From 72e56024ef6bf34aecd7574ad033b2f5413afdc9 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Tue, 12 Sep 2023 15:32:36 +0200
Subject: [PATCH 01/28] Add server conf to configuration handling

---
 config.ini               |  3 +++
 lib/LiBro/Config.hs      | 15 +++++++++++++--
 test/LiBro/ConfigSpec.hs | 31 ++++++++++++++++++++++---------
 3 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/config.ini b/config.ini
index 2ed888e..fbf32ee 100644
--- a/config.ini
+++ b/config.ini
@@ -2,3 +2,6 @@
 directory     = data-storage
 tasks-file    = tasks.csv
 tracking-file = tracking.csv
+
+[server]
+port = 8080
diff --git a/lib/LiBro/Config.hs b/lib/LiBro/Config.hs
index 1e6a3c5..a906cf7 100644
--- a/lib/LiBro/Config.hs
+++ b/lib/LiBro/Config.hs
@@ -18,13 +18,22 @@ data StorageConfig = Storage
 instance Default StorageConfig where
   def = Storage "data-storage" "persons.xlsx" "tasks.xlsx" "tracking.xlsx"
 
+-- |  Configuration of server details
+data ServerConfig = Server
+  { port :: Int
+  } deriving (Eq, Show)
+
+instance Default ServerConfig where
+  def = Server 8080
+
 -- |  Global settings.
 data Config = Config
   { storage :: StorageConfig
+  , server  :: ServerConfig
   } deriving (Eq, Show)
 
 instance Default Config where
-  def = Config def
+  def = Config def def
 
 -- |  Parses a 'Config' value from a given 'Text'
 --    or gives a parsing error message.
@@ -35,7 +44,9 @@ parseConfig = flip parseIniFile $ do
             <*> fieldOf "person-file"   string
             <*> fieldOf "tasks-file"    string
             <*> fieldOf "tracking-file" string
-  return $ Config st
+  srv <- section "server" $
+    Server <$> fieldOf "port" number
+  return $ Config st srv
 
 -- |  Reads a 'Config' value from @config.ini@.
 --    Prints parsing error messages to @STDERR@ when failing.
diff --git a/test/LiBro/ConfigSpec.hs b/test/LiBro/ConfigSpec.hs
index 0c4348d..9c376d6 100644
--- a/test/LiBro/ConfigSpec.hs
+++ b/test/LiBro/ConfigSpec.hs
@@ -18,22 +18,28 @@ import System.IO.Silently
 writeConfig :: Config -> Text
 writeConfig c = T.unlines
   [ "[storage]"
-  , "directory = "      <> T.pack (directory s)
-  , "person-file = "    <> T.pack (personFile s)
-  , "tasks-file = "     <> T.pack (tasksFile s)
-  , "tracking-file = "  <> T.pack (trackingFile s)
+  , "directory = "      <> T.pack (directory    st)
+  , "person-file = "    <> T.pack (personFile   st)
+  , "tasks-file = "     <> T.pack (tasksFile    st)
+  , "tracking-file = "  <> T.pack (trackingFile st)
+  , ""
+  , "[server]"
+  , "port = "           <> T.pack (show $ port srv)
   ] <> "\n"
-  where s = storage c
+  where st  = storage c
+        srv = server c
 
 instance Arbitrary Config where
   arbitrary = do
-    st <- Storage <$> name <*> name <*> name <*> name
-    return $ Config st
+    st  <- Storage  <$> name <*> name <*> name <*> name
+    srv <- Server   <$> port
+    return $ Config st srv
     where chars = [choose ('a','z'), choose ('A','Z'), return '/']
           name  = do  a   <- oneof chars
                       z   <- oneof chars
                       as  <- listOf $ oneof (return ' ' : chars)
                       return (a : as ++ [z])
+          port  = elements [1024 .. 49151] -- Wikipedia "Registered port"
 
 spec :: Spec
 spec = describe "INI file configuration" $ do
@@ -49,6 +55,9 @@ defaultConfig = describe "Default config values" $ do
     it "person file"    $ personFile    st `shouldBe` "persons.xlsx"
     it "tasks file"     $ tasksFile     st `shouldBe` "tasks.xlsx"
     it "tracking file"  $ trackingFile  st `shouldBe` "tracking.xlsx"
+  describe "Server configuration" $ do
+    let srv = server dc
+    it "port" $ port srv `shouldBe` 8080
   where dc = def :: Config
 
 parsing :: Spec
@@ -56,7 +65,9 @@ parsing = describe "Configuration parsing" $ do
 
   context "With simple values" $
     it "parse correct simple values" $ do
-      let simple = Config $ Storage "foo" "bar" "baz" "quux"
+      let simple = Config
+                    (Storage "foo" "bar" "baz" "quux")
+                    (Server 1742)
       parseConfig (writeConfig simple) `shouldBe` Right simple
 
   context "With invalid ini input" $
@@ -71,7 +82,9 @@ reading :: Spec
 reading = describe "Reading configuration from file" $ do
 
   context "With existing test config file" $ do
-    let simple = Config $ Storage "bar" "baz" "quux" "quuux"
+    let simple = Config
+                  (Storage "bar" "baz" "quux" "quuux")
+                  (Server 4217)
     config <- runIO $ withSystemTempFile "config.ini" $ \fp h -> do
       hPutStr h (T.unpack $ writeConfig simple) >> hClose h
       readConfigFrom fp

From 00afc4325692e56e158f1e2838927554cd308508 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Tue, 12 Sep 2023 15:37:29 +0200
Subject: [PATCH 02/28] Improve arbitrary storage config instance

---
 test/LiBro/ConfigSpec.hs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/LiBro/ConfigSpec.hs b/test/LiBro/ConfigSpec.hs
index 9c376d6..939328e 100644
--- a/test/LiBro/ConfigSpec.hs
+++ b/test/LiBro/ConfigSpec.hs
@@ -34,10 +34,10 @@ instance Arbitrary Config where
     st  <- Storage  <$> name <*> name <*> name <*> name
     srv <- Server   <$> port
     return $ Config st srv
-    where chars = [choose ('a','z'), choose ('A','Z'), return '/']
-          name  = do  a   <- oneof chars
-                      z   <- oneof chars
-                      as  <- listOf $ oneof (return ' ' : chars)
+    where chars = '/' : ['a'..'z'] ++ ['A'..'Z']
+          name  = do  a   <- elements chars
+                      z   <- elements chars
+                      as  <- listOf $ elements (' ' : chars)
                       return (a : as ++ [z])
           port  = elements [1024 .. 49151] -- Wikipedia "Registered port"
 

From 53538da3e08fa592cd12c0262525f95f83cd76ef Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Tue, 12 Sep 2023 15:45:16 +0200
Subject: [PATCH 03/28] Bugfix: fix example config.ini file (person-file)

---
 config.ini | 1 +
 1 file changed, 1 insertion(+)

diff --git a/config.ini b/config.ini
index fbf32ee..1ad8937 100644
--- a/config.ini
+++ b/config.ini
@@ -1,5 +1,6 @@
 [storage]
 directory     = data-storage
+person-file   = persons.csv
 tasks-file    = tasks.csv
 tracking-file = tracking.csv
 

From 5230fb9116e135af4f84cefc1f2b0c6fab444624 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Tue, 12 Sep 2023 16:15:12 +0200
Subject: [PATCH 04/28] Update server source directory

---
 libro-backend.cabal     | 2 +-
 {app => server}/Main.hs | 0
 2 files changed, 1 insertion(+), 1 deletion(-)
 rename {app => server}/Main.hs (100%)

diff --git a/libro-backend.cabal b/libro-backend.cabal
index 7c961cf..2953980 100644
--- a/libro-backend.cabal
+++ b/libro-backend.cabal
@@ -57,7 +57,7 @@ executable libro-backend
   main-is:            Main.hs
   build-depends:      base >=4.14.0.0
                     , libro-backend
-  hs-source-dirs:     app
+  hs-source-dirs:     server
 
 test-suite libro-backend-test
   default-language:   Haskell2010
diff --git a/app/Main.hs b/server/Main.hs
similarity index 100%
rename from app/Main.hs
rename to server/Main.hs

From 02a6aad2eb6f899e374b477793c70f8514d2c9a0 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Tue, 12 Sep 2023 16:45:56 +0200
Subject: [PATCH 05/28] Add basic web service setup with "Hello world" route

