import {Path} from './Path';
import {Container} from './Container';
import {InkObject} from './Object';

export class Pointer{
  public container: Container | null = null;
  public index: number = -1;

	constructor();
	constructor(container: Container | null, index: number)
	constructor(){
		if (arguments.length === 2) {
			this.container = arguments[0];
			this.index = arguments[1];
		}
	}

	public Resolve(): InkObject | null{
		if (this.index < 0) return this.container;
		if (this.container == null) return null;
		if (this.container.content.length == 0) return this.container;
		if (this.index >= this.container.content.length) return null;

		return this.container.content[this.index];
	}

	get isNull(): boolean{
		return this.container == null;
	}

	get path(): Path | null{
		if (this.isNull) return null;

		if (this.index >= 0)
			return this.container!.path.PathByAppendingComponent(new Path.Component(this.index));
		else
			return this.container!.path;
	}

	public toString(): string{
		if (!this.container)
			return 'Ink Pointer (null)';

		return 'Ink Pointer -> ' + this.container.path.toString() + ' -- index ' + this.index;
	}

	// This method does not exist in the original C# code, but is here to maintain the
	// value semantics of Pointer.
	public copy(): Pointer{
		return new Pointer(this.container, this.index);
	}

	public static StartOf(container: Container | null): Pointer{
		return new Pointer(container, 0);
	}

	public static get Null(): Pointer {
		return new Pointer(null, -1);
	}
}