#include <stdio.h>
#include <math.h>
#include <string.h>
#include <ctype.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];
  char line[] = "********************************";

  // Display Program Purpose
  printf("%s%s%s*\n", line, line, line);
  printf("*\tThis program will calculate your BMI, Life Expectancy, and BSA(mulitple methods)\t*\n");
  printf("*\twith just your weight(kg), height(cm), and gender.\t\t\t\t\t*\n");
  printf("%s%s%s*\n", line, line, line);

  // Read in weight, height, and gender from user
  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);
  }

  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 < strlen(gender); i++) {
      gender[i] = tolower(gender[i]);
    }

    // Check if gender is valid
    if (!(strcmp("male", gender)) || !(strcmp("female", gender))) {
      break; 
    } else {
      printf("Bad value: Please enter either male or female\n");
    }
  }
  

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

  // 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 (strcmp("male", gender)) {
    if (bmi > 25) {
      lifeExpect = 81.4;
    } else {
      lifeExpect = 83.5;
    }
  } else {
    if (bmi > 25) {
      lifeExpect = 77.3;
    } else {
      lifeExpect = 79.4;
    }
  }

  // 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;
}