{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TemplateHaskell #-}

-- |
-- > import qualified Kcd.Parser as KCD
-- > main = do
-- >   kcd <- KCD.parseKcdFile "example.kcd"
-- >   print kcd

module Text.Kcd.Parser
  (
    parseKcdFile
  , parseNetworkDefinition
  , BasicLabelTypeValue (..)
  , Bus (..)
  , Consumer (..)
  , Document (..)
  , Endianess (..)
  , Label (..)
  , LabelGroup (..)
  , LabelSet (..)
  , Message (..)
  , MessageId (..)
  , MessageLength (..)
  , Multiplex (..)
  , MuxGroup (..)
  , NetworkDefinition (..)
  , Node (..)
  , NodeRef (..)
  , Notes (..)
  , Producer (..)
  , Signal (..)
  , Value (..)
  , ValueType (..)
  , Var (..)
  )
where

import           Control.Applicative          ((<|>))
import           Control.Lens.TH              (makeLenses)
import           Control.Monad                (join)
import           Control.Monad.Catch          (MonadCatch, MonadThrow)
import           Control.Monad.Trans.Resource (runResourceT)
import           Data.Conduit                 (($$), ConduitM)
import           Data.Maybe                   (fromMaybe)
import           Data.Monoid                  ((<>))
import           Data.Text                    (Text, pack, unpack)
import           Data.Text.Read               (Reader, hexadecimal)
import           Data.XML.Types               (Event, Name(..))
import           Text.XML.Stream.Parse

-- | Definition of one or more CAN bus networks in one file.
data NetworkDefinition = NetworkDefinition
  { _networkDefinitionDocument ::  Document
  , _networkDefinitionNodes :: [Node]
  , _networkDefinitionBuses :: [Bus]
  } deriving (Show, Eq)

-- | Describes the scope of application e.g. the target vehicle or controlled device.
data Document = Document
  { -- | The name of the network definition document.
    _documentName :: Maybe Text
    -- | The version of the network definition document.
  , _documentVersion :: Maybe Text
    -- | The owner or author of the network definition document.
  , _documentAuthor :: Maybe Text
    -- | The owner company of the network definition document.
  , _documentCompany :: Maybe Text
    -- | The release date of this version of the network definition document.
  , _documentDate :: Maybe Text
  , _documentContent :: Text
  } deriving (Show, Eq)

-- |  network transport system that transfers the data between several nodes.
data Bus = Bus
  { _busMessages :: [Message]
    -- | Human-readable name of the bus network (e.g. "Comfort").
  , _busName :: Text
    -- | Nominal data transfer rate in baud (e.g. 500000, 125000, 100000 or 83333).
  , _busBaudrate :: Int
  } deriving (Show, Eq)

-- | An endpoint connected to the network (e.g. an electronic control unit) that is able to
-- | send messages to or receive messages from other endpoints.
data Node = Node
  { -- | Unique identifier of the network node.
    _nodeId :: Text
    -- | Human-readable name of the network node (e.g. "Brake").
  , _nodeName :: Maybe Text
  , _nodeVars :: [Var]
  } deriving (Show, Eq)

-- | A variable, a symbolic name associated to a chunk of information (e.g. a string or a value).
data Var = Var
  { _varValue :: Value
  , _varNotes :: Maybe Notes
    -- | Unique name of the variable.
  , _varName :: Text
  } deriving (Show, Eq)

newtype MessageId = MessageId { _unMessageId :: Int } deriving (Eq, Show, Ord)

data MessageLength =
    Auto
  | LengthValue Int deriving (Show, Eq)

data Message = Message
  { _messageNotes :: Maybe Notes
  , _messageProducer :: Maybe Producer
  , _messageMultiplex :: Maybe Multiplex
  , _messageSignals :: [Signal]
  , _messageId :: MessageId
  , _messageName :: Text
  , _messageLength :: MessageLength
  -- | Repetition interval of a cyclic network message in milliseconds
  , _messageInterval :: Int
  -- | Sending behavior of the network message. True, if message is triggered by signal changes.
  , _messageTriggered :: Bool
  -- | Frame format of the network message.
  , _messageFormat :: Text
  -- | True, if message is a remote frame
  , _messageRemote :: Bool
  } deriving (Show, Eq)

-- | A looping counter to make a group of signals (MuxGroup) alternately active at a time.
data Multiplex = Multiplex
  { _multiplexMuxGroup :: [MuxGroup]
  , _multiplexNotes :: Maybe Notes
  , _multiplexConsumer :: Maybe Consumer
  , _multiplexValue :: Maybe Value
  , _multiplexLabels :: [Label]
  , _multiplexEndianess :: Endianess
    -- | Bit length of the signal.
  , _multiplexLength :: Int
    -- | Human readable name of the signal
  , _multiplexName :: Text
    -- | Least significant bit offset of the signal relative to the least significant bit of the messages data payload
  , _multiplexOffset :: Int
  } deriving (Show, Eq)

