/* CSCI 200: Lab 1A (Math Equation Solver): Tyler Beckman
 *
 * Author: Tyler Beckman
 *
 * A C++ program to interactively solve 10 different mathmatical equations,
 * using the appropriate constants where relevant. I decided to implement all 10
 * rather than just 2 because it sounded interesting and I wanted to challenge
 * myself. It also will keep prompting for the equation to solve until you
 * explicitly respond with a 0 or CTRL+C it, rather than just exit once the
 * equation is calculated.
 */
#include "math.h"

#include <iostream>
#include <limits>

double input_double(std::string prompt) {
  double out;
  while (true) {
    std::cout << prompt + ": ";
    std::cin >> out;

    if (std::cin.fail()) {
      // The clear and ignore are necessary because otherwise it seems to keep
      // reusing the first input a person enters
      std::cin.clear();
      std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
      std::cout << "Invalid number, please make sure your number is formatted "
                   "correctly."
                << std::endl;
    } else {
      break;
    }
  }

  return out;
}

int main() {
  while (true) {
    std::cout << "[0] Quit program" << std::endl
              << "[1] Ideal gas law" << std::endl
              << "[2] Average acceleration" << std::endl
              << "[3] Ohm's law" << std::endl
              << "[4] Universal gravitation" << std::endl
              << "[5] Pythagorean theorem" << std::endl
              << "[6] Sphere volume" << std::endl
              << "[7] Deflection" << std::endl
              << "[8] Heat transfer rate" << std::endl
              << "[9] Stress" << std::endl
              << "[10] Shear Stress" << std::endl
              << "[11] Coulomb's law" << std::endl;
    int equationChoice =
        input_double("Which equation would you like to calculate?");

    double calculatedValue;

    switch (equationChoice) {
      case 0:
        return 0;
      case 1:
        calculatedValue = ideal_gas_law(
            input_double("Please enter amount of moles"),
            input_double("Please enter the gas absolute temperate"),
            input_double("Please enter the volume"));
        break;
      case 2:
        calculatedValue = average_acceleration(
            input_double("Please enter the starting position"),
            input_double("Please enter the ending position"),
            input_double("Please enter the starting time"),
            input_double("Please enter the ending time"));
        break;
      case 3:
        calculatedValue = ohms_law(input_double("Please input the voltage"),
                                   input_double("Please input the resistance"));
        break;
      case 4:
        calculatedValue = universal_gravitation(
            input_double("Please input the mass of object 1"),
            input_double("Please input the mass of object 2"),
            input_double("Please input the distance between objects"));
        break;
      case 5:
        calculatedValue =
            pythagorean_theorem(input_double("Please input the x distance"),
                                input_double("Please input the y distance"));
        break;
      case 6:
        calculatedValue =
            sphere_volume(input_double("Please input the sphere radius"));
        break;
      case 7:
        calculatedValue =
            deflection(input_double("Please input the force of weight"),
                       input_double("Please input the length"),
                       input_double("Please input the elasticity modulus"),
                       input_double("Please input the moment of inertia"));
        break;
      case 8:
        calculatedValue = heat_transfer_rate(
            input_double("Please input the transfer coefficient"),
            input_double("Please input the surface area"),
            input_double("Please input the change in temperature"));
        break;
      case 9:
        calculatedValue =
            stress(input_double("Please input the amount of force"),
                   input_double("Please input the surface area"));
        break;
      case 10:
        calculatedValue = shear_stress(
            input_double("Please enter σ_x"), input_double("Please enter σ_y"),
            input_double("Please enter τ_xy"),
            input_double("Please enter θ (in radians)"));
        break;
      case 11:
        calculatedValue = coulombs_law(
            input_double("Please input the first charge"),
            input_double("Please input the second charge"),
            input_double("Please input the relative static permittivity"),
            input_double("Please input the distance between charges"));
        break;
      default:
        std::cout << "That is not a valid equation choice. Please try again."
                  << std::endl;
        continue;
    }
    std::cout << "The result of that calculation is: " << calculatedValue
              << std::endl;
  }
}