%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2021-12-26 23:23:06
 % @LastEditTime: 2021-12-29 20:53:27

 % for each voronoi cell
 % update the MMC variables based on voronoi-edges & nodes
%--------------------------
function [MMCs, MMCs_poly] = update_MMCs(MMCs_edges, MMCs_nodes, t0)

    npnts = size(MMCs_edges, 1);
    MMCs = cell(npnts, 1);
    MMCs_poly = cell(npnts, 1);

%     figure; 
    parfor ele = 1 : npnts
        % MMCs variables
        edges = MMCs_edges{ele};
        nodes = MMCs_nodes{ele};

        nodes1 = nodes(edges(:, 1), :);
        nodes2 = nodes(edges(:, 2), :);

        nodes3 = (nodes1 + nodes2) / 2;
        x = nodes3(:,1);
        y = nodes3(:,2);

        len = vecnorm(nodes2 - nodes1, 2, 2);

        sina = abs(nodes2(:,2) - nodes1(:,2)) ./ len;
        dir = (nodes2(:,2) < nodes1(:,2)) .* (nodes2(:,1) < nodes1(:,1)) + ...
              (nodes2(:,2) > nodes1(:,2)) .* (nodes2(:,1) > nodes1(:,1));
        sina(dir < 1) = -sina(dir < 1); 

        t = repmat(t0, size(edges, 1), 3);

        mmc = [t, x, y, len/2, sina]; % [n,7]
        MMCs{ele} = mmc;

        % the polygon of each MMC
        cosa = sqrt(1 - sina.^2);
        stepx = t0/2 * abs(sina);
        stepy = t0/2 * cosa;
        stepy(dir>0) = -stepy(dir>0);
        n0 = [nodes1(:,1) - stepx, nodes1(:,2) - stepy]; % [n,2]
        n1 = [nodes1(:,1) + stepx, nodes1(:,2) + stepy];
        n2 = [nodes2(:,1) + stepx, nodes2(:,2) + stepy];
        n3 = [nodes2(:,1) - stepx, nodes2(:,2) - stepy];
        
        poly0 = [n0'; n1'; n2'; n3'];
        poly1 = reshape(poly0, 2, 4, []);
        MMCs_poly{ele} = permute(poly1, [2,1,3]); % [4,2,n]
        
%         % test polyshape
%         for i = 1:size(n0,1)
%             n = [n0(i,:); n1(i,:); n2(i,:); n3(i,:)];
%             p = polyshape(n);
%             plot(p); hold on;
%         end
    end
end