import { describe, expect, it } from '@jest/globals';
import { L, undef } from '../src/core';
import { toNOrd as $o, NOrd } from '../src/ord';
import { toBoolean as $b, fromBoolean as _b } from '../src/bool';
import { toNumber as $, Num, Succ, Zero, fromNumber as _, cmp, div, eq, ge, gt, ifz, le, lt, mod, mul, pred, sub, succ, sum } from '../src/num';

describe('Num', () => {
  const infinity: Num = new L(() => Succ._(infinity).value);

  describe('toNumber', () => {
    it('converts 0', () => {
      expect($(Zero)).toBe(0);
    });

    it('converts 1', () => {
      expect($(Succ._(Zero))).toBe(1);
    });

    it('converts 2', () => {
      expect($(Succ._(Succ._(Zero)))).toBe(2);
    });
  });

  describe('fromNumber', () => {
    it('converts 0', () => {
      expect($(_(0))).toBe(0);
    });

    it('converts 1', () => {
      expect($(_(1))).toBe(1);
    });

    it('converts 2', () => {
      expect($(_(2))).toBe(2);
    });
  });

  describe('ifz', () => {
    it('returns zero branch', () => {
      expect($b(ifz._(_(0))._(_b(true))._(_b(false)))).toBe(true);
    });

    it('returns non-zero branch', () => {
      expect($b(ifz._(_(1))._(_b(true))._(_b(false)))).toBe(false);
    });

    it('returns non-zero branch', () => {
      expect($b(ifz._(_(10))._(_b(true))._(_b(false)))).toBe(false);
    });

    it('handles infinity', () => {
      expect($b(ifz._(infinity)._(_b(true))._(_b(false)))).toBe(false);
    });
  });

  describe('succ', () => {
    it('succ 0 is 1', () => {
      expect($(succ._(_(0)))).toBe(1);
    });

    it('succ 1 is 2', () => {
      expect($(succ._(_(1)))).toBe(2);
    });

    it('succ 10 is 11', () => {
      expect($(succ._(_(10)))).toBe(11);
    });
  });

  describe('pred', () => {
    it('pred 0 is 0', () => {
      expect($(pred._(_(0)))).toBe(0);
    });

    it('pred 1 is 0', () => {
      expect($(pred._(_(1)))).toBe(0);
    });

    it('pred 10 is 9', () => {
      expect($(pred._(_(10)))).toBe(9);
    });
  });

  describe('cmp', () => {
    it('0 cmp 0 is EQ', () => {
      expect($o(cmp._(_(0))._(_(0)))).toBe(NOrd.EQ);
    });

    it('0 cmp 1 is LT', () => {
      expect($o(cmp._(_(0))._(_(1)))).toBe(NOrd.LT);
    });

    it('1 cmp 0 is GT', () => {
      expect($o(cmp._(_(1))._(_(0)))).toBe(NOrd.GT);
    });

    it('3 cmp 3 is EQ', () => {
      expect($o(cmp._(_(3))._(_(3)))).toBe(NOrd.EQ);
    });

    it('3 cmp 7 is LT', () => {
      expect($o(cmp._(_(3))._(_(7)))).toBe(NOrd.LT);
    });

    it('7 cmp 3 is GT', () => {
      expect($o(cmp._(_(7))._(_(3)))).toBe(NOrd.GT);
    });

    it('handles infinity', () => {
      expect($o(cmp._(_(7))._(infinity))).toBe(NOrd.LT);
      expect($o(cmp._(infinity)._(_(7)))).toBe(NOrd.GT);
    });
  });

  describe('lt', () => {
    it('0 lt 0 is False', () => {
      expect($b(lt._(_(0))._(_(0)))).toBe(false);
    });

    it('0 lt 1 is True', () => {
      expect($b(lt._(_(0))._(_(1)))).toBe(true);
    });

    it('1 lt 0 is False', () => {
      expect($b(lt._(_(1))._(_(0)))).toBe(false);
    });

