  /** Whether this item acts as a "select all" toggle */
  isSelectAll?: boolean;
};

export type CarbonMultiSelectContext = {
  declareRef: (data: {
    key: "field" | "selection";
    ref: HTMLDivElement | HTMLButtonElement;
  }) => void;
};

type $RestProps = SvelteHTMLElements["input"];

type $Props<Item extends MultiSelectItem<any> = MultiSelectItem<any>> = {
  /**
   * Set the multiselect items.
   * @default []
   */
  items?: ReadonlyArray<Item>;

  /**
   * Override the display of a multiselect item.
   */
  itemToString?: (item: Item) => string | Item["id"];

  /**
   * Override the item name, title, labelText, or value passed to the user-selectable checkbox input as well as the hidden inputs.
   */
  itemToInput?: (item: Item) => {
    name?: string;
    labelText?: any;
    title?: string;
    value?: string;
  };

  /**
   * Set the selected ids.
   * @default []
   */
  selectedIds?: ReadonlyArray<Item["id"]>;

  /**
   * Specify the multiselect value.
   * @default ""
   */
  value?: string;

  /**
   * Set the size of the multiselect.
   * @default undefined
   */
  size?: "sm" | "lg" | "xl";

  /**
   * Specify the type of multiselect.
   * @default "default"
   */
  type?: "default" | "inline";

  /**
   * Specify the direction of the multiselect dropdown menu.
   * @default "bottom"
   */
  direction?: "bottom" | "top";

  /**
   * Specify the selection feedback after selecting items.
   * @default "top-after-reopen"
   */
  selectionFeedback?: "top" | "fixed" | "top-after-reopen";

  /**
   * Set to `true` to disable the dropdown
   * @default false
   */
  disabled?: boolean;

  /**
   * Set to `true` to filter items
   * @default false
   */
  filterable?: boolean;

  /**
   * Override the filtering logic.
   * The default filtering is an exact string comparison.
   */
  filterItem?: (item: Item, value: string) => boolean;

  /**
   * Set to `true` to open the dropdown.
   * @default false
   */
  open?: boolean;

  /**
   * Set to `true` to enable the light variant
   * @default false
   */
  light?: boolean;

  /**
   * Set to `true` to use the fluid variant.
   * Inherited from the parent `FluidForm` context,
   * so it does not need to be set when used inside `FluidForm`.
   * Cannot be combined with the inline variant.
   * @default false
   */
  fluid?: boolean;

  /**
   * Set to `true` to render condensed menu items in the fluid variant.
   * Menu items use the default height instead of the taller fluid height.
   * Only applies when the fluid variant is active.
   * @default false
   */
  condensed?: boolean;

  /**
   * Specify the locale
   * @default "en"
   */
  locale?: string;

  /**
   * Specify the placeholder text
   * @default ""
   */
  placeholder?: string;

  /**
   * Override the sorting logic.
   * The default sorting compare the item text value.
   */
  sortItem?: ((a: Item, b: Item) => number) | (() => void);

  /**
   * Override the chevron icon label based on the open state.
   * Defaults to "Open menu" when closed and "Close menu" when open.
   * @default undefined
   */
  translateWithId?: (
    id: import("../ListBox/ListBoxMenuIcon.svelte").ListBoxMenuIconTranslationId,
  ) => string;

  /**
   * Override the label of the clear button when the input has a selection.
   * Defaults to "Clear selected item" and "Clear all items" if more than one item is selected.
   * @default undefined
   */
  translateWithIdSelection?: (
    id: import("../ListBox/ListBoxSelection.svelte").ListBoxSelectionTranslationId,
  ) => string;

  /**
   * Specify the label text
   * @default ""
   */
  labelText?: string;

  /**
   * Set to `true` to pass the item to `itemToString` in the checkbox
   * @default false
   */
  useTitleInItem?: boolean;

  /**
   * Set to `true` to indicate an invalid state
   * @default false
   */
  invalid?: boolean;

  /**
   * Specify the invalid state text
   * @default ""
   */
  invalidText?: string;

  /**
   * Set to `true` to indicate a warning state
   * @default false
   */
  warn?: boolean;

  /**
   * Specify the warning state text
   * @default ""
   */
  warnText?: string;

  /**
   * Specify the helper text
   * @default ""
   */
  helperText?: string;

  /**
   * Specify the list box label
   * @default ""
   */
  label?: string;

