phino-0.0.0.56: src/XMIR.hs

{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE NumericUnderscores #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}

-- SPDX-FileCopyrightText: Copyright (c) 2025 Objectionary.com
-- SPDX-License-Identifier: MIT

module XMIR
  ( programToXMIR
  , printXMIR
  , toName
  , parseXMIR
  , parseXMIRThrows
  , xmirToPhi
  , defaultXmirContext
  , XmirContext (XmirContext)
  )
where

import AST
import Control.Exception (Exception (displayException), throwIO)
import qualified Data.Bifunctor
import Data.Foldable (foldlM)
import Data.List (intercalate)
import qualified Data.Map as M
import Data.Maybe (catMaybes)
import qualified Data.Text as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.Lazy.Builder as TB
import Data.Time (UTCTime, getCurrentTime)
import Data.Time.Clock.POSIX (utcTimeToPOSIXSeconds)
import Data.Time.Format (defaultTimeLocale, formatTime)
import Data.Version (showVersion)
import Misc
import Paths_phino (version)
import Printer
import Text.Printf (printf)
import qualified Text.Read as TR
import Text.XML
import qualified Text.XML.Cursor as C

data XmirContext = XmirContext
  { omitListing :: Bool
  , omitComments :: Bool
  , listing :: Program -> String
  }

defaultXmirContext :: XmirContext
defaultXmirContext = XmirContext True True (const "")

data XMIRException
  = UnsupportedProgram Program
  | UnsupportedExpression Expression
  | UnsupportedBinding Binding
  | CouldNotParseXMIR String
  | InvalidXMIRFormat String C.Cursor
  deriving (Exception)

instance Show XMIRException where
  show (UnsupportedProgram prog) = printf "XMIR does not support such program:\n%s" (printProgram prog)
  show (UnsupportedExpression expr) = printf "XMIR does not support such expression:\n%s" (printExpression expr)
  show (UnsupportedBinding bd) = printf "XMIR does not support such bindings: %s" (printBinding bd)
  show (CouldNotParseXMIR msg) = printf "Couldn't parse given XMIR, cause: %s" msg
  show (InvalidXMIRFormat msg cur) =
    printf
      "Couldn't traverse though given XMIR, cause: %s\nXMIR:\n%s"
      msg
      ( case C.node cur of
          NodeElement el -> printXMIR (Document (Prologue [] Nothing []) el [])
          _ -> "Unknown"
      )

toName :: String -> Name
toName str = Name (T.pack str) Nothing Nothing

element :: String -> [(String, String)] -> [Node] -> Element
element name attrs children = do
  let name' = toName name
      attrs' = M.fromList (map (Data.Bifunctor.bimap toName T.pack) attrs)
  Element name' attrs' children

object :: [(String, String)] -> [Node] -> Node
object attrs children = NodeElement (element "o" attrs children)

expression :: Expression -> XmirContext -> IO (String, [Node])
expression ExThis _ = pure (printExpression ExThis, [])
expression ExGlobal _ = pure (printExpression ExGlobal, [])
expression (ExFormation bds) ctx = do
  nested <- nestedBindings bds ctx
  pure ("", nested)
expression (ExDispatch expr attr) ctx = do
  (base, children) <- expression expr ctx
  let attr' = printAttribute attr
  if null base
    then pure ('.' : attr', [object [] children])
    else
      if head base == '.' || not (null children)
        then pure ('.' : attr', [object [("base", base)] children])
        else pure (base ++ ('.' : attr'), children)
expression (DataNumber bytes) XmirContext{..} =
  let bts =
        object
          [("as", printAttribute (AtAlpha 0)), ("base", "Φ.org.eolang.bytes")]
          [object [] [NodeContent (T.pack (printBytes bytes))]]
   in pure
        ( "Φ.org.eolang.number"
        , if omitComments
            then [bts]
            else
              [ NodeComment (T.pack (either show show (btsToNum bytes)))
              , bts
              ]
        )
expression (DataString bytes) XmirContext{..} =
  let bts =
        object
          [("as", printAttribute (AtAlpha 0)), ("base", "Φ.org.eolang.bytes")]
          [object [] [NodeContent (T.pack (printBytes bytes))]]
   in pure
        ( "Φ.org.eolang.string"
        , if omitComments
            then [bts]
            else
              [ NodeComment (T.pack ('"' : btsToStr bytes ++ "\""))
              , bts
              ]
        )
expression (ExApplication expr (BiTau attr texpr)) ctx = do
  (base, children) <- expression expr ctx
  (base', children') <- expression texpr ctx
  let as = printAttribute attr
      attrs =
        if null base'
          then [("as", as)]
          else [("as", as), ("base", base')]
  pure (base, children ++ [object attrs children'])
expression (ExApplication (ExFormation bds) tau) _ = throwIO (UnsupportedExpression (ExApplication (ExFormation bds) tau))
expression expr _ = throwIO (UnsupportedExpression expr)

