/*********************
* Name: Yair Benamou.*
* Lesson: 8.         *
* Ex: Mid Project    *
**********************/

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<conio.h>
#include<malloc.h>


// No Prototypes
int fileSize(FILE* pToFile);
int fastScan(FILE* pToFile, FILE* pToVirus, int size);
int choseScan(void);


/**
The function 'fileLen' get a file and count how much characters he have.

Input: pToFile - Getting the pointer to the file.

Output: numCharacters - The counter.
*/
int fileSize(FILE* pToFile)
{
	int count = 0;
	while (fgetc(pToFile) != EOF) // Counting the chars
	{
		count++;
	}
	return (count);
}



/**
The function 'choseScan' ask the user which scan he wants to do.

Inputs: None.

Outputs: The user's choice.
*/
int choseScan(void)
{
	int choice;

	printf("\nWhich scan you want to do?\n1) FAST SCAN.\n2) REGULAR SCAN.\n");
	scanf("%d", &choice);

	return(choice);
}



/**
The function 'fastScan' gets a file and his size. The function will scan the file
on the fast way: 20% of the file beginning, and 20% from the end.

Input: pToFile - The file to scan
pToVirus - The pointer to the virus file.
size - The file's size.

Output: 1 if there is a virus.
0 if the file is clean.
*/
int fastScan(FILE* pToFile, FILE* pToVirus, int size)
{
	float heuristic;
	int i, position;
	int j = 0;
	int ch, ch2;
	long virusLen;
	int flag, bigFlag = 0; // Turn up the flag to 2 when the virus is detected.

	heuristic = (float)(size * 0.2); // Getting 20% of the file size.

	fseek(pToVirus, 0, SEEK_END);
	virusLen = ftell(pToVirus);

	fseek(pToVirus, 0, SEEK_SET);
	fseek(pToFile, 0, SEEK_SET); // To put the seek on the file beginning.

	while (j < (int)heuristic)
	{
		flag = 1;
		fseek(pToVirus, 0, SEEK_SET);
		ch = fgetc(pToFile);
		ch2 = fgetc(pToVirus);

		position = ftell(pToFile);
		if (ch == ch2) // Verifying if the first char of the virus sign is equal to the current char on the file.
		{
			for (i = 1; i < virusLen; i++)
			{
				ch = fgetc(pToFile);
				ch2 = fgetc(pToVirus);
				if (ch != ch2)
				{
					flag = 0;
				}
			}

			if (!flag)
			{
				fseek(pToFile, -(position - 1), SEEK_CUR);
			}
			else
			{
				printf("There is a VIRUS!!!!\n");
				break;
			}
		}
		j++;
	}

	printf("\n\n\n");

	return (bigFlag);
}



/**
This is the main function of the program, which is responsible
to both start and end the running of the program.
input: argc - How much strings are.
argv - The strings.

output: The program returns 0 upon successful completion of its running (windows convention).
*/
int main(int argc, char** argv)
{
	/*
	char* myPath = (char*)malloc(strlen("dir  /b /A:-d") + strlen(argv[1]));
	strcpy(myPath, "dir ");
	strcat(myPath, argv[1]);
	strcat(myPath, " /a:-d");

	system(myPath);
	*/


	int size;
	FILE* pToFile = fopen("C:\\Users\\User\\Desktop\\Mid Project\\Songs\\Happy.avi", "rb");
	FILE* pToVirus = fopen("C:\\Users\\User\\Desktop\\Mid Project\\YouTubeSign", "rb");

	if (!pToFile) // Verifying if the file didn't opened successfuly.
	{
		printf("An error occured opening the file.\n");
		return 1;
	}

	if (!pToVirus)
	{
		printf("An error occured opening the file.\n");
		return 1;
	}

	size = fileSize(pToFile); // Getting the file's size
	printf("File Size: %d.\n", size);

	if (choseScan() == 1)
	{
		printf("bigFlag: %d\n", fastScan(pToFile, pToVirus, size));
	}
	else
	{
		// regularScan();
	}

	fclose(pToFile);

	system("PAUSE");
	return (0);
}