#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define DICEFACES 6

#if ! defined(__cplusplus)
typedef unsigned char bool;
#define false 0
#define true  1
#endif

typedef struct
{
	long price;
	long next;
} cell;

static long minimum = 0;
static long maximum = 0;
static long increment = 0;
static long iterations = 0;
static long cell_count = 0;
cell* board = NULL;
static long initial_investment = 0;
static long average_balance = 0;
static long reached_goals = 0;
static long game_balance = 0;
static bool game_reached_goal = false;

void reset_file_variables()
{
	cell_count = 0;
	free(board); board = NULL;
	initial_investment = 0;
	average_balance = 0;
	reached_goals = 0;
	game_balance = 0;
	game_reached_goal = false;
}

bool process_params(int argc, char* argv[])
{
	if ( argc < 6 ) return false;
	minimum = atol(argv[1]);
	maximum = atol(argv[2]);
	increment = atol(argv[3]);
	iterations = atol(argv[4]);
	return true;
}

int print_usage()
{
	fprintf(stderr, "%s\n", "usage: escser min max increment iterations file1 [file2 ... fileN]");
	return 1;
}

bool count_lines(FILE* file)
{
	for ( int ch = 0; (ch = fgetc(file) ) != EOF; )
		if ( ch == '\n' )
			++cell_count;
	return true;
}

bool load_file(FILE* file)
{
	board = (cell*) malloc( cell_count * sizeof(cell) );
	assert(board);
	for ( long i = 0; i < cell_count; ++i )
	{
		fscanf(file, "%li", & board[i].price);
		fscanf(file, "%li", & board[i].next);
	}
	return true;
}

bool simulate_game()
{
	game_reached_goal = false;
	game_balance = initial_investment;
	long position = -1;
	while ( game_balance >= 0 )
	{
		position += rand() % DICEFACES + 1;
		if ( position >= cell_count )
			position = cell_count - 1;
		game_balance += board[position].price;
		if ( position == cell_count - 1 )
			return game_reached_goal = true;
		if ( board[position].next )
			position = board[position].next - 1;
	}
	return false;
}

void simulate_games()
{
	reached_goals = 0;
	long total_balances = 0;
	for ( long i = 0; i < iterations; ++i )
	{
		simulate_game();
		total_balances += (game_balance - initial_investment);
		reached_goals += game_reached_goal;
	}
	average_balance = (long)(total_balances / (double)iterations);
}

void simulate_investments()
{
	printf("%18s %18s %18s\n", "InitialInvestment", "AverageBalance", "ReachedGoals");
	for ( initial_investment = minimum; initial_investment <= maximum; initial_investment += increment)
	{
		simulate_games();
		printf("%18li %18li %18li\n", initial_investment, average_balance, reached_goals);
	}
}

bool process_filename(const char* filename)
{
	printf("\n%s:\n", filename);
	FILE* file = fopen(filename, "r");
	if ( ! file ) return false;
	reset_file_variables();
	count_lines(file);
	rewind(file);
	if ( load_file(file) )
		simulate_investments();
	free(board); board = NULL;
	fclose(file);
	return true;
}

int main(int argc, char* argv[])
{
	if ( ! process_params(argc, argv) )
		return print_usage();

	srand( time(NULL) );
	for ( int i = 5; i < argc; ++i )
		process_filename(argv[i]);

	return 0;
}