MTracker

local m = peripheral.wrap("back")
m.open(1)
channels = {65533, 65534, 65535}
local m2 = peripheral.wrap("top")
local function trilaterate( A1, B1, C1 )
    local A = A1
    A.vPosition = vector.new(A1.vPosition.x,A1.vPosition.y,A1.vPosition.z)
    local B = B1
    B.vPosition = vector.new(B1.vPosition.x,B1.vPosition.y,B1.vPosition.z)
    local C = C1
    C.vPosition = vector.new(C1.vPosition.x,C1.vPosition.y,C1.vPosition.z)
    local a2b = B.vPosition - A.vPosition
    local a2c = C.vPosition - A.vPosition

    if math.abs( a2b:normalize():dot( a2c:normalize() ) ) > 0.999 then
        return nil
    end

    local d = a2b:length()
    local ex = a2b:normalize( )
    local i = ex:dot( a2c )
    local ey = (a2c - (ex * i)):normalize()
    local j = ey:dot( a2c )
    local ez = ex:cross( ey )

    local r1 = A.nDistance
    local r2 = B.nDistance
    local r3 = C.nDistance

    local x = (r1*r1 - r2*r2 + d*d) / (2*d)
    local y = (r1*r1 - r3*r3 - x*x + (x-i)*(x-i) + j*j) / (2*j)

    local result = A.vPosition + (ex * x) + (ey * y)

    local zSquared = r1*r1 - x*x - y*y
    if zSquared > 0 then
        local z = math.sqrt( zSquared )
        local result1 = result + (ez * z)
        local result2 = result - (ez * z)

        local rounded1, rounded2 = result1:round( 0.01 ), result2:round( 0.01 )
        if rounded1.x ~= rounded2.x or rounded1.y ~= rounded2.y or rounded1.z ~= rounded2.z then
            return rounded1, rounded2
        else
            return rounded1
        end
    end
    return result:round( 0.01 )

end

local args = ({...})
if #args > 0 then
    if args[1] == "config" then
        local cmp = {}
        for ai = 1, 3 do
            cmp[ai] = {}
            cmp[ai]["vPosition"] = {}
            write("Computer "..ai.." X: ")
            cmp[ai]["vPosition"].x = tonumber(read())
            write("Computer "..ai.." Y: ")
            cmp[ai]["vPosition"].y = tonumber(read())
            write("Computer "..ai.." Z: ")
            cmp[ai]["vPosition"].z = tonumber(read())
        end
        write("File name: ")
        local f = fs.open(read(),"w")
        f.write(textutils.serialize(cmp))
        f.close()
    else
        local compid = 0
        compid = tonumber(args[1])
        for o = 1, #channels do
            m2.open(channels[o])
        end
        if compid == 0 then
            error("No computer index specified.")
        end
        if compid == 1 then
            if fs.exists(args[2]) then
                local f = fs.open(args[2],"r")
                local f2 = f.readAll()
                local ecmp = textutils.unserialize(f2)
                f.close()
                while true do
                    local msg = "Test"
                    local cmp = {}
                    while true do
                        local e = {os.pullEvent("modem_message")}
                        if e[2] == "top" then
                            ecmp[1]["nDistance"] = e[6]
                            cmp[1] = true
                            msg = e[5]
                        else
                            if type(e[5]) == "table" then
                                ecmp[tonumber(e[5][1])]["nDistance"] = tonumber(e[5][2])
                                msg = e[5][3]
                                cmp[tonumber(e[5][1])] = true
                            end
                        end
                        if cmp[1] ~= nil and cmp[2] ~= nil and cmp[3] ~= nil then
                            break
                        end
                    end
                    tri = trilaterate(ecmp[1],ecmp[2],ecmp[3])
                    print(msg.." ("..tri.x..", "..tri.y..", "..tri.z..")")
                    if #args >= 3 then
                        local f = fs.open(args[3],"a")
                        f.write(msg.." ("..tri.x..", "..tri.y..", "..tri.z..")")
                        f.close()
                    end
                end
            else
                print("Configuration file does not exist.")
            end
        else
            while true do
                local e = {os.pullEvent("modem_message")}
                m.transmit(1,1,{compid,e[6],e[5]})
                print(e[5])
            end
        end
    end
else
    print("mtracker <config, or computer index (1-3)> <config filename>")
    print("If index is 1, the computer is the main computer.")
    print("Main computer requires the config filename argument.")
end