SASS mixin with if statements to handle conditions - sass

Question

I was writing a mixin in SCSS to handle a map (padding, margin, etc etc), but I am getting a little stuck with all the #if logic to get the proper output.
In my defaults.scss file I have 2 variable, $size and $prefixes:
$size: auto, 1, 2, 2\.5, 4;
$prefixes: (
padding: (
top: "pt",
right: "pr",
bottom: "pb",
left: "pl",
x: "px",
y: "py",
all: "p",
),
);
I created mixin.scss that would take in $sizes, $prefixes, and a $property (ie "padding") like:
#include mixer.create-space(
$sizes: $sizes,
$prefixes: $padding,
$property: "padding"
);
The $padding in this case was just assigned earlier with map.get like
$padding: map-get($prefixes, "padding");
I know I need to #each through the $sizes and #each through the $prefixes to assign the right values, but I am really getting lost in my conditions.
px and py need 2 properties each (left/right || top/bottom)
if $size == auto, only assign to px/py (Currently it is being added to every class)
#mixin create-space($sizes, $prefixes, $property) {
// $size => 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 72, 80, 96
#each $size in $sizes {
// $alignment => "top", "bottom", "left", "right", "y", "x", "all"
// $prefix => "pt", "pr", "pb", "pl", "py", "px", "p"
#each $alignment, $prefix in $prefixes {
// If $alignments is x, then $property-left and $property-right
// If $alignments is y, then $property-top and $property-bottom
// If $alignments is all, then $property
// If $size is auto for $alignment top, right, bottom, left, then $property: auto
#if $alignment == "x" {
.#{$prefix}-#{$size} {
#{$property}-left: calc(($size * 4) / 16) + rem;
#{$property}-right: calc(($size * 4) / 16) + rem;
}
} #else if $alignment == "y" {
.#{$prefix}-#{$size} {
#{$property}-top: $size * 4;
#{$property}-bottom: calc(($size * 4));
}
} #else if $size == "auto" {
.#{$prefix}-#{$size} {
#{$property}: auto;
}
} #else if $alignment == "all" {
.#{$prefix}-#{$size} {
#{$property}: calc(($size * 4) / 16) + rem;
}
} #else {
.#{$prefix}-#{$size} {
#{$property}-#{$alignment}: calc(($size * 4) / 16) + rem;
}
}
}
}
}
My mixin does work, but I run into errors when I am trying to calc the $size into rems when I run into $size: auto etc. Really, it is just becoming a mess.
** Edit **
It really seems that the decimal numbers were throwing everything off in the long run.