scroll/src/common/editor/editor.ts

import Ansi from './ansi.ts';
import Buffer from './buffer.ts';
import { importDefaultForRuntime } from '../runtime.ts';
import { ctrl_key } from '../strings.ts';
import { ITerminalSize } from '../types.ts';

export class Editor {
	#buffer: Buffer;
	#screenRows: number;
	#screenCols: number;
	constructor(terminalSize: ITerminalSize) {
		this.#buffer = new Buffer();
		this.#screenRows = terminalSize.rows;
		this.#screenCols = terminalSize.cols;
	}

	/**
	 * Determine what to do based on input
	 * @param input - the decoded chunk of stdin
	 */
	public processKeyPress(input: string): boolean {
		switch (input) {
			case ctrl_key('q'):
				this.clearScreen();
				return false;

			default:
				return true;
		}
	}

	/**
	 * Clear the screen and write out the buffer
	 */
	public async refreshScreen(): Promise<void> {
		const { write } = await importDefaultForRuntime('terminal_io');

		this.clearScreen();
		this.drawRows();

		await write(this.#buffer.getBuffer());
		this.#buffer.clear();
	}

	private drawRows(): void {
		for (let y = 0; y <= this.#screenRows; y++) {
			this.#buffer.appendLine('~');
		}
	}

	private clearScreen(): void {
		this.#buffer.append(Ansi.ClearScreen);
		this.#buffer.append(Ansi.ResetCursor);
	}
}