upstream-affine/blocksuite/framework/std/src/gfx/interactivity/extension/base.ts

import { type Container, createIdentifier } from '@blocksuite/global/di';
import { BlockSuiteError, ErrorCode } from '@blocksuite/global/exceptions';
import { Extension } from '@blocksuite/store';

import type { GfxController } from '../../controller.js';
import { GfxControllerIdentifier } from '../../identifiers.js';
import type { GfxModel } from '../../model/model.js';
import type { GfxInteractivityContext, SupportedEvents } from '../event.js';
import type { ExtensionElementsCloneContext } from '../types/clone.js';
import type {
  DragExtensionInitializeContext,
  ExtensionDragEndContext,
  ExtensionDragMoveContext,
  ExtensionDragStartContext,
} from '../types/drag.js';
import type {
  ExtensionElementResizeContext,
  ExtensionElementResizeEndContext,
  ExtensionElementResizeMoveContext,
  ExtensionElementResizeStartContext,
} from '../types/resize.js';
import type { ExtensionElementSelectContext } from '../types/select.js';

export const InteractivityExtensionIdentifier =
  createIdentifier<InteractivityExtension>('interactivity-extension');

export class InteractivityExtension extends Extension {
  static key: string;

  get std() {
    return this.gfx.std;
  }

  event: Omit<InteractivityEventAPI, 'emit'> = new InteractivityEventAPI();

  action: Omit<InteractivityActionAPI, 'emit'> = new InteractivityActionAPI();

  constructor(protected readonly gfx: GfxController) {
    super();
  }

  mounted() {}

  /**
   * Override this method should call `super.unmounted()`
   */
  unmounted() {
    this.event.destroy();
    this.action.destroy();
  }

  static override setup(di: Container) {
    if (!this.key) {
      throw new BlockSuiteError(
        ErrorCode.ValueNotExists,
        'key is not defined in the InteractivityExtension'
      );
    }

    di.add(
      this as unknown as { new (gfx: GfxController): InteractivityExtension },
      [GfxControllerIdentifier]
    );
    di.addImpl(InteractivityExtensionIdentifier(this.key), provider =>
      provider.get(this)
    );
  }
}

export class InteractivityEventAPI {
  private readonly _handlersMap = new Map<
    SupportedEvents,
    ((evt: GfxInteractivityContext) => void)[]
  >();

  on(
    eventName: SupportedEvents,
    handler: (evt: GfxInteractivityContext) => void
  ) {
    const handlers = this._handlersMap.get(eventName) ?? [];
    handlers.push(handler);
    this._handlersMap.set(eventName, handlers);

    return () => {
      const idx = handlers.indexOf(handler);

      if (idx > -1) {
        handlers.splice(idx, 1);
      }
    };
  }

  emit(eventName: SupportedEvents, evt: GfxInteractivityContext) {
    const handlers = this._handlersMap.get(eventName);
    if (!handlers) {
      return;
    }

    for (const handler of handlers) {
      handler(evt);
    }
  }

  destroy() {
    this._handlersMap.clear();
  }
}

export type ActionContextMap = {
  dragInitialize: {
    context: DragExtensionInitializeContext;
    returnType: {
      onDragStart?: (context: ExtensionDragStartContext) => void;
      onDragMove?: (context: ExtensionDragMoveContext) => void;
      onDragEnd?: (context: ExtensionDragEndContext) => void;
      clear?: () => void;
    };
  };
  elementsClone: {
    context: ExtensionElementsCloneContext;
    returnType: Promise<
      | {
          elements: GfxModel[];
        }
      | undefined
    >;
  };
  elementResize: {
    context: ExtensionElementResizeContext;
    returnType: {
      onResizeStart?: (context: ExtensionElementResizeStartContext) => void;
      onResizeMove?: (context: ExtensionElementResizeMoveContext) => void;
      onResizeEnd?: (context: ExtensionElementResizeEndContext) => void;
    };
  };
  elementSelect: {
    context: ExtensionElementSelectContext;
    returnType: void;
  };
};

export class InteractivityActionAPI {
  private readonly _handlers: Partial<{
    [K in keyof ActionContextMap]: (
      ctx: ActionContextMap[K]['context']
    ) => ActionContextMap[K]['returnType'];
  }> = {};

  onDragInitialize(
    handler: (
      ctx: ActionContextMap['dragInitialize']['context']
    ) => ActionContextMap['dragInitialize']['returnType']
  ) {
    this._handlers['dragInitialize'] = handler;

    return () => {
      delete this._handlers['dragInitialize'];
    };
  }

  onElementResize(
    handler: (
      ctx: ActionContextMap['elementResize']['context']
    ) => ActionContextMap['elementResize']['returnType']
  ) {
    this._handlers['elementResize'] = handler;

    return () => {
      return delete this._handlers['elementResize'];
    };
  }

  onRequestElementsClone(
    handler: (
      ctx: ActionContextMap['elementsClone']['context']
    ) => ActionContextMap['elementsClone']['returnType']
  ) {
    this._handlers['elementsClone'] = handler;

    return () => {
      return delete this._handlers['elementsClone'];
    };
  }

  onElementSelect(
    handler: (
      ctx: ActionContextMap['elementSelect']['context']
    ) => ActionContextMap['elementSelect']['returnType']
  ) {
    this._handlers['elementSelect'] = handler;

    return () => {
      return delete this._handlers['elementSelect'];
    };
  }

  emit<K extends keyof ActionContextMap>(
    event: K,
    context: ActionContextMap[K]['context']
  ): ActionContextMap[K]['returnType'] | undefined {
    const handler = this._handlers[event];

    return handler?.(context);
  }

  destroy() {
    for (const key in this._handlers) {
      delete this._handlers[key as keyof typeof this._handlers];
    }
  }
}