//Match patterns from several files.

#define _GNU_SOURCE

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<inttypes.h>

char *chomp ( char * );
void read_file ( char * , int32_t * );

int32_t main ( int32_t argc , char ** argv )
{
	char *dat_line = NULL;
	char *txt_line = NULL;
	char *file_name_txt = NULL;
	char *file_name_dat = NULL;
	char *entire_dat_file = NULL;
	char *line_from_txt_file = NULL;
	char *chomped_line = NULL;


	unsigned long int summation = 0;
	unsigned long int value = 1;
	float average = 0.0;
	float scope = 0;

	unsigned long int dat_len = 0;
	unsigned long int read;
	unsigned long int txt_len = 0;
	unsigned long int number_of_characters = 0;
	unsigned long int number_of_words = 0;
	unsigned long int i = 0;

	FILE *open_dat_file = NULL;
	FILE *open_txt_file = NULL;
	FILE *output = NULL;

	//let get the TXT files...
	system ("ls -1 *.txt > text_files.tmp" );
	
	//lets get the DAT files...
	system ( "ls -1 *.dat > dat_files.tmp" );

	//Outer look is for the DAT files and inner loop is for the TXT
	//files...

	FILE *txt_pointer = NULL;
	txt_pointer = fopen ( "text_files.tmp" , "r" );
	if ( txt_pointer == NULL )
	{
		fprintf ( stderr , "The file list for text files does not exist\n" );
	}

	FILE *dat_pointer = NULL;
	dat_pointer = fopen ( "dat_files.tmp" , "r" );
	if ( dat_pointer == NULL )
	{
		fprintf ( stderr , "The file list for the dat files does not exist\n" );
	}


	output = fopen ( "average_values.res" , "a" );
	if ( output == NULL )
	{
		fprintf ( stderr , "File append error\n" );
	}


	while ( ( read = getline ( &dat_line , &dat_len , dat_pointer ) ) != -1 )
	{
		file_name_dat = chomp ( dat_line );
		open_dat_file = fopen ( file_name_dat , "r" );

		( void ) fseek ( open_dat_file , 0L , SEEK_END );
		number_of_characters = ftell ( open_dat_file );

		entire_dat_file = ( char * ) malloc ( ( number_of_characters + 1 ) * sizeof ( char ) );
		if ( entire_dat_file == NULL )
		{
			fprintf ( stderr , "malloc() memory allocation failure in entire_dat_file\n" );
		}

		rewind ( open_dat_file );

		read_file ( file_name_dat , &number_of_words );

		fgets ( entire_dat_file , number_of_characters , open_dat_file );

		while ( ( read = getline ( &txt_line , &txt_len , txt_pointer ) ) != -1 )
		{
			file_name_txt = chomp ( txt_line );
			open_txt_file = fopen ( file_name_txt , "r" );

			//Now read to read the txt files one by one and search for the pattern...
		
			while ( ( read = getline ( &line_from_txt_file , &txt_len , open_txt_file ) ) != 1 && !feof ( open_txt_file ) )
			{
				chomped_line = chomp ( line_from_txt_file );
				if ( strstr ( entire_dat_file , chomped_line ) != NULL )
				{
					summation = summation + value;
				}
				value ++;
			}
			value = 1;
			fclose ( open_txt_file );
			memset ( file_name_txt , 0 , strlen ( file_name_txt ) );
		}

		average = ( float ) summation / ( number_of_words + 1 );
		average = - average;
		scope = powf ( 2.71828183 , average );
		fprintf ( output , "%f\n" , scope );
		number_of_words = 0;
		summation = 0;
		value = 0;
		average = 0;
		scope = 0;
		number_of_characters = 0;

		rewind ( txt_pointer );
		free ( entire_dat_file );
		fclose ( open_dat_file );
		memset ( file_name_dat , 0 , strlen ( file_name_dat ) );
	}

	fclose ( output );

	if ( txt_line )
	{
		free ( txt_line );
	}

	if ( dat_line )
	{
		free ( dat_line );
	}

	fclose ( dat_pointer );
	fclose (txt_pointer );

	return ( EXIT_SUCCESS );
}


char *chomp ( char *s )
{
	unsigned long int len = 0;
	len = strlen ( s );
	if ( s [ len - 1 ] == '\n' )
	{
		s [ len - 1 ] = 0;
	}
	return ( s );
}


void read_file ( char *path , int32_t *number_of_words )
{
	FILE *pointer = NULL;

	char ch;

	pointer = fopen ( path , "r" );
	if ( pointer == NULL)
	{
		perror ( "File read error " );
	}

	(*number_of_words) = 0;

	while ( !feof ( pointer ) )
	{
		ch = fgetc ( pointer );
		if ( ch == ' ' && ch != EOF )
		{
			(*number_of_words) ++;
		}
	}

	fclose ( pointer );
}