{-

Copyright (C) 2010 Scott R Parish <srp@srparish.net>

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

-}

module Database.MongoDB.BSON
    (
     BSValue(..),
     BSONObject(..),
     toBSONObject,
     BinarySubType(..)
    )
where
import Control.Monad
import Data.Binary
import Data.Binary.Get
import Data.Binary.IEEE754
import Data.Binary.Put
import Data.Bits
import Data.ByteString.Char8
import qualified Data.ByteString.Lazy as L
import qualified Data.ByteString.Lazy.Char8 as LC
import qualified Data.ByteString.Lazy.UTF8 as L8
import Data.Int
import qualified Data.Map as Map
import qualified Data.List as List
import Data.Time.Clock.POSIX
import Database.MongoDB.Util

data BSValue
    = BSDouble Double
    | BSString L8.ByteString
    | BSObject BSONObject
    | BSArray [BSValue]
    | BSUndefined
    | BSBinary BinarySubType L.ByteString
    | BSObjectId L.ByteString
    | BSBool !Bool
    | BSDate POSIXTime
    | BSNull
    | BSRegex L8.ByteString String
    | BSSymbol L8.ByteString
    | BSInt32 Int32
    | BSInt64 Int64
    | BSMinKey
    | BSMaxKey
    deriving (Show, Eq, Ord)

newtype BSONObject = BSONObject {
      fromBSONObject :: Map.Map L8.ByteString BSValue
    }
    deriving (Eq, Ord, Show)

toBSONObject :: [(L8.ByteString, BSValue)] -> BSONObject
toBSONObject = BSONObject . Map.fromList

data DataType =
    Data_min_key        | -- -1
    Data_number         | -- 1
    Data_string         | -- 2
    Data_object	        | -- 3
    Data_array          | -- 4
    Data_binary         | -- 5
    Data_undefined      | -- 6
    Data_oid            | -- 7
    Data_boolean        | -- 8
    Data_date           | -- 9
    Data_null           | -- 10
    Data_regex          | -- 11
    Data_ref            | -- 12
    Data_code           | -- 13
    Data_symbol	        | -- 14
    Data_code_w_scope   | -- 15
    Data_int            | -- 16
    Data_timestamp      | -- 17
    Data_long           | -- 18
    Data_max_key          -- 127
    deriving (Show, Read, Enum, Eq, Ord)

toDataType :: Int -> DataType
toDataType (-1) = Data_min_key
toDataType 127 = Data_max_key
toDataType d = toEnum d

fromDataType :: DataType -> Int
fromDataType Data_min_key = (-1)
fromDataType Data_max_key = 127
fromDataType d = fromEnum d


data BinarySubType =
    BSTUNDEFINED_1     |
    BSTFunction        | -- 1
    BSTByteArray       | -- 2
    BSTUUID            | -- 3
    BSTUNDEFINED_2     |
    BSTMD5             | -- 5
    BSTUserDefined
    deriving (Show, Read, Enum, Eq, Ord)

toBinarySubType :: Int -> BinarySubType
toBinarySubType 0x80 = BSTUserDefined
toBinarySubType d = toEnum d

fromBinarySubType :: BinarySubType -> Int
fromBinarySubType BSTUserDefined = 0x80
fromBinarySubType d = fromEnum d

instance Binary BSONObject where
    get = liftM snd getObj
    put = putObj

getVal :: DataType -> Get (Integer, BSValue)
getVal Data_number = getFloat64le >>= return . (,) 8 . BSDouble
getVal Data_string = do
  sLen1 <- getI32
  (sLen2, s) <- getS
  return (fromIntegral $ 4 + sLen1, BSString s)
getVal Data_object = getObj >>= \(len, obj) -> return (len, BSObject obj)
getVal Data_array = do
  (len, arr) <- getRawObj
  let arr2 = Map.fold (:) [] arr -- reverse and remove key
  return (len, BSArray arr2)
getVal Data_binary = do
  skip 4
  st   <- getI8
  len2 <- getI32
  bs   <- getLazyByteString $ fromIntegral len2
  return (4 + 1 + 4 + fromIntegral len2, BSBinary (toBinarySubType st) bs)
getVal Data_undefined = return (1, BSUndefined)
getVal Data_oid = getLazyByteString 12 >>= return . (,) 12 . BSObjectId
getVal Data_boolean = getI8 >>= return . (,) 1 . BSBool . (/= 0)
getVal Data_date =
    getI64 >>= return . (,) 8 . BSDate . flip (/) 1000 . realToFrac
getVal Data_null = return (1, BSNull)
getVal Data_int = getI32 >>= return . (,) 4 . BSInt32 . fromIntegral
getVal Data_long = getI64 >>= return . (,) 8 . BSInt64

