## Copyright (C) 2009-2016   Lukas F. Reichlin
##
## This file is part of LTI Syncope.
##
## LTI Syncope is free software: you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## LTI Syncope is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with LTI Syncope.  If not, see <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## Display routine for FRD objects.

## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
## Created: February 2010
## Version: 0.2

function display (sys)

  sysname = inputname (1);
  [inname, outname, tsam] = __lti_data__ (sys.lti);

  [inname, m] = __labels__ (inname, "u");
  [outname, p] = __labels__ (outname, "y");
  
  w = __freq2str__ (sys.w);

  disp ("");

  for k = 1 : m
    disp (["Frequency response '", sysname, "' from input '", inname{k}, "' to output ..."]);
    disp ("");
    __disp_resp__ (sys.H(:,k,:), w, outname);
  endfor

  display (sys.lti);  # display sampling time

  if (isstaticgain (sys))
    disp ("Static gain.");
  elseif (tsam == 0)
    disp ("Continuous-time frequency response.");
  else
    disp ("Discrete-time frequency response.");
  endif

endfunction


function __disp_resp__ (H, w, outname)

  p = rows (H);       # number of outputs
  len = size (H, 3);  # number of frequencies

  H = mat2cell (H, ones (1, p), 1, len)(:);
  H = cellfun (@__resp2str__, H, outname, "uniformoutput", false);
  
  tsize = terminal_size ();
  col_freq = columns (w);
  col_resp = cellfun (@columns, H);
  col_max = tsize(2) - col_freq;
  width = cumsum (col_resp);
  
  start = 0;
  stop = col_max;
  while (start < width(end))
    idx = find (width > start & width <= stop);
    disp ([w, H{idx}]);
    disp ("");
    start = width(idx(end));
    stop = start + col_max;
  endwhile

  ## FIXME: Handle case where tsize(2) is not enough
  ##        to display frequencies and one output.

endfunction


function str = __freq2str__ (w, title = "w [rad/s]")

  len = rows (w);
  str = __vec2str__ (w);
  line = repmat ("-", 1, max (columns (str), columns (title)));
  str = strvcat (title, line, str);
  space = repmat ("  ", len+2, 1);
  str = [space, str];
  
endfunction


function str = __resp2str__ (H, outname)

  H = H(:);
  len = length (H);
  real_str = __vec2str__ (real (H));
  im = imag (H);
  if (any (im))
    imag_str = __vec2str__ (abs (im), "i");
    sign_str = repmat (" + ", len, 1);
    neg = im < 0;
    sign_str(neg, 2) = "-";
    str = [real_str, sign_str, imag_str];
  else
    str = real_str;
  endif
  line = repmat ("-", 1, max (columns (str), columns (outname)));
  str = strvcat (outname, line, str);
  space = repmat ("    ", len+2, 1);
  str = [space, str];

endfunction


function str = __vec2str__ (vec, post)

  vec = vec(:);
  tmp = isfinite (vec);
  tmp = abs (vec(tmp & vec != 0));
  if (isempty (tmp) || min (tmp) < 1e-3 || max (tmp) > 1e4)
    str = arrayfun (@(x) sprintf ("%.3e", x), vec, "uniformoutput", false);
  elseif (all (floor (tmp) == tmp))
    str = arrayfun (@(x) sprintf ("%d", x), vec, "uniformoutput", false);
  else
    str = arrayfun (@(x) sprintf ("%.4f", x), vec, "uniformoutput", false);
  endif
  str = strjust (char (str), "right");
  if (nargin > 1)
    str = [str, repmat(post, length (vec), 1)];
  endif

endfunction
