%318810637 Perov Danny
%318455813 Eden Klainer
%
%The function finds circles in the given grayscale image using Hough transform.
%It also prints a list of the circles in the image.
%Input: grayscale image
%Output: list of circles, image which contains the original image with the
%marked circles.
function [circles,cImg] = findCircles(img)

%Detect the edges in the image.
edges = edgeDetect(img);

[rows, cols] = size(edges);

%Create the count matrix.
Rm = round(min(rows, cols) / 2);
Count = zeros(cols, rows, Rm);

%Go over all the pixels, and for the ones that are turned on, calculate the
%radius, and increment the Count matrix.
for colIndex = 1 : cols
    for rowIndex = 1 : rows
        if(edges(rowIndex, colIndex) == 1)
            for Cx = 1 : cols
                for Cy = 1 : rows
                    radius = round(sqrt((colIndex - Cx)^2 + (rowIndex - Cy)^2));
                    if(radius > 0 && radius < Rm)
                        Count(Cx, Cy, radius) = Count(Cx, Cy, radius) + 1;
                    end
                end
            end
        end
    end
end

%TODO add explanation to the threshold
threshold = max(max(max(Count))) * 0.85; % there is a good result when it's 60

result = [];

%Go over the Count matrix, detect the circles, and add them to the list.
for Cx = 1 : cols
    for Cy = 1 : rows
        for radius = 1 : min(rows, cols)

            %threshold = pi * radius;

            if(radius > 0 && radius < Rm && Count(Cx, Cy, radius) > threshold)
                if(isMaximal(Count, Cx, Cy, radius))
                    result = [result ; Cx, Cy, radius];
                end
            end
        end
    end
end

circles = filterCircles(result);

%Print the list into the screen.
printList(circles);

%Mark the circles in the original image.
cImg = addCircles(img, circles);

end

%The function filters the circles list.
%Input: circles list
%Output: filtered list
function filteredList = filterCircles(circles)

[rows, cols] = size(circles);
filteredList = [];
counter = 1;

for r1 = 1 : rows
   for r2 = 1 : rows
       if(r1 ~= r2)
           x1 = circles(r1, 1);
           y1 = circles(r1, 2);
           x2 = circles(r2, 1);
           y2 = circles(r2, 2);
           distance = sqrt((x1 - x2)^2 + (y1 - y2)^2);
           if(distance < 5)
               %if(y1 < y2)
                %filteredList = [filteredList ; x1, y1, circles(r1, 3)];
                %counter = counter + 1;
                    circles(r2, 1) = 0;
                    circles(r2, 2) = 0;
                    circles(r2, 3) = 0;
              % else
              %      circles(r1, 1) = 0;
              %      circles(r1, 2) = 0;
              %      circles(r1, 3) = 0;
              % end
           end
       end
   end
end

for r = 1 : size(circles, 1)
    if(circles(r, 3) ~= 0)
        filteredList = [filteredList ; circles(r, 1), circles(r, 2), circles(r, 3)];
    end
end

end

%The function prints a given list according to the stated format.
%Input: circles list.
function [] = printList(circles)

rows = size(circles, 1);

for r = 1 : rows
    fprintf('Circle %d: %d, %d, %d\n',r ,circles(r, 1), circles(r, 2), circles(r, 3));
end
end

%The function checks if the given value is maximal when compared to its
%neighbours.
%Input: Count matrix, Cx, Cy, radius.
%Output: boolean
function answer = isMaximal(Count, Cx, Cy, radius)

currentValue = Count(Cx, Cy, radius);
[rows, cols, depth] = size(Count);

if(Cx > 1 &&Count(Cx - 1, Cy, radius) > currentValue)
    answer = 0;
elseif (Cx < cols && Count(Cx + 1, Cy, radius) > currentValue)
    answer = 0;
elseif(Cy > 1 && Count(Cx, Cy - 1, radius) > currentValue)
    answer = 0;
elseif(Cy < rows && Count(Cx, Cy + 1, radius) > currentValue)
    answer = 0;
elseif(radius > 1 && Count(Cx, Cy, radius - 1) > currentValue)
    answer = 0;
elseif(radius < depth && Count(Cx, Cy, radius + 1) > currentValue)
    answer = 0;
else
    answer = 1;
end
end

%The function draws circles on the given image, using the given list.
function imageWithCircles = addCircles(img, circles)

rows = (size(circles, 1));

if(rows > 0)

    circleParameters = circles(1, :);
    imageWithCircles = insertShape(img,'circle',circleParameters,'LineWidth',2);

    for r = 2 : rows
        circleParameters = circles(r, :);
        imageWithCircles = insertShape(imageWithCircles,'circle',circleParameters,'LineWidth',2);
    end
end
end