function table.indexof(arr,x)
    for i,v in ipairs(arr)
    do
        if v == x
        then return i
        end
    end
end
function table.arrperm(arr1,arr2)
    out = {}
    for i,v in ipairs(arr1)
    do
        table.insert(out,table.indexof(arr2,v))
    end
    return out
end
function table.invert(arr)
    out = {}
    for k,v in pairs(arr)
    do
        out[v] = k
    end
    return out
end
function table.getkey1(arr,x)
    for k,v in pairs(arr)
    do
        if table.equals1(x,v)
        then return k
        end
    end
end
function string.startsWith(str,ex)
    return string.sub(str,1,string.len(ex)) == ex
end
function string.without(str,ex)
    return string.sub(str,string.len(ex)+1,-1)
end
function table.equals1(arr1,arr2)
    for i,v in ipairs(arr1)
    do
        if arr2[i] ~= v
        then return false
        end
    end
    return #arr1 == #arr2
end

local function nodeboxDistance(nb,p)
    return
        (((nb[1] < p[1]) and (p[1] - nb[1])) or ((p[1] < nb[4]) and (nb[4] - p[1])) or 0) +
        (((nb[2] < p[2]) and (p[2] - nb[2])) or ((p[2] < nb[5]) and (nb[5] - p[2])) or 0) +
        (((nb[3] < p[3]) and (p[3] - nb[3])) or ((p[3] < nb[6]) and (nb[6] - p[3])) or 0)
end
function logikraft.nearestNodeboxIndex(nodeboxes,point)
    local minindex=-1
    local minvalue = 9999
    for i,nb in ipairs(nodeboxes)
    do
        local d = nodeboxDistance(nb,point)
        if d < minvalue
        then
            minvalue = d
            minindex = i
        end
    end
    return minindex
end

function logikraft.lookingAtNbIndex(user,under)
    local range=5
    local eye = vector.add(user:get_pos(),{x=0,y=1.625,z=0})
    local objective = vector.add(eye, vector.multiply(user:get_look_dir(),range))
    local ray = minetest.raycast(eye,objective,false,false)
    for p in ray
    do
        if p.under.x==under.x and p.under.y==under.y and p.under.z==under.z
        then return p.box_id
        end
    end
    return 0
end

function logikraft.vecTo8dir(vec)
    local x = vec[1]
    local z = vec[3]
    return
        x<0  and z>=0 and -z<=x and 0 or
        x>=0 and z>=0 and  z>x  and 1 or
        x>=0 and z>=0 and  z<=x and 2 or
        x>=0 and z<0  and -z<x  and 3 or
        x>=0 and z<0  and -z>=x and 4 or
        x<0  and z<0  and  z<x  and 5 or
        x<0  and z<0  and  z>=x and 6 or
        x<0  and z>=0 and -z>x  and 7 or
        0 -- Should not happen
end

function logikraft.dir8to4(dir)
    return math.floor(dir / 2)
end
    
function logikraft.addToPos8dir(dir,pos,w,h)
    local x = pos[1]
    local y = pos[2]
    local z = pos[3]
    return
        dir == 0 and {x = x-w, y = y, z = z+h} or
        dir == 1 and {x = x+w, y = y, z = z+h} or
        dir == 2 and {x = x+h, y = y, z = z+w} or
        dir == 3 and {x = x+h, y = y, z = z-w} or
        dir == 4 and {x = x+w, y = y, z = z-h} or
        dir == 5 and {x = x-w, y = y, z = z-h} or
        dir == 6 and {x = x-h, y = y, z = z-w} or
        dir == 7 and {x = x-h, y = y, z = z+w} or
        pos -- Should not happen
end

function logikraft.addToPos4dir(dir,pos,w,h)
    return logikraft.addToPos8dir(dir*2+1,pos,w,h)
end