---
 README.md                      |  6 ++++++
 lib/LiBro/WebService/API.hs    |  9 +++++++++
 lib/LiBro/WebService/Server.hs | 10 ++++++++++
 libro-backend.cabal            |  9 +++++++++
 server/Main.hs                 | 13 ++++++++++++-
 test/LiBro/WebServiceSpec.hs   | 21 +++++++++++++++++++++
 6 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 lib/LiBro/WebService/API.hs
 create mode 100644 lib/LiBro/WebService/Server.hs
 create mode 100644 test/LiBro/WebServiceSpec.hs

diff --git a/README.md b/README.md
index ef43295..ec80369 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,12 @@ Haskell dependencies:
 cabal install --only-dependencies all
 ```
 
+## Run the RESTful JSON web service
+
+```
+cabal run libro-backend
+```
+
 ## Run tests
  
 Running all the tests with `make test` may take some time. Run individual tests with
diff --git a/lib/LiBro/WebService/API.hs b/lib/LiBro/WebService/API.hs
new file mode 100644
index 0000000..fdc9231
--- /dev/null
+++ b/lib/LiBro/WebService/API.hs
@@ -0,0 +1,9 @@
+module LiBro.WebService.API where
+
+import Data.Proxy
+import Servant.API
+
+type LiBroAPI = "hello" :> Get '[PlainText] String
+
+libroApi :: Proxy LiBroAPI
+libroApi = Proxy
diff --git a/lib/LiBro/WebService/Server.hs b/lib/LiBro/WebService/Server.hs
new file mode 100644
index 0000000..cb73d7e
--- /dev/null
+++ b/lib/LiBro/WebService/Server.hs
@@ -0,0 +1,10 @@
+module LiBro.WebService.Server where
+
+import LiBro.WebService.API
+import Servant
+
+server :: Server LiBroAPI
+server = return "Hello LiBro!"
+
+libro :: Application
+libro = serve libroApi server
diff --git a/libro-backend.cabal b/libro-backend.cabal
index 2953980..f43b992 100644
--- a/libro-backend.cabal
+++ b/libro-backend.cabal
@@ -27,11 +27,15 @@ library
   default-language:   Haskell2010
   default-extensions: OverloadedStrings
                     , DeriveGeneric
+                    , DataKinds
+                    , TypeOperators
   exposed-modules:    LiBro.Config
                     , LiBro.Data
                     , LiBro.Data.Storage
                     , LiBro.Data.SafeText
                     , LiBro.Control
+                    , LiBro.WebService.API
+                    , LiBro.WebService.Server
                     , LiBro.Util
   build-depends:      base >=4.14.0.0
                     , aeson
@@ -46,6 +50,8 @@ library
                     , mtl
                     , process
                     , QuickCheck
+                    , servant
+                    , servant-server
                     , temporary
                     , text
                     , unordered-containers
@@ -57,6 +63,7 @@ executable libro-backend
   main-is:            Main.hs
   build-depends:      base >=4.14.0.0
                     , libro-backend
+                    , warp
   hs-source-dirs:     server
 
 test-suite libro-backend-test
@@ -72,10 +79,12 @@ test-suite libro-backend-test
                     , LiBro.Data.StorageSpec
                     , LiBro.Data.SafeTextSpec
                     , LiBro.ControlSpec
+                    , LiBro.WebServiceSpec
                     , LiBro.UtilSpec
   main-is:            run-all-tests.hs
   build-depends:      base >=4.14.0.0
                     , hspec
+                    , hspec-wai
                     , QuickCheck
                     , quickcheck-text
                     , generic-arbitrary
diff --git a/server/Main.hs b/server/Main.hs
index ef52089..93bc118 100644
--- a/server/Main.hs
+++ b/server/Main.hs
@@ -1,4 +1,15 @@
 module Main where
 
+import LiBro.Config as Conf
+import LiBro.WebService.Server
+import Network.Wai.Handler.Warp
+
+configuredMain :: Config -> IO ()
+configuredMain config = do
+  let port = Conf.port $ Conf.server config
+  putStrLn $ "Serving LiBro backend on port " ++ show port ++ "."
+  run port libro
+
 main :: IO ()
-main = putStrLn "42"
+main = readConfig >>= maybe complain configuredMain
+  where complain = putStrLn "Invalid config: aborting"
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
new file mode 100644
index 0000000..0edb0f4
--- /dev/null
+++ b/test/LiBro/WebServiceSpec.hs
@@ -0,0 +1,21 @@
+module LiBro.WebServiceSpec where
+
+import Test.Hspec
+import Test.Hspec.Wai
+
+import LiBro.WebService.Server
+
+spec :: Spec
+spec = describe "RESTful JSON web service" $ do
+  helloLibro
+
+helloLibro :: Spec
+helloLibro = describe "Dummy: hello libro!" $ with (return libro) $ do
+
+  describe "Root" $ do
+    it "Respond with 404" $ do
+      get "/" `shouldRespondWith` 404
+
+  describe "Hello endpoint" $ do
+    it "Respond with greeting" $ do
+      get "/hello" `shouldRespondWith` "Hello LiBro!"

From 41f736f2b3e364a138d82b875d9171722f97fd9e Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Tue, 12 Sep 2023 18:05:36 +0200
Subject: [PATCH 06/28] Also test status with hello web service test

---
 test/LiBro/WebServiceSpec.hs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 0edb0f4..e800cd8 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -17,5 +17,5 @@ helloLibro = describe "Dummy: hello libro!" $ with (return libro) $ do
       get "/" `shouldRespondWith` 404
 
   describe "Hello endpoint" $ do
-    it "Respond with greeting" $ do
-      get "/hello" `shouldRespondWith` "Hello LiBro!"
+    it "Respond with 200 greeting" $ do
+      get "/hello" `shouldRespondWith` "Hello LiBro!" {matchStatus = 200}

From 8faac1b6c1696fa22cecb092caf8bee3a90138d5 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Wed, 13 Sep 2023 15:30:33 +0200
Subject: [PATCH 07/28] Test all no-hello endpoints using QuickCheck

---
 test/LiBro/WebServiceSpec.hs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index e800cd8..ac6f6e9 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -2,8 +2,10 @@ module LiBro.WebServiceSpec where
 
 import Test.Hspec
 import Test.Hspec.Wai
+import Test.Hspec.Wai.QuickCheck
 
 import LiBro.WebService.Server
+import Data.ByteString
 
 spec :: Spec
 spec = describe "RESTful JSON web service" $ do
@@ -12,10 +14,12 @@ spec = describe "RESTful JSON web service" $ do
 helloLibro :: Spec
 helloLibro = describe "Dummy: hello libro!" $ with (return libro) $ do
 
-  describe "Root" $ do
-    it "Respond with 404" $ do
-      get "/" `shouldRespondWith` 404
-
   describe "Hello endpoint" $ do
     it "Respond with 200 greeting" $ do
       get "/hello" `shouldRespondWith` "Hello LiBro!" {matchStatus = 200}
+
+  describe "Any other endpoint" $ do
+    it "Respond with 404" $ do
+      property $ \endpoint ->
+        show endpoint /= "hello" ==>
+        get (pack endpoint) `shouldRespondWith` 404

From 8d3ab7fa274ae62e817e01cc3422eca26275031e Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Thu, 14 Sep 2023 09:09:00 +0200
Subject: [PATCH 08/28] Add serve to Makefile

---
 Makefile  | 5 ++++-
 README.md | 2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 4ceaf2f..cf1d584 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: all build test test_only doc stats
+.PHONY: all build test test_only doc serve stats
 
 all: build test doc stats
 
@@ -14,6 +14,9 @@ test_only:
 doc:
 	cabal haddock --haddock-hyperlinked-source --haddock-html-location='https://hackage.haskell.org/package/$$pkg-$$version/docs'
 
+serve:
+	cabal run libro-backend
+
 stats:
 	find lib -name '*.hs' -not -path "./dist-newstyle/*" | sort | xargs wc -l
 	find test -name '*.hs' -not -path "./dist-newstyle/*" | sort | xargs wc -l
diff --git a/README.md b/README.md
index ec80369..255ee10 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ cabal install --only-dependencies all
 ## Run the RESTful JSON web service
 
