import { expect } from "chai";

import { DPT8 } from "../src/DPT8"
import { BufferLengthError } from "../src/errors/BufferLengthError";
import { InvalidValueError } from "../src/errors/InvalidValueError";

import { compareBuffers } from "./util"

let value: number = 256
let overflowValue: number = 40000

let bufferPositive = Buffer.from([1, 0])
let bufferNegative = Buffer.from([255, 0])

let bufferEmpty = Buffer.from([])
let bufferBiggerSize = Buffer.from([0xff, 0xff, 0x63, 0xc0])

describe("Test DPT008", (): void => {

  let dpt = new DPT8();

  it("Decode buffer acceptable", async function () {
    expect(dpt.decoder(bufferPositive)).is.equal(value);
    expect(dpt.decoder(bufferNegative)).is.equal(-value);
  });


  it("Decode empty buffer", async function () {
    var testFunction = function () {
      const value = dpt.decoder(bufferEmpty)
    }
    expect(testFunction).to.throw(BufferLengthError);
  });

  it("Decode oversized buffer", async function () {
    var testFunction = function () {
      const value = dpt.decoder(bufferBiggerSize)
    }
    expect(testFunction).to.throw(BufferLengthError);
  });

  /* Encoder tests */
  it("encode valid", async function () {
    expect(compareBuffers(dpt.encoder(value), bufferPositive)).is.true;
    expect(compareBuffers(dpt.encoder(-value), bufferNegative)).is.true;
  });

  it("encode invalid", async function () {
    var testFunction1 = function () {
      const value = dpt.encoder(-overflowValue)
    }
    var testFunction2 = function () {
      const value = dpt.encoder(overflowValue)
    }

    expect(testFunction1).to.throw(InvalidValueError);
    expect(testFunction2).to.throw(InvalidValueError);
  });

  it("encode undefined", async function () {
    var testFunction = function () {
      const value = dpt.encoder(undefined)
    }
    expect(testFunction).to.throw(InvalidValueError);
  });
});