import { Scalar, CustomScalar } from "@nestjs/graphql";
import { Kind, ValueNode } from "graphql";
import { fromCursor, toCursor } from "../utils";

@Scalar("Cursor")
export class CursorScalar implements CustomScalar<string, string> {
  description = "Cursor scalar type";

  parseValue(value: string): string | null {
    return fromCursor(value);
  }

  serialize(value: string): string | null {
    if (value) {
      return toCursor({ value });
    } else {
      return null;
    }
  }
  //@ts-ignore
  parseLiteral(ast: ValueNode): string | null {
    if (ast.kind === Kind.STRING) {
      return fromCursor(ast.value);
    }
    return null;
  }
}