import { expect } from 'chai';
import max from 'lodash/max';
import min from 'lodash/min';
import range from 'lodash/range';

import { getNodeAtPath, MosaicNode } from '../src/index';
import {
  Corner,
  createBalancedTreeFromLeaves,
  getAndAssertNodeAtPathExists,
  getLeaves,
  getPathToCorner,
  isParent,
} from '../src/util/mosaicUtilities';

const ROOT_ONLY_TREE: MosaicNode<number> = 1;
const MEDIUM_TREE: MosaicNode<number> = {
  direction: 'row',
  first: 1,
  second: {
    direction: 'column',
    first: {
      direction: 'column',
      first: 2,
      second: 3,
    },
    second: 4,
  },
};

const FALSY_TREE: MosaicNode<number | string> = {
  direction: 'row',
  first: 0,
  second: '',
};

const NINE_LEAVES = range(1, 10);
const THOUSAND_AND_ONE_LEAVES = range(1, 1002);

const NUMERICAL_SORT = (a: number, b: number) => a - b;

function getTreeDepths(tree: MosaicNode<any>): { min: number; max: number } {
  if (isParent(tree)) {
    const first = getTreeDepths(tree.first);
    const second = getTreeDepths(tree.second);
    return {
      min: min([first.min, second.min])! + 1,
      max: max([first.max, second.max])! + 1,
    };
  } else {
    return {
      min: 0,
      max: 0,
    };
  }
}

describe('mosaicUtilities', () => {
  describe('getNodeAtPath', () => {
    it('should get root', () => {
      expect(getNodeAtPath(MEDIUM_TREE, [])).to.equal(MEDIUM_TREE);
    });
    it('should get MosaicParent', () => {
      expect(getNodeAtPath(MEDIUM_TREE, ['second'])).to.equal(MEDIUM_TREE.second);
    });
    it('should get leaf', () => {
      expect(getNodeAtPath(MEDIUM_TREE, ['second', 'first', 'second'])).to.equal(3);
    });
    it('should return null on incorrect path', () => {
      expect(getNodeAtPath(MEDIUM_TREE, ['second', 'first', 'second', 'first'])).to.equal(null);
    });
    it('should return null on null root', () => {
      expect(getNodeAtPath(null, ['second', 'first', 'second', 'first'])).to.equal(null);
    });
    it('should work with falsy values', () => {
      expect(getNodeAtPath(FALSY_TREE, ['first'])).to.equal(0);
    });
  });
  describe('getAndAssertNodeAtPathExists', () => {
    it('should get root', () => {
      expect(getAndAssertNodeAtPathExists(MEDIUM_TREE, [])).to.equal(MEDIUM_TREE);
    });
    it('should get MosaicParent', () => {
      expect(getAndAssertNodeAtPathExists(MEDIUM_TREE, ['second'])).to.equal(MEDIUM_TREE.second);
    });
    it('should get leaf', () => {
      expect(getAndAssertNodeAtPathExists(MEDIUM_TREE, ['second', 'first', 'second'])).to.equal(3);
    });
    it('should error on incorrect path', () => {
      expect(() => getAndAssertNodeAtPathExists(MEDIUM_TREE, ['second', 'first', 'second', 'first'])).to.throw(Error);
    });
    it('should error on null root', () => {
      expect(() => getAndAssertNodeAtPathExists(null, ['second', 'first', 'second', 'first'])).to.throw(Error);
    });
  });
  describe('getLeaves', () => {
    it('should get leaves of simple tree', () => {
      expect(getLeaves(ROOT_ONLY_TREE)).to.deep.equal([1]);
    });
    it('should get leaves of medium tree', () => {
      expect(getLeaves(MEDIUM_TREE).sort(NUMERICAL_SORT)).to.deep.equal([1, 2, 3, 4]);
    });
    it('should return empty array when provided an empty tree', () => {
      expect(getLeaves(null)).to.deep.equal([]);
    });
  });
  describe('createBalancedTreeFromLeaves', () => {
    it('should be balanced', () => {
      const tree = createBalancedTreeFromLeaves(NINE_LEAVES);
      const depths = getTreeDepths(tree);
      expect(depths.max - depths.min).to.be.lessThan(2);
    });
    it('should be balanced when huge', () => {
      const tree = createBalancedTreeFromLeaves(THOUSAND_AND_ONE_LEAVES);
      const depths = getTreeDepths(tree);
      expect(depths.max - depths.min).to.be.lessThan(2);
    });
    it('should include all leaves', () => {
      const tree = createBalancedTreeFromLeaves(THOUSAND_AND_ONE_LEAVES);
      const leaves = getLeaves(tree);
      expect(leaves.sort(NUMERICAL_SORT)).to.deep.equal(THOUSAND_AND_ONE_LEAVES);
    });
    it('should return empty tree when provided no leaves', () => {
      const tree = createBalancedTreeFromLeaves([]);
      expect(tree).to.equal(null);
    });
  });
  describe('getPathToCorner', () => {
    it('should get top left', () => {
      const path = getPathToCorner(MEDIUM_TREE, Corner.TOP_LEFT);
      expect(getNodeAtPath(MEDIUM_TREE, path)).to.equal(1);
    });
    it('should get top right', () => {
      const path = getPathToCorner(MEDIUM_TREE, Corner.TOP_RIGHT);
      expect(getNodeAtPath(MEDIUM_TREE, path)).to.equal(2);
    });
    it('should get bottom left', () => {
      const path = getPathToCorner(MEDIUM_TREE, Corner.BOTTOM_LEFT);
      expect(getNodeAtPath(MEDIUM_TREE, path)).to.equal(1);
    });
    it('should get bottom right', () => {
      const path = getPathToCorner(MEDIUM_TREE, Corner.BOTTOM_RIGHT);
      expect(getNodeAtPath(MEDIUM_TREE, path)).to.equal(4);
    });
  });
});