formationBinding :: Binding -> XmirContext -> IO (Maybe Node)
formationBinding (BiTau (AtLabel label) (ExFormation bds)) ctx = do
  inners <- nestedBindings bds ctx
  pure (Just (object [("name", label)] inners))
formationBinding (BiTau (AtLabel label) expr) ctx = do
  (base, children) <- expression expr ctx
  pure (Just (object [("name", label), ("base", base)] children))
formationBinding (BiTau AtPhi expr) ctx = do
  (base, children) <- expression expr ctx
  pure (Just (object [("name", show AtPhi), ("base", base)] children))
formationBinding (BiTau AtRho _) _ = pure Nothing
formationBinding (BiDelta bytes) _ = pure (Just (NodeContent (T.pack (printBytes bytes))))
formationBinding (BiLambda _) _ = pure (Just (object [("name", show AtLambda)] []))
formationBinding (BiVoid AtRho) _ = pure Nothing
formationBinding (BiVoid AtPhi) _ = pure (Just (object [("name", show AtPhi), ("base", "∅")] []))
formationBinding (BiVoid (AtLabel label)) _ = pure (Just (object [("name", label), ("base", "∅")] []))
formationBinding binding _ = throwIO (UnsupportedBinding binding)

nestedBindings :: [Binding] -> XmirContext -> IO [Node]
nestedBindings bds ctx = catMaybes <$> mapM (`formationBinding` ctx) bds

programToXMIR :: Program -> XmirContext -> IO Document
programToXMIR prog@(Program expr@(ExFormation [BiTau (AtLabel _) arg, BiVoid AtRho])) ctx@XmirContext{..} = case arg of
  ExFormation _ -> programToXMIR'
  ExApplication _ _ -> programToXMIR'
  ExDispatch _ _ -> programToXMIR'
  ExGlobal -> programToXMIR'
  _ -> throwIO (UnsupportedProgram prog)
  where
    programToXMIR' :: IO Document
    programToXMIR' = do
      (pckg, expr') <- getPackage expr
      root <- rootExpression expr' ctx
      now <- getCurrentTime
      let text = listing prog
          listingContent =
            if omitListing
              then show (length (lines text)) ++ " line(s)"
              else text
          listing' = NodeElement (element "listing" [] [NodeContent (T.pack listingContent)])
          metas = metasWithPackage (intercalate "." pckg)
      pure
        ( Document
            (Prologue [] Nothing [])
            ( element
                "object"
                [ ("dob", formatTime defaultTimeLocale "%Y-%m-%dT%H:%M:%S" now)
                , ("ms", "0")
                , ("revision", "1234567")
                , ("time", time now)
                , ("version", showVersion version)
                , ("xmlns:xsi", "http://www.w3.org/2001/XMLSchema-instance")
                , ("xsi:noNamespaceSchemaLocation", "https://raw.githubusercontent.com/objectionary/eo/refs/heads/gh-pages/XMIR.xsd")
                ]
                ( if null pckg
                    then [listing', root]
                    else [listing', metas, root]
                )
            )
            []
        )
    -- Extract package from given expression
    -- The function returns tuple (X, Y), where
    -- - X: list of package parts
    -- - Y: root object expression
    getPackage :: Expression -> IO ([String], Expression)
    getPackage (ExFormation [BiTau (AtLabel label) (ExFormation [bd, BiLambda "Package", BiVoid AtRho]), BiVoid AtRho]) = do
      (pckg, expr') <- getPackage (ExFormation [bd, BiLambda "Package", BiVoid AtRho])
      pure (label : pckg, expr')
    getPackage (ExFormation [BiTau (AtLabel label) (ExFormation [bd, BiLambda "Package", BiVoid AtRho]), BiLambda "Package", BiVoid AtRho]) = do
      (pckg, expr') <- getPackage (ExFormation [bd, BiLambda "Package", BiVoid AtRho])
      pure (label : pckg, expr')
    getPackage (ExFormation [BiTau at ex, BiLambda "Package", BiVoid AtRho]) = pure ([], ExFormation [BiTau at ex, BiVoid AtRho])
    getPackage (ExFormation [bd, BiVoid AtRho]) = pure ([], ExFormation [bd, BiVoid AtRho])
    getPackage ex = throwIO (userError (printf "Can't extract package from given expression:\n %s" (printExpression ex)))
    -- Convert root Expression to Node
    rootExpression :: Expression -> XmirContext -> IO Node
    rootExpression (ExFormation [bd, BiVoid AtRho]) c = do
      [bd'] <- nestedBindings [bd] c
      pure bd'
    rootExpression ex _ = throwIO (UnsupportedExpression ex)
    -- Returns metas Node with package:
    -- <metas>
    --   <meta>
    --     <head>package</head>
    --     <tail><!-- package here --></tail>
    --     <part><!-- package here --></part>
    --   </meta>
    -- </metas>
    metasWithPackage :: String -> Node
    metasWithPackage pckg =
      NodeElement
        ( element
            "metas"
            []
            [ NodeElement
                ( element
                    "meta"
                    []
                    [ NodeElement (element "head" [] [NodeContent (T.pack "package")])
                    , NodeElement (element "tail" [] [NodeContent (T.pack pckg)])
                    , NodeElement (element "part" [] [NodeContent (T.pack pckg)])
                    ]
                )
            ]
        )
    time :: UTCTime -> String
    time now = do
      let base = formatTime defaultTimeLocale "%Y-%m-%dT%H:%M:%S" now
          posix = utcTimeToPOSIXSeconds now
          fractional :: Double
          fractional = realToFrac posix - fromInteger (floor posix)
          nanos = floor (fractional * 1_000_000_000) :: Int
      base ++ "." ++ printf "%09d" nanos ++ "Z"
programToXMIR prog _ = throwIO (UnsupportedProgram prog)