 ```
-cabal run libro-backend
+make serve
 ```
 
 ## Run tests

From f0bd51cc925a309b196be4fbb9b3734751c99f5d Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Thu, 16 Nov 2023 11:58:19 +0100
Subject: [PATCH 09/28] Skip GHC 9.8 for now (dependency problems in this
 branch)

---
 .github/workflows/haskell-ci.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/haskell-ci.yml b/.github/workflows/haskell-ci.yml
index 2601972..a183f4f 100644
--- a/.github/workflows/haskell-ci.yml
+++ b/.github/workflows/haskell-ci.yml
@@ -12,7 +12,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        ghc-version: ['9.4', '9.6', '9.8']
+        ghc-version: ['9.4', '9.6']
     steps:
 
       - name: Checkout repository content

From 9de8070bbbc8646b54b5a8e5e968cf2cf17f1834 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 16 Feb 2024 14:35:31 +0100
Subject: [PATCH 10/28] Restructure WebService code with JSON example

---
 lib/LiBro/WebService.hs        | 29 +++++++++++++++++++++++++++++
 lib/LiBro/WebService/API.hs    |  9 ---------
 lib/LiBro/WebService/Server.hs | 10 ----------
 lib/LiBro/WebService/State.hs  | 25 +++++++++++++++++++++++++
 libro-backend.cabal            |  7 +++++--
 server/Main.hs                 |  2 +-
 test/LiBro/WebServiceSpec.hs   | 13 ++++++++++---
 test/run-all-tests.hs          |  2 ++
 8 files changed, 72 insertions(+), 25 deletions(-)
 create mode 100644 lib/LiBro/WebService.hs
 delete mode 100644 lib/LiBro/WebService/API.hs
 delete mode 100644 lib/LiBro/WebService/Server.hs
 create mode 100644 lib/LiBro/WebService/State.hs

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
new file mode 100644
index 0000000..fe44060
--- /dev/null
+++ b/lib/LiBro/WebService.hs
@@ -0,0 +1,29 @@
+module LiBro.WebService where
+
+import Data.Aeson
+import Data.Proxy
+import Servant
+import GHC.Generics
+
+newtype PersonIDs = PersonIDs {personIDs :: [Int]} deriving Generic
+instance ToJSON PersonIDs
+
+type LiBroAPI = "hello" :> Get '[JSON]      PersonIDs
+          :<|>  "yay"   :> Get '[PlainText] String
+
+libroServer :: Server LiBroAPI
+libroServer =     handleHello
+            :<|>  handleYay
+  where
+        handleHello :: Handler PersonIDs
+        handleHello = return $ PersonIDs [17, 42]
+
+        handleYay :: Handler String
+        handleYay = return "Yay!"
+
+libroApi :: Proxy LiBroAPI
+libroApi = Proxy
+
+libro :: Application
+libro = serve libroApi libroServer
+
diff --git a/lib/LiBro/WebService/API.hs b/lib/LiBro/WebService/API.hs
deleted file mode 100644
index fdc9231..0000000
--- a/lib/LiBro/WebService/API.hs
+++ /dev/null
@@ -1,9 +0,0 @@
-module LiBro.WebService.API where
-
-import Data.Proxy
-import Servant.API
-
-type LiBroAPI = "hello" :> Get '[PlainText] String
-
-libroApi :: Proxy LiBroAPI
-libroApi = Proxy
diff --git a/lib/LiBro/WebService/Server.hs b/lib/LiBro/WebService/Server.hs
deleted file mode 100644
index cb73d7e..0000000
--- a/lib/LiBro/WebService/Server.hs
+++ /dev/null
@@ -1,10 +0,0 @@
-module LiBro.WebService.Server where
-
-import LiBro.WebService.API
-import Servant
-
-server :: Server LiBroAPI
-server = return "Hello LiBro!"
-
-libro :: Application
-libro = serve libroApi server
diff --git a/lib/LiBro/WebService/State.hs b/lib/LiBro/WebService/State.hs
new file mode 100644
index 0000000..6beec0f
--- /dev/null
+++ b/lib/LiBro/WebService/State.hs
@@ -0,0 +1,25 @@
+module LiBro.WebService.State where
+
+import LiBro.Config
+import LiBro.Data
+import LiBro.Control
+import Control.Concurrent
+
+data LiBroState = LiBroState
+  { config      :: Config
+  , mvBlocking  :: MVar Blocking
+  , mvData      :: MVar LiBroData
+  }
+
+lsConfig :: LiBroState -> IO Config
+lsConfig = return . config
+
+lsData :: LiBroState -> IO LiBroData
+lsData = readMVar . mvData
+
+lsInit :: Config -> IO LiBroState
+lsInit config = do
+  mvb <- newEmptyMVar
+  mvd <- newEmptyMVar
+  initData config mvb mvd
+  return $ LiBroState config mvb mvd
diff --git a/libro-backend.cabal b/libro-backend.cabal
index fda5d1d..fefc78d 100644
--- a/libro-backend.cabal
+++ b/libro-backend.cabal
@@ -41,8 +41,8 @@ library
                     , LiBro.Data.Storage
                     , LiBro.Data.SafeText
                     , LiBro.Control
-                    , LiBro.WebService.API
-                    , LiBro.WebService.Server
+                    , LiBro.WebService
+                    , LiBro.WebService.State
                     , LiBro.Util
   build-depends:      aeson
                     , attoparsec
@@ -75,6 +75,7 @@ executable libro-backend
 test-suite libro-backend-test
   import:             consumer
   default-extensions: OverloadedStrings
+                    , QuasiQuotes
                     , DeriveGeneric
   type:               exitcode-stdio-1.0
   hs-source-dirs:     test
@@ -91,6 +92,7 @@ test-suite libro-backend-test
   build-depends:      libro-backend
                     , hspec
                     , hspec-wai
+                    , hspec-wai-json
                     , QuickCheck
                     , quickcheck-text
                     , generic-arbitrary
@@ -108,3 +110,4 @@ test-suite libro-backend-test
                     , text
                     , transformers
                     , vector
+                    , wai
diff --git a/server/Main.hs b/server/Main.hs
index 93bc118..2b6a3a9 100644
--- a/server/Main.hs
+++ b/server/Main.hs
@@ -1,7 +1,7 @@
 module Main where
 
 import LiBro.Config as Conf
-import LiBro.WebService.Server
+import LiBro.WebService
 import Network.Wai.Handler.Warp
 
 configuredMain :: Config -> IO ()
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index ac6f6e9..33d2be5 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -2,9 +2,10 @@ module LiBro.WebServiceSpec where
 
 import Test.Hspec
 import Test.Hspec.Wai
+import Test.Hspec.Wai.JSON
 import Test.Hspec.Wai.QuickCheck
 
-import LiBro.WebService.Server
+import LiBro.WebService
 import Data.ByteString
 
 spec :: Spec
@@ -14,9 +15,15 @@ spec = describe "RESTful JSON web service" $ do
 helloLibro :: Spec
 helloLibro = describe "Dummy: hello libro!" $ with (return libro) $ do
 
-  describe "Hello endpoint" $ do
+  describe "Yay endpoint" $ do
     it "Respond with 200 greeting" $ do
-      get "/hello" `shouldRespondWith` "Hello LiBro!" {matchStatus = 200}
+      get "/yay" `shouldRespondWith` "Yay!" {matchStatus = 200}
+
+  describe "Dummy person ID endpoint" $ do
+    it "Respond with IDs" $ do
+      get "/hello" `shouldRespondWith`
+        [json|{"personIDs":[17,42]}|]
+        {matchStatus = 200}
 
   describe "Any other endpoint" $ do
     it "Respond with 404" $ do
diff --git a/test/run-all-tests.hs b/test/run-all-tests.hs
index d5459a5..a048e30 100644
--- a/test/run-all-tests.hs
+++ b/test/run-all-tests.hs
@@ -10,6 +10,7 @@ import qualified LiBro.ConfigSpec         as Config
 import qualified LiBro.ControlSpec        as Control
 import qualified LiBro.TestUtilSpec       as TestUtil
 import qualified LiBro.UtilSpec           as Util
+import qualified LiBro.WebServiceSpec     as WebService
 
 withLibreOffice :: IO () -> IO ()
 withLibreOffice runTests = do
@@ -31,3 +32,4 @@ main = hspec $ aroundAll_ withLibreOffice $ do
   Control.spec
   TestUtil.spec
   Util.spec
+  WebService.spec

From 7b1ba6dca9e6c259770129cbc5a5e380bb215611 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Mon, 19 Feb 2024 10:30:00 +0100
Subject: [PATCH 11/28] Add config to web service actions

---
 lib/LiBro/WebService.hs      | 12 ++++++------
 server/Main.hs               |  6 +++---
 test/LiBro/WebServiceSpec.hs |  6 +++++-
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index fe44060..cfececb 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -1,5 +1,6 @@
 module LiBro.WebService where
 
+import LiBro.Config
 import Data.Aeson
 import Data.Proxy
 import Servant
@@ -11,9 +12,9 @@ instance ToJSON PersonIDs
 type LiBroAPI = "hello" :> Get '[JSON]      PersonIDs
           :<|>  "yay"   :> Get '[PlainText] String
 
