type direction =
  | Row
  | Row_reverse  
  | Col
  | Col_reverse

type wrap =
  | Wrap
  | Wrap_reverse
  | Nowrap

type justify =
  | Normal
  | Start
  | End
  | Center
  | Between
  | Around
  | Evenly
  | Stretch

type align_items =
  | Start
  | End
  | Center
  | Baseline
  | Stretch

type align_content =
  | Normal
  | Start
  | End
  | Center
  | Between
  | Around
  | Evenly
  | Stretch
  | Baseline

type align_self =
  | Auto
  | Start
  | End  
  | Center
  | Stretch
  | Baseline

type t = 
  | Direction of direction
  | Wrap_setting of wrap
  | Justify of justify
  | Align_items of align_items
  | Align_content of align_content
  | Align_self of align_self
  | Grow of int option
  | Shrink of int option
  | Basis of Size.t
  | Flex of [`Initial | `One | `Auto | `None]

let to_class = function
  | Direction Row -> Css.make "flex-row"
  | Direction Row_reverse -> Css.make "flex-row-reverse"
  | Direction Col -> Css.make "flex-col"  
  | Direction Col_reverse -> Css.make "flex-col-reverse"
  | Wrap_setting Wrap -> Css.make "flex-wrap"
  | Wrap_setting Wrap_reverse -> Css.make "flex-wrap-reverse"
  | Wrap_setting Nowrap -> Css.make "flex-nowrap"
  | Justify Normal -> Css.make "justify-normal"
  | Justify Start -> Css.make "justify-start"
  | Justify End -> Css.make "justify-end"
  | Justify Center -> Css.make "justify-center"
  | Justify Between -> Css.make "justify-between"
  | Justify Around -> Css.make "justify-around"
  | Justify Evenly -> Css.make "justify-evenly"
  | Justify Stretch -> Css.make "justify-stretch"
  | Align_items Start -> Css.make "items-start"
  | Align_items End -> Css.make "items-end"
  | Align_items Center -> Css.make "items-center"
  | Align_items Baseline -> Css.make "items-baseline"
  | Align_items Stretch -> Css.make "items-stretch"
  | Align_content Normal -> Css.make "content-normal"
  | Align_content Start -> Css.make "content-start"
  | Align_content End -> Css.make "content-end"
  | Align_content Center -> Css.make "content-center"
  | Align_content Between -> Css.make "content-between"
  | Align_content Around -> Css.make "content-around"
  | Align_content Evenly -> Css.make "content-evenly"
  | Align_content Stretch -> Css.make "content-stretch"
  | Align_content Baseline -> Css.make "content-baseline"
  | Align_self Auto -> Css.make "self-auto"
  | Align_self Start -> Css.make "self-start"
  | Align_self End -> Css.make "self-end"
  | Align_self Center -> Css.make "self-center"
  | Align_self Stretch -> Css.make "self-stretch"
  | Align_self Baseline -> Css.make "self-baseline"
  | Grow None -> Css.make "grow-0"
  | Grow (Some 0) -> Css.make "grow-0" 
  | Grow (Some n) -> Css.make (Printf.sprintf "grow-%d" n)
  | Shrink None -> Css.make "shrink-0"
  | Shrink (Some 0) -> Css.make "shrink-0"
  | Shrink (Some n) -> Css.make (Printf.sprintf "shrink-%d" n)
  | Basis size -> Css.make (Printf.sprintf "basis-%s" (Size.to_string size))
  | Flex `Initial -> Css.make "flex-initial"
  | Flex `One -> Css.make "flex-1"
  | Flex `Auto -> Css.make "flex-auto"
  | Flex `None -> Css.make "flex-none"

let direction d = Direction d
let wrap w = Wrap_setting w  
let justify j = Justify j
let align_items a = Align_items a
let align_content a = Align_content a
let align_self a = Align_self a
let grow g = Grow g
let shrink s = Shrink s
let basis b = Basis b
let flex f = Flex f

let combine ts = Css.concat (List.map to_class ts)