/*
 * This code/software is licensed under the 
 * CC-GNU GPL version 2.0 or later.
 *
 * see: http://creativecommons.org/licenses/GPL/2.0/
 * 
 * Author: Florian Streibelt <florian@freitagsrunde.org> 
 *  C-Kurs der Freitagsrunde, TU-Berlin September 2010
 *
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

typedef struct product_t {
  char   *name;
  enum _punit { UNDEF,Pieces, KGrams, Liters} punit;
  union {
      struct{
          int    count;
          double price_p_piece; 
      } ppiece;
      struct{
          double weight;
          double price_p_kilo;
      } pkilo;
      struct {
          double liter;
          double price_p_liter;
      } pliter;
  };
} product;


//-----------[begin: listen.tex]

typedef struct bondetail_t{
    product *prod;
    double pricesum;
} bondetail;


typedef struct bonrow_t{
  bondetail* data;
  struct bonrow_t* next;
}bonrow;


//---------[ende: listen.tex]

double calc_price(product *foo){
 double sum=-1;
 switch (foo->punit){
   default:  printf ("ERROR.\n");
                break;
   case KGrams: 
   sum=(foo->pkilo.weight * foo->pkilo.price_p_kilo)/1000;
                break;
   case Pieces: 
   sum=foo->ppiece.count * foo->ppiece.price_p_piece;
                break;
   case Liters: 
   sum=foo->pliter.liter * foo->pliter.price_p_liter; 
                break;
    }
   return sum; 
}

//---------[begin: listen.tex]

bondetail* newPiecesP(int amount, char* name,
                                     double price)
{

    product *prod = 
             (product*) calloc(1,sizeof(product));

    prod->name=strdup(name);
    prod->punit=Pieces;
    prod->ppiece.count=amount;
    prod->ppiece.price_p_piece=price;


    bondetail *item = 
      (bondetail*) calloc(1,sizeof(bondetail));

    item->prod=prod;
   
    return item;
}

bondetail* newKilosP(double amount, char* name,
                                     double price)
{
    product *prod = 
             (product*) calloc(1,sizeof(product));

    prod->name=strdup(name);
    prod->punit=KGrams;
    prod->pkilo.weight=amount;
    prod->pkilo.price_p_kilo=price;

    bondetail *item = 
      (bondetail*) calloc(1,sizeof(bondetail));

    item->prod=prod;
   
    return item;
}



bondetail* newLiterP(double amount, char* name,
                                     double price)
{

    product *prod = 
             (product*) calloc(1,sizeof(product));

    prod->name=strdup(name);
    prod->punit=Liters;
    prod->pliter.liter=amount;
    prod->pliter.price_p_liter=price;


    bondetail *item = 
      (bondetail*) calloc(1,sizeof(bondetail));

    item->prod=prod;
   
    return item;
}


//---------[end: listen.tex]


double calc_sum(bonrow* firstelement){
  bonrow* current_row = firstelement;
  double sum=0;
  while(current_row!=NULL){
    double price = calc_price(current_row->data->prod);
    current_row->data->pricesum=price;
    sum+=price;
    current_row=current_row->next;
  }  
  return sum;
}



void dump_bonhead(){
    printf("%20s CKURS 2010\n"," ");
    printf("%5s Wir lieben C! Immer in Ihrer Nähe.\n\n"," ");
    printf(" %s %-25s   %s     %s   \n",
        "Menge","Produkt","EP","GP");
}

void dump_bonsum(double sum){
    double mwst=0.17*sum;

    printf("     %30s:    %6.2f \n",
        "MwSt (17%)",mwst);

    printf("     %30s:    %6.2f \n",
        "GESAMTPREIS",sum);
}

void dump_bonelement(bondetail* elem){

switch (elem->prod->punit){
   default:  printf ("<ERROR IN PRODUCT>\n");
                break;
   case KGrams: 
    printf(" %4.0fg %-25s %6.2f %6.2f \n",
         elem->prod->pkilo.weight, elem->prod->name, 
         elem->prod->pkilo.price_p_kilo, elem->pricesum);
                break;
   case Pieces: 
    printf(" %4.0i  %-25s %6.2f %6.2f \n",
         elem->prod->ppiece.count, elem->prod->name, 
         elem->prod->ppiece.price_p_piece, elem->pricesum);
                break;
   case Liters: 
    printf(" %4.0fL %-25s %6.2f %6.2f \n",
         elem->prod->pliter.liter, elem->prod->name, 
         elem->prod->pliter.price_p_liter, elem->pricesum);
                break;
    }
}




void print_bon(bonrow* firstelement,double sum){
    dump_bonhead();
    bonrow* current_row = firstelement;

    while(current_row!=NULL){
     dump_bonelement(current_row->data);
     current_row=current_row->next;
    }  
 
    dump_bonsum(sum);
}




int main(int argc, char** argv){

//---------[begin: listen.tex]

 bonrow *k_head, *k_tail;

 //first element
 k_tail = calloc(1,sizeof(bonrow));
 k_head = k_tail;
 k_tail->next = NULL;
 k_tail->data = newPiecesP(5,"Club Mate",0.75);

 //next element
 k_tail->next=calloc(1,sizeof(bonrow));
 k_tail=k_tail->next;
 k_tail->next=NULL;
 k_tail->data= newKilosP(750,"Wiener",4.90);
 
 
 //next element
 k_tail->next=calloc(1,sizeof(bonrow));
 k_tail=k_tail->next;
 k_tail->next=NULL;
 k_tail->data= newLiterP(75,"Vollmilch 3.9%",1.90);


 double sum = calc_sum(k_head);
 print_bon(k_head,sum);


//---------[end: listen.tex]

return 0;
}