diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,29 @@
+BSD 3-Clause License
+
+Copyright (c) 2018, Joe Vargas
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+# key-state
+
+Manage key and button states and statuses
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,6 @@
+-- This script is used to build and install your package. Typically you don't
+-- need to change it. The Cabal documentation has more information about this
+-- file: <https://www.haskell.org/cabal/users-guide/installing-packages.html>.
+import qualified Distribution.Simple
+main :: IO ()
+main = Distribution.Simple.defaultMain
diff --git a/key-state.cabal b/key-state.cabal
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--- /dev/null
+++ b/key-state.cabal
@@ -0,0 +1,51 @@
+-- This file has been generated from package.yaml by hpack version 0.17.1.
+--
+-- see: https://github.com/sol/hpack
+
+name:           key-state
+version:        0.0.0
+synopsis:       Manage key and button states and statuses
+description:    Manage key and button states and statuses
+category:       Game
+homepage:       https://github.com/jxv/key-state#readme
+bug-reports:    https://github.com/jxv/key-state/issues
+maintainer:     Joe Vargas
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+cabal-version:  >= 1.10
+
+extra-source-files:
+    package.yaml
+    README.md
+    stack.yaml
+
+source-repository head
+  type: git
+  location: https://github.com/jxv/key-state
+
+library
+  hs-source-dirs:
+      library
+  default-extensions: NamedFieldPuns
+  ghc-options: -Wall
+  build-depends:
+      base >=4.7 && <5
+  exposed-modules:
+      KeyState
+  default-language: Haskell2010
+
+test-suite key-state-tests
+  type: exitcode-stdio-1.0
+  main-is: Main.hs
+  hs-source-dirs:
+      tests
+  default-extensions: NamedFieldPuns
+  ghc-options: -Wall -rtsopts -threaded -with-rtsopts=-N
+  build-depends:
+      base
+    , key-state
+    , hspec
+  other-modules:
+      KeyStateSpec
+  default-language: Haskell2010
diff --git a/library/KeyState.hs b/library/KeyState.hs
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--- /dev/null
+++ b/library/KeyState.hs
@@ -0,0 +1,33 @@
+module KeyState where
+
+data KeyStatus
+  = KeyStatus'Untouched
+  | KeyStatus'Pressed
+  | KeyStatus'Held
+  | KeyStatus'Released
+  deriving (Show, Eq, Ord, Enum)
+
+data KeyState count = KeyState
+  { ksStatus :: KeyStatus
+  , ksCounter :: Maybe count -- ^ Counter
+  } deriving (Show, Eq)
+
+initKeyState :: KeyState count
+initKeyState = KeyState KeyStatus'Untouched Nothing
+
+updateKeyState
+  :: Num count
+  => count -- ^ Counter delta
+  -> KeyState count
+  -> Bool -- ^ Touched
+  -> KeyState count
+updateKeyState delta KeyState{ksStatus, ksCounter} True = case ksStatus of
+  KeyStatus'Untouched -> KeyState KeyStatus'Pressed Nothing
+  KeyStatus'Pressed -> KeyState KeyStatus'Held Nothing
+  KeyStatus'Held -> KeyState KeyStatus'Held (Just $ delta + (case ksCounter of Nothing -> 0; Just counter -> counter))
+  KeyStatus'Released -> KeyState KeyStatus'Pressed Nothing
+updateKeyState delta KeyState{ksStatus, ksCounter} False = case ksStatus of
+  KeyStatus'Untouched -> KeyState KeyStatus'Untouched (Just $ delta + (case ksCounter of Nothing -> 0; Just counter -> counter))
+  KeyStatus'Pressed -> KeyState KeyStatus'Released Nothing
+  KeyStatus'Held -> KeyState KeyStatus'Released Nothing
+  KeyStatus'Released -> KeyState KeyStatus'Untouched Nothing
diff --git a/package.yaml b/package.yaml
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--- /dev/null
+++ b/package.yaml
@@ -0,0 +1,31 @@
+name: key-state
+version: '0.0.0'
+category: Game
+synopsis: Manage key and button states and statuses
+description: Manage key and button states and statuses
+maintainer: Joe Vargas
+default-extensions:
+- NamedFieldPuns
+extra-source-files:
+- package.yaml
+- README.md
+- stack.yaml
+ghc-options: -Wall
+library:
+  dependencies:
+  - base >=4.7 && <5
+  source-dirs: library
+tests:
+ key-state-tests:
+    dependencies:
+    - base
+    - key-state
+    - hspec
+    ghc-options:
+    - -rtsopts
+    - -threaded
+    - -with-rtsopts=-N
+    main: Main.hs
+    source-dirs: tests
+github: jxv/key-state
+license: BSD3
diff --git a/stack.yaml b/stack.yaml
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--- /dev/null
+++ b/stack.yaml
@@ -0,0 +1,6 @@
+resolver: lts-9.14
+packages:
+- '.'