  /**
   * Set to `true` to visually hide the label text
   * @default false
   */
  hideLabel?: boolean;

  /**
   * Set an id for the list box component
   * @default `ccs-${Math.random().toString(36)}`
   */
  id?: string;

  /**
   * Set to `true` to use the read-only variant
   * @default false
   */
  readonly?: boolean;

  /**
   * Specify a name attribute for the select.
   * @default undefined
   */
  name?: string;

  /**
   * Obtain a reference to the input HTML element.
   * @default null
   */
  inputRef?: null | HTMLInputElement;

  /**
   * Obtain a reference to the outer div element.
   * @default null
   */
  multiSelectRef?: null | HTMLDivElement;

  /**
   * Obtain a reference to the field box element.
   * @default null
   */
  fieldRef?: null | HTMLButtonElement;

  /**
   * Obtain a reference to the selection element.
   * @default null
   */
  selectionRef?: null | HTMLDivElement;

  /**
   * Id of the highlighted ListBoxMenuItem.
   * @default null
   */
  highlightedId?: null | Item["id"];

  /**
   * The post-sort, post-selection-feedback list of items rendered by the dropdown.
   * Bind to read the resolved order without recomputing it from `items`, `selectedIds`, and `sortItem`.
   * @default []
   */
  sortedItems?: ReadonlyArray<Item & { checked: boolean }>;

  /**
   * Enable virtualization for large lists. Virtualization renders only the items currently visible in the viewport, improving performance for large lists.
   *
   * By default, virtualization is automatically enabled for lists with more than 100 items.
   *
   * Set `virtualize={false}` to explicitly disable virtualization, even for large lists.
   *
   * Set `virtualize={true}` to explicitly enable virtualization with default settings.
   *
   * Provide an object to customize virtualization behavior:
   * - `itemHeight` (default: size-based, or 64px for fluid unless `condensed`): Height of each item in pixels. Override when custom slots change row height.
   * - `containerHeight` (default: 300): The maximum height in pixels of the dropdown container.
   * - `overscan` (default: 3): The number of extra items to render above and below the viewport for smoother scrolling. Higher values may cause more flickering during very fast scrolling.
   * - `threshold` (default: 100): The minimum number of items required before virtualization activates. Lists with fewer items will render all items normally without virtualization.
   * - `maxItems` (default: undefined): The maximum number of items to render. When undefined, all visible items are rendered.
   * @default undefined
   */
  virtualize?:
    | undefined
    | boolean
    | {
        itemHeight?: number;
        containerHeight?: number;
        overscan?: number;
        threshold?: number;
        maxItems?: number;
      };

  /**
   * Set to `true` to render the dropdown menu in a portal,
   * allowing it to escape containers with `overflow: hidden`.
   * When inside a Modal, defaults to `true` unless explicitly set to `false`.
   * @default undefined
   */
  portalMenu?: boolean | undefined;

  /**
   * Obtain a reference to the list HTML element.
   * @default null
   */
  listRef?: null | HTMLDivElement;

  labelChildren?: (this: void) => void;

  children?: (
    this: void,
    ...args: [
      { item: Item; index: number; selected: boolean; highlighted: boolean },
    ]
  ) => void;

  [key: `data-${string}`]: unknown;
};

export type MultiSelectProps<
  Item extends MultiSelectItem<any> = MultiSelectItem<any>,
> = Omit<$RestProps, keyof $Props<Item>> & $Props<Item>;

export default class MultiSelect<
  Item extends MultiSelectItem<any> = MultiSelectItem<any>,
> extends SvelteComponentTyped<
  MultiSelectProps<Item>,
  {
    blur: FocusEvent | CustomEvent<FocusEvent>;
    clear: CustomEvent<null>;
    close: CustomEvent<{ trigger: "escape-key" | "outside-click" }>;
    focus: WindowEventMap["focus"];
    input: WindowEventMap["input"];
    keydown: WindowEventMap["keydown"];
    keyup: WindowEventMap["keyup"];
    paste: WindowEventMap["paste"];
    scroll: WindowEventMap["scroll"];
    select: CustomEvent<{
      selectedIds: Item["id"][];
      selected: Item[];
      unselected: Item[];
    }>;
  },
  {
    default: {
      item: Item;
      index: number;
      selected: boolean;
      highlighted: boolean;
    };
    labelChildren: Record<string, never>;
  }
> {}