/*
   defines

   CHEAT          print values during the game
*/

#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#define MAX_DESC_LEN 128
#define RESERVOIR 8

struct Thing {
   char description[MAX_DESC_LEN+1];
   int value;
};

unsigned int sample(char* filename, unsigned int nofentries, struct Thing selected[nofentries]) {
   FILE* fp = fopen(filename, "r");
   if (!fp) return 0;
   const unsigned int buflen = MAX_DESC_LEN + 32;
   char buf[buflen];
   unsigned int filled = 0;
   unsigned int number_of_records = 0;
   while (fgets(buf, buflen, fp)) {
      char* sep = 0;
      for (char* cp = buf; *cp && cp < buf + buflen; ++cp) {
	 if (*cp == ':') {
	    sep = cp; *sep = 0; break;
	 }
      }
      if (!sep) continue;
      ++number_of_records;
      unsigned int index = filled;
      if (filled < nofentries) {
	 ++filled;
      } else {
	 index = rand() % number_of_records;
      }
      if (index < nofentries) {
	 strncpy(selected[index].description, buf, MAX_DESC_LEN);
	 selected[index].description[MAX_DESC_LEN] = 0;
	 selected[index].value = atoi(sep + 1);
      }
   }
   fclose(fp);
   return filled;
}

unsigned int game(unsigned int nofentries, struct Thing things[nofentries]) {
   unsigned int chosen[nofentries]; /* chosen things in sorted order */
   unsigned int selected = 0; /* number of chosen things */
   unsigned int points = 0;
   bool taken[nofentries];
   for (unsigned int i = 0; i < nofentries; ++i) {
      taken[i] = false;
   }
   while (selected < nofentries) {
      /* display current state */
      printf("Current state:\n");
      printf(" %2d:\n", 1);
      for (unsigned int i = 0; i < selected; ++i) {
	 unsigned int index = chosen[i];
#ifdef CHEAT
	 printf("     %4d %s\n", things[index].value, things[index].description);
#else
	 printf("     %s\n", things[index].description);
#endif
	 printf(" %2d:\n", i + 2);
      }
      printf("Still to be sorted:\n");
      for (unsigned int i = 0; i < nofentries; ++i) {
	 if (!taken[i]) {
#ifdef CHEAT
	    printf(" %2d: %4d %s\n", i + 1, things[i].value, things[i].description);
#else
	    printf(" %2d: %s\n", i + 1, things[i].description);
#endif
	 }
      }
      unsigned int what; unsigned int where;
      for(;;) {
	 printf("What is to be inserted where? ");
	 if (scanf("%u %u", &what, &where) != 2) {
	    printf("Bad input."); return 0;
	 }
	 if (what-- == 0 || what >= nofentries || taken[what]) {
	    printf("Bad value for what.\n"); continue;
	 }
	 if (where-- == 0 || where > selected) {
	    printf("Bad value for where.\n"); continue;
	 }
	 break;
      }
      int value = things[what].value;
      if ((where > 0 && value < things[chosen[where-1]].value) ||
	    (where < selected && value > things[chosen[where]].value)) {
	 printf("Sorry, then it is no longer sorted:\n");
	 for (int i = 0; i <= selected; ++i) {
	    unsigned int index = chosen[i];
	    if (i == where) {
	       printf("-->  %4d %s\n", things[what].value, things[what].description);
	    }
	    if (i < selected) {
	       printf("     %4d %s\n", things[index].value, things[index].description);
	    }
	 }
	 printf("Bye!\n");
	 return points;
      }
      for (int i = selected; i > where; --i) {
	 chosen[i] = chosen[i-1];
      }
      chosen[where] = what; ++selected; ++points;
      taken[what] = true;
   }
   return points;
}

int main() {
   srand(getpid() ^ time(0));
   struct Thing things[RESERVOIR];
   unsigned int filled = sample("berge", RESERVOIR, things);
   unsigned int points = game(filled, things);
   printf("You got %d points.\n", points);
   /*
   for (unsigned int i = 0; i < filled; ++i) {
      printf("%4d %s\n", things[i].value, things[i].description);
   }
   */
}