"use strict";

const evolve = require("../../src/deps/fp/evolve");

const add = require("../../src/deps/math/add");

const eq = (x, y, msg) => expect(x).toEqual(y);

describe('evolve', function () {
  it('creates a new object by evolving the `object` according to the `transformation` functions', function () {
    var transf = {
      elapsed: add(1),
      remaining: add(-1)
    };
    var object = {
      name: 'Tomato',
      elapsed: 100,
      remaining: 1400
    };
    var expected = {
      name: 'Tomato',
      elapsed: 101,
      remaining: 1399
    };
    eq(evolve(transf, object), expected);
  });
  it('does not invoke function if object does not contain the key', function () {
    var transf = {
      n: add(1),
      m: add(1)
    };
    var object = {
      m: 3
    };
    var expected = {
      m: 4
    };
    eq(evolve(transf, object), expected);
  });
  it('is not destructive', function () {
    var transf = {
      elapsed: add(1),
      remaining: add(-1)
    };
    var object = {
      name: 'Tomato',
      elapsed: 100,
      remaining: 1400
    };
    var expected = {
      name: 'Tomato',
      elapsed: 100,
      remaining: 1400
    };
    evolve(transf, object);
    eq(object, expected);
  });
  it('is recursive', function () {
    var transf = {
      nested: {
        second: add(-1),
        third: add(1)
      }
    };
    var object = {
      first: 1,
      nested: {
        second: 2,
        third: 3
      }
    };
    var expected = {
      first: 1,
      nested: {
        second: 1,
        third: 4
      }
    };
    eq(evolve(transf, object), expected);
  });
  it('is curried', function () {
    var tick = evolve({
      elapsed: add(1),
      remaining: add(-1)
    });
    var object = {
      name: 'Tomato',
      elapsed: 100,
      remaining: 1400
    };
    var expected = {
      name: 'Tomato',
      elapsed: 101,
      remaining: 1399
    };
    eq(tick(object), expected);
  });
  it('ignores primitive value transformations', function () {
    var transf = {
      n: 2,
      m: 'foo'
    };
    var object = {
      n: 0,
      m: 1
    };
    var expected = {
      n: 0,
      m: 1
    };
    eq(evolve(transf, object), expected);
  });
  it('ignores null transformations', function () {
    var transf = {
      n: null
    };
    var object = {
      n: 0
    };
    var expected = {
      n: 0
    };
    eq(evolve(transf, object), expected);
  });
});