import {
  ElementModel,
  ElementTypeIri,
  LinkTypeIri,
  PropertyTypeIri,
  LinkModel,
} from "./model";
import { LinkDirection } from "../diagram/elements";
import { CancellationToken } from "../viewUtils/async";

export interface MetadataApi {
  /**
   * Can user create element and link from this element?
   */
  canDropOnCanvas(
    source: ElementModel,
    ct: CancellationToken
  ): Promise<boolean>;

  /**
   * Can we create link between two elements? Maybe it's unnesesary.
   */
  canDropOnElement(
    source: ElementModel,
    target: ElementModel,
    ct: CancellationToken
  ): Promise<boolean>;

  /**
   * Links of which types can we create between elements?
   */
  possibleLinkTypes(
    source: ElementModel,
    target: ElementModel,
    ct: CancellationToken
  ): Promise<DirectedLinkType[]>;

  /**
   * If new element is created by dragging link from existing element, this should return available element types.
   */
  typesOfElementsDraggedFrom(
    source: ElementModel,
    ct: CancellationToken
  ): Promise<ElementTypeIri[]>;

  /**
   * List properties for type meant to be edited in-place.
   */
  propertiesForType(
    type: ElementTypeIri,
    ct: CancellationToken
  ): Promise<PropertyTypeIri[]>;

  filterConstructibleTypes(
    types: ReadonlySet<ElementTypeIri>,
    ct: CancellationToken
  ): Promise<ReadonlySet<ElementTypeIri>>;

  canDeleteElement(
    element: ElementModel,
    ct: CancellationToken
  ): Promise<boolean>;

  canEditElement(
    element: ElementModel,
    ct: CancellationToken
  ): Promise<boolean>;

  canLinkElement(
    element: ElementModel,
    ct: CancellationToken
  ): Promise<boolean>;

  canDeleteLink(
    link: LinkModel,
    source: ElementModel,
    target: ElementModel,
    ct: CancellationToken
  ): Promise<boolean>;

  canEditLink(
    link: LinkModel,
    source: ElementModel,
    target: ElementModel,
    ct: CancellationToken
  ): Promise<boolean>;

  generateNewElement(
    types: readonly ElementTypeIri[],
    ct: CancellationToken
  ): Promise<ElementModel>;
}

export interface DirectedLinkType {
  readonly linkTypeIri: LinkTypeIri;
  readonly direction: LinkDirection;
}