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)