#!/usr/bin/octave -qf
% \usr\bin\octave

%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Miessen 2014
%
%%%%%%%%%%%%%%%%%%%%%%%%%%


%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  getParameters
%
%%%%%%%%%%%%%%%%%%%%%%%%%%

function setParameters(config)
  global parameters;
  
%  parameters.grating_distance = getConfigValue(config, "grating_width");
  parameters.dim_x = int32(getConfigValue(config, "dim_x"));
  parameters.dim_y = int32(getConfigValue(config, "dim_y"));
  parameters.free_space_loss = getConfigValue(config, "free_space_loss");
  parameters.gap_width = getConfigValue(config, "gap_width");
  parameters.grating_count = int32(getConfigValue(config, "grating_count"));
  parameters.grating_distance = getConfigValue(config, "grating_distance");
  parameters.offset_x = int32(getConfigValue(config, "offset_x"));
  parameters.scaling_meter_per_px = getConfigValue(config, "scaling_meter_per_px");
  parameters.wave_length = getConfigValue(config, "wave_length");
endfunction

%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  findGapPositions
%
%%%%%%%%%%%%%%%%%%%%%%%%%%

function gaps = findGapPositions(grating_distance, grating_count)
  if (grating_count < 2)
    error("grating_count too small");
  endif
  
  width = grating_distance * (double(grating_count)-1);
  gaps = [];
  for i = 0:(grating_count-1)
    gaps = [gaps (i*grating_distance-width/2)];
  endfor
endfunction

%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  gratingSignalStrength
%
%%%%%%%%%%%%%%%%%%%%%%%%%%

function amplitude = gratingSignalStrength(x, y, gaps, wave_length, free_space_loss)
% grating {gaps, sub_steps, gap_width }
% free_space_loss not implemented

  % calculate distances
  distances = [];
  for gap_pos = gaps
    distances = [ distances sqrt((y-gap_pos)^2 + x^2) ];
  endfor
  
  % calculate amplitudes
  c_amps = [];
  base_distance = sqrt(x^2 + y^2);
  
  for d = distances
%    delay = d - base_distance;
%    phase = 2. * pi * delay/wave_length;

    % amplitude phasor = c_amp
    residual = rem(d, wave_length);
    phase = 2. * pi * residual/wave_length;
    c_amp = complex(cos(phase), sin(phase));
    c_amp = c_amp / d; % free_space_loss ?? check - Integrate a slit!

    c_amps = [c_amps c_amp];
  endfor
  
  % calculate amplitude
  amplitude = abs(sum(c_amps))/length(gaps);

  % eliminate free_space_loss
  max_sum = sum(abs(c_amps))/length(gaps);
  amplitude = amplitude/max_sum;
  
endfunction

%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  slitSignalStrength
%
%%%%%%%%%%%%%%%%%%%%%%%%%%

function amplitude = slitSignalStrength(x, y, sub_steps, gap_width, wave_length, free_space_loss)

endfunction

%%%%%%%%%%%%%%%%%%%%%%%%%%
%
%  calculateDiffraction
%
%%%%%%%%%%%%%%%%%%%%%%%%%%

function amplitudes = calculateDiffraction(gaps )
  printf("Calculate Diffraction\n");


  global parameters;
  
  % Read globals
  dim_y = parameters.dim_y;
  dim_x = parameters.dim_x;
  scaling_meter_per_px = parameters.scaling_meter_per_px;
  offset_x = parameters.offset_x;
  wave_length = parameters.wave_length;
  free_space_loss = parameters.free_space_loss;

  % Calculate dimensions
  x_max = double(dim_x - offset_x - 1) * scaling_meter_per_px;
  y_width = double(dim_y - 1) * scaling_meter_per_px;
  y_max = y_width / 2.;
  y_min = -1. * y_max;
  
  % Initialize
  amplitudes = zeros(dim_y, dim_x - offset_x);
  
  
  for amp_pos_x = int32(1:(dim_x - offset_x))
    printf("%3d%%", 100 * amp_pos_x/(dim_x - offset_x));
    for amp_pos_y = int32(1:1:dim_y)
      x = double(amp_pos_x) * scaling_meter_per_px;
      y = y_min + double(amp_pos_y) * scaling_meter_per_px;
      
      amp = gratingSignalStrength(x, y, gaps, wave_length, free_space_loss );
      amplitudes(amp_pos_y, amp_pos_x) = amp; % row = y / column = x
    endfor
    printf("\b\b\b\b");
  endfor
  printf("Finished calculateDiffraction\n");
  
