import GridError from "../../errors/graph/layering/grid/GridError.js";

/**
 * Стека для укладка графа на двумерной плоскости
 */
export class Grid<TElement> {
	/**
     * Ячейки сетки, которые могут хранить в себе элементы
     * @protected
     */
	protected readonly _cells: (TElement | undefined)[][];

	/**
	 * Количество элементов в каждой из строк сетки
	 * @private
	 */
	private readonly width: number;
	/**
	 * Количество элементов в каждом из столбцов сетки
	 * @private
	 */
	private readonly height: number;

	public constructor(width: number, height: number) {
		this.width = width;
		this.height = height;
		this._cells = Array.from({ length: height }, () => new Array(width));
	}

	public set(row: number, col: number, value: TElement) : this {
		this.validate(row, col);

		if(row >= this._cells.length)
			this._cells.length = row + 1;

		if(this._cells[row] === undefined)
			this._cells[row] = [];

		const r = this._cells[row]!;

		if(col >= r.length)
			r.length = col + 1;

		r[col] = value;

		return this;
	}

	public get(row: number, col: number) : TElement | undefined {
		this.validate(row, col);
		return this._cells[row]![col];
	}

	public delete(row: number, col: number) : this {
		this.validate(row, col);

		const r = this._cells[row];
		if(!r)
			return this;

		delete r[col];

		return this;
	}

	public isEmpty(row: number, col: number) : boolean {
		this.validate(row, col);

		const r = this._cells[row];
		if(!r)
			return true;

		return r[col] === undefined;
	}

	public getSize(): { width: number; height: number } {
		return { width: this.width, height: this.height };
	}

	protected validate(row: number, col: number) : void {
		if(row < 0 || row >= this._cells.length)
			throw new GridError(`Row index is out of bounds [0, ${this._cells.length - 1}]: ${row}`);

		const r = this._cells[row]!;

		if(col < 0 || col >= r.length)
			throw new GridError(`Column index is out of bounds [0, ${r.length - 1}]: ${row}`);
	}
}