-- Add indentation (2 spaces per level).
indent :: Int -> TB.Builder
indent n = TB.fromText (T.replicate n (T.pack "  "))

newline' :: Bool -> TB.Builder
newline' True = newline
newline' False = ""

newline :: TB.Builder
newline = TB.fromString "\n"

-- >>> printElement 0 (element "doc" [("a", ""), ("b", ""), ("c", ""), ("d", ""), ("e", "")] []) True
-- "<doc a=\"\" b=\"\" c=\"\" d=\"\" e=\"\"/>\n"
printElement :: Int -> Element -> Bool -> TB.Builder
printElement indentLevel (Element name attrs nodes) eol
  | null nodes =
      indent indentLevel
        <> TB.fromString "<"
        <> TB.fromText (nameLocalName name)
        <> attrsText
        <> TB.fromString "/>"
        <> newline' eol
  | all isTextNode nodes =
      indent indentLevel
        <> TB.fromString "<"
        <> TB.fromText (nameLocalName name)
        <> attrsText
        <> TB.fromString ">"
        <> mconcat (map printRawText nodes)
        <> TB.fromString "</"
        <> TB.fromText (nameLocalName name)
        <> TB.fromString ">"
        <> newline' eol
  | otherwise =
      indent indentLevel
        <> TB.fromString "<"
        <> TB.fromText (nameLocalName name)
        <> attrsText
        <> TB.fromString ">"
        <> newline
        <> mconcat (map (printNode (indentLevel + 1)) nodes)
        <> indent indentLevel
        <> TB.fromString "</"
        <> TB.fromText (nameLocalName name)
        <> TB.fromString ">"
        <> newline' eol
  where
    attrsText =
      mconcat
        [ TB.fromString " " <> TB.fromText (nameLocalName k) <> TB.fromString "=\"" <> TB.fromText v <> TB.fromString "\""
        | (k, v) <- M.toList attrs
        ]

    isTextNode (NodeContent _) = True
    isTextNode _ = False

    printRawText (NodeContent t) = TB.fromText t
    printRawText _ = mempty

-- >>> printNode 0 (NodeComment (T.pack "--hello--"))
-- "<!-- &#45;&#45;hello&#45;&#45; -->\n"
printNode :: Int -> Node -> TB.Builder
printNode _ (NodeContent t) = TB.fromText t -- print text exactly as-is
printNode i (NodeElement e) = printElement i e True -- pretty-print elements
printNode i (NodeComment t) =
  indent i
    <> TB.fromString "<!-- "
    <> TB.fromText (T.replace "--" "&#45;&#45;" t)
    <> TB.fromString " -->"
    <> newline
printNode _ _ = mempty

printXMIR :: Document -> String
printXMIR (Document _ root _) =
  TL.unpack
    ( TB.toLazyText
        ( TB.fromString "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
            <> newline
            <> printElement 0 root False
        )
    )