  

endfunction

%%%%%%%%%%%%%%%%%%%%
%
%  generateGrating
%
%%%%%%%%%%%%%%%%%%%%

function rgb = generateGrating(rgb)
  printf("Generate Grating\n");
  global parameters;
  
  dim_y = parameters.dim_y;
  grating_count = parameters.grating_count;
  grating_distance = parameters.grating_distance;
  gap_width = parameters.gap_width;
  offset_x = parameters.offset_x;
  scaling_meter_per_px = parameters.scaling_meter_per_px;

%//  gray = zeros(dim_y, offset_x);

  y_width = double(dim_y - 1) * scaling_meter_per_px;
  y_max = y_width / 2.;
  
  % even or odd 
  if ( round(rem(grating_count, 2)) != 1. )
    even_factor = 0.5; % grating_distance/2.;
  else
    even_factor = 0.;
  endif
  
  
  for y_px = int32(1:dim_y)
    y = double(y_px) * scaling_meter_per_px;
    stepper = y / grating_distance; % normalize
    sub_stepper = stepper + even_factor - round(stepper);
    % sub_stepper = rem(stepper,1);
    % stepper
    % odd: -0.5..+0.5
    % even: 0.0..1.0
    % Nachkommazahlen
  
  % sub_stepper +/- 0.5 * grating_distance around gap
    for x_px = offset_x-int32(double(offset_x)/40.):offset_x
      if(abs(sub_stepper) <= gap_width)
        rgb(y_px, x_px, :) = [0., 0., 0.];
      else
        rgb(y_px, x_px, :) = [0.8, 0.8, 0.8];
      endif
    endfor
  endfor
   
endfunction


%%%%%%%%%%%%%%%%%%%
%
%  generateLaser
%
%%%%%%%%%%%%%%%%%%%

function amplitudes = generateLaser()
  printf("Generate Laser\n");
  global parameters;

  dim_y = parameters.dim_y;
  grating_count = parameters.grating_count;
  grating_distance = parameters.grating_distance;
  offset_x = parameters.offset_x;
  scaling_meter_per_px = parameters.scaling_meter_per_px;
  
  y_width = double(dim_y - 1) * scaling_meter_per_px;
  y_min = -1. * y_width / 2.; 
  
  laser_width = grating_distance * double(grating_count)
  
  amplitudes = [];
 
  for y_px = int32(1:dim_y)
    y = y_min + double(y_px) * scaling_meter_per_px;
    
    if (abs(y) <= laser_width / 2.) 
      amplitudes = [amplitudes; ones(1,offset_x)];
    else
      amplitudes = [amplitudes; zeros(1,offset_x)];
    endif
  endfor
  
endfunction

%%%%%%%%%%%%%
%           %
%  M A I N  %
%           %
%%%%%%%%%%%%%

global parameters

begin_cputime = cputime();


printf("Including CSV library\n");
echo_csv_lib = 0;
source ("./lib/csv_lib.m");
printf("Including config library\n");
global echo_config_lib = 0;
source ("./lib/load_config_lib.m");

printf("Starting\n");


arg_list = argv ();

if (rows(arg_list) != 2);
  printf("wrong parameters, config file and output file needed.\n");
  exit();
endif

config_filename = arg_list{1};
output_filename = arg_list{2};

config = loadConfig(config_filename);

% config

setParameters(config);

gaps = findGapPositions(parameters.grating_distance, parameters.grating_count);

gaps

% dim
% step
% wavelength
%

printf("Dimensions:\n");

% Debug
%x_width = parameters.scaling_meter_per_px * double(parameters.dim_x)
%y_width = parameters.scaling_meter_per_px * double(parameters.dim_y)
%amp = gratingSignalStrength(x_width, 0, gaps, parameters.wave_length, parameters.free_space_loss );
%amp

diffractionMap = calculateDiffraction(gaps);
max(max(diffractionMap))
diffractionPowerMap = diffractionMap.^2;

laserMap = generateLaser();
laserPowerMap = laserMap.^2;


map = jet();

diffractionInd = gray2ind(diffractionPowerMap);
diffractionRgb = ind2rgb (diffractionInd, map);

laserInd = gray2ind(laserPowerMap);
laserRgb = ind2rgb (laserInd, map);



offsetRgb = generateGrating(laserRgb);

finalRgb = [offsetRgb diffractionRgb];
%finalRgb = [offsetRgb]; % debug



imwrite(finalRgb, output_filename, "png");


printf("Total cpu time: %f seconds\n", cputime()-begin_cputime);
printf("Finished\n");

%
% GNU Octave library to write results to a csv file
%

1; % not a function file


%
% Add header to CSV file
%

function csvFile = addCsvFileHeader(csvFile, header)
  if (isfield(csvFile, "headerList") == true)
    csvFile.headerList = [csvFile.headerList; header];
  else
    csvFile.headerList = [header];
  endif
endfunction

