import 'package:d4rt_formulas/formula_evaluator.dart';
import 'package:d4rt_formulas/formula_models.dart';
import 'package:flutter_test/flutter_test.dart';
import 'dart:math' as Math;


void main() {
  test("Solve x^2", () {
    Number f(Number x) => x*x;
    var root = functionSolver(f, hint: 10, step: 1);
    expect(root, closeTo(0, 0.1));
  });


  test("Solve (x-1000)^2", () {
    Number f(Number x) => (x-1000)*(x-1000);
    var root = functionSolver(f, hint: 10, step: 1, maxTries: 1000);
    expect(root, closeTo(1000, 0.1));
  });

  test("Solve x^2 + 1", () {
    Number f(Number x) => x*x+1;

    expect(()=> functionSolver(f, hint: 10, step: 1), throwsA(isA<NoSolutionException>()));
  });

  test("Solve (x-2)(x-10", () {
    Number f(Number x) => (x-2)*(x-10);

    expect( functionSolver(f, hint: 10, step: 1), closeTo(10, 0.1));
  });

  test('Solve sqrt(x) = 2  => x = 4', () {
    Number f(Number x) => Math.sqrt(x) - 2;
    var root = functionSolver(f, hint: 5, step: 1);
    expect(root, closeTo(4, 0.1));
  });

  test('Solve sin(x) = 0 near pi (hint 3)', () {
    Number f(Number x) => Math.sin(x);
    var root = functionSolver(f, hint: 3, step: 1);
    expect(root, closeTo(Math.pi, 0.01));
  });

  test('Solve tan(x) = 1 => x = pi/4', () {
    Number f(Number x) => Math.tan(x) - 1;
    var root = functionSolver(f, hint: 0, step: 1);
    expect(root, closeTo(Math.pi / 4, 0.01));
  });

  test('Solve exp(x) = 2 => x = ln(2)', () {
    Number f(Number x) => Math.exp(x) - 2;
    var root = functionSolver(f, hint: 1, step: 1);
    expect(root, closeTo(Math.log(2), 0.01));
  });

}