#include <stdio.h>
#include <string.h>
#include <stdlib.h>
 
///////////////  user defined data  /////////////////////
struct State
{
	char * name;	// state name
	int year;		// year of entry into the union
	char * cap;		// state capital
	int popRank;	// population ranking
};
 
struct Database
{
	struct State * list;	// array of states
	int count;				// total count of states
	char * filename;		// input filename
};
 
 
///////////////  function prototypes  ////////////////////
struct Database * initDatabase (char * filename);
void deleteDatabase (struct Database * db);
void fillDatabase (struct Database * db);
void insertDatabase (struct Database* db, int index, struct State * state);
void printDatabase (struct Database * db);
 
int initState (struct State * state, char * name, int year, char * cap, int popRank);
void deleteState (struct State * state);
void copyState (struct State * from, struct State * to);
void printState (struct State * state);
 
 
 
//////////////////////////  program start  ///////////////////////////////////////
int main(void)
{
	struct Database * db;
 
 	if (db = initDatabase("states.txt"))	// allocate memory for Database struct,
  			 								// then initialize fields of Database struct
	{
		fillDatabase(db);	// read from file
		printDatabase(db);	// print data
		deleteDatabase(db);	// free memory in Database struct
		free(db);			// free Database struct itself
 
		return 0;
	}
	else  // not successful
	{
	 	 return 1;
   }
}
 
//////////////////////  Database functions  ////////////////////////////////
 
//initDatabase - allocates memory for Database struct and initializes 
//               each field
//input: input filename
//return: pointer to Database struct if success
//        NULL if fail
struct Database * initDatabase (char * filename)
{
	FILE * fpIn;
	struct Database * db;
	struct State * states;
	char * string;
 
	// open input file and check for open success
	if ( ( fpIn = fopen( filename, "r" ) ) )
	{
		// allocate memory for Database struct and check for success
		if ( db = ( struct Database * )malloc( sizeof( struct Database ) ) )
		{
			// allocate memory for filename field and initializes with filename
			if ( string = ( char * )malloc( sizeof( char ) * strlen( filename ) ) )
			{
				strcpy( string, filename );
				db->filename = string;
			}
			else
			{
				printf("Not enough memory!\n");
				exit(0);
			}
 
			// initialize count field to 50
			db->count = 50;
 
			// initialize list field by allocating memory for array of 50 states 
			// and check for success
			if ( states = ( struct State * )malloc( sizeof( struct State ) * 50 ) )
			{
				db->list = states;
			}
			else
			{
				printf("Not enough memory!\n");
				exit(0);
			}
		}
 
	}
	else
	{
		printf("Error with file!\n");
		exit(0);
	}
 
	// close input file
	fclose( fpIn );
 
	return db;
}
 
//deleteDatabase - frees allocated memory inside a Database struct
//input: pointer to Database struct
//return: nothing
void deleteDatabase (struct Database * db)
{
	while ( db->list )
	{
		deleteState( db->list );
		db->list++;
	}
}
 
//fillDatabase - reads info from file and stores in array of State structs
//input: pointer to Database struct
//return: nothing
void fillDatabase (struct Database * db)
{
   struct State tempState;  // temp State struct to store data from file
   char name[80];	// temp variables
   int year;		// to store
   char cap[80];	// input data
   int popRank;		// from file
   int index = 0;		// index into array of State structs
 
   FILE *fpIn;
   int cnt;
 
	// open file from filename field of db
	// don't need to check for file open success because initDatabase already checked
	fpIn = fopen( db->filename, "r" );	
 
	// loop through all the states
	for ( cnt = 0; cnt < db->count; cnt++ )
	{
	    // read and parse one line of file into 4 input data fields
		if ( fscanf( fpIn, "%[^,], %d, %[^,], %d", name, &year, cap, &popRank ) == 4 )
		{
			// if tempState is created successfully from the 4 input data
			if ( initState (&tempState, name, year, cap, popRank) )
			{	// then copy tempState data into array of states at the current index
				insertDatabase (db, index, &tempState);  
			}
			index++;
		}
		else
		{
			printf("Error reading file!\n");
			exit(0);
		}
	}
 
 	// close file
 	fclose( fpIn );
}
 
//insertDatabase - copy state data from tempState into appropriate place in array
//input: pointer to Database struct
//       current index in array
//       pointer to tempState containing state data
//return: nothing
void insertDatabase (struct Database * db, int index, struct State * state)
{
   // set pCurrent to location to be inserted in array
	struct State *pCurrent = db->list + index;
	// copy from state to pCurrent
	copyState (state, pCurrent);
 
	return;
}
 
//printDatabase - print data of state array
//input: pointer to Database struct
//return: nothing
void printDatabase (struct Database * db)
{
	int i;
 
	printf (" State name      Year     Capital      Pop. rank\n");
	printf ("------------------------------------------------\n");
	for (i = 0; i < db->count; i++)
		printState(db->list+i);
 
	return;
}
 
////////////////////////  State functions  //////////////////////////////
 
//initState - initializes a State struct with input data
//input: pointer to State struct
//       name, year, capital, and population rank of state
//return: true for success
//        false for fail
int initState (struct State * state, char * name, int year, char * cap, int popRank)
{
	char * stateName;
	char * capital;
   // if memory allocation is successful, store name
   if ( stateName = ( char * )malloc( sizeof( char ) * strlen( name ) ) )
   {
	   strcpy( stateName, name );
  		state->name = stateName;
   }
   else
   {
	   printf("Not enough memory!\n");
	   return 0;
   }
 
   // store year
   state->year = year;
 
   // if memory allocation is successful, store capital
   if ( capital = ( char * )malloc( sizeof( char ) * strlen( cap ) ) )
   {
	   strcpy( capital, cap );
	   state->cap = capital;
   }
   else
   {
	   printf("Not enough memory!\n");
	   return 0;
   }
 
   // store population ranking
	state->popRank = popRank;
 
	return 1;
}
 
//deleteState - frees allocated memory inside a State struct
//input: pointer to State struct
//return: nothing
void deleteState (struct State * state)
{
	free( state->name );
	free( state->cap );
	free( state );
}
 
//copyState - copies contents between two State structs
//input: pointer to source State struct
//       pointer to destination State struct
//return: nothing
void copyState (struct State * from, struct State * to)
{
	to->name = from->name;
	to->year = from->year;
	to->cap = from->cap;
	to->popRank = from->popRank;
}
 
//printState - displays State data
//input: pointer to State struct
//return: nothing
void printState (struct State * state)
{
	printf ("%-17s%-8d%-18s%2d\n", state->name, state->year, state->cap, state->popRank);
 
	return;
}