import assert from 'assert';
import lodashStable from 'lodash';
import { noop, identity, isNpm, mapCaches } from './utils.js';
import mergeWith from '../mergeWith.js';
import last from '../last.js';

describe('mergeWith', function() {
  it('should handle merging when `customizer` returns `undefined`', function() {
    var actual = mergeWith({ 'a': { 'b': [1, 1] } }, { 'a': { 'b': [0] } }, noop);
    assert.deepStrictEqual(actual, { 'a': { 'b': [0, 1] } });

    actual = mergeWith([], [undefined], identity);
    assert.deepStrictEqual(actual, [undefined]);
  });

  it('should clone sources when `customizer` returns `undefined`', function() {
    var source1 = { 'a': { 'b': { 'c': 1 } } },
        source2 = { 'a': { 'b': { 'd': 2 } } };

    mergeWith({}, source1, source2, noop);
    assert.deepStrictEqual(source1.a.b, { 'c': 1 });
  });

  it('should defer to `customizer` for non `undefined` results', function() {
    var actual = mergeWith({ 'a': { 'b': [0, 1] } }, { 'a': { 'b': [2] } }, function(a, b) {
      return lodashStable.isArray(a) ? a.concat(b) : undefined;
    });

    assert.deepStrictEqual(actual, { 'a': { 'b': [0, 1, 2] } });
  });

  it('should provide `stack` to `customizer`', function() {
    var actual;

    mergeWith({}, { 'a': { 'b': 2 } }, function() {
      actual = last(arguments);
    });

    assert.ok(isNpm
      ? actual.constructor.name == 'Stack'
      : actual instanceof mapCaches.Stack
    );
  });

  it('should overwrite primitives with source object clones', function() {
    var actual = mergeWith({ 'a': 0 }, { 'a': { 'b': ['c'] } }, function(a, b) {
      return lodashStable.isArray(a) ? a.concat(b) : undefined;
    });

    assert.deepStrictEqual(actual, { 'a': { 'b': ['c'] } });
  });

  it('should pop the stack of sources for each sibling property', function() {
    var array = ['b', 'c'],
        object = { 'a': ['a'] },
        source = { 'a': array, 'b': array };

    var actual = mergeWith(object, source, function(a, b) {
      return lodashStable.isArray(a) ? a.concat(b) : undefined;
    });

    assert.deepStrictEqual(actual, { 'a': ['a', 'b', 'c'], 'b': ['b', 'c'] });
  });
});