/**
 * Copyright (c) 2018-present, Blue Marble Payroll, LLC
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

import { Interpreter, ResolverFunction as InterpreterResolverFunction } from "./interpreter/interpreter";
import { NodeVisitor } from "./interpreter/node_visitor";
import { ILexer, SimpleLexer } from "./lexer/lexer";
import { Node } from "./parser/ast/node";
import { Parser } from "./parser/parser";

export type IResolverFunction = (value: string, input: any) => boolean;

const objectResolver: IResolverFunction = (value: string, input: any): boolean => input && !!input[value];

const cache: Record<string, Node> = {};

function resolverWrapper(input: any, resolver: IResolverFunction): InterpreterResolverFunction {
  if (resolver) {
    return (expr: string) => resolver(expr, input);
  }

  return (expr: string) => objectResolver(expr, input);
}

function get(expression: string): Node {
  if (cache[expression]) {
    return cache[expression];
  }

  const lexer: ILexer = new SimpleLexer(expression);
  const parser: Parser = new Parser(lexer);

  return cache[expression] = parser.parse();
}

export function evaluate(expression: string, input: any, resolver?: IResolverFunction): boolean {
  const rootNode: Node = get(expression);
  const wrapper: InterpreterResolverFunction = resolverWrapper(input, resolver);
  const interpreter: NodeVisitor = new Interpreter(wrapper);

  return interpreter.visit(rootNode);
}