-----------------------------------------------------------------------------
-- |
-- Module      :  Data.Map
-- Copyright   :  (c) 2020-2021 EMQ Technologies Co., Ltd.
-- License     :  BSD-style (see the LICENSE file)
--
-- Maintainer  :  Feng Lee, feng@emqx.io
--                Yang M, yangm@emqx.io
-- Stability   :  experimental
-- Portability :  portable
--
-- The Map datatype.
--
-----------------------------------------------------------------------------
module Data.Map where

import Data.Maybe (Maybe)
import Foreign (ffi0, ffi1, ffi2, ffi3, ffi4)

foreign import data Map :: Type -> Type -> Type

-- | Returns a new empty map.
empty :: forall k v. Map k v
empty = ffi0 :maps :new

-- | Create a map with only one key-value pair.
foreign import singleton :: forall k v. k -> v -> Map k v

-- | Test if the map is empty.
foreign import isEmpty :: forall k v. Map k v -> Boolean

-- | Test if the Key exists in the Map.
isKey :: forall k v. k -> Map k v -> Boolean
isKey = ffi2 :maps :is_key

-- | Insert the key-value pair into a map.
put :: forall k v. k -> v -> Map k v -> Map k v
put = ffi3 :maps :put

insert :: forall k v. k -> v -> Map k v -> Map k v
insert = put

-- | Return the `Value` associated with `Key`. Throw exception if the `Key` does not exist.
get :: forall k v. k -> Map k v -> v
get = ffi2 :maps :get

-- | Return the `Value` associated with `Key`.
foreign import lookup :: forall k v. k -> Map k v -> Maybe v

-- | Test if a key is a member of a Map.
member :: forall k v. k -> Map k v -> Boolean
member = ffi2 :maps :is_key

-- | Test if a key is not a member of a Map.
foreign import notMember :: forall k v. k -> Map k v -> Boolean

fold :: forall k v acc. ((k, v, acc) -> acc) -> acc -> Map k v -> acc
fold = ffi3 :maps :fold

mapWithKey :: forall k a b. (k -> a -> b) -> Map k a -> Map k b
mapWithKey = ffi2 :maps :map

-- | Update an existed key-value pair.
update :: forall k v. k -> v -> Map k v -> Map k v
update = ffi3 :maps :update

-- | Update a value in a Map1 associated with Key by calling Fun on the old value to get a new value.
updateWith :: forall k v. k -> (v -> v) -> Map k v -> Map k v
updateWith = ffi3 :maps :update_with

updateWithInit :: forall k v. k -> (v -> v) -> v -> Map k v -> Map k v
updateWithInit = ffi4 :maps :update_with

-- | TODO: docs later...
foreign import take :: forall k v.  k -> Map k v -> Maybe (v, (Map k v))

-- | Delete the key-value pair, if it exists.
delete :: forall k v. k -> Map k v -> Map k v
delete = ffi2 :maps :remove

-- | Returns the size of the Map.
size :: forall k v. Map k v -> Integer
size = ffi1 :maps :size

-- | Returns a map Map for which predicate Pred holds true in Map.
foreign import filter :: forall k v. ((k, v) -> Boolean) -> Map k v -> Map k v

-- | Merges two maps into a single map.
merge :: forall k v. Map k v -> Map k v -> Map k v
merge = ffi2 :maps :merge

-- | An alias of `toList` function.
assocs :: forall k v. Map k v -> [(k,v)]
assocs = toList

-- | Returns a list of keys contained in a map.
keys :: forall k v. Map k v -> List k
keys = ffi1 :maps :keys

-- | Returns a list of values contained in a map.
values :: forall k v. Map k v -> List v
values = ffi1 :maps :values

-- | Builds a map from a list of key-value tuples.
fromList :: forall k v. [(k,v)] -> Map k v
fromList = ffi1 :maps :from_list

-- | Returns a list of pairs representing the key-value associations of Map.
toList :: forall k v. Map k v -> [(k,v)]
toList = ffi1 :maps :to_list

-- | TODO: docs later...
with :: forall k v. [k] -> Map k v -> Map k v
with = ffi2 :maps :with

-- | TODO: docs later...
without :: forall k v. [k] -> Map k v -> Map k v
without = ffi2 :maps :without


tzip :: forall a b. [a] -> [b] -> [(a,b)]
tzip x [] = []
tzip [] y = []
tzip [x|xs] [y|ys] = [ (x,y) | tzip xs ys ]