module Vdom.Diff (createViewDiff, createElementDiff) where

import Data.Array as Array
import Data.Array.NonEmpty (NonEmptyArray)
import Data.Array.NonEmpty as NonEmptyArray
import Data.Maybe (Maybe(..))
import Data.Maybe as Maybe
import Data.Tuple as Tuple
import Prelude as Prelude
import Vdom.PatchState as VdomPatchState
import Vdom.VdomPicked as Data
import Html.Wellknown as HtmlWellknown

createViewDiff :: forall message location. Data.VdomPicked message location -> Data.VdomPicked message location -> Data.ViewDiff message location
createViewDiff (Data.VdomPicked oldVdom) (Data.VdomPicked newVdom) =
  Data.ViewDiff
    { patchOperationList:
        Array.catMaybes
          [ if Prelude.notEq oldVdom.pageName newVdom.pageName then
              Maybe.Just (Data.ChangePageName newVdom.pageName)
            else
              Maybe.Nothing
          , if Prelude.notEq oldVdom.themeColor newVdom.themeColor then
              Maybe.Just (Data.ChangeThemeColor newVdom.themeColor)
            else
              Maybe.Nothing
          , if Prelude.notEq oldVdom.language newVdom.language then
              Maybe.Just (Data.ChangeLanguage newVdom.language)
            else
              Maybe.Nothing
          , if Prelude.notEq oldVdom.bodyClass newVdom.bodyClass then
              Maybe.Just (Data.ChangeBodyClass newVdom.bodyClass)
            else
              Maybe.Nothing
          ]
    , childrenDiff: createChildListDiff oldVdom.children newVdom.children
    , newMessageData:
        Data.MessageData
          { messageMap: VdomPatchState.newMessageMapParameterEmpty
          , pointerMove: newVdom.pointerMove
          , pointerDown: newVdom.pointerDown
          }
    }

createElementDiff :: forall message location. (Prelude.Eq location) => Data.Element message location -> Data.Element message location -> String -> Data.ElementDiff message location
createElementDiff (Data.ElementDiv old) (Data.ElementDiv new) newKey = Data.createDivDiff newKey old new

createElementDiff (Data.ElementExternalLink old) (Data.ElementExternalLink new) newKey = Data.externalLinkDiff newKey old new

createElementDiff (Data.ElementSameOriginLink old) (Data.ElementSameOriginLink new) newKey =
  Data.localLinkDiff
    newKey
    old
    new

createElementDiff (Data.ElementButton old) (Data.ElementButton new) newKey =
  Data.buttonDiff
    newKey
    old
    new

createElementDiff (Data.ElementImg (Data.Img old)) (Data.ElementImg (Data.Img new)) newKey =
  Data.imgDiff
    newKey
    { alt: createDiff old.alt new.alt
    , src: createDiff old.src new.src
    }

createElementDiff (Data.ElementInputRadio (Data.InputRadio old)) (Data.ElementInputRadio (Data.InputRadio new)) newKey =
  Data.inputRadioDiff
    newKey
    { checked: createDiff old.checked new.checked
    , name: createDiff old.name new.name
    }

createElementDiff (Data.ElementInputText (Data.InputText old)) (Data.ElementInputText (Data.InputText new)) newKey =
  Data.inputTextDiff
    newKey
    { readonly: createReadonlyDiff old.inputOrReadonly new.inputOrReadonly
    , value: createDiff old.value new.value
    }

createElementDiff (Data.ElementTextArea (Data.TextArea old)) (Data.ElementTextArea (Data.TextArea new)) newKey =
  Data.textAreaDiff
    newKey
    { readonly: createReadonlyDiff old.inputOrReadonly new.inputOrReadonly
    , value: createDiff old.value new.value
    }

createElementDiff (Data.ElementLabel (Data.Label old)) (Data.ElementLabel (Data.Label new)) newKey =
  Data.labelDiff
    newKey
    { for: createDiff old.for new.for
    , children: createChildrenDiff old.children new.children
    }

createElementDiff ( Data.ElementSvg
    (Data.Svg { attributes: Data.SvgAttributes { viewBox: HtmlWellknown.ViewBox oldViewBox }, children: oldChildren })
) (Data.ElementSvg (Data.Svg { attributes: Data.SvgAttributes { viewBox: HtmlWellknown.ViewBox newViewBox }, children: newChildren })) newKey =
  Data.svgDiff
    newKey
    { viewBoxX: createDiff oldViewBox.x newViewBox.x
    , viewBoxY: createDiff oldViewBox.y newViewBox.y
    , viewBoxWidth: createDiff oldViewBox.width newViewBox.width
    , viewBoxHeight: createDiff oldViewBox.height newViewBox.height
    , children: createChildListDiff oldChildren newChildren
    }

createElementDiff (Data.ElementSvgPath (Data.SvgPath old)) (Data.ElementSvgPath (Data.SvgPath new)) newKey =
  Data.svgPathDiff
    newKey
    { d: createDiff old.d new.d
    , fill: createDiff old.fill new.fill
    }

createElementDiff (Data.ElementSvgCircle (Data.SvgCircle old)) (Data.ElementSvgCircle (Data.SvgCircle new)) newKey =
  Data.svgCircleDiff
    newKey
    { fill: createDiff old.fill new.fill
    , stroke: createDiff old.stroke new.stroke
    , cx: createDiff old.cx new.cx
    , cy: createDiff old.cy new.cy
    , r: createDiff old.r new.r
    , children: createChildListDiff old.children new.children
    }

createElementDiff (Data.ElementSvgAnimate (Data.SvgAnimate old)) (Data.ElementSvgAnimate (Data.SvgAnimate new)) newKey =
  Data.svgAnimateDiff
    newKey
    { attributeName: createDiff old.attributeName new.attributeName
    , dur: createDiff old.dur new.dur
    , repeatCount: createDiff old.repeatCount new.repeatCount
    , from: createDiff old.from new.from
    , to: createDiff old.to new.to
    }

createElementDiff _ new newKey = Data.replace newKey new

createDiff :: forall a. Prelude.Eq a => a -> a -> Maybe.Maybe a
createDiff old new =
  if Prelude.eq old new then
    Maybe.Nothing
  else
    Maybe.Just new

createReadonlyDiff :: forall message. Maybe.Maybe (String -> message) -> Maybe.Maybe (String -> message) -> Maybe.Maybe Boolean
createReadonlyDiff Maybe.Nothing (Maybe.Just _) = Maybe.Just true

createReadonlyDiff (Maybe.Just _) (Maybe.Nothing) = Maybe.Just false

createReadonlyDiff _ _ = Maybe.Nothing

createChildrenDiff :: forall message location. Data.Children message location -> Data.Children message location -> Data.ChildrenDiff message location
createChildrenDiff (Data.ChildrenText old) (Data.ChildrenText new)
  | Prelude.eq old new = Data.ChildrenDiffSkip

createChildrenDiff _ (Data.ChildrenText new) = Data.ChildrenDiffSetText new

createChildrenDiff (Data.ChildrenText _) (Data.ChildrenElementList list) = Data.ChildrenDiffResetAndInsert list

createChildrenDiff (Data.ChildrenElementList old) (Data.ChildrenElementList new) = Data.ChildDiffList (createElementListChildrenDiff old new)

createChildListDiff ::
  forall message location.
  Array (Tuple.Tuple String (Data.ElementAndClass message location)) ->
  Array (Tuple.Tuple String (Data.ElementAndClass message location)) ->
  Data.ChildrenDiff message location
createChildListDiff oldChildren newChildren = case Tuple.Tuple (NonEmptyArray.fromArray oldChildren) (NonEmptyArray.fromArray newChildren) of
  Tuple.Tuple (Just oldNonEmpty) (Just newNonEmpty) -> Data.ChildDiffList (createElementListChildrenDiff oldNonEmpty newNonEmpty)
  Tuple.Tuple Nothing Nothing -> Data.ChildrenDiffSkip
  Tuple.Tuple (Just _) Nothing -> Data.ChildrenDiffSetText ""
  Tuple.Tuple Nothing (Just newNonEmpty) -> Data.ChildrenDiffResetAndInsert newNonEmpty

-- | TODO
createElementListChildrenDiff ::
  forall message location.
  NonEmptyArray (Tuple.Tuple String (Data.ElementAndClass message location)) ->
  NonEmptyArray (Tuple.Tuple String (Data.ElementAndClass message location)) ->
  NonEmptyArray (Data.ElementDiff message location)
createElementListChildrenDiff _oldChildren _newChildren = NonEmptyArray.singleton Data.skip