%--------------------------
 % @Author: Jingqiao Hu
 % @Date: 2021-12-29 20:23:06
 % @LastEditTime: 2022-01-11 12:42:34

 % for each voronoi edge
 % update the MMC variables based on voronoi-edges
%--------------------------
function [MMC, MMCpoly] = update_MMCs(vor_edges, T, nnbSeedIDX, seed)

    %% MMC properties
    nodes1 = vor_edges(:,[1,2]);
    nodes2 = vor_edges(:,[3,4]);

    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); 

    MMC0 = [x, y, len/2, sina]; % [n,7]

    Tedge = T_edge2seed(T, nnbSeedIDX, seed, MMC0);
    MMC = [repmat(Tedge, 1, 3), MMC0];

    %% the polygon of each MMC
    cosa = sqrt(1 - sina.^2);
    stepx = Tedge/2 .* abs(sina);
    stepy = Tedge/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];
    
    MMCpoly = [n0, n1, n2, n3];
    
%     % test polyshape
%     figure(1); clf
%     parfor i = 1:size(n0,1)
%         n = [n0(i,:); n1(i,:); n2(i,:); n3(i,:)];
%         p = polyshape(n);
%         plot(p); hold on;
%     end
%     axis equal;
end

% projection to width for each edge based on the distance to two neighbor seed
function Tedge = T_edge2seed(Tseed, nnbSeedIDX, seed, MMC)

    nedge = size(MMC, 1);
    Tedge = zeros(nedge, 1);

    % FIXME:
    parfor i = 1 : nedge
        mmc = MMC(i, 1:2); % [x,y]

        sid = nnbSeedIDX(i,:);
        s = seed(sid, :); % 2*[x,y]

        t = Tseed(sid); % 2*1

        % compute the distance from seed to mmc
%         dist0 = s - repmat(mmc, 2, 1);
%         dist1 = vecnorm(dist0, 2, 2);
%         Tedge(i) = mean(t ./ dist1);

        Tedge(i) = mean(t);
    end
end