-- | A group of signals that is just valid when the count value of the group matches with the looping
-- | counter (Multiplex).
data MuxGroup = MuxGroup
  { _muxGroupSignals :: [Signal]
    -- | count value of the Multiplex when the signals of this group become valid.
  , _muxGroupCount :: Int
  } deriving (Show, Eq)

-- | A discrete part of information contained in the payload of a message.
data Signal = Signal
  { -- | Describes the purpose of the signal/variable and/or comments on its usage.
    _signalNotes :: Maybe Notes
  , _signalConsumer :: Maybe Consumer
  , _signalValue :: Maybe Value
    -- | A set of label and label groups. Each label describes the meaning of a single raw value by an alias name.
    -- | A single value can only belong to a one label or label group.
  , _signalLabelSet :: [LabelSet]
    -- | Determines if Byteorder is big-endian (Motorola), little-endian (Intel) otherwise.
  , _signalEndianess :: Endianess
    -- | Bit length of the signal.
  , _signalLength :: Int
    -- | Human readable name of the signal
  , _signalName :: Text
    -- | Least significant bit offset of the signal relative to the least significant bit of the messages data payload
  , _signalOffset :: Int
  } deriving (Show, Eq)

data ValueType =
  ValueTypeUnsigned -- Unsigned
  | ValueTypeSigned -- Signed
  | ValueTypeSingle -- Single
  | ValueTypeDouble -- Double
  deriving (Show, Eq)

-- | Details of how the raw value of the signal/variable shall be interpreted.
data Value = Value
  { -- | Lower validity limit of the interpreted value after using the slope/intercept equation.
    _valueMin :: Double
    -- | Upper validity limit of the interpreted value after using the slope/intercept equation.
  , _valueMax :: Double
    -- | The slope "m" of a linear equation y = mx + b.
  , _valueSlope :: Double
    -- | The y-axis intercept "b" of a linear equation y = mx + b.
  , _valueIntercept :: Double
    -- | Physical unit of the value written as unit term as described in "The Unified Code for Units of Measure"
    -- | (http :://unitsofmeasure.org/ucum.html)
  , _valueUnit :: Text
    -- | Datatype of the value e.g. "unsigned","signed" or IEE754 "single", "double".
  , _valueType :: ValueType
  } deriving (Show, Eq)

-- | Network node that is a user/receiver of the assigned signal.
data Consumer = Consumer
  { _consumerNodeRef :: [NodeRef]
  } deriving (Show, Eq)

-- | Origin network node that is the sender of the assigned message.
data Producer = Producer
  { _producerNodeRef :: [NodeRef]
  } deriving (Show, Eq)

-- | An endpoint connected to the network that is able to send messages to or receive messages from other endpoints.
data NodeRef = NodeRef
  { -- | Referencing a network node by its unique identifier.
    _nodeRefId :: Text
  } deriving (Show, Eq)

-- | Descriptive name for a single value e.g. to describe an enumeration, mark special,invalid or error values.
data Label = Label
  {  -- | Signal raw value that is described here.
    _labelValue :: Int
    -- | Human readable name of the signal
  , _labelName :: Text
  , _labelType ::  BasicLabelTypeValue
  } deriving (Show, Eq)

data LabelGroup = LabelGroup
  { -- | Signal raw value the label group is starting with.
   _labelGroupFrom :: Text
    -- | Signal raw value the label group is ending with.
  , _labelGroupTo :: Text
    -- | Human-readable name for this value.
  , _labelGroupName :: Text
    -- | Type of value :: "value", "invalid" or "error"
  , _labelGroupType :: BasicLabelTypeValue
  } deriving (Show, Eq)

data LabelSet = LabelSet
  { _labelSetLabel :: [Label]
  , _labelSetLabelGroup :: [LabelGroup]
  } deriving (Show, Eq)

data BasicLabelTypeValue =
  TypeValue -- Value
  | TypeInvalid -- Invalid
  | TypeError  -- Error
  deriving (Show, Eq)

data Endianess =
  LittleEndian -- Little
  | BigEndian -- Big
  deriving (Show, Eq)