parseXMIR :: String -> Either String Document
parseXMIR xmir = case parseText def (TL.pack xmir) of
  Right doc -> Right doc
  Left err -> Left (displayException err)

parseXMIRThrows :: String -> IO Document
parseXMIRThrows xmir = case parseXMIR xmir of
  Right doc -> pure doc
  Left err -> throwIO (CouldNotParseXMIR err)

xmirToPhi :: Document -> IO Program
xmirToPhi xmir =
  let doc = C.fromDocument xmir
   in case C.node doc of
        NodeElement el
          | nameLocalName (elementName el) == "object" -> do
              obj <- case doc C.$/ C.element (toName "o") of
                [o] -> xmirToFormationBinding o []
                _ -> throwIO (InvalidXMIRFormat "Expected single <o> element in <object>" doc)
              let pckg =
                    [ T.unpack t
                    | meta <- doc C.$/ C.element (toName "metas") C.&/ C.element (toName "meta")
                    , let heads = meta C.$/ C.element (toName "head") C.&/ C.content
                    , heads == ["package"]
                    , tail' <- meta C.$/ C.element (toName "tail") C.&/ C.content
                    , t <- T.splitOn "." tail'
                    ]
              if null pckg
                then pure (Program (ExFormation [obj, BiVoid AtRho]))
                else
                  let bd = foldr (\part acc -> BiTau (AtLabel part) (ExFormation [acc, BiLambda "Package", BiVoid AtRho])) obj pckg
                   in pure (Program (ExFormation [bd, BiVoid AtRho]))
          | otherwise -> throwIO (InvalidXMIRFormat "Expected single <object> element" doc)
        _ -> throwIO (InvalidXMIRFormat "NodeElement is expected as root element" doc)

xmirToFormationBinding :: C.Cursor -> [String] -> IO Binding
xmirToFormationBinding cur fqn
  | not (hasAttr "name" cur) = throwIO (InvalidXMIRFormat "Formation children must have @name attribute" cur)
  | not (hasAttr "base" cur) = do
      name <- getAttr "name" cur
      bds <- mapM (`xmirToFormationBinding` (name : fqn)) (cur C.$/ C.element (toName "o")) >>= uniqueBindings'
      case name of
        "λ" -> pure (BiLambda (intercalate "_" ("L" : reverse fqn)))
        ('α' : _) -> throwIO (InvalidXMIRFormat "Formation child @name can't start with α" cur)
        "φ" -> pure (BiTau AtPhi (ExFormation (withVoidRho bds)))
        _ -> pure (BiTau (AtLabel name) (ExFormation (withVoidRho bds)))
  | otherwise = do
      name <- getAttr "name" cur
      base <- getAttr "base" cur
      attr <- case name of
        "φ" -> pure AtPhi
        ('α' : _) -> throwIO (InvalidXMIRFormat "Formation child @name can't start with α" cur)
        _ -> pure (AtLabel name)
      case base of
        "∅" -> pure (BiVoid attr)
        _ -> do
          expr <- xmirToExpression cur fqn
          pure (BiTau attr expr)

xmirToExpression :: C.Cursor -> [String] -> IO Expression
xmirToExpression cur fqn
  | hasAttr "base" cur = do
      base <- getAttr "base" cur
      case base of
        '.' : rest ->
          if null rest
            then throwIO (InvalidXMIRFormat "The @base attribute can't be just '.'" cur)
            else
              let args = cur C.$/ C.element (toName "o")
               in if null args
                    then throwIO (InvalidXMIRFormat (printf "Element with @base='%s' must have at least one child" base) cur)
                    else do
                      expr <- xmirToExpression (head args) fqn
                      attr <- toAttr rest cur
                      let disp = ExDispatch expr attr
                      xmirToApplication disp (tail args) fqn
        "ξ" ->
          if null (cur C.$/ C.element (toName "o"))
            then pure ExThis
            else throwIO (InvalidXMIRFormat "Application of 'ξ' is illegal in XMIR" cur)
        "Φ" ->
          if null (cur C.$/ C.element (toName "o"))
            then pure ExGlobal
            else throwIO (InvalidXMIRFormat "Application of 'Φ' is illegal in XMIR" cur)
        'Φ' : '.' : rest -> xmirToExpression' ExGlobal "Φ" rest cur fqn
        'ξ' : '.' : rest -> xmirToExpression' ExThis "ξ" rest cur fqn
        _ -> throwIO (InvalidXMIRFormat "The @base attribute must be either ['∅'|'Φ'] or start with ['Φ.'|'ξ.'|'.']" cur)
  | otherwise = do
      bds <- mapM (`xmirToFormationBinding` fqn) (cur C.$/ C.element (toName "o")) >>= uniqueBindings'
      pure (ExFormation (withVoidRho bds))
  where
    xmirToExpression' :: Expression -> String -> String -> C.Cursor -> [String] -> IO Expression
    xmirToExpression' start symbol rst c names =
      if null rst
        then throwIO (InvalidXMIRFormat (printf "The @base='%s.' is illegal in XMIR" symbol) c)
        else do
          head' <-
            foldlM
              (\acc part -> ExDispatch acc <$> toAttr (T.unpack part) c)
              start
              (T.splitOn "." (T.pack rst))
          xmirToApplication head' (c C.$/ C.element (toName "o")) names