-libroServer :: Server LiBroAPI
-libroServer =     handleHello
-            :<|>  handleYay
+libroServer :: Config -> Server LiBroAPI
+libroServer cfg =     handleHello
+                :<|>  handleYay
   where
         handleHello :: Handler PersonIDs
         handleHello = return $ PersonIDs [17, 42]
@@ -24,6 +25,5 @@ libroServer =     handleHello
 libroApi :: Proxy LiBroAPI
 libroApi = Proxy
 
-libro :: Application
-libro = serve libroApi libroServer
-
+libro :: Config -> Application
+libro = serve libroApi . libroServer
diff --git a/server/Main.hs b/server/Main.hs
index 2b6a3a9..2a4ed5b 100644
--- a/server/Main.hs
+++ b/server/Main.hs
@@ -5,10 +5,10 @@ import LiBro.WebService
 import Network.Wai.Handler.Warp
 
 configuredMain :: Config -> IO ()
-configuredMain config = do
-  let port = Conf.port $ Conf.server config
+configuredMain cfg = do
+  let port = Conf.port $ Conf.server cfg
   putStrLn $ "Serving LiBro backend on port " ++ show port ++ "."
-  run port libro
+  run port (libro cfg)
 
 main :: IO ()
 main = readConfig >>= maybe complain configuredMain
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 33d2be5..961fe09 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -5,7 +5,9 @@ import Test.Hspec.Wai
 import Test.Hspec.Wai.JSON
 import Test.Hspec.Wai.QuickCheck
 
+import LiBro.Config
 import LiBro.WebService
+import Data.Default
 import Data.ByteString
 
 spec :: Spec
@@ -13,7 +15,7 @@ spec = describe "RESTful JSON web service" $ do
   helloLibro
 
 helloLibro :: Spec
-helloLibro = describe "Dummy: hello libro!" $ with (return libro) $ do
+helloLibro = describe "Dummy: hello libro!" $ with (return cfgLibro) $ do
 
   describe "Yay endpoint" $ do
     it "Respond with 200 greeting" $ do
@@ -30,3 +32,5 @@ helloLibro = describe "Dummy: hello libro!" $ with (return libro) $ do
       property $ \endpoint ->
         show endpoint /= "hello" ==>
         get (pack endpoint) `shouldRespondWith` 404
+
+  where cfgLibro = libro $ Config def def

From 94db8213b8779856eb20bb647bab098703adfdaa Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Wed, 21 Feb 2024 12:01:45 +0100
Subject: [PATCH 12/28] Avoid identifier warnings (config/cfg) with LiBroState

---
 lib/LiBro/Control.hs      | 8 ++++----
 test/LiBro/ControlSpec.hs | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/LiBro/Control.hs b/lib/LiBro/Control.hs
index 01dfc8b..e8badd6 100644
--- a/lib/LiBro/Control.hs
+++ b/lib/LiBro/Control.hs
@@ -16,21 +16,21 @@ data Blocking
 -- |  Initially load data and put it into the shared state.
 --    Expects the given 'MVar' to be empty.
 initData :: Config -> MVar Blocking -> MVar LiBroData -> IO ()
-initData config blocking libroData = do
+initData cfg blocking libroData = do
   putMVar blocking Reading
-  putMVar libroData =<< loadData config
+  putMVar libroData =<< loadData cfg
   _ <- takeMVar blocking
   return ()
 
 -- |  Try to store shared state data. Expects the given blocking MVar
 --    to be empty. Iff not, returns 'False'.
 saveData :: Config -> MVar Blocking -> MVar LiBroData -> IO Bool
-saveData config blocking libroData = do
+saveData cfg blocking libroData = do
   isBlocked <- not <$> isEmptyMVar blocking
   if isBlocked
     then return False
     else do
       putMVar blocking Writing
-      storeData config =<< readMVar libroData
+      storeData cfg =<< readMVar libroData
       _ <- takeMVar blocking
       return True
diff --git a/test/LiBro/ControlSpec.hs b/test/LiBro/ControlSpec.hs
index 6b5ee94..1ce34f7 100644
--- a/test/LiBro/ControlSpec.hs
+++ b/test/LiBro/ControlSpec.hs
@@ -20,14 +20,14 @@ dataInitialization :: Spec
 dataInitialization = describe "Blocking data loading" $ do
 
   context "With simple data files" $ do
-    let config = def { storage = def { directory = "test/storage-files/data" }}
-    expectedData  <- runIO $ loadData config
+    let cfg = def { storage = def { directory = "test/storage-files/data" }}
+    expectedData  <- runIO $ loadData cfg
     blocking      <- runIO $ newEmptyMVar
     libroData     <- runIO $ newEmptyMVar
     (beb, bed, aeb, aned, ld) <- runIO $ do
       beforeEmptyBlocking <- isEmptyMVar blocking
       beforeEmptyData     <- isEmptyMVar libroData
-      initData config blocking libroData
+      initData cfg blocking libroData
       afterEmptyBlocking  <- isEmptyMVar blocking
       afterNonEmptyData   <- isEmptyMVar libroData
       loadedData          <- readMVar libroData

From 5705aa72f37b709a8185e4116a92ebc230d2c63b Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Wed, 21 Feb 2024 12:03:39 +0100
Subject: [PATCH 13/28] Move libro state modifiers to Control

---
 lib/LiBro/Control.hs          | 49 +++++++++++++++++++++++++++++++++++
 lib/LiBro/WebService/State.hs | 25 ------------------
 libro-backend.cabal           |  1 -
 3 files changed, 49 insertions(+), 26 deletions(-)
 delete mode 100644 lib/LiBro/WebService/State.hs

diff --git a/lib/LiBro/Control.hs b/lib/LiBro/Control.hs
index e8badd6..f8e73e2 100644
--- a/lib/LiBro/Control.hs
+++ b/lib/LiBro/Control.hs
@@ -5,6 +5,7 @@ import LiBro.Config
 import LiBro.Data
 import LiBro.Data.Storage
 import Control.Concurrent
+import Control.Monad.Reader
 
 -- |  Represents a blocking action because the system is loading
 --    or saving data.
@@ -34,3 +35,51 @@ saveData cfg blocking libroData = do
       storeData cfg =<< readMVar libroData
       _ <- takeMVar blocking
       return True
+
+-- |  Shared libro system state to access data any time.
+data LiBroState = LiBroState
+  { config      :: Config
+  , mvBlocking  :: MVar Blocking
+  , mvData      :: MVar LiBroData
+  }
+
+-- |  Initialization of a 'LiBroState'.
+initLiBroState :: Config -> IO LiBroState
+initLiBroState cfg = do
+  mvb <- newEmptyMVar
+  mvd <- newEmptyMVar
+  initData cfg mvb mvd
+  return $ LiBroState cfg mvb mvd
+
+-- |  'Config' accessor action.
+lsConfig :: ReaderT LiBroState IO Config
+lsConfig = asks config
+
+-- |  Checks whether the system is blocked
+--    and by what type of 'Blocking' action.
+lsBlockedBy :: ReaderT LiBroState IO (Maybe Blocking)
+lsBlockedBy = do
+  mvb <- asks mvBlocking
+  lift $ tryTakeMVar mvb
+
+-- |  'LiBroData' accessor action.
+lsData :: ReaderT LiBroState IO LiBroData
+lsData = do
+  mvd <- asks mvData
+  lift $ readMVar mvd
+
+-- |  'initData' action.
+lsInitData :: ReaderT LiBroState IO ()
+lsInitData = do
+  cfg <- asks config
+  mvb <- asks mvBlocking
+  mvd <- asks mvData
+  lift $ initData cfg mvb mvd
+
+-- |  'saveData' action.
+lsSaveData :: ReaderT LiBroState IO Bool
+lsSaveData = do
+  cfg <- asks config
+  mvb <- asks mvBlocking
+  mvd <- asks mvData
+  lift $ saveData cfg mvb mvd
diff --git a/lib/LiBro/WebService/State.hs b/lib/LiBro/WebService/State.hs
deleted file mode 100644
index 6beec0f..0000000
--- a/lib/LiBro/WebService/State.hs
+++ /dev/null
@@ -1,25 +0,0 @@
-module LiBro.WebService.State where
-
-import LiBro.Config
-import LiBro.Data
-import LiBro.Control
-import Control.Concurrent
-
-data LiBroState = LiBroState
-  { config      :: Config
-  , mvBlocking  :: MVar Blocking
-  , mvData      :: MVar LiBroData
-  }
-
-lsConfig :: LiBroState -> IO Config
-lsConfig = return . config
-
-lsData :: LiBroState -> IO LiBroData
-lsData = readMVar . mvData
-
-lsInit :: Config -> IO LiBroState
-lsInit config = do
-  mvb <- newEmptyMVar
-  mvd <- newEmptyMVar
-  initData config mvb mvd
-  return $ LiBroState config mvb mvd
diff --git a/libro-backend.cabal b/libro-backend.cabal
index fefc78d..bbda8c0 100644
--- a/libro-backend.cabal
+++ b/libro-backend.cabal
@@ -42,7 +42,6 @@ library
                     , LiBro.Data.SafeText
                     , LiBro.Control
                     , LiBro.WebService
-                    , LiBro.WebService.State
                     , LiBro.Util
   build-depends:      aeson
                     , attoparsec

From 04579baa862dfd1876b0ace9f07cf316344541c8 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 10:53:45 +0100