-- | Describes the purpose of the signal/variable and/or comments on its usage.
newtype Notes = Notes Text deriving (Show, Eq);

parseSettings :: ParseSettings
parseSettings = def { psDecodeEntities   = decodeHtmlEntities
                    , psRetainNamespaces = False }

parseKcdFile :: String -> IO NetworkDefinition
parseKcdFile f = runResourceT $
    parseFile parseSettings f $$
      force "Missing NetworkDefinition" parseNetworkDefinition

parseNetworkDefinition :: MonadThrow m => ConduitM Event o m (Maybe NetworkDefinition)
parseNetworkDefinition = tagIgnoreAttrs (ns "NetworkDefinition") $ do
  document <- force "Missing document" parseDocument
  nodes    <- many parseNode
  buses    <- many parseBus
  return $ NetworkDefinition document nodes buses

parseDocument :: MonadThrow m => ConduitM Event o m (Maybe Document)
parseDocument = tagName (ns "Document") attrs $ \(name, version, author, company, date) -> do
  docContent <- content
  return $ Document name version author company date docContent
  where attrs = do
         name    <- attr "name"
         version <- attr "version"
         author  <- attr "author"
         company <- attr "company"
         date    <- attr "date"
         return $ (,,,,) name version author company date

parseVar :: MonadThrow m => ConduitM Event o m (Maybe Var)
parseVar = tagName (ns "Var") (requireAttr "name") $ \name -> do
  notes <- parseNotes
  value <- force "Missing Value" parseValue
  return $ Var value notes name

parseBus :: MonadThrow m => ConduitM Event o m (Maybe Bus)
parseBus = tagName (ns "Bus") attrs $ \(name, baudrate)-> do
  messages <- many parseMessage
  return $ Bus messages name baudrate
  where attrs = do
          name     <- requireAttr "name"
          baudrate <- fromMaybe 500000 <$> attrRead "baudrate"
          return (name, baudrate)

parseMessageLength :: Text -> MessageLength
parseMessageLength "auto" = Auto
parseMessageLength i = LengthValue $ read $ unpack i

parseMessage :: MonadThrow m => ConduitM Event o m (Maybe Message)
parseMessage = tagName (ns "Message") attrs $ \(id, name, length, interval, triggered, count, format, remote) -> do
  notes     <- parseNotes
  producer  <- parseProducer
  multiplex <- parseMultiplex
  signals   <- many parseSignal
  return $ Message notes producer multiplex signals id name length interval triggered format remote
  where attrs = do
          id        <- (MessageId . readHexNumber) <$> requireAttr "id"
          name      <- requireAttr "name"
          length    <- maybe Auto parseMessageLength <$> attr "length"
          interval  <- fromMaybe 0 <$> attrRead "interval"
          triggered <- fromMaybe False <$> attrRead "triggered"
          count     <- fromMaybe 0 <$> attrRead "count"
          format    <- fromMaybe "standard" <$> attr "format"
          remote    <- fromMaybe False <$> attrRead "remote"
          return (id, name, length, interval, triggered, count, format, remote)

readHexNumber :: Text -> Int
readHexNumber s = let (Right (n, _)) = hexadecimal s in n

basicSignalAttrs ::  AttrParser (Endianess, Int, Text, Int)
basicSignalAttrs = do
  endianess <- (fromMaybe LittleEndian . join . fmap  parseEndianess) <$> attr "endianess"
  length    <- fromMaybe 1 <$> attrRead "length"
  name      <- requireAttr "name"
  offset    <- (read . unpack) <$> requireAttr "offset"
  return (endianess, length, name, offset)

parseMultiplex :: MonadThrow m => ConduitM Event o m (Maybe Multiplex)
parseMultiplex = tagName (ns "Multiplex") basicSignalAttrs $ \(endianess, length, name, offset)  -> do
  muxGroup <- many parseMuxGroup
  notes    <- parseNotes
  consumer <- parseConsumer
  value    <- parseValue
  labels   <- many parseLabel
  return $ Multiplex muxGroup notes consumer value labels endianess length name offset

parseMuxGroup :: MonadThrow m => ConduitM Event o m (Maybe MuxGroup)
parseMuxGroup = tagName (ns "MuxGroup") countAttr $ \count -> do
  signals <- many parseSignal
  return $ MuxGroup signals count
  where countAttr = (read . unpack) <$> requireAttr "count"

parseSignal :: MonadThrow m => ConduitM Event o m (Maybe Signal)
parseSignal = tagName (ns "Signal") basicSignalAttrs $ \(endianess, length, name, offset)  -> do
  notes    <- parseNotes
  consumer <- parseConsumer
  value    <- parseValue
  labelSet <- many parseLabelSet
  return $ Signal notes consumer value labelSet endianess length name offset