    it('3 lt 3 is False', () => {
      expect($b(lt._(_(3))._(_(3)))).toBe(false);
    });

    it('3 lt 7 is True', () => {
      expect($b(lt._(_(3))._(_(7)))).toBe(true);
    });

    it('7 lt 3 is False', () => {
      expect($b(lt._(_(7))._(_(3)))).toBe(false);
    });

    it('handles infinity', () => {
      expect($b(lt._(_(7))._(infinity))).toBe(true);
      expect($b(lt._(infinity)._(_(7)))).toBe(false);
    });
  });

  describe('le', () => {
    it('0 le 0 is True', () => {
      expect($b(le._(_(0))._(_(0)))).toBe(true);
    });

    it('0 le 1 is True', () => {
      expect($b(le._(_(0))._(_(1)))).toBe(true);
    });

    it('1 le 0 is False', () => {
      expect($b(le._(_(1))._(_(0)))).toBe(false);
    });

    it('3 le 3 is True', () => {
      expect($b(le._(_(3))._(_(3)))).toBe(true);
    });

    it('3 le 7 is True', () => {
      expect($b(le._(_(3))._(_(7)))).toBe(true);
    });

    it('7 le 3 is False', () => {
      expect($b(le._(_(7))._(_(3)))).toBe(false);
    });

    it('handles infinity', () => {
      expect($b(le._(_(7))._(infinity))).toBe(true);
      expect($b(le._(infinity)._(_(7)))).toBe(false);
    });
  });

  describe('eq', () => {
    it('0 eq 0 is True', () => {
      expect($b(eq._(_(0))._(_(0)))).toBe(true);
    });

    it('0 eq 1 is False', () => {
      expect($b(eq._(_(0))._(_(1)))).toBe(false);
    });

    it('1 eq 0 is False', () => {
      expect($b(eq._(_(1))._(_(0)))).toBe(false);
    });

    it('3 eq 3 is True', () => {
      expect($b(eq._(_(3))._(_(3)))).toBe(true);
    });

    it('3 eq 7 is False', () => {
      expect($b(eq._(_(3))._(_(7)))).toBe(false);
    });

    it('7 eq 3 is False', () => {
      expect($b(eq._(_(7))._(_(3)))).toBe(false);
    });

    it('handles infinity', () => {
      expect($b(eq._(_(7))._(infinity))).toBe(false);
      expect($b(eq._(infinity)._(_(7)))).toBe(false);
    });
  });

  describe('ge', () => {
    it('0 ge 0 is True', () => {
      expect($b(ge._(_(0))._(_(0)))).toBe(true);
    });

    it('0 ge 1 is False', () => {
      expect($b(ge._(_(0))._(_(1)))).toBe(false);
    });

    it('1 ge 0 is True', () => {
      expect($b(ge._(_(1))._(_(0)))).toBe(true);
    });

    it('3 ge 3 is True', () => {
      expect($b(ge._(_(3))._(_(3)))).toBe(true);
    });

    it('3 ge 7 is False', () => {
      expect($b(ge._(_(3))._(_(7)))).toBe(false);
    });

    it('7 ge 3 is True', () => {
      expect($b(ge._(_(7))._(_(3)))).toBe(true);
    });

    it('handles infinity', () => {
      expect($b(ge._(_(7))._(infinity))).toBe(false);
      expect($b(ge._(infinity)._(_(7)))).toBe(true);
    });
  });

  describe('gt', () => {
    it('0 gt 0 is False', () => {
      expect($b(gt._(_(0))._(_(0)))).toBe(false);
    });

    it('0 gt 1 is False', () => {
      expect($b(gt._(_(0))._(_(1)))).toBe(false);
    });

    it('1 gt 0 is True', () => {
      expect($b(gt._(_(1))._(_(0)))).toBe(true);
    });

    it('3 gt 3 is False', () => {
      expect($b(gt._(_(3))._(_(3)))).toBe(false);
    });