xmirToApplication :: Expression -> [C.Cursor] -> [String] -> IO Expression
xmirToApplication = xmirToApplication' 0
  where
    xmirToApplication' :: Int -> Expression -> [C.Cursor] -> [String] -> IO Expression
    xmirToApplication' _ expr [] _ = pure expr
    xmirToApplication' idx expr (arg : args) fqn = do
      let app
            | hasAttr "name" arg = throwIO (InvalidXMIRFormat "Application argument can't have @name attribute" arg)
            | hasAttr "base" arg && hasText arg = throwIO (InvalidXMIRFormat "It's illegal in XMIR to have @base and text() at the same time" arg)
            | not (hasAttr "base" arg) && not (hasText arg) = do
                bds <- mapM (`xmirToFormationBinding` fqn) (arg C.$/ C.element (toName "o"))
                as <- asToAttr arg idx
                pure (ExApplication expr (BiTau as (ExFormation (withVoidRho bds))))
            | not (hasAttr "base" arg) && hasText arg = do
                as <- asToAttr arg idx
                bytes <- getText arg
                pure (ExApplication expr (BiTau as (ExFormation [BiDelta (bytesToBts bytes), BiVoid AtRho])))
            | otherwise = do
                as <- asToAttr arg idx
                arg' <- xmirToExpression arg fqn
                pure (ExApplication expr (BiTau as arg'))
      app' <- app
      xmirToApplication' (idx + 1) app' args fqn

    asToAttr :: C.Cursor -> Int -> IO Attribute
    asToAttr cur idx
      | hasAttr "as" cur = do
          as <- getAttr "as" cur
          attr <- toAttr as cur
          case attr of
            AtRho -> throwIO (InvalidXMIRFormat "The 'ρ' in @as attribute is illegal in XMIR" cur)
            other -> pure other
      | otherwise = pure (AtAlpha idx)

toAttr :: String -> C.Cursor -> IO Attribute
toAttr attr cur = case attr of
  'α' : rest' ->
    case TR.readMaybe rest' :: Maybe Int of
      Just idx -> pure (AtAlpha idx)
      Nothing -> throwIO (InvalidXMIRFormat "The attribute started with 'α' must be followed by integer" cur)
  "φ" -> pure AtPhi
  "ρ" -> pure AtRho
  _
    | head attr `notElem` ['a' .. 'z'] -> throwIO (InvalidXMIRFormat (printf "The attribute '%s' must start with ['a'..'z']" attr) cur)
    | '.' `elem` attr -> throwIO (InvalidXMIRFormat "Attribute can't contain dots" cur)
    | otherwise -> pure (AtLabel attr)

hasAttr :: String -> C.Cursor -> Bool
hasAttr key cur = not (null (C.attribute (toName key) cur))

getAttr :: String -> C.Cursor -> IO String
getAttr key cur =
  let attrs = C.attribute (toName key) cur
   in if null attrs
        then throwIO (InvalidXMIRFormat (printf "Couldn't find attribute '%s'" key) cur)
        else
          let attr = (T.unpack . head) attrs
           in if null attr
                then throwIO (InvalidXMIRFormat (printf "The attribute '%s' is not expected to be empty" attr) cur)
                else pure attr

hasText :: C.Cursor -> Bool
hasText cur = any isNonEmptyTextNode (C.child cur)
  where
    isNonEmptyTextNode cur' = case C.node cur' of
      NodeContent t -> not (T.null (T.strip t)) -- strip to ignore whitespace-only
      _ -> False

getText :: C.Cursor -> IO String
getText cur =
  case [t | c <- C.child cur, NodeContent t <- [C.node c]] of
    (t : _) -> pure (T.unpack t)
    [] -> throwIO (InvalidXMIRFormat "Text content inside <o> element can't be empty" cur)