/* Name: Garrett Haldrup
BMI.c
Problem: Take in the weight, heightm, and gender of a user and calculate and display their BMI, Life Expectancy, and BSA score using multiple methods.
Certification of Authenticity:
I certify that this assignment is entirely my own work.
*/

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <ctype.h>
#include <stdbool.h>

int main(){

  // Declare Variables
  // Float values for calculations
  float bmi, weight, height, mostellar, duBois, boyd, lifeExpect;

  // Int values to store the result of the scanf fucntion
  int weightResult, heightResult;

  // Char to store the gender with max length of 7 and a line string for formatting
  char gender[7];

  // declare and set bools to false as default
  bool isMale = false;
  bool isFemale = false;
  bool overWeight = false;


  // Display Program Purpose
  printf("***Purpose**********************************************************************\n");
  printf("*    This program will calculate your BMI, Life Expectancy, and                *\n");
  printf("*    BSA(multiple methods) with just your weight(kg), height(cm), and          *\n");
  printf("*    gender.                                                                   *\n");
  printf("********************************************************************************\n");

  // Nice little space
  printf("\n");

  // Litte overview of the data input section
  printf("***Data Input*******************************************************************\n");
  printf("*    Please enter your weight in kg fmt: XX.X and your height in cm fmt:       *\n");
  printf("*    XXX.X, Male and Female are the only valid options for gender.             *\n");
  printf("********************************************************************************\n");

  // Read in weight, height, and gender from user
  // Make sure correct values for weight is entered
  printf("Please enter your weight(kg): ");
  weightResult = scanf("%f", &weight);
  while (weight <= 0 || weightResult != 1) {
    while (getchar() != '\n');
    if (weight <= 0) {
      printf("Bad Value: Weight must greater than 0! fmt: XX.X\n");
    } else {
      printf("Bad Value: Please enter a decimal input! fmt: XX.X\n");
    }
    printf("Please re-enter your weight(kg): ");
    weightResult = scanf("%f", &weight);
  }

  // Make sure correct values for weight is entered
  printf("Please enter your height(cm): ");
  heightResult = scanf("%f", &height);
  while (height <= 0 || heightResult != 1) {
    while (getchar() != '\n');
    if (height <= 0) {
      printf("Bad Value: Height must greater than 0! fmt: XX.X\n");
    } else {
      printf("Bad Value: Please enter a decimal input! fmt: XX.X\n");
    }
    printf("Please re-enter your height(cm): ");
    heightResult = scanf("%f", &height);
  }
    
  // Make sure correct values for gender are entered
  while (1) {
    // Read in gender from user
    printf("Please enter your gender(male or female): ");
    scanf("%s", gender);
    
    // Loop through all chars in gender and convert to lower case
    for (int i = 0; i < (int)strlen(gender); i++) {
      gender[i] = tolower(gender[i]);
    }
    isMale = !strcmp("male", gender);
    isFemale = !strcmp("female", gender);

    // Check if gender is valid
    if (isMale || isFemale) {
      break; 
    } else {
      printf("Bad value: Please enter either male or female\n");
    }
  }
  
  // nice space
  printf("\n"); 

  // Calculate the BMI
  bmi = 10000 * (weight / pow(height, 2));

  // Assign bool
  overWeight = bmi > 25;

  // Calculate the BSA(Mosteller's)
  mostellar = sqrt((height * weight) / 3600);

  // Calculate the BSA(Dubois)
  duBois = (0.20247 * pow((height / 100), 0.725)) * pow(weight, 0.425);

  // Calculate the BSA(boyd)
  boyd = (0.0003207 * pow(height, 0.3)) * pow((1000 * weight), (0.6721 - (0.0188 * log10(weight))));

  // Check if overweight and gender to select correct life expectancy message
  // Only need to check one since the input screens to just two options
  if (isFemale) {
    if (overWeight) {
      lifeExpect = 81.4;
    } else {
      lifeExpect = 83.5;
    }
  } else {
    if (overWeight) {
      lifeExpect = 77.3;
    } else {
      lifeExpect = 79.4;
    }
  }

  // Demark output
  printf("***Output***********************************************************************\n");

  // Display values and output
  printf("For a %s with weight(kg) of %.1fkg and height(cm) of %.1fcm\n", gender, weight, height);
  printf("You have a BMI of %.1f and a life expectancy of %.1f years\n", bmi, lifeExpect);
  printf("You also have a BSA calculated using\n");
  printf("   - Mosteller's:\t%.3f\n", mostellar);
  printf("   - DuBois:\t\t%.3f\n", duBois);
  printf("   - Boyd:\t\t%.3f\n", boyd);

  return 0;
}