Subject: [PATCH 14/28] Fix some intermediate warnings

---
 lib/LiBro/Data.hs        | 2 +-
 server/Main.hs           | 6 +++---
 test/LiBro/ConfigSpec.hs | 8 ++++----
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/LiBro/Data.hs b/lib/LiBro/Data.hs
index 5a3b89f..1878c9b 100644
--- a/lib/LiBro/Data.hs
+++ b/lib/LiBro/Data.hs
@@ -50,7 +50,7 @@ type Tasks = Forest Task
 
 -- |  Find all 'Task's assigned to a given 'Person'.
 assignedTasks :: Person -> Tasks -> [Task]
-assignedTasks p = filter ((p `elem`) . assignees) . concatMap flatten
+assignedTasks p = concatMap (filter ((p `elem`) . assignees) . flatten)
 
 -- |  Complete LiBro state in one type
 data LiBroData = LBS
diff --git a/server/Main.hs b/server/Main.hs
index 2a4ed5b..c6c1d3a 100644
--- a/server/Main.hs
+++ b/server/Main.hs
@@ -6,9 +6,9 @@ import Network.Wai.Handler.Warp
 
 configuredMain :: Config -> IO ()
 configuredMain cfg = do
-  let port = Conf.port $ Conf.server cfg
-  putStrLn $ "Serving LiBro backend on port " ++ show port ++ "."
-  run port (libro cfg)
+  let p = Conf.port $ Conf.server cfg
+  putStrLn $ "Serving LiBro backend on port " ++ show p ++ "."
+  run p (libro cfg)
 
 main :: IO ()
 main = readConfig >>= maybe complain configuredMain
diff --git a/test/LiBro/ConfigSpec.hs b/test/LiBro/ConfigSpec.hs
index 73033ba..b20c47a 100644
--- a/test/LiBro/ConfigSpec.hs
+++ b/test/LiBro/ConfigSpec.hs
@@ -33,15 +33,15 @@ writeConfig c = T.unlines
 
 instance Arbitrary Config where
   arbitrary = do
-    st  <- Storage  <$> name <*> name <*> name <*> name
-    srv <- Server   <$> port
+    st  <- Storage  <$> aname <*> aname <*> aname <*> aname
+    srv <- Server   <$> aport
     return $ Config st srv
     where chars = '/' : ['a'..'z'] ++ ['A'..'Z']
-          name  = do  a   <- elements chars
+          aname = do  a   <- elements chars
                       z   <- elements chars
                       as  <- listOf $ elements (' ' : chars)
                       return (a : as ++ [z])
-          port  = elements [1024 .. 49151] -- Wikipedia "Registered port"
+          aport = elements [1024 .. 49151] -- Wikipedia "Registered port"
 
 spec :: Spec
 spec = describe "INI file configuration" $ do

From bee31ce0f2287b85008823ae92255dce5833372a Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 12:51:12 +0100
Subject: [PATCH 15/28] Gitignore LibreOffice swap files

---
 .gitignore | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/.gitignore b/.gitignore
index 72b1946..18efc33 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,9 @@
 # Vim swap files
 *.sw[a-p]
 
+# LibreOffice swap files
+.~lock.*#
+
 # Generated documentstion
 api-docs
 

From 48f1c60556d1cf8e121fbfd64205cdc533d4fe39 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 14:04:45 +0100
Subject: [PATCH 16/28] Redesign web service actions for the person IDs listing
 endpoint

---
 lib/LiBro/Control.hs         | 13 ++++++++-----
 lib/LiBro/WebService.hs      | 32 ++++++++++++++++++++++----------
 server/Main.hs               |  8 +++++---
 test/LiBro/WebServiceSpec.hs | 28 +++++++++-------------------
 4 files changed, 44 insertions(+), 37 deletions(-)

diff --git a/lib/LiBro/Control.hs b/lib/LiBro/Control.hs
index f8e73e2..30f5ffb 100644
--- a/lib/LiBro/Control.hs
+++ b/lib/LiBro/Control.hs
@@ -51,25 +51,28 @@ initLiBroState cfg = do
   initData cfg mvb mvd
   return $ LiBroState cfg mvb mvd
 
+-- |  Type alias for actions holding a 'LiBroState' inside 'ReaderT'.
+type Action = ReaderT LiBroState IO
+
 -- |  'Config' accessor action.
-lsConfig :: ReaderT LiBroState IO Config
+lsConfig :: Action Config
 lsConfig = asks config
 
 -- |  Checks whether the system is blocked
 --    and by what type of 'Blocking' action.
-lsBlockedBy :: ReaderT LiBroState IO (Maybe Blocking)
+lsBlockedBy :: Action (Maybe Blocking)
 lsBlockedBy = do
   mvb <- asks mvBlocking
   lift $ tryTakeMVar mvb
 
 -- |  'LiBroData' accessor action.
-lsData :: ReaderT LiBroState IO LiBroData
+lsData :: Action LiBroData
 lsData = do
   mvd <- asks mvData
   lift $ readMVar mvd
 
 -- |  'initData' action.
-lsInitData :: ReaderT LiBroState IO ()
+lsInitData :: Action ()
 lsInitData = do
   cfg <- asks config
   mvb <- asks mvBlocking
@@ -77,7 +80,7 @@ lsInitData = do
   lift $ initData cfg mvb mvd
 
 -- |  'saveData' action.
-lsSaveData :: ReaderT LiBroState IO Bool
+lsSaveData :: Action Bool
 lsSaveData = do
   cfg <- asks config
   mvb <- asks mvBlocking
diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index cfececb..633efc3 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -1,29 +1,41 @@
 module LiBro.WebService where
 
-import LiBro.Config
+import LiBro.Control
+import LiBro.Data
+import qualified Data.Map as M
 import Data.Aeson
 import Data.Proxy
 import Servant
+import Control.Monad.Reader
 import GHC.Generics
 
 newtype PersonIDs = PersonIDs {personIDs :: [Int]} deriving Generic
 instance ToJSON PersonIDs
 
-type LiBroAPI = "hello" :> Get '[JSON]      PersonIDs
+type LiBroHandler = ReaderT LiBroState Handler
+
+runAction :: Action a -> LiBroHandler a
+runAction action = ask >>= liftIO . runReaderT action
+
+type LiBroAPI = "person":> Get '[JSON]      PersonIDs
           :<|>  "yay"   :> Get '[PlainText] String
 
-libroServer :: Config -> Server LiBroAPI
-libroServer cfg =     handleHello
-                :<|>  handleYay
+libroServer :: ServerT LiBroAPI LiBroHandler
+libroServer =     hPersonIDs
+            :<|>  handleYay
   where
-        handleHello :: Handler PersonIDs
-        handleHello = return $ PersonIDs [17, 42]
+        hPersonIDs :: LiBroHandler PersonIDs
+        hPersonIDs = do
+          ps <- persons <$> runAction lsData
+          return $ PersonIDs (M.keys ps)
 
-        handleYay :: Handler String
+        handleYay :: LiBroHandler String
         handleYay = return "Yay!"
 
 libroApi :: Proxy LiBroAPI
 libroApi = Proxy
 
-libro :: Config -> Application
-libro = serve libroApi . libroServer
+libro :: LiBroState -> Application
+libro initState =
+  let server = hoistServer libroApi (`runReaderT` initState) libroServer
+  in  serve libroApi server
diff --git a/server/Main.hs b/server/Main.hs
index c6c1d3a..5340a1e 100644
--- a/server/Main.hs
+++ b/server/Main.hs
@@ -1,14 +1,16 @@
 module Main where
 
-import LiBro.Config as Conf
+import LiBro.Config
+import LiBro.Control
 import LiBro.WebService
 import Network.Wai.Handler.Warp
 
 configuredMain :: Config -> IO ()
 configuredMain cfg = do
-  let p = Conf.port $ Conf.server cfg
+  let p = port $ server cfg
   putStrLn $ "Serving LiBro backend on port " ++ show p ++ "."
-  run p (libro cfg)
+  initState <- initLiBroState cfg
+  run p $ libro initState
 
 main :: IO ()
 main = readConfig >>= maybe complain configuredMain
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 961fe09..71654ec 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -3,34 +3,24 @@ module LiBro.WebServiceSpec where
 import Test.Hspec
 import Test.Hspec.Wai
 import Test.Hspec.Wai.JSON
-import Test.Hspec.Wai.QuickCheck
 
 import LiBro.Config
+import LiBro.Control
 import LiBro.WebService
 import Data.Default
-import Data.ByteString
 
 spec :: Spec
 spec = describe "RESTful JSON web service" $ do
-  helloLibro
+  personSpecs
 
-helloLibro :: Spec
-helloLibro = describe "Dummy: hello libro!" $ with (return cfgLibro) $ do
+personSpecs :: Spec
+personSpecs = describe "Person related endpoints" $ with lws $ do
 
-  describe "Yay endpoint" $ do
-    it "Respond with 200 greeting" $ do
-      get "/yay" `shouldRespondWith` "Yay!" {matchStatus = 200}
-
-  describe "Dummy person ID endpoint" $ do
+  describe "Person ID listing endpoint" $ do
     it "Respond with IDs" $ do
-      get "/hello" `shouldRespondWith`
-        [json|{"personIDs":[17,42]}|]
+      get "/person" `shouldRespondWith`
+        [json|{"personIDs": [1,2]}|]
         {matchStatus = 200}
 
-  describe "Any other endpoint" $ do
-    it "Respond with 404" $ do
-      property $ \endpoint ->