getInnerObj 1 obj = obj
getInnerObj bytesLeft obj = do
  typ <- getDataType
  (keySz, key) <- getS
  (valSz, val) <- getVal typ
  getInnerObj (bytesLeft - 1 - fromIntegral keySz - fromIntegral valSz) $
              liftM (Map.insert key val) obj

getRawObj = do
  bytes <- getI32
  obj <- getInnerObj (bytes - 4) $ return Map.empty
  getNull
  return (fromIntegral bytes, obj)

getObj = getRawObj >>= \(len, obj) ->  return (len, BSONObject obj)

getDataType = liftM toDataType getI8

putType BSDouble{}   = putDataType Data_number
putType BSString{}   = putDataType Data_string
putType BSObject{}   = putDataType Data_object
putType BSArray{}    = putDataType Data_array
putType BSBinary{}   = putDataType Data_binary
putType BSUndefined  = putDataType Data_undefined
putType BSObjectId{} = putDataType Data_oid
putType BSBool{}     = putDataType Data_boolean
putType BSDate{}     = putDataType Data_date
putType BSNull       = putDataType Data_null
putType BSRegex{}    = putDataType Data_regex
-- putType = putDataType Data_ref
-- putType = putDataType Data_code
putType BSSymbol{}   = putDataType Data_symbol
-- putType = putDataType Data_code_w_scope
putType (BSInt32 i)  = putDataType Data_int
putType (BSInt64 i)  = putDataType Data_long
-- putType = putDataType Data_timestamp
putType BSMinKey     = putDataType Data_min_key
putType BSMaxKey     = putDataType Data_max_key


putVal (BSDouble d)   = putFloat64le d
putVal (BSString s)   = putI32 (fromIntegral $ 1 + L8.length s) >> putS s
putVal (BSObject o)   = putObj o
putVal (BSArray es)   = putOutterObj bs
    where bs = runPut $ forM_ (List.zip [0..] es) $ \(i, e) ->
               putType e >> (putS $ L8.fromString $ show i) >> putVal e
putVal (BSBinary t bs)= do putI32 $ fromIntegral $ 4 + L.length bs
                           putI8 $ fromBinarySubType t
                           putI32 $ fromIntegral $ L.length bs
                           putLazyByteString bs
putVal BSUndefined    = putNothing
putVal (BSObjectId o) = putLazyByteString o
putVal (BSBool False) = putI8 0
putVal (BSBool True)  = putI8 1
putVal (BSDate pt)    = putI64 $ round $ 1000 * realToFrac pt
putVal BSNull         = putNothing
putVal (BSRegex r opt)= do putS r
                           putByteString $ pack $ List.sort opt
                           putNull
putVal (BSSymbol s)   = putI32 (fromIntegral $ 1 + L8.length s) >> putS s
putVal (BSInt32 i)    = putI32 i
putVal (BSInt64 i)    = putI64 i
putVal BSMinKey       = putNothing
putVal BSMaxKey       = putNothing

putObj obj   = putOutterObj bs
    where bs = runPut $ forM_ (Map.toList (fromBSONObject obj)) $ \(k, v) ->
               putType v >> putS k >> putVal v

putOutterObj bytes = do
  -- the length prefix and null term are included in the length
  putI32 $ fromIntegral $ 4 + 1 + L.length bytes
  putLazyByteString bytes
  putNull

putDataType = putI8 . fromDataType