+extra-deps: []
+flags: {}
+extra-package-dbs: []
diff --git a/tests/KeyStateSpec.hs b/tests/KeyStateSpec.hs
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--- /dev/null
+++ b/tests/KeyStateSpec.hs
@@ -0,0 +1,70 @@
+{-# LANGUAGE LambdaCase #-}
+module KeyStateSpec where
+
+import Test.Hspec
+import KeyState
+
+spec :: Spec
+spec = do
+  describe "updateKeyState" $ do
+    context "Not touching" $ do
+      it "Untouched key state (init)" $ do
+        let ks = initKeyState :: KeyState Int
+        let expected = KeyState KeyStatus'Untouched (Just 1)
+        updateKeyState 1 ks False `shouldBe` expected
+
+      it "Untouched key state" $ do
+        let ks = initKeyState { ksCounter = Just 10 } :: KeyState Int
+        let expected = KeyState KeyStatus'Untouched (Just 11)
+        updateKeyState 1 ks False `shouldBe` expected
+
+      it "Pressed key state (init)" $ do
+        let ks = initKeyState { ksStatus = KeyStatus'Pressed } :: KeyState Int
+        let expected = KeyState KeyStatus'Released Nothing
+        updateKeyState 1 ks False `shouldBe` expected
+
+      it "Pressed key state" $ do
+        let ks = KeyState KeyStatus'Pressed (Just 10) :: KeyState Int
+        let expected = KeyState KeyStatus'Released Nothing
+        updateKeyState 1 ks False `shouldBe` expected
+
+      it "Held key state" $ do
+        let ks = KeyState KeyStatus'Held (Just 10) :: KeyState Int
+        let expected = KeyState KeyStatus'Released Nothing
+        updateKeyState 1 ks False `shouldBe` expected
+
+      it "Released key state" $ do
+        let ks = KeyState KeyStatus'Released (Just 10) :: KeyState Int
+        let expected = KeyState KeyStatus'Untouched Nothing
+        updateKeyState 1 ks False `shouldBe` expected
+
+    context "Touching" $ do
+      it "Untouched key state (init)" $ do
+        let ks = initKeyState :: KeyState Int
+        let expected = KeyState KeyStatus'Pressed Nothing
+        updateKeyState 1 ks True `shouldBe` expected
+
+      it "Untouched key state" $ do
+        let ks = initKeyState { ksCounter = Just 10 } :: KeyState Int
+        let expected = KeyState KeyStatus'Pressed Nothing
+        updateKeyState 1 ks True `shouldBe` expected
+
+      it "Pressed key state (init)" $ do
+        let ks = initKeyState { ksStatus = KeyStatus'Pressed } :: KeyState Int
+        let expected = KeyState KeyStatus'Held Nothing
+        updateKeyState 1 ks True `shouldBe` expected
+
+      it "Pressed key state" $ do
+        let ks = KeyState KeyStatus'Pressed (Just 10) :: KeyState Int
+        let expected = KeyState KeyStatus'Held Nothing
+        updateKeyState 1 ks True `shouldBe` expected
+
+      it "Held key state" $ do
+        let ks = KeyState KeyStatus'Held (Just 10) :: KeyState Int
+        let expected = KeyState KeyStatus'Held (Just 11)
+        updateKeyState 1 ks True `shouldBe` expected
+
+      it "Released key state" $ do
+        let ks = KeyState KeyStatus'Released (Just 10) :: KeyState Int
+        let expected = KeyState KeyStatus'Pressed Nothing
+        updateKeyState 1 ks True `shouldBe` expected
diff --git a/tests/Main.hs b/tests/Main.hs
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--- /dev/null
+++ b/tests/Main.hs
@@ -0,0 +1,1 @@
+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}