-        show endpoint /= "hello" ==>
-        get (pack endpoint) `shouldRespondWith` 404
-
-  where cfgLibro = libro $ Config def def
+  where lws = libro <$> initLiBroState cfg
+        cfg = Config (def {directory = "test/storage-files/data"}) def

From 751fc69df5a62ba850696da1fe3d2175f2bc2d61 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 14:24:17 +0100
Subject: [PATCH 17/28] Fix typos in default config

---
 .gitignore | 3 +++
 config.ini | 6 +++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/.gitignore b/.gitignore
index 18efc33..4caa3f7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,9 @@
 # LibreOffice swap files
 .~lock.*#
 
+# Data storage files
+data-storage/*.xlsx
+
 # Generated documentstion
 api-docs
 
diff --git a/config.ini b/config.ini
index 1ad8937..6bd6409 100644
--- a/config.ini
+++ b/config.ini
@@ -1,8 +1,8 @@
 [storage]
 directory     = data-storage
-person-file   = persons.csv
-tasks-file    = tasks.csv
-tracking-file = tracking.csv
+person-file   = persons.xlsx
+tasks-file    = tasks.xlsx
+tracking-file = tracking.xlsx
 
 [server]
 port = 8080

From 58441d230535d72c976fed1825313736f65f0f25 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 14:29:58 +0100
Subject: [PATCH 18/28] Add person details endpoint

---
 lib/LiBro/WebService.hs      | 10 +++++++++-
 test/LiBro/WebServiceSpec.hs |  6 ++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index 633efc3..8c625ac 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -3,6 +3,7 @@ module LiBro.WebService where
 import LiBro.Control
 import LiBro.Data
 import qualified Data.Map as M
+import Data.Map ((!))
 import Data.Aeson
 import Data.Proxy
 import Servant
@@ -17,11 +18,13 @@ type LiBroHandler = ReaderT LiBroState Handler
 runAction :: Action a -> LiBroHandler a
 runAction action = ask >>= liftIO . runReaderT action
 
-type LiBroAPI = "person":> Get '[JSON]      PersonIDs
+type LiBroAPI = "person"                        :> Get '[JSON]  PersonIDs
+          :<|>  "person"  :> Capture "pid" Int  :> Get '[JSON]  Person
           :<|>  "yay"   :> Get '[PlainText] String
 
 libroServer :: ServerT LiBroAPI LiBroHandler
 libroServer =     hPersonIDs
+            :<|>  hPersonDetails
             :<|>  handleYay
   where
         hPersonIDs :: LiBroHandler PersonIDs
@@ -29,6 +32,11 @@ libroServer =     hPersonIDs
           ps <- persons <$> runAction lsData
           return $ PersonIDs (M.keys ps)
 
+        hPersonDetails :: Int -> LiBroHandler Person
+        hPersonDetails pId = do
+          ps <- persons <$> runAction lsData
+          return $ ps ! pId
+
         handleYay :: LiBroHandler String
         handleYay = return "Yay!"
 
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 71654ec..dc9bb83 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -22,5 +22,11 @@ personSpecs = describe "Person related endpoints" $ with lws $ do
         [json|{"personIDs": [1,2]}|]
         {matchStatus = 200}
 
+  describe "Person details endpoint" $ do
+    it "Respond with correct details" $ do
+      get "/person/2" `shouldRespondWith`
+        [json|{"pid": 2, "name": "Baz Quux", "email": "baz@quux.com"}|]
+        {matchStatus = 200}
+
   where lws = libro <$> initLiBroState cfg
         cfg = Config (def {directory = "test/storage-files/data"}) def

From 3bea8362e461a4e50ae577ae7267bacf2f19167f Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 14:30:50 +0100
Subject: [PATCH 19/28] Remove dummy endpoint

---
 lib/LiBro/WebService.hs | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index 8c625ac..85dccf0 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -20,12 +20,10 @@ runAction action = ask >>= liftIO . runReaderT action
 
 type LiBroAPI = "person"                        :> Get '[JSON]  PersonIDs
           :<|>  "person"  :> Capture "pid" Int  :> Get '[JSON]  Person
-          :<|>  "yay"   :> Get '[PlainText] String
 
 libroServer :: ServerT LiBroAPI LiBroHandler
 libroServer =     hPersonIDs
             :<|>  hPersonDetails
-            :<|>  handleYay
   where
         hPersonIDs :: LiBroHandler PersonIDs
         hPersonIDs = do
@@ -37,9 +35,6 @@ libroServer =     hPersonIDs
           ps <- persons <$> runAction lsData
           return $ ps ! pId
 
-        handleYay :: LiBroHandler String
-        handleYay = return "Yay!"
-
 libroApi :: Proxy LiBroAPI
 libroApi = Proxy
 

From 10d5dcd3b4f0970c50b83ea9c0fdfc4347b98db3 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 14:42:23 +0100
Subject: [PATCH 20/28] Restructure web service endpoint tests

---
 test/LiBro/WebServiceSpec.hs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index dc9bb83..de97522 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -11,10 +11,10 @@ import Data.Default
 
 spec :: Spec
 spec = describe "RESTful JSON web service" $ do
-  personSpecs
+  listings
 
-personSpecs :: Spec
-personSpecs = describe "Person related endpoints" $ with lws $ do
+listings :: Spec
+listings = describe "Simple data listing endpoints" $ with lws $ do
 
   describe "Person ID listing endpoint" $ do
     it "Respond with IDs" $ do

From 1555f168112b9bd774f2b95a3c53db589f0cb1c6 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 14:47:36 +0100
Subject: [PATCH 21/28] Add top-level task ID listing endpoint

---
 lib/LiBro/WebService.hs      | 12 +++++++++++-
 test/LiBro/WebServiceSpec.hs |  6 ++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index 85dccf0..f095e72 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -4,14 +4,17 @@ import LiBro.Control
 import LiBro.Data
 import qualified Data.Map as M
 import Data.Map ((!))
+import Data.Tree
 import Data.Aeson
 import Data.Proxy
 import Servant
 import Control.Monad.Reader
 import GHC.Generics
 
-newtype PersonIDs = PersonIDs {personIDs :: [Int]} deriving Generic
+newtype PersonIDs = PersonIDs {personIDs  :: [Int]} deriving Generic
+newtype TaskIDs   = TaskIDs   {taskIDs    :: [Int]} deriving Generic
 instance ToJSON PersonIDs
+instance ToJSON TaskIDs
 
 type LiBroHandler = ReaderT LiBroState Handler
 
@@ -20,10 +23,12 @@ runAction action = ask >>= liftIO . runReaderT action
 
 type LiBroAPI = "person"                        :> Get '[JSON]  PersonIDs
           :<|>  "person"  :> Capture "pid" Int  :> Get '[JSON]  Person
+          :<|>  "task"                          :> Get '[JSON]  TaskIDs
 
 libroServer :: ServerT LiBroAPI LiBroHandler
 libroServer =     hPersonIDs
             :<|>  hPersonDetails
+            :<|>  hTaskIDs
   where
         hPersonIDs :: LiBroHandler PersonIDs
         hPersonIDs = do
@@ -35,6 +40,11 @@ libroServer =     hPersonIDs
           ps <- persons <$> runAction lsData
           return $ ps ! pId
 
+        hTaskIDs :: LiBroHandler TaskIDs
+        hTaskIDs = do
+          ts <- tasks <$> runAction lsData
+          return $ TaskIDs (tid . rootLabel <$> ts)
+
 libroApi :: Proxy LiBroAPI
 libroApi = Proxy
 
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index de97522..642f03d 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -28,5 +28,11 @@ listings = describe "Simple data listing endpoints" $ with lws $ do
         [json|{"pid": 2, "name": "Baz Quux", "email": "baz@quux.com"}|]
         {matchStatus = 200}
 
+  describe "Task ID listing endpoint" $ do
+    it "Respond with correct IDs" $ do
+      get "/task" `shouldRespondWith`
+        [json|{"taskIDs": [17]}|]
+        {matchStatus = 200}
+
   where lws = libro <$> initLiBroState cfg
         cfg = Config (def {directory = "test/storage-files/data"}) def

From 11167e9d295cf46446d5666f27edcc22e503c265 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 15:15:08 +0100
Subject: [PATCH 22/28] Improve listing endpoint test structure

---
 test/LiBro/WebServiceSpec.hs | 42 ++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 642f03d..f0d5d0a 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -14,25 +14,29 @@ spec = describe "RESTful JSON web service" $ do
   listings
 
 listings :: Spec
