/* Projekt č. 2, předmět IZP
 * Autor: Dominik Dvořák, xdvora1t@stud.fit.vutbr.cz
 * Skupina: 1BIA
 * Datum: 24.11.2014
 * Název souboru: proj2.c
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

void Help()
    {
        printf("Program implementuje vypocet fce tg se zadanym poctem iteraci \n"
               "a dale vypocet delky a vysky pomoci udaju zadanych uzivatelem.\n"
                "\n"
                "Spusteni programu:\n"
                "./proj2 --help\n"
                "./proj2 --tan A N M\n"
                "./proj2 [-c X] -m A [B]\n"
                "A, B - uhel [rad]\n"
                "N, M - pocet iteraci [1]\n"
                "X - vyska mereni [m]\n"
                "\n"
                "Priklady spravneho spusteni:\n"
                "./proj2 --tan 1.024 6 10\n"
                "./proj2 -m 0.3 0.9\n"
                "./proj2 -c 1.7 -m 0.15 1.3\n"
                "\n"
                "Rozsah moznych hodnot:\n"
                "N >= M\n"
                "0 < N <= M < 14\n"
                "0 < A <= 1.4\n"
                "0 < B <= 1.4\n"
                "0 < X <= 100\n"
                "(implicitni hodnota X je 1.5)\n"
              );
    }
//**************************************
int Error(unsigned int n) //funce pro výpis chybových stavů
    {
        if (n == 1) fprintf(stderr,"Error! \n - chyba v argumentech, pro napovedu zadejte jmeno programu a --help\n"); //chyba argumentu
        if (n == 2) fprintf(stderr,"Error! \n - chyba velikosti uhlu, rozmezi je pouze (0;1.4>, pro napovedu zadejte jmeno programu a --help\n\n"); //chyba velikosti uhlu
        if (n == 3) fprintf(stderr,"Error! \n - chyba vysky arg. -c, rozmezi je pouze (0;100>, pro napovedu zadejte jmeno programu a --help\n\n"); //chyba velikosti vysky
        return 1;
    }
//**************************************
double dabs(double number)  //fce na absolutni hodnotu
    {
        if (number < 0) number *= -1;
        return number;
    }
//**************************************
double Taylor_Tan(double rad, unsigned int iter)  //fce pro vypocet tangens pomoci Taylorovy rady
    {
        long long numer[13] = {1, 1, 2, 17, 62, 1382, 21844, 929569, 6404582, //citatele pro Taylorovu radu
                              443861162, 18888466084, 113927491862, 58870668456604};
        long long denom[13] = {1, 3, 15, 315, 2835, 155925, 6081075, 638512875, //jmenovatele
                              10854718875, 1856156927625, 194896477400625,
                              49308808782358125, 3698160658676859375};
        unsigned int i = 1; //
        unsigned int a = 1; //
        unsigned int x = 0; //
        double powa = rad;
        double result;
        while (x != iter)
            {
                if (x == 0)
                    {
                        result = rad;
                    }
                else
                    {
                        while (i != a)
                            {
                                powa = rad * powa;
                                i++;
                            }
                        result = result + ((numer[x] * powa) / denom[x]);
                        i = 1;
                        powa = rad;
                    }
                x++;
                a = a + 2;
            }
        return result;
    }
//**************************************
double Cfrac_Tan(double rad, unsigned int n)  //fce pro vypocet tg pomoci zretezenych zlomku
    {
        unsigned int k = n; //pocet iteraci
        double numer = rad * rad; //mocnina
        double addend;
        double fraction;
        for (; k >= 1 ; k--)
            {
                 addend = (k+1) * 2 - 1;
                 fraction = numer / (addend - fraction);
            }
        return rad / (1 - fraction);
    }
//**************************************
void Tan_Comp(double rad, unsigned int begin, unsigned int end) //fce pro porovnání vypoctu tg pomocí Taylora a zretez. zlomku
    {
        unsigned int arr_ix = 1;
        double CArray [end - begin];
        double TArray [end - begin];
        for (unsigned int i = begin; i != end + 1; i++)
            {
                CArray [arr_ix] = Cfrac_Tan(rad, i - 1);
                TArray [arr_ix] = Taylor_Tan(rad, i);
                double x = dabs(TArray [arr_ix] - tan (rad));
                double y = dabs(CArray [arr_ix] - tan (rad));
                printf("%d %e %e %e ", i , tan(rad), TArray [arr_ix], x);
                printf("%e %e\n", CArray [arr_ix], y);
                arr_ix++;
            }
    }
//**************************************
void Measur_Dist(double alpha, double beta, double c) //fce pro vypocet vzdalenosti
    {
        double result = 0, result_old = 1;
        unsigned int n = 1;
        while (dabs(result - result_old) > 0.0000000001) //pocet iteraci je dan presnosti na  10 desetinnych mist
            {
                result_old = result;
                result = Cfrac_Tan (alpha, n);
                n++;
            }
        double lenght = c / result;
        printf("%.10e\n", lenght);
        if (beta != -42)
            {
                result = 0;
                result_old = 1;
                n = 1;
                while (dabs(result - result_old) > 0.0000000001)
                    {
                        result_old = result;
                        result = Cfrac_Tan (beta, n);
                        n++;
                    }
                printf("%.10e\n", lenght * result + c);
            }
    }
//**************************************
int main(int argc, char **argv)
    {
        if (argc>1)
          {

            if ((strcmp(argv[1], "--help")) == 0)   //vypis napovedy
                {
                    Help();
                }
            else if ((strcmp(argv[1], "--tan")) == 0)
                {
                    if (atoi(argv[3]) < 1 || atoi(argv[4]) > 13 || atoi(argv[3]) > atoi(argv[4])) Error(1); //kontrola rozsahu
                    else if (strtod(argv[2], NULL) > 1.4 || strtod(argv[2], NULL) <= 0) Error(2); //kontrola velikosti uhlu
                    else Tan_Comp(strtod(argv[2], NULL), atoi(argv[3]), atoi(argv[4]));
                }
            else if ((strcmp(argv[1], "-m")) == 0)
                {
                    double c = 1.5;
                    unsigned int error = 0;
                    double beta = -42; //pokud neni zadana beta, je dosazena -42 - ovlivnuje pozdejsi chovani programu
                    if (argc==4) //jen pokud je zadana i beta
                        {
                            beta = strtod(argv[3],NULL);
                            if (beta > 1.4 || beta <= 0) error = Error(2); //kontrola bety
                        }
                    if (strtod(argv[2], NULL) > 1.4 || strtod(argv[2], NULL) <= 0) error = Error(2); //kontrola alphy
                    if (error == 0) Measur_Dist(strtod(argv[2], NULL), beta, c); //spusti se, pokud nejsou zadne predchozi errory
                }
            else if ((strcmp(argv[1], "-c")) == 0)
                {
                    double c = 1.5;
                    unsigned int error = 0;
                    c = strtod(argv[2], NULL);
                    if (c > 100 || c <= 0) error = Error(3); //kontrola c
                    double beta = -42;
                    if (argc == 6)
                        {
                            beta = strtod(argv[5], NULL);
                            if (beta > 1.4 || beta <= 0) error = Error(2);
                        }
                    if (strtod(argv[4], NULL) > 1.4 || strtod(argv[4], NULL) <= 0) error = Error(2);
                    if (error == 0) Measur_Dist(strtod(argv[4], NULL), beta, c);
                }
            else Error(1); //chybny argument
          }
        return (EXIT_SUCCESS);
    }