-- clears the area on all sides around a Builzone so that is can be saved as screenshot for quick results preview
-- it requires user to place a computer with this prgoram in the wanted buildzone
-- coordinates are calculated based on cumpoert location and the PHV grid set in the main game script

BUILDZONE_WIDTH = 62 -- the actual zone width is 63 blocks, but for some reason due to how minecraft handles relative coordinates this has to be 62

FIRSTZONE= {
	x=11685,
	y=57,
	z=-1869
}


POINT_IN_BUILDZONE={
	x=11701,
	z=-1955
}

local ox,oy,oz = commands.getBlockPosition() -- get the position of the computer

-- the CreateFillParams function takes in a point in the buildzone to be deleted (filled with air)
-- it returns the coordinates needed for the minecraft fill command (start point x1,y1,z1 and end point x2,y2,z2)
-- the minecraft fill command has a limitation of 32768 blocks (enough for the equivalent of eight chunk sections)
-- therefore a list of multiple fill commands is generated if the volume of the buildzone is bigger
function CreateFillParams(pointInBuildzone, from, to)
	local gt = {} -- the variable to hold the fill coordinates data for all layers of the buildzone. Like a cake :)


	local layerHeight = math.floor(32768/(BUILDZONE_WIDTH*BUILDZONE_WIDTH))
	--print(layerHeight)
	local counter = 1
	for y = from, to, layerHeight do
		local gtLayer = {} -- a variable to hold the fill variables for one layer of the buildzone, each layer is so tall so that Volume = buildzone_width^2*layerHeight < 32768
		gtLayer.x1 = math.floor((pointInBuildzone.x-FIRSTZONE.x)/(BUILDZONE_WIDTH+1))*(BUILDZONE_WIDTH+1)+FIRSTZONE.x
		--print(gtLayer.x1)
		gtLayer.y1 = y
		--print(gtLayer.y1)
		gtLayer.z1 = math.floor((pointInBuildzone.z-FIRSTZONE.z)/(BUILDZONE_WIDTH+1))*(BUILDZONE_WIDTH+1)+FIRSTZONE.z
		--print(gtLayer.z1)
		gtLayer.x2 = gtLayer.x1 + BUILDZONE_WIDTH
		--print(gtLayer.x2)
		gtLayer.y2 = y+layerHeight-1
		--print(gtLayer.y2)
		gtLayer.z2 = gtLayer.z1 + BUILDZONE_WIDTH
		--print(gtLayer.z2)
		--add to the fill params array
		gt[counter] = gtLayer
		counter = counter + 1
	end
	return gt
end

-- the CloneBuildZone function takes in a point in the buildzone A and a point in the buildzone B as parameters
function CleanAroundBuildZone()
	commands.say("clearing around zone")
	for xi=-2,2 do
	   for zi=-2,2 do
		   local p = {
			   x=ox+xi*BUILDZONE_WIDTH,
			   y=oy,
			   z=oz+zi*BUILDZONE_WIDTH
		   }
		   if (xi~=0 or zi~=0) then
			   local cp = CreateFillParams(p,0,254)
			   for i,layer in ipairs(cp) do
				   print("filling layer at: "..layer.x1..", "..layer.y1..", "..layer.z1.." to "..layer.x2..", "..layer.y2..", "..layer.z2)
			   	commands.fill(layer.x1,layer.y1,layer.z1,layer.x2,layer.y2,layer.z2,"minecraft:air",0)
				end
			else
 			   local cp = CreateFillParams(p,0,47)
 			   for i,layer in ipairs(cp) do
 				   print("filling layer at: "..layer.x1..", "..layer.y1..", "..layer.z1.." to "..layer.x2..", "..layer.y2..", "..layer.z2)
 			   	commands.fill(layer.x1,layer.y1,layer.z1,layer.x2,layer.y2,layer.z2,"minecraft:air",0)
 				end
	  	 	end
		end
	end
	commands.say("area around the zone is cleared")
end

CleanAroundBuildZone()