-listings = describe "Simple data listing endpoints" $ with lws $ do
-
-  describe "Person ID listing endpoint" $ do
-    it "Respond with IDs" $ do
-      get "/person" `shouldRespondWith`
-        [json|{"personIDs": [1,2]}|]
-        {matchStatus = 200}
-
-  describe "Person details endpoint" $ do
-    it "Respond with correct details" $ do
-      get "/person/2" `shouldRespondWith`
-        [json|{"pid": 2, "name": "Baz Quux", "email": "baz@quux.com"}|]
-        {matchStatus = 200}
-
-  describe "Task ID listing endpoint" $ do
-    it "Respond with correct IDs" $ do
-      get "/task" `shouldRespondWith`
-        [json|{"taskIDs": [17]}|]
-        {matchStatus = 200}
+listings = describe "Simple data listing" $ with lws $ do
+
+  context "Person listing endpoints" $ do
+
+    describe "ID listing" $ do
+      it "Correct IDs" $ do
+        get "/person" `shouldRespondWith`
+          [json|{"personIDs": [1,2]}|]
+          {matchStatus = 200}
+
+    describe "details" $ do
+      it "Correct details" $ do
+        get "/person/2" `shouldRespondWith`
+          [json|{"pid": 2, "name": "Baz Quux", "email": "baz@quux.com"}|]
+          {matchStatus = 200}
+
+  context "Task listing endpoints" $ do
+
+    describe "ID listing" $ do
+      it "Correct IDs" $ do
+        get "/task" `shouldRespondWith`
+          [json|{"taskIDs": [17]}|]
+          {matchStatus = 200}
 
   where lws = libro <$> initLiBroState cfg
         cfg = Config (def {directory = "test/storage-files/data"}) def

From 0a1aa2fb13e60b31ec1b9c0e0e3dfe681f7bfa9e Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 15:21:39 +0100
Subject: [PATCH 23/28] Handle bad person ID requests correctly

---
 lib/LiBro/WebService.hs      | 5 +++--
 test/LiBro/WebServiceSpec.hs | 4 ++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index f095e72..48bbe73 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -3,7 +3,6 @@ module LiBro.WebService where
 import LiBro.Control
 import LiBro.Data
 import qualified Data.Map as M
-import Data.Map ((!))
 import Data.Tree
 import Data.Aeson
 import Data.Proxy
@@ -38,7 +37,9 @@ libroServer =     hPersonIDs
         hPersonDetails :: Int -> LiBroHandler Person
         hPersonDetails pId = do
           ps <- persons <$> runAction lsData
-          return $ ps ! pId
+          case M.lookup pId ps of
+            Just p  -> return p
+            Nothing -> throwError err404 {errBody = "Person not found"}
 
         hTaskIDs :: LiBroHandler TaskIDs
         hTaskIDs = do
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index f0d5d0a..326dd9d 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -29,6 +29,10 @@ listings = describe "Simple data listing" $ with lws $ do
         get "/person/2" `shouldRespondWith`
           [json|{"pid": 2, "name": "Baz Quux", "email": "baz@quux.com"}|]
           {matchStatus = 200}
+      it "404 if person does not exist" $ do
+        get "/person/42" `shouldRespondWith`
+          "Person not found"
+          {matchStatus = 404}
 
   context "Task listing endpoints" $ do
 

From 35d67ce2da318b3dbd665f1ee7891cc7a1034d28 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Fri, 23 Feb 2024 15:50:53 +0100
Subject: [PATCH 24/28] Add tasks of a person endpoint

---
 lib/LiBro/WebService.hs      | 16 +++++++++++++---
 test/LiBro/WebServiceSpec.hs | 14 ++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index 48bbe73..45e7e7a 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -20,13 +20,16 @@ type LiBroHandler = ReaderT LiBroState Handler
 runAction :: Action a -> LiBroHandler a
 runAction action = ask >>= liftIO . runReaderT action
 
-type LiBroAPI = "person"                        :> Get '[JSON]  PersonIDs
-          :<|>  "person"  :> Capture "pid" Int  :> Get '[JSON]  Person
-          :<|>  "task"                          :> Get '[JSON]  TaskIDs
+type LiBroAPI =
+        "person"                                  :> Get '[JSON]  PersonIDs
+  :<|>  "person"  :> Capture "pid" Int            :> Get '[JSON]  Person
+  :<|>  "person"  :> Capture "pid" Int  :> "task" :> Get '[JSON]  TaskIDs
+  :<|>  "task"                                    :> Get '[JSON]  TaskIDs
 
 libroServer :: ServerT LiBroAPI LiBroHandler
 libroServer =     hPersonIDs
             :<|>  hPersonDetails
+            :<|>  hPersonTasks
             :<|>  hTaskIDs
   where
         hPersonIDs :: LiBroHandler PersonIDs
@@ -41,6 +44,13 @@ libroServer =     hPersonIDs
             Just p  -> return p
             Nothing -> throwError err404 {errBody = "Person not found"}
 
+        hPersonTasks :: Int -> LiBroHandler TaskIDs
+        hPersonTasks pId = do
+          d <- runAction lsData
+          case M.lookup pId (persons d) of
+            Just p  -> return $ TaskIDs (tid <$> assignedTasks p (tasks d))
+            Nothing -> throwError err404 {errBody = "Person not found"}
+
         hTaskIDs :: LiBroHandler TaskIDs
         hTaskIDs = do
           ts <- tasks <$> runAction lsData
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 326dd9d..5bab529 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -34,6 +34,20 @@ listings = describe "Simple data listing" $ with lws $ do
           "Person not found"
           {matchStatus = 404}
 
+    describe "tasks of a person" $ do
+      it "Correct tasks of person with 1 task" $ do
+        get "/person/1/task" `shouldRespondWith`
+          [json|{"taskIDs": [17]}|]
+          {matchStatus = 200}
+      it "Correct tasks of person with 2 task" $ do
+        get "/person/2/task" `shouldRespondWith`
+          [json|{"taskIDs": [17, 37]}|]
+          {matchStatus = 200}
+      it "404 if person does not exist" $ do
+        get "/person/42" `shouldRespondWith`
+          "Person not found"
+          {matchStatus = 404}
+
   context "Task listing endpoints" $ do
 
     describe "ID listing" $ do

From 9600bf3848f258971fb1edf2b882b2280e6a3a26 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Mon, 26 Feb 2024 17:20:07 +0100
Subject: [PATCH 25/28] Restructure and improve ID-only API

---
 lib/LiBro/WebService.hs      | 61 +++++++++++++++++---------------
 test/LiBro/WebServiceSpec.hs | 68 +++++++++++++++++++++++++-----------
 2 files changed, 80 insertions(+), 49 deletions(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index 45e7e7a..56374e8 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -10,51 +10,54 @@ import Servant
 import Control.Monad.Reader
 import GHC.Generics
 
-newtype PersonIDs = PersonIDs {personIDs  :: [Int]} deriving Generic
-newtype TaskIDs   = TaskIDs   {taskIDs    :: [Int]} deriving Generic
-instance ToJSON PersonIDs
-instance ToJSON TaskIDs
-
 type LiBroHandler = ReaderT LiBroState Handler
 
 runAction :: Action a -> LiBroHandler a
 runAction action = ask >>= liftIO . runReaderT action
 
+data PersonDetails = PersonDetails
+  { person      :: Person
+  , personTasks :: [Task]
+  } deriving Generic
+instance ToJSON PersonDetails
+
+-- JSON-friendly rewrite of Forest/Tree, their ToJSON instance is weird
+type TaskForest = [TaskTree]
+data TaskTree   = TaskTree
+  { task        :: Task
+  , subTasks    :: TaskForest
+  } deriving Generic
+instance ToJSON TaskTree
+
 type LiBroAPI =
-        "person"                                  :> Get '[JSON]  PersonIDs
-  :<|>  "person"  :> Capture "pid" Int            :> Get '[JSON]  Person
-  :<|>  "person"  :> Capture "pid" Int  :> "task" :> Get '[JSON]  TaskIDs
-  :<|>  "task"                                    :> Get '[JSON]  TaskIDs
+        "person"                        :> Get '[JSON]  [Person]
+  :<|>  "person"  :> Capture "pid" Int  :> Get '[JSON]  PersonDetails
+  :<|>  "task"                          :> Get '[JSON]  [Task]
+  :<|>  "task"    :> "tree"             :> Get '[JSON]  TaskForest
 
 libroServer :: ServerT LiBroAPI LiBroHandler
-libroServer =     hPersonIDs
+libroServer =     hPersonList
             :<|>  hPersonDetails
-            :<|>  hPersonTasks
-            :<|>  hTaskIDs