%
% Add record to a structure CsvLine based on existing header
%

function csvLine = addCsvLineRecord(csvLine, header, value)

  csvLine.(header) = value; 

endfunction

%
% Close CSV file
%

function csvFile = closeCsvFile(csvFile)

  fclose(csvFile.fid);

  csvFile.isOpened = false;
endfunction

%
% Create a CSV line for this file
%

function csvLine = createCsvFileLine(csvFile)

  csvLine.headerList = csvFile.headerList;
  for header = csvLine.headerList'
    csvLine.(strtrim(header')) = "";
  endfor

endfunction

%
% Output values of a csv line
%

function csvLine = printCsvLine(csvLine)

  csvLine

endfunction

%
% Open CSV file
%

function csvFile = openCsvFile(filename)
  csvFile.filename = filename;
  
  % test if already exists
  
  csvFile.fid = fopen(csvFile.filename, "w");

  csvFile.isOpened = true;

endfunction

%
%
%

function csvLine = writeCsvFileHeader(csvFile)
  line = "";
  for header = csvFile.headerList'
    line = [line, strtrim(header')];
    line = [line, ","];
  endfor

  line = substr(line, 1, length(line)-1);
  fprintf(csvFile.fid, "%s\r\n", line);

endfunction

%
%
%

function csvLine = writeCsvLine(csvFile, csvLine)
  line = "";
  for header = csvLine.headerList'
    line = [line, csvLine.(strtrim(header'))];
    line = [line, ","];  
  endfor
  line = substr(line, 1, length(line)-1); % remove last comma
  fprintf(csvFile.fid, "%s\r\n", line);
endfunction

%
% GNU Octave library to load values from a config file
%

if(exist("echo_config_lib", "var") == 0)
  global echo_config_lib = 1;
endif



%
%
%

function value = getConfigValue(config, var_name)
  if (isfield(config, var_name) == false)
    printf("Error: \"%s\" missing in config file\n", var_name); 
    exit();
  endif
  [value, success] = str2num(config.(var_name));
  if(success != true)
    printf("Error: Converting \"%s\" failed!\n", var_name); 
    exit();
  endif
endfunction


%
%
%

function value = getConfigInt32(config, var_name)
  if (isfield(config, var_name) == false)
    printf("Error: \"%s\" missing in config file\n", var_name); 
    exit();
  endif
  [value, success] = str2double(config.(var_name));
  if(success != true)
    printf("Error: Converting \"%s\" failed!\n", var_name); 
    exit();
  endif
endfunction


%
%
%

function value = getConfigString(config, var_name)
  if (isfield(config, var_name) == false)
    printf("Error: \"%s\" missing in config file\n", var_name); 
    exit();
  endif
  value = config.(var_name);
endfunction


%
%
%

function arrayKeyValuePair = loadConfig(filename)
  % open file
  % while has next line
  % skip if blank
  % skip if comment
  % add key value pair to array
  
  global echo_config_lib;
  
  file = fopen (filename, "r");
  line = fgetl(file);
  lineNum = 1;
  while (ischar(line));
    if (echo_config_lib != 0)
      printf("Line %i: %s\n",lineNum, line);
    endif
    if (strcmp(line, "") == 0);
      if (strcmp(substr(line,1,1), ";") == 0);
        if(length(findstr(line, "="))== 0)
          printf("Error: Invalid line!\n");
          exit();
        endif
        key = substr(line, 1, findstr(line, "=")(1)-1);
        key = strtrim(key);
        value = substr(line
            , findstr(line, "=")(1)+1
            , length(line)-findstr(line, "=")(1) );
        value = strtrim(value);
        printf("key = %s\n", key);
        printf("value = %s\n", value);
        if(strcmp(key, "") != 0)
          printf("Error: Invalid key!\n");
          exit();
        endif
        if(isfield("arrayKeyValuePair", "key") != 0)
          printf("Error: Duplicate key!\n");
          exit();
        endif
      arrayKeyValuePair.(key) = value;
      else
        if (echo_config_lib != 0);
          printf("Comment\n");
        endif
      endif      
    else
      if (echo_config_lib != 0);
        printf("Blank line\n");
      endif
    endif
    line = fgetl(file);
    lineNum += 1;
  endwhile

  fclose(file);
endfunction



% INI format
% no white space at the beginning of a line
% empty lines allowed
% comment lines start with a semicolon
% key an value are seperated by a "="
% ascending white spaces are trimed from key
% prepending and ascending white spaces are trimed from values
% in case of duplicate values the first is valid
% crlf prefered, see RFC
%