// SPDX-FileCopyrightText: 2022 Johannes Loher
//
// SPDX-License-Identifier: MIT

import { describe, expect, it } from "vitest";

import { literals, safeOperators } from "../../src/expression-evaluation/grammar";
import { Validator } from "../../src/expression-evaluation/validator";

describe("Validator", () => {
    it("allows identifier according to the given predicate", () => {
        // given
        const predicate = (identifier: string) => identifier === "true";
        const validator = new Validator(predicate);
        const input = "true";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).not.toThrow();
    });

    it("disallows identifier according to the given predicate", () => {
        // given
        const predicate = (identifier: string) => identifier === "false";
        const validator = new Validator(predicate);
        const input = "true";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).toThrowError("'true' is not an allowed identifier");
    });

    it("allows multiple identifiers according to the given predicate", () => {
        // given
        const predicate = (identifier: string) => identifier === "true" || identifier === "null";
        const validator = new Validator(predicate);
        const input = "true null";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).not.toThrow();
    });

    it("allows multiple identifiers in a more complex expression according to the given rule", () => {
        // given
        const predicate = (identifier: string) => identifier === "true" || identifier === "null";
        const validator = new Validator(predicate);
        const input = "true === null";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).not.toThrow();
    });

    it("mentions the first not allowed identifier in the thrown errror", () => {
        // given
        const predicate = (identifier: string) => identifier === "true" || identifier === "null";
        const validator = new Validator(predicate);
        const input = "true === null && undefined === false";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).toThrowError("'undefined' is not an allowed identifier.");
    });

    it("disallows invalid invalid tokens", () => {
        // given
        const validator = new Validator();
        const input = ";";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).toThrowError("Invalid or unexpected token (0)");
    });

    it("allows a complicated valid expression", () => {
        // given
        const predicate = (identifier: string) =>
            [...safeOperators, ...literals, "floor", "random"].includes(identifier);
        const validator = new Validator(predicate);
        const input = "typeof (floor(random() * 5) / 2) === 'number' ? 42 : 'foo'";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).not.toThrow();
    });

    it("disallows a complicated expression if it contains a disallowed identifier", () => {
        // given
        const predicate = (identifier: string) => [...safeOperators, ...literals, "ceil"].includes(identifier);
        const validator = new Validator(predicate);
        const input = "ceil.constructor('alert(1); return 1;')()";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).toThrowError("'constructor' is not an allowed identifier.");
    });

    it("disallows arrow functions", () => {
        // given
        const validator = new Validator();
        const input = "() => {}";

        // when
        const validate = () => validator.validate(input);

        // then
        expect(validate).toThrowError("Invalid or unexpected token (3)");
    });
});