home = vector.new(-1, 186, 126)
up = vector.new(0,1,0)
south = vector.new(0,0,1)
east = vector.new(1,0,0)
function greedystep(target)
    if (target-position):dot(facing) > 0 then
        if turtle.forward() then
            position = position + facing
        elseif position + facing ==target then
            return false, "the target is occupied"
        else
            
            
            temp = (target-position):dot(facing:cross(up))
            if temp>0 then
                turtle.turnRight()
                facing = facing:cross(up)
            elseif temp<0 then
                turtle.turnLeft()
                facing = - facing:cross(up)
            else
                temp = (target-position):dot(up)
                if temp>0 then
                    if turtle.up() then
                        position = position+up
                    end
                elseif temp<0 then
                    if turtle.down() then
                        position = position-up
                    end
                else
                    error("help me im stuck")
                end 
            end
        end
    else
        --we did not need to move in that direction
        temp = (target-position):dot(facing:cross(up)) 
        if temp > 0 then
            turtle.turnRight()
            facing=facing:cross(up)
        elseif temp < 0 then
            turtle.turnLeft()
            facing=facing:cross(-up)
        else
            if (target-position):dot(facing) == 0 then
                temp = (target-position):dot(up)
                if temp == 0 then
                    return false,"the target has been reached" 
                else
                    if temp > 0 then
                        if turtle.up() then
                            position:add(up)
                        else
                            position.sub(up)
                        end
                    end
                end
                
                            
            end    
        end
    end
--    print(position,facing)
    _G.position = position
    _G.facing = facing
    return true    
end
greedystep = require("pathfinding2").greedystep
function to(target)
    print(tostring(target))
    while greedystep(target) do
    end
end
function returnhome()
    to(home)
    if facing == south then
        turtle.turnRight()
        facing=facing:cross(up)
    end
    if facing == east then
        turtle.turnLeft()
        facing=facing:cross(-up)
    end
    if facing == -south then
        turtle.turnLeft()
        facing=facing:cross(-up)
    end
    _G.facing = facing
    _G.position = position        
end
function lookat(target)
    print("lookat"..target:tostring())
    while (position+facing).x ~= target.x 
    or   (position+facing).z ~= target.z do
        greedystep(target)
    end
    print("temp")
    temp = target.y-position.y
    while target.y > position.y do
        turtle.up()
        position = position+up        
    end
    while target.y < position.y do
        turtle.down()
        position = position-up
    end
    _G.position = position
end
return {to = to,
returnHome=returnhome,
lookat = lookat,
home = home}