using Images, Color, FixedPointNumbers, ImageView

impath = joinpath(Pkg.dir("TestImages"), "images/lena_gray_512.tif")
img = imread(impath);
mask = copy(img);
mask.data[1:end] = 1;
marks = falses(size(img.data));

#view(img)
#view(mask)

tol = 0.15

function reducelevels(img, nlev)
    l1 = 0.0
    l2 = 0.0
    for n in 1:nlev
        l1 = l2
        l2 = n/nlev
        av = (l1+l2)/2
        img[l1 .<= img .<= l2] = av
    end
    nothing
end

function growto(p1, p2, msk, pmsk)
    #ret = (abs(p1 - p2) <= tol) || (msk && (avg(pmsk - p2) <= tol))
    ret = (p1 >= p2) # || (msk && (pmsk <= p2)) # || (p1 <= (p2-tol)) || (msk && (pmsk <= (p2-tol)))
    ret
end

function walk(data, mask, marks, x, y)
    visited = falses(size(data))
    marked = falses(size(data))

    MX,MY = size(data)
    cont = true
    ref = data[x, y]
    while cont
        cont = false
        ref = data[x, y]
        visited[x,y] = marked[x,y] = true

        cont2 = true
        xS = x
        yS = y
        for X in (-1, 0, 1)
            for Y in (-1, 0, 1)
                xX = xS + X
                yY = yS + Y

                ((xX > 0) && (yY > 0) && (xX <= MX) && (yY <= MY)) || continue
                visited[xX,yY] && continue

                visited[xX,yY] = true

                if growto(data[xX,yY], ref, marks[xX,yY], mask[xX,yY])
                    #println("    -> growing to $xX,$yY. marked: $(marks[xX,yY])")
                    #if marks[xX, yY]
                    #    ref = mask[xX,yY]
                    #    cont2 = false
                    #    break
                    #else
                        x = xX
                        y = yY
                        cont = true
                        ref = data[xX, yY]
                    #end
                end
            end
        end
    end
    mask[marked] = ref
    marks[marked] = true
    nothing
end

#reducelevels(img, 10)
for x in 1:size(img)[1]
   for y in 1:size(img)[2]
       marks[x,y] || walk(img.data, mask.data, marks, x, y)
   end
end

view(mask)


#img = rand(5, 5)
#mask = copy(img)
#mask[1:end] = 1;
#marks = falses(size(img));
#for x in 1:size(img)[1]
#   for y in 1:size(img)[2]
#       marks[x,y] || walk(img, mask, marks, x, y)
#   end
#end
#println(img)
#println(mask)



#function climb(img, x, y)
#    data = img.data
#    visited = falses(size(data))
#
#    maxiter = 512*512
#    cont = true
#    while cont && (maxiter > 0)
#        cont = false
#        maxiter -= 1
#        ref = data[x, y]
#        visited[x,y] = true
#
#        for X in (-1, 0, 1)
#            for Y in (-1, 0, 1)
#                xX = x + X
#                yY = y + Y
#
#                ((xX > 0) && (yY > 0) && (xX <= 512) && (yY <= 512)) || continue
#                visited[xX,yY] && continue
#
#                visited[xX,yY] = true
#                if data[xX, yY] >= ref
#                    x = xX
#                    y = yY
#                    cont = true
#                    ref = data[xX, yY]
#                end
#            end
#        end
#    end
#    (x,y)
#end
#
#function grow(img, mask, x, y)
#    data = img.data
#    maskdata = mask.data
#
#    pipeline = Int[]
#    push!(pipeline, x, y)
#
#    maxiter = 512*512
#
#    while !isempty(pipeline) && (maxiter > 0)
#        maxiter -= 1
#        x = shift!(pipeline)
#        y = shift!(pipeline)
#        ref = data[x, y]
#        maskdata[x,y] = 0
#        println("$x,$y = 0")
#
#        for X in (-1, 0, 1)
#            for Y in (-1, 0, 1)
#                xX = x + X
#                yY = y + Y
#                ((xX > 0) && (yY > 0) && (xX <= 512) && (yY <= 512)) || continue
#                (maskdata[xX, yY] == gray(1)) || continue
#                println("checking $xX,$yY... maskdata: $(maskdata[xX, yY])")
#                if data[xX, yY] <= ref
#                    maskdata[xX, yY] = 0
#                    println("$xX,$yY = 0")
#                    push!(pipeline, xX, yY)
#                    #grow(img, mask, xX, yY)
#                else
#                    maskdata[xX, yY] = 0.5
#                    println("$x,$y = 0.5")
#                end
#            end
#        end
#    end
#    nothing
#end
#
##grow(img, mask, beginat[1], beginat[2])
#grow(img, mask, 493, 345)