+            :<|>  hTaskTopLevelList
+            :<|>  hTaskFullForest
   where
-        hPersonIDs :: LiBroHandler PersonIDs
-        hPersonIDs = do
-          ps <- persons <$> runAction lsData
-          return $ PersonIDs (M.keys ps)
+        hPersonList :: LiBroHandler [Person]
+        hPersonList = M.elems . persons <$> runAction lsData
 
-        hPersonDetails :: Int -> LiBroHandler Person
+        hPersonDetails :: Int -> LiBroHandler PersonDetails
         hPersonDetails pId = do
-          ps <- persons <$> runAction lsData
-          case M.lookup pId ps of
-            Just p  -> return p
-            Nothing -> throwError err404 {errBody = "Person not found"}
-
-        hPersonTasks :: Int -> LiBroHandler TaskIDs
-        hPersonTasks pId = do
           d <- runAction lsData
           case M.lookup pId (persons d) of
-            Just p  -> return $ TaskIDs (tid <$> assignedTasks p (tasks d))
+            Just p  ->  let ts = assignedTasks p (tasks d)
+                        in  return $ PersonDetails p ts
             Nothing -> throwError err404 {errBody = "Person not found"}
 
-        hTaskIDs :: LiBroHandler TaskIDs
-        hTaskIDs = do
-          ts <- tasks <$> runAction lsData
-          return $ TaskIDs (tid . rootLabel <$> ts)
+        hTaskTopLevelList :: LiBroHandler [Task]
+        hTaskTopLevelList = map rootLabel . tasks <$> runAction lsData
+
+        hTaskFullForest :: LiBroHandler TaskForest
+        hTaskFullForest = map convert . tasks <$> runAction lsData
+          where convert (Node t sts) = TaskTree t (convert <$> sts)
 
 libroApi :: Proxy LiBroAPI
 libroApi = Proxy
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 5bab529..84ca4e9 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -18,31 +18,32 @@ listings = describe "Simple data listing" $ with lws $ do
 
   context "Person listing endpoints" $ do
 
-    describe "ID listing" $ do
-      it "Correct IDs" $ do
+    describe "Person listing" $ do
+      it "Correct list" $ do
         get "/person" `shouldRespondWith`
-          [json|{"personIDs": [1,2]}|]
+          [json|[
+            {"pid": 1,  "name": "Foo Bar",  "email": "foo@bar.com"},
+            {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+          ]|]
           {matchStatus = 200}
 
     describe "details" $ do
       it "Correct details" $ do
         get "/person/2" `shouldRespondWith`
-          [json|{"pid": 2, "name": "Baz Quux", "email": "baz@quux.com"}|]
+          [json|{
+            "person": {"pid": 2, "name": "Baz Quux", "email": "baz@quux.com"},
+            "personTasks": [
+              {"tid": 17, "title": "t17", "description": "d17", "assignees": [
+                {"pid": 1,  "name": "Foo Bar",  "email": "foo@bar.com"},
+                {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+              ]},
+              {"tid": 37, "title": "t37", "description": "d37", "assignees": [
+                {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+              ]}
+            ]
+          }|]
           {matchStatus = 200}
-      it "404 if person does not exist" $ do
-        get "/person/42" `shouldRespondWith`
-          "Person not found"
-          {matchStatus = 404}
 
-    describe "tasks of a person" $ do
-      it "Correct tasks of person with 1 task" $ do
-        get "/person/1/task" `shouldRespondWith`
-          [json|{"taskIDs": [17]}|]
-          {matchStatus = 200}
-      it "Correct tasks of person with 2 task" $ do
-        get "/person/2/task" `shouldRespondWith`
-          [json|{"taskIDs": [17, 37]}|]
-          {matchStatus = 200}
       it "404 if person does not exist" $ do
         get "/person/42" `shouldRespondWith`
           "Person not found"
@@ -50,10 +51,37 @@ listings = describe "Simple data listing" $ with lws $ do
 
   context "Task listing endpoints" $ do
 
-    describe "ID listing" $ do
-      it "Correct IDs" $ do
+    describe "Top level tasks" $ do
+      it "Correct list" $ do
         get "/task" `shouldRespondWith`
-          [json|{"taskIDs": [17]}|]
+          [json|[
+            {"tid": 17, "title": "t17", "description": "d17", "assignees": [
+              {"pid": 1,  "name": "Foo Bar",  "email": "foo@bar.com"},
+              {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+            ]}
+          ]|]
+          {matchStatus = 200}
+
+    describe "Full task hierarchy" $ do
+      it "Correct forest" $ do
+        get "/task/tree" `shouldRespondWith`
+          [json|[
+            { "task": {"tid": 17, "title": "t17", "description": "d17", "assignees": [
+                {"pid": 1,  "name": "Foo Bar",  "email": "foo@bar.com"},
+                {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+              ]},
+              "subTasks": [
+                { "task": {"tid": 37, "title": "t37", "description": "d37", "assignees": [
+                    {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+                  ]},
+                  "subTasks": []
+                },
+                { "task": {"tid": 42, "title": "t42", "description": "d42", "assignees": []},
+                  "subTasks": []
+                }
+              ]
+            }
+          ]|]
           {matchStatus = 200}
 
   where lws = libro <$> initLiBroState cfg

From b00490d37d03b68e73776cd35fdcfad410a667f1 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Tue, 27 Feb 2024 11:58:47 +0100
Subject: [PATCH 26/28] Add forest search to utilities

---
 lib/LiBro/Util.hs      | 10 +++++++++-
 test/LiBro/UtilSpec.hs | 26 ++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/lib/LiBro/Util.hs b/lib/LiBro/Util.hs
index e374501..99d2de4 100644
--- a/lib/LiBro/Util.hs
+++ b/lib/LiBro/Util.hs
@@ -2,9 +2,10 @@
 --    in more than one place.
 module LiBro.Util
   (
-  -- * Tree building
+  -- * Tree utilities
     ParentList
   , readForest
+  , findSubtree
   -- * Counting monad transformer
   , CountingT
   , next
@@ -59,6 +60,13 @@ readForest pairs =
                               Nothing -> []; Just [] -> []
                               Just xs -> fill cs <$> sort xs
 
+-- |  Find the first matching subtree of a forest
+findSubtree :: (a -> Bool) -> Forest a -> Maybe (Tree a)
+findSubtree p = asum . map findTree
+  where findTree t@(Node x cs)
+          | p x       = Just t
+          | otherwise = findSubtree p cs
+
 -- |  Simple monad transformer that allows to read an increasing 'Int'.
 type CountingT m = StateT Int m
 
diff --git a/test/LiBro/UtilSpec.hs b/test/LiBro/UtilSpec.hs
index ade6ee0..abbafb1 100644
--- a/test/LiBro/UtilSpec.hs
+++ b/test/LiBro/UtilSpec.hs
@@ -18,6 +18,7 @@ import System.IO.Temp
 spec :: Spec
 spec = describe "Helper stuff" $ do
   forestFromParentList
+  findInForest
   countingT
   xlsx
   guarding
@@ -35,6 +36,31 @@ forestFromParentList = describe "Read Forest from parent list" $ do
         , Node 42 [ Node 84 [ Node (168 :: Int) [] ]]
         ]
 
+findInForest :: Spec
+findInForest = describe "Find matching subtrees in a forest" $ do
+  let forest  = [ Node 2 [ Node 4 [Node 8 []], Node 6 [Node 12 [Node 24 []]]]
+                , Node 3 [ Node 6 [Node 12 []], Node 9 [Node 18 [], Node 27 []]]
+                , Node 5 [ Node 10 []]
+                ] :: Forest Int
+  -- runIO $ putStr $ drawForest $ map (fmap show) forest
+
+  context "Nothing to find" $ do
+    it "Get Nothing from empty forest" $
+      findSubtree even ([] :: Forest Int) `shouldBe` Nothing
+    it "Nothing matches" $
+      findSubtree (> 42) forest `shouldBe` Nothing
+
+  context "Finding subtrees" $ do
+    it "Catch-all predicate: first tree" $
+      findSubtree (const True) forest `shouldBe` Just (head forest)
+    it "Find the first '6' subtree" $
+      findSubtree (== 6) forest `shouldBe` Just (Node 6 [Node 12 [Node 24[]]])
+    it "Find the first odd subtree" $
+      findSubtree odd forest `shouldBe`
+        Just ( Node 3 [ Node 6