textui/ui.ts

import { BufferDrawing, BufferSize, CharBuffer } from "./base.ts";
import { Display } from "./display.ts";

/**
 * Common abstraction for a textual UI
 */
export class TextUI {
  private screen = new CharBuffer({ w: 1, h: 1 });

  constructor(private display: Display) {
  }

  get drawing(): BufferDrawing {
    return new BufferDrawing(this.screen);
  }

  /**
   * Initializes the display
   */
  async init(): Promise<void> {
    var size = await this.display.getSize();
    this.screen = new CharBuffer(size);
    await this.display.clear();
  }

  /**
   * Get the current display size
   */
  getSize(): BufferSize {
    return this.screen.getSize();
  }

  /**
   * Flush the internal buffer to the display
   */
  async flush(): Promise<void> {
    // TODO only dirty chars
    const { w, h } = this.screen.getSize();
    for (let x = 0; x < w; x++) {
      for (let y = 0; y < h; y++) {
        await this.display.setChar({ x, y }, this.screen.get({ x, y }));
      }
    }
  }

  /**
   * Start the event loop, waiting for input
   */
  async loop(refresh = 1000): Promise<void> {
    while (true) {
      await this.flush();
      await new Promise((resolve) => setTimeout(resolve, refresh));
    }
  }
}