#include <stdio.h>
#include <limits.h>
#include <stdbool.h>

#include "exponent.h"
#include "logarithmus.h"

double absD(double x){
    if(x<0){
        return -1 * x;
    }
    return x;
}

double p(double exp, double base){
    double prod = 1.0;
    if(exp==0.0){
        return 1;
    }else{
        for(int i = 1; i <= (int) exp; i++){
            prod *= base;
        }
        return prod;
    }
}

double powerD(double exp, double base){
    if(absD(exp) - ((int) absD(exp)) < 0.000001){
        if(exp>=0.0){
            return p(exp, base);
        }
        else{
            if (base == 0.0){
                return -1.0;
            }
            return  (1.0 / p((exp*-1), base));
        }   
    }else if(base > 0.0){
        if(exp>=0.0){
            return exponential(exp*logN(base));
        }
        else{
            if (base == 0.0){
                return -1.0;
            }
            return (1.0 / exponential((-1*exp)*logN(base)));
        }
    }
    return -1.0;
}

unsigned long long fac(int x){
    unsigned long long prod = 1;
    if(x==0) return 1;
    for (int i = 1; i <= x; i++){
        if (prod > ULLONG_MAX / i){
            break;
        }
        prod*=i;
    }
    return prod;
}


double exponential(double x){
    double sum = 0.0;
    for(int i = 0; i<=21; i++){
        sum += (1.0/fac(i)*(powerD(i,x)));
    }
    return sum;
}