move

--check for right arguments
local args  = {...}
if #args ~= 3 then
    error("please enter x,y,z of the target position")
end
local x,y,z = tonumber(args[1]),tonumber(args[2]),tonumber(args[3])


--open Rednet
if not rednet.isOpen() then
    peripheral.find("modem", rednet.open)
end


--check for enderchests
local slot15 = turtle.getItemDetail(15)
local slot16 = turtle.getItemDetail(16)
if slot15 and slot16 then
    if not(slot15.name == "enderstorage:ender_chest" and slot15.name == "enderstorage:ender_chest") then
        print("enderchest missing")
        error()
    end
else
    print("enderchest missing")
    error()
end


--place enderchest, take lava bucket, refuel and put enderchest back in inventory
function refuel()
    if turtle.getFuelLevel() < 1000 then
        print("fuel = "..turtle.getFuelLevel())
        turtle.select(16)
        turtle.digUp()
        turtle.up()
        turtle.digUp()
        turtle.down()
        local ok,err = turtle.placeUp()
        if not ok then
            print("could not place enderchest")
            print(err)
            error()
        end
        turtle.suckUp()
        turtle.refuel()
        turtle.dropUp()
        turtle.digUp()
    end
end


-- -x = 1, -z = 2, +x = 3, +z = 4
function getDirection()
    local loc1 = vector.new(gps.locate(2, false))
    if not turtle.forward() then
        for j=1,6 do
            if not turtle.forward() then
                turtle.dig()
            else
                break
            end
        end
    end
    loc2 = vector.new(gps.locate(2, false))
    heading = loc2 - loc1
    turtle.back()
    return ((heading.x + math.abs(heading.x) * 2) + (heading.z + math.abs(heading.z) * 3))
end


-- -x = 1, -z = 2, +x = 3, +z = 4
function turn(cfacing, tfacing)
    print(cfacing, tfacing)
    while cfacing ~= tfacing do
        local facingDiff = tfacing - cfacing
        if math.abs(facingDiff) ~= 3 then
            if facingDiff > 0 then
                turtle.turnRight()
                cfacing = cfacing + 1
            else
                turtle.turnLeft()
                cfacing = cfacing - 1
            end
        else
            if facingDiff > 0 then
                turtle.turnLeft()
                cfacing = cfacing + 3
            else
                turtle.turnRight()
                cfacing = cfacing - 3
            end
        end
    end
end


function moveToPos(tx,ty,tz)
    local cfacing = getDirection()
    local cx,cy,cz = gps.locate()
    refuel()
    os.sleep(2)
    print(cy, ty)
    print(gps.locate())
    if cy < ty then
        while cy < ty do
            if not turtle.up() then
                turtle.digUp()
            else
                cy = cy + 1
            end
        end
    end
    refuel()
    if cx ~= tx then
        if cx < tx then --move to +x
            turn(cfacing,3)
            cfacing = 3
            while cx < tx do
                turtle.forward()
                cx = cx + 1
            end
        else --move to -x
            turn(cfacing,1)
            cfacing = 1
            while cx > tx do
                turtle.forward()
                cx = cx - 1
            end
        end
    end
    refuel()
    if cz ~= tz then
        if cz < tz then --move to +x
            turn(cfacing,4)
            cfacing = 4
            while cz < tz do
                turtle.forward()
                cz = cz + 1
            end
        else --move to -x
            turn(cfacing,2)
            cfacing = 2
            while cz > tz do
                turtle.forward()
                cz = cz - 1
            end
        end
    end
    refuel()
    if cy > ty then
        while cy > ty do
            if not turtle.down() then
                turtle.digDown()
            else
                cy = cy - 1
            end
        end
    end
end

moveToPos(x,y,z)
rednet.broadcast(string.format("arrived at: x: %s, y: %s, z: %s",x,y,z))