module Editable exposing (..)


type Editable ofType
    = NotEditing { value : ofType }
    | Editing { originalValue : ofType, buffer : ofType }


value : Editable ofType -> ofType
value editable =
    case editable of
        NotEditing { value } ->
            value

        Editing { originalValue } ->
            originalValue


bufferValue : Editable ofType -> ofType
bufferValue editable =
    case editable of
        NotEditing { value } ->
            value

        Editing { buffer } ->
            buffer


setBuffer : Editable ofType -> ofType -> Editable ofType
setBuffer editable newBuffer =
    case editable of
        NotEditing _ ->
            editable

        Editing values ->
            Editing { values | buffer = newBuffer }


newEditing : ofType -> Editable ofType
newEditing value =
    Editing { originalValue = value, buffer = value }


newNotEditing : ofType -> Editable ofType
newNotEditing value =
    NotEditing { value = value }


startEditing : Editable ofType -> Editable ofType
startEditing editable =
    case editable of
        NotEditing { value } ->
            newEditing value

        Editing _ ->
            editable


finishEditing : Editable ofType -> Editable ofType
finishEditing editable =
    case editable of
        NotEditing _ ->
            editable

        Editing { buffer } ->
            NotEditing { value = buffer }


cancelEditing : Editable ofType -> Editable ofType
cancelEditing editable =
    case editable of
        NotEditing _ ->
            editable

        Editing { originalValue } ->
            NotEditing { value = originalValue }


isEditing : Editable ofType -> Bool
isEditing editable =
    case editable of
        NotEditing _ ->
            False

        Editing _ ->
            True


hasChanged : Editable comparable -> Bool
hasChanged editable =
    case editable of
        NotEditing _ ->
            False

        Editing { originalValue, buffer } ->
            originalValue /= buffer