parseValueType :: Text -> Maybe ValueType
parseValueType "unsigned" = Just ValueTypeUnsigned
parseValueType "signed"   = Just ValueTypeSigned
parseValueType "single"   = Just ValueTypeSingle
parseValueType "double"   = Just ValueTypeDouble
parseValueType _          = Nothing

parseValue :: MonadThrow m => ConduitM Event o m (Maybe Value)
parseValue = tagName (ns "Value") attrs $ \value -> return value
  where attrs = do
          min   <- fromMaybe 0.0 <$> attrRead "min"
          max   <- fromMaybe 0.0 <$> attrRead "max"
          slope <- fromMaybe 0.0 <$> attrRead "slope"
          intercept <- fromMaybe 0.0 <$> attrRead "intercept"
          unit <- fromMaybe "1" <$> attr "unit"
          type' <- (fromMaybe ValueTypeUnsigned . join . fmap parseValueType) <$> attr "type"
          return $ Value min max slope intercept unit type'

parseConsumer ::  MonadThrow m => ConduitM Event o m (Maybe Consumer)
parseConsumer = tagNoAttr (ns "Consumer") $ do
  nodeRefs <- many parseNodeRef
  return $ Consumer nodeRefs

parseProducer ::  MonadThrow m => ConduitM Event o m (Maybe Producer)
parseProducer = tagNoAttr (ns "Producer") $ do
  nodeRefs <- many parseNodeRef
  return $ Producer nodeRefs

parseNode :: MonadThrow m => ConduitM Event o m (Maybe Node)
parseNode = tagName (ns "Node") attrs $ \(id, name) -> do
  vars <- many parseVar
  return $ Node id name vars
  where attrs = do
          id   <- requireAttr "id"
          name <- attr "name"
          return (id, name)

parseNodeRef :: MonadThrow m => ConduitM Event o m (Maybe NodeRef)
parseNodeRef = tagName (ns "NodeRef") (requireAttr "id") $ \id -> return $ NodeRef id

parseLabel :: MonadThrow m => ConduitM Event o m (Maybe Label)
parseLabel = tagName (ns "Label") attrs $ \(value, name, type') ->
  return $ Label value name type'
  where attrs = do
          value     <- (read . unpack) <$> requireAttr "value"
          name      <- requireAttr "name"
          type'    <- (fromMaybe TypeValue . join) . fmap parseBasicLabelTypeValue <$> attr "type"
          return (value,  name, type')

parseLabelGroup :: MonadThrow m => ConduitM Event o m (Maybe LabelGroup)
parseLabelGroup = tagName (ns "LabelGroup") attrs $ \(from, to, name, type') ->  return $ LabelGroup from to name type'
  where attrs = do
          from  <- requireAttr "from"
          to    <- requireAttr "to"
          name  <- requireAttr "name"
          type' <- (fromMaybe TypeValue . join . fmap parseBasicLabelTypeValue) <$> attr "type"
          return (from, to, name, type')

parseNotes :: MonadThrow m => ConduitM Event o m (Maybe Notes)
parseNotes = tagNoAttr (ns "Notes") $ do
  note <- content
  return $ Notes note

parseBasicLabelTypeValue :: Text -> Maybe BasicLabelTypeValue
parseBasicLabelTypeValue "value"   = Just TypeValue
parseBasicLabelTypeValue "invalid" = Just TypeInvalid
parseBasicLabelTypeValue "error"   = Just TypeError
parseBasicLabelTypeValue _ = Nothing

parseEndianess :: Text -> Maybe Endianess
parseEndianess "little" = Just LittleEndian
parseEndianess "big"    = Just BigEndian
parseEndianess _ = Nothing

parseLabelSet :: MonadThrow m => ConduitM Event o m (Maybe LabelSet)
parseLabelSet = tagNoAttr (ns "LabelSet") $ do
  labels      <- many parseLabel
  labelGroups <- many parseLabelGroup
  return $ LabelSet labels labelGroups

attrRead :: Read a => Name ->  AttrParser (Maybe a)
attrRead name = fmap (read . unpack) <$> attr name

ns :: Text -> Name
ns n = let ns' = Just "http://kayak.2codeornot2code.org/1.0"
           pfx = Nothing
           in Name n ns' pfx

makeLenses ''Bus
makeLenses ''Consumer
makeLenses ''Document
makeLenses ''Label
makeLenses ''LabelGroup
makeLenses ''LabelSet
makeLenses ''Message
makeLenses ''Multiplex
makeLenses ''MuxGroup
makeLenses ''NetworkDefinition
makeLenses ''Node
makeLenses ''NodeRef
makeLenses ''Producer
makeLenses ''Signal
makeLenses ''Value
makeLenses ''Var