Flexbox Mixin

/*
 * Example: @include flex-container("down", "top", "left", "nowrap");
 *
 * 1st Arg:     -- Main Axis --
 *  - "down":   Defines the main axis as vertical.
 *  - "across": Defines the main axis as horizontal.
 *
 * 2nd Arg:     -- Vertical Centering --
 *  - "top":    Aligns items in the flexbox to the upper edge.
 *  - "center": Vertically centers items in the flexbox.
 *  - "bottom": Aligns items in the flexbox to the lower edge.
 *
 * 3rd Arg:     -- Horizontal Centering --
 *  - "left":   Aligns items in the flexbox to the left edge.
 *  - "center": Horizontally centers items in the flexbox.
 *  - "right":  Aligns items in the flexbox to the right edge.
 *
 * 4th Arg:     -- Wrapping --
 *  - "nowrap": Does not wrap items to new columns (vertical flexbox) or new rows (horizontal flexbox).
 *  - "wrap":   Wraps items to new columns (vertical flexbox) or new rows (horizontal flexbox).
 */
@mixin flex-container($direction, $verticalCentering, $horizontalCentering, $wrapping) {

    display: flex;

    @if($direction == "down") {

        flex-direction: column;

        @if($verticalCentering == "top") {

            justify-content: flex-start;

        } @else if($verticalCentering == "bottom") {

            justify-content: flex-end;

        } @else if ($verticalCentering == "center"){

            justify-content: center;

        } @else {

            @error "The 'flex-container' mix-in recieved an invalid parameter for '$verticalCentering', of '" + $verticalCentering + "', where it should have recieved 'top', 'bottom', or 'center'."

        }

        @if($horizontalCentering == "left") {

            align-items: flex-start;

        } @else if($horizontalCentering == "right") {

            align-items: flex-end;

        } @else if ($horizontalCentering == "center") {

            align-items: center;

        } @else {

            @error "The 'flex-container' mix-in recieved an invalid parameter for '$horizontalCentering', of '" + $horizontalCentering + "', where it should have recieved 'left', 'right', or 'center'."

        }

    } @else {

        flex-direction: row;

        @if($verticalCentering == "top") {

            align-items: flex-start;

        } @else if($verticalCentering == "bottom") {

            align-items: flex-end;

        } @else if ($verticalCentering == "center") {

            align-items: center;

        } @else {

            @error "The 'flex-container' mix-in recieved an invalid parameter for '$verticalCentering', of '" + $verticalCentering + "', where it should have recieved 'top', 'bottom', or 'center'."

        }

        @if($horizontalCentering == "left") {

            justify-content: flex-start;

        } @else if($horizontalCentering == "right") {

            justify-content: flex-end;

        } @else if ($horizontalCentering == "center") {

            justify-content: center;

        } @else {

            @error "The 'flex-container' mix-in recieved an invalid parameter for '$horizontalCentering', of '" + $horizontalCentering + "', where it should have recieved 'left', 'right', or 'center'."

        }

    }

    @if($wrapping == "wrap") {

        flex-wrap: wrap;

    } @else if ($wrapping == "nowrap") {

        flex-wrap: nowrap;

    } @else {

        @error "The 'flex-container' mix-in recieved an invalid parameter for '$wrapping', of '" + $wrapping + "', where it should have recieved 'wrap' or 'nowrap'."

    }

}