    it('3 gt 7 is False', () => {
      expect($b(gt._(_(3))._(_(7)))).toBe(false);
    });

    it('7 gt 3 is True', () => {
      expect($b(gt._(_(7))._(_(3)))).toBe(true);
    });

    it('handles infinity', () => {
      expect($b(gt._(_(7))._(infinity))).toBe(false);
      expect($b(gt._(infinity)._(_(7)))).toBe(true);
    });
  });

  describe('sum', () => {
    it('0 sum 0 is 0', () => {
      expect($(sum._(_(0))._(_(0)))).toBe(0);
    });

    it('0 sum 1 is 1', () => {
      expect($(sum._(_(0))._(_(1)))).toBe(1);
    });

    it('1 sum 0 is 1', () => {
      expect($(sum._(_(1))._(_(0)))).toBe(1);
    });

    it('3 sum 4 is 7', () => {
      expect($(sum._(_(3))._(_(4)))).toBe(7);
    });
  });

  describe('sub', () => {
    it('0 sub 0 is 0', () => {
      expect($(sub._(_(0))._(_(0)))).toBe(0);
    });

    it('0 sub 1 is 0', () => {
      expect($(sub._(_(0))._(_(1)))).toBe(0);
    });

    it('1 sub 0 is 1', () => {
      expect($(sub._(_(1))._(_(0)))).toBe(1);
    });

    it('7 sub 4 is 3', () => {
      expect($(sub._(_(7))._(_(4)))).toBe(3);
    });
  });

  describe('mul', () => {
    it('0 mul 0 is 0', () => {
      expect($(mul._(_(0))._(_(0)))).toBe(0);
    });

    it('0 mul 10 is 0', () => {
      expect($(mul._(_(0))._(_(10)))).toBe(0);
    });

    it('10 mul 0 is 0', () => {
      expect($(mul._(_(1))._(_(0)))).toBe(0);
    });

    it('1 mul 10 is 10', () => {
      expect($(mul._(_(1))._(_(10)))).toBe(10);
    });

    it('10 mul 1 is 10', () => {
      expect($(mul._(_(10))._(_(1)))).toBe(10);
    });

    it('3 mul 4 is 12', () => {
      expect($(mul._(_(3))._(_(4)))).toBe(12);
    });

    it('0 mul ignores second argument', () => {
      expect($(mul._(_(0))._(undef))).toBe(0);
    });
  });

  describe('div', () => {
    it('0 div 10 is 0', () => {
      expect($(div._(_(0))._(_(10)))).toBe(0);
    });

    it('1 div 10 is 0', () => {
      expect($(div._(_(1))._(_(10)))).toBe(0);
    });

    it('10 div 1 is 10', () => {
      expect($(div._(_(10))._(_(1)))).toBe(10);
    });

    it('10 div 5 is 2', () => {
      expect($(div._(_(10))._(_(5)))).toBe(2);
    });

    it('10 div 3 is 3', () => {
      expect($(div._(_(10))._(_(3)))).toBe(3);
    });

    it.failing('0 div ignores second argument', () => {
      expect($(div._(_(0))._(undef))).toBe(0);
    });
  });

  describe('mod', () => {
    it('0 mod 10 is 0', () => {
      expect($(mod._(_(0))._(_(10)))).toBe(0);
    });

    it('1 mod 10 is 1', () => {
      expect($(mod._(_(1))._(_(10)))).toBe(1);
    });

    it('10 mod 1 is 0', () => {
      expect($(mod._(_(10))._(_(1)))).toBe(0);
    });

    it('10 mod 5 is 0', () => {
      expect($(mod._(_(10))._(_(5)))).toBe(0);
    });

    it('10 mod 3 is 1', () => {
      expect($(mod._(_(10))._(_(3)))).toBe(1);
    });

    it.failing('0 mod ignores second argument', () => {
      expect($(mod._(_(0))._(undef))).toBe(0);
    });
  });
});