/*
 * =====================================================================================
 *
 *       Filename:  1.01.bildverarbeitung3.cc
 *
 *    Description:  
 *
 *        Version:  1.0
 *        Created:  20.03.2014 12:24:17
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  Stefan Suhren (SSuhren), suhren.stefan@fh-swf.de
 *   Organization:  FH Südwestfalen, Iserlohn
 *
 * =====================================================================================
 */

#include	<cstdlib>
#include	<iostream>
#include	<fstream>
#include	<string>
#include	<cmath>

using namespace std;

//-----------------------------------------------------------------------------
//  Type Defs
//-----------------------------------------------------------------------------

typedef unsigned char Pixel;

// ##### DATA TYPES - LOCAL TO THIS SOURCE FILE ##############################
struct pgm_bild
{
	char 	magic[2];	// Bildtyp
	int		nx;			// Zeilenzahl
	int		ny;			// Spaltenzahl
	int		graumax;	// max. Grauwert
	Pixel 	**bild;		// Bildmatrix
};		// ---------- end of struct pgm_bild ----------

// ##### LOCAL PROTOTYPES ######################################################
void bild_lesen( pgm_bild *bild, char *ifs_file_name );
void bild_schreiben( pgm_bild *bild, char *ofs_file_name );
void delete_pixel_matrix( Pixel **m );
Pixel** new_pixel_matrix( size_t rows, size_t columns );
void glaetten( pgm_bild *bild1, pgm_bild *bild2 );
void invertieren( pgm_bild *bild1, pgm_bild *bild2 );
void kantenbildung( pgm_bild *bild1, pgm_bild *bild2 );
void kopiere_bildkopf( pgm_bild *bild1, pgm_bild *bild2 );
void schwellwert( pgm_bild *bild1, pgm_bild *bild2, Pixel schwellwert );

// ===  FUNCTION  ======================================================================
//         Name:  main
//  Description:  Main loop for user interactions
//    Exitcodes:  0		success
//    			  1		file open failure
//    			  2		type missmatch
//    			  3		header corrupted
//    			  4		image to narrow
//    			  5		image to low
//    			  6		pixel read error
//    			  7		pixel outside of interval
// =====================================================================================
int main( int argc, char *argv[] ){

	pgm_bild pic1;
	pgm_bild pic2;

	char menu = 'e';	// user input for conversion
	
	char ifs_file_name[] = "dreifach.pgm";   // input  file name 
	char ofs_file_name[] = "dreifach.out.pgm"; // output file name 

	bild_lesen(&pic1, ifs_file_name);
	pic2.bild = new_pixel_matrix(1,1);

	do{			// repeates till user presses e
		cout << "c Kopieren\ng Glätten\ni Invertieren\nk Kantenbildung\ns Schwellwert\ne ENDE\n?";
		cin >> menu;
		if(menu != 'e'){

			switch (menu){			// change output
				case 'g':
					glaetten(&pic1, &pic2);
					break;
				case 'i':
					invertieren(&pic1, &pic2);
					break;
				case 'k':
					kantenbildung(&pic1, &pic2);
					break;
				case 's':				
					schwellwert(&pic1, &pic2, 150);
					break;
				case 'c':
					kopiere_bildkopf(&pic1, &pic2);
					for(int i = 0; i < pic2.nx; i++){				// height
						for(int j = 0; j < pic2.ny; j++){			// width
							pic2.bild[i][j] = pic1.bild[i][j];
						}
					}
					break;
			}
			
			bild_schreiben(&pic2, ofs_file_name);
		}

	}while(menu != 'e');

	return EXIT_SUCCESS;
}				// ----------  end of function main  ---------- 

// ===  FUNCTION  ======================================================================
//         Name:  bild_lesen
//  Description:  Reads image from the file ifs_file_name
// =====================================================================================
void bild_lesen( pgm_bild *bild, char *ifs_file_name ){

	int temp = 0;		// reads the vales from input file

	string cod;			// coding string at the beginning

	// Open file for manipulation
	ifstream  ifs;                        // create ifstream object 

	ifs.open ( ifs_file_name );           // open ifstream 
	if (!ifs) {
		cerr << "\nERROR : failed to open input  file " << ifs_file_name << endl;
		exit (EXIT_FAILURE);
	}

	getline(ifs, cod);					// reads hole line 

	if( cod != "P2"){					// type must match
		ifs.close();					// release file handler
		cerr << "File type wrong.";
		exit(2);								
	}
	else{
		bild->magic[0] = cod[0];
		bild->magic[1] = cod[1];
	}

	if(!(ifs >> bild->ny)){				// Header corrupted (width)
		ifs.close();
		cerr << "Header corrupted.";
		exit(3);
	}

	if(!(ifs >> bild->nx)){				// Header corrupted (height)
		ifs.close();
		cerr << "Header corrupted.";
		exit(3);
	}

	if(!(ifs >> bild->graumax)){		// Header corrupted
		ifs.close();
		cerr << "Header corrupted.";
		exit(3);
	}

	if( bild->ny <= 0 ){				// image to narrow
		ifs.close();					// release file handler
		cerr << "Image is to narrow.";
		exit(4);
	}

	if( bild->nx <= 0 ){				// image to low
		ifs.close();					// release file handler
		cerr << "Image is to low.";
		exit(5);
	}

	// Create a new pixel matrix for the image
	bild->bild = new_pixel_matrix(bild->nx, bild->ny);

	cout << "File type: " << bild->magic << endl 		// printing for debug perposes
		 << "Width:     " << bild->ny << endl
		 << "Height:    " << bild->nx << endl
		 << "maxGrey:   " << bild->graumax << endl;

	for(int i = 0; i < bild->nx; i++){		// Height
		for(int j = 0; j < bild->ny; j++){	// Width
			if(ifs >> temp){				// to prevent char by char reading
				if(temp >= 0 && temp <= bild->graumax){
					bild->bild[i][j] = temp;			// reading input file
				}
				else{
					cerr << "Pixel out of interval";
					ifs.close();
					exit(7);
				}
			}
			else{
				cerr << "Pixel read error" << endl;
				ifs.close();
				exit(6);
			}
		}
	}

	ifs.close ();                         // close ifstream
}

// ===  FUNCTION  ======================================================================
//         Name:  bild_schreiben
//  Description:  Writes image to file ofs_file_name
// =====================================================================================
void bild_schreiben( pgm_bild *bild, char *ofs_file_name ){

	ofstream  ofs;									// create ofstream object 

	ofs.open ( ofs_file_name );						// open ofstream 
	if (!ofs) {
		cerr << "\nERROR : failed to open output file " << ofs_file_name << endl;
		exit (EXIT_FAILURE);
	}

	ofs << bild->magic << endl						// writing header
		<< bild->ny << " " << bild->nx << endl
		<< bild->graumax << endl;

	for(int i = 0; i < bild->nx; i++){
		for(int j = 0; j < bild->ny; j++){
			ofs << (int) bild->bild[i][j] << ' ';	// and writing changed image (don't forget the ' ')
		}
			ofs << endl;
	}	

	ofs.close ();									// close ofstream 
}

void delete_pixel_matrix( Pixel **m ){
	delete[] *m; // delete data pointer
	delete[]  m; // delete pointer array
}


// ===  FUNCTION  ======================================================================
//         Name:  new_pixel_matrix
//  Description:  Creates a new pixel matrix with a few tricks
// =====================================================================================
Pixel** new_pixel_matrix( size_t rows, size_t columns ){
	size_t i;
	Pixel **m;
	m = new Pixel* [rows];			// allocate pointer array
	*m = new Pixel [rows*columns];	// allocate data array
	for( i = 1; i<rows; i++){		// set pointers
		m[i] = m[i-1] + columns;
	}
	return m;
}

// ===  FUNCTION  ======================================================================
//         Name:  glaetten
//  Description:  bild2 is a smoothed version of bild1
// =====================================================================================
void glaetten( pgm_bild *bild1, pgm_bild *bild2){
	// Copy the neccessary values
	kopiere_bildkopf( bild1, bild2);

	for(int i = 0; i < bild2->ny; i++){								// width
		bild2->bild[0][i] = bild1->bild[0][i];						// copy first row
	}
	for(int i = 1; i < bild2->nx-1; i++){							// height
		bild2->bild[i][0] = bild1->bild[i][0];						// copy first pixel every row
		for(int j = 1; j < bild2->ny-1; j++){						// width
			bild2->bild[i][j] = 	( bild1->bild[i-1][j-1]
									+ bild1->bild[i-1][j]
									+ bild1->bild[i-1][j+1]
									+ bild1->bild[i][j-1]
									+ bild1->bild[i][j]
									+ bild1->bild[i][j+1]
									+ bild1->bild[i+1][j-1]
									+ bild1->bild[i+1][j]
									+ bild1->bild[i+1][j+1]) / 9;
		}
		bild2->bild[i][bild2->ny-1] = bild1->bild[i][bild2->ny-1];	// copy last pixel every row
	}	
	for(int i = 0; i < bild2->ny; i++){								// width
		bild2->bild[bild2->nx-1][i] = bild1->bild[bild2->nx-1][i];	// copy last row
	}
}

// ===  FUNCTION  ======================================================================
//         Name:  invertieren
//  Description:  bild2 is a inverted version of bild1
// =====================================================================================
void invertieren( pgm_bild *bild1, pgm_bild *bild2 ){
	// Copy the neccessary values
	kopiere_bildkopf( bild1, bild2 );

	for(int i = 0; i < bild2->nx; i++){								// height
		for(int j = 0; j < bild2->ny; j++){							// width
			bild2->bild[i][j] = bild2->graumax - bild1->bild[i][j];	// inverts value by subtracting from graumax
		}
	}	 
}

// ===  FUNCTION  ======================================================================
//         Name:  kantenbildung
//  Description:  bild2 is a edged version of bild1
// =====================================================================================
void kantenbildung( pgm_bild *bild1, pgm_bild *bild2 ){
	// Copy the neccessary values
	kopiere_bildkopf( bild1, bild2);

	for(int i = 0; i < bild2->ny; i++){					// width
		bild2->bild[0][i] = 0;							// blacken the first row
	}
	for(int i = 1; i < bild2->nx-1; i++){				// height
		bild2->bild[i][0] = 0;							// blacken the first pixel every row
		for(int j = 1; j < bild2->ny-1; j++){			// width
			bild2->bild[i][j] = abs(( -1*bild1->bild[i-1][j]
									  -1*bild1->bild[i][j-1]
									  +4*bild1->bild[i][j]
									  -1*bild1->bild[i][j+1]
									  -1*bild1->bild[i+1][j] ) /9 );
		}
		bild2->bild[i][bild2->ny-1] = 0;				// blacken the last pixel every row
	}	
	for(int i = 0; i < bild2->ny; i++){					// width
		bild2->bild[bild2->nx-1][i] = 0;				// blacken the last row
	}
}

// ===  FUNCTION  ======================================================================
//         Name:  kopiere_bildkopf
//  Description:  Copies the Header and allocates a new matrix (frees old)
// =====================================================================================
void kopiere_bildkopf( pgm_bild *bild1, pgm_bild *bild2 ){
	// Copy the magic value
	for(unsigned int i = 0; i < (sizeof bild1->magic/sizeof bild1->magic[0]); i++){
		bild2->magic[i] = bild1->magic[i];
	}

	// Copy over the height/width
	bild2->nx = bild1->nx;
	bild2->ny = bild1->ny;

	// Copy graumax
	bild2->graumax = bild1->graumax;
	
	//Free memory
	delete_pixel_matrix(bild2->bild);
	bild2->bild = new_pixel_matrix( bild2->nx, bild2->ny);
}

// ===  FUNCTION  ======================================================================
//         Name:  schwellwert
//  Description:  bild2 is a polarised version of bild1 parted by schwellwert 
// =====================================================================================
void schwellwert( pgm_bild *bild1, pgm_bild *bild2, Pixel schwellwert){
	for(int i = 0; i < bild2->nx; i++){				// height
		for(int j = 0; j < bild2->ny; j++){			// width
			if( bild1->bild[i][j] < schwellwert ){	// value < schwellwert, image black
				bild2->bild[i][j] = 0;
			}
			else{									// else white
				bild2->bild[i][j] = bild2->graumax;
			}
		}
	}	
}