import { STDIN_FILENO, TCSANOW, ITermios, TERMIOS_SIZE } from "../common/termios";
import { cfmakeraw, tcgetattr, tcsetattr, ptr } from "./ffi";

/**
 * Implementation to toggle raw mode with Bun runtime
 */
export class Termios implements ITermios {
	/**
	 * Are we in raw mode?
	 * @private
	 */
	#inRawMode:boolean;

	/**
	 * The saved version of the termios struct for cooked/canonical mode
	 * @private
	 */
	#cookedTermios: Uint8Array;

	/**
	 * The data for the termios struct we are manipulating
	 * @private
	 */
	#termios: Uint8Array;

	/**
	 * The pointer to the termios struct
	 * @private		// this.#ptr = ptr(this.#termios);
	 */
	#ptr: any;

	constructor() {
		this.#inRawMode = false;

		// These are the TypedArrays linked to the raw pointer data
		this.#cookedTermios = new Uint8Array(TERMIOS_SIZE);
		this.#termios = new Uint8Array(TERMIOS_SIZE);

		// The current pointer for C
		this.#ptr = ptr(this.#termios);
	}

	get inRawMode() {
		return this.#inRawMode;
	}

	enableRawMode() {
		if (this.#inRawMode) {
			throw new Error('Can not enable raw mode when in raw mode');
		}

		// Get the current termios settings
		tcgetattr(STDIN_FILENO, this.#ptr);

		// The #ptr property is pointing to the #termios TypedArray. As the pointer
		// is manipulated, the TypedArray is as well. We will use this to save
		// the original canonical/cooked terminal settings for disabling raw mode later.
		this.#cookedTermios = new Uint8Array(this.#termios, 0, 60);

		// Update termios struct with raw settings
		cfmakeraw(this.#ptr);

		// Actually set the new termios settings
		tcsetattr(STDIN_FILENO, TCSANOW, this.#ptr);
		this.#inRawMode = true;
	}

	disableRawMode() {
		// Don't even bother throwing an error if we try to disable raw mode
		// and aren't in raw mode. It just doesn't really matter.
		if (!this.#inRawMode) {
			return;
		}

		const oldTermiosPtr = ptr(this.#cookedTermios);
		tcsetattr(STDIN_FILENO, TCSANOW, oldTermiosPtr);

		this.#inRawMode = false;
	}
}