From 47000929c9a4b46e8757d5daf0c23ede3fd30199 Mon Sep 17 00:00:00 2001
From: Adrian Cochrane <adrian@openwork.nz>
Date: Tue, 5 Sep 2023 15:37:04 +1200
Subject: [PATCH] Parse <input> tags.

TODO: Parse other form input elements, <datalist>, & <label>.
---
 bureaucromancy.cabal  |   2 +-
 src/Text/HTML/Form.hs | 133 ++++++++++++++++++++++++++++++++++++++----
 2 files changed, 124 insertions(+), 11 deletions(-)

diff --git a/bureaucromancy.cabal b/bureaucromancy.cabal
index ace7556..aa5e29a 100644
--- a/bureaucromancy.cabal
+++ b/bureaucromancy.cabal
@@ -72,7 +72,7 @@ library
 
     -- Other library packages from which modules are imported.
     build-depends:    base ^>=4.16.4.0, ginger,
-            bytestring, text, xml-conduit, network-uri
+            bytestring, text, xml-conduit, network-uri, regex-tdfa
 
     -- Directories containing source files.
     hs-source-dirs:   src
diff --git a/src/Text/HTML/Form.hs b/src/Text/HTML/Form.hs
index 5b28fdc..135542c 100644
--- a/src/Text/HTML/Form.hs
+++ b/src/Text/HTML/Form.hs
@@ -1,14 +1,19 @@
-{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE OverloadedStrings, TypeSynonymInstances, FlexibleInstances #-}
 module Text.HTML.Form (Form(..), Input(..), parseElement, parseDocument) where
 
 import Data.Text (Text)
 import qualified Data.Text as Txt
 import Text.XML.Cursor
-import Text.XML (Document)
+import Text.XML (Document, Name)
 
-import Data.Maybe (fromMaybe)
+import Data.Maybe (fromMaybe, listToMaybe, mapMaybe)
 import Network.URI (parseURIReference, URI, nullURI)
 import Data.Char (isDigit)
+import Data.List (nub)
+import Text.Read (readMaybe)
+
+import Text.Regex.TDFA (Regex, defaultCompOpt, defaultExecOpt)
+import Text.Regex.TDFA.Text (compile)
 
 data Form = Form {
     action :: URI,
@@ -18,31 +23,133 @@ data Form = Form {
     target :: Text,
     acceptCharset :: [Text],
     autocomplete :: Bool,
-    name :: Text,
+    formName :: Text,
     rel :: Text,
     inputs :: [Input]
 }
 
-data Input = Input
+data Input = Input {
+    -- Core attributes
+    inputType :: Text,
+    dirname :: Text,
+    inputName :: Text,
+    -- State
+    value :: Text,
+    inputAutocomplete :: Text,
+    autofocus :: Bool,
+    checked :: Bool,
+    disabled :: Bool,
+    readonly :: Bool,
+    -- Input behaviour
+    multiple :: Bool,
+    formAction :: Maybe URI,
+    formEnctype :: Maybe Text,
+    formMethod :: Maybe Text,
+    formValidate :: Bool,
+    formTarget :: Maybe Text,
+    inputMode :: Text,
+    list :: [(Text, Text)],
+    -- Validation
+    range :: (Maybe Text, Maybe Text),
+    step :: Maybe Text,
+    lengthRange :: (Maybe Int, Maybe Int),
+    pattern :: Maybe Regex,
+    required :: Bool,
+    -- Presentation
+    placeholder :: Text,
+    -- sort by tabindex?
+    title :: Text,
+    size :: Maybe Int,
+    fileData :: FileSelector,
+    imageData :: ImageData
+}
+data FileSelector = FileSelector {
+    fileAccept :: [Text],
+    fileCapture :: Text
+}
+data ImageData = ImageData {
+    imgAlt :: Maybe Text,
+    imgSize :: (Maybe Int, Maybe Int),
+    imgSrc :: Maybe Text
+}
 
 attr :: Text -> Cursor -> Text -> Text
 attr n el def | [ret] <- n `laxAttribute` el = ret
     | otherwise = def
 attr' :: Text -> Cursor -> (Text -> a) -> Text -> a
 attr' n el cb def = cb $ attr n el def
+attr'' :: Text -> Cursor -> (String -> a) -> Text -> a
+attr'' n el cb def = attr' n el (cb . Txt.unpack) def
+hasAttr :: Name -> Cursor -> Bool
+hasAttr n = not . null . hasAttribute n
+mAttr :: Text -> Cursor -> Maybe Text
+mAttr n = listToMaybe . laxAttribute n
 parseElement :: Cursor -> Maybe Form
 parseElement el | _:_ <- laxElement "form" el = Just Form {
-        action = attr' "action" el
-            (fromMaybe nullURI . parseURIReference . Txt.unpack) ".",
+        action = attr'' "action" el (fromMaybe nullURI . parseURIReference) ".",
         enctype = attr "enctype" el "",
         method = attr "method" el "GET",
         validate = null $ hasAttribute "novalidate" el,
         target = attr "target" el "_self",
         acceptCharset = attr' "accept-charset" el Txt.words "utf-8",
-        autocomplete = not $ null $ hasAttribute "autocomplete" el,
-        name = attr "name" el "",
+        autocomplete = hasAttr "autocomplete" el,
+        formName = attr "name" el "",
         rel = attr "rel" el "",
-        inputs = []
+        inputs = mapMaybe parseInput $ queryInputs el
+      }
+    | otherwise = Nothing
+
+queryInputs :: Cursor -> [Cursor]
+queryInputs form = (allInputs >=> inForm) form
+  where
+    allInputs = last' ancestor >=> descendant >=> laxElement "input"
+    inForm = check nestedInForm &++
+        check (\x -> laxAttribute "form" x == laxAttribute "id" form)
+    nestedInForm x = listToMaybe ((ancestor >=> laxElement "form") x) == Just form
+    last' f x | ret:_ <- reverse $ f x = [ret]
+        | otherwise = []
+    f &++ g = \x -> nub (f x ++ g x)
+parseInput :: Cursor -> Maybe Input
+parseInput el | _:_ <- laxElement "input" el = Just Input {
+        inputType = attr "type" el "text",
+        value = attr "value" el "",
+        inputAutocomplete = attr "autocomplete" el "on",
+        autofocus = hasAttr "autofocus" el,
+        checked = hasAttr "checked" el,
+        disabled = hasAttr "disabled" el,
+        readonly = hasAttr "readonly" el,
+        multiple = hasAttr "multiple" el,
+        dirname = attr "dirname" el "",
+        inputName = attr "name" el "",
+        formAction = if hasAttr "formaction" el
+            then attr' "formaction" el (parseURIReference . Txt.unpack) ""
+            else Nothing,
+        formEnctype = mAttr "formenctype" el,
+        formMethod = mAttr "formmethod" el,
+        formValidate = not $ hasAttr "formnovalidate" el,
+        formTarget = mAttr "formtarget" el,
+        inputMode = attr "inputmode" el "text",
+        list = [], -- TODO
+        range = (mAttr "min" el, mAttr "max" el),
+        step = mAttr "step" el,
+        lengthRange = (attr'' "minlength" el readMaybe "",
+            attr'' "maxLength" el readMaybe ""),
+        pattern = attr' "pattern" el
+            (rightToMaybe . compile defaultCompOpt defaultExecOpt) ".*",
+        required = hasAttr "required" el,
+        placeholder = attr "placeholder" el "",
+        title = attr "title" el "",
+        size = attr'' "size" el readMaybe "",
+        fileData = FileSelector {
+            fileAccept = attr' "accept" el Txt.words "*",
+            fileCapture = attr "capture" el ""
+        },
+        imageData = ImageData {
+            imgAlt = mAttr "alt" el,
+            imgSize = (attr'' "width" el readMaybe "",
+                attr'' "height" el readMaybe ""),
+            imgSrc = mAttr "src" el
+        }
       }
     | otherwise = Nothing
 
@@ -56,3 +163,9 @@ parseDocument doc n
   where
     forms = orSelf descendant >=> laxElement "form"
     doc' = fromDocument doc
+
+rightToMaybe :: Either a b -> Maybe b
+rightToMaybe (Left _)  = Nothing
+rightToMaybe (Right x) = Just x
+instance Eq Cursor where
+    a == b = node a == node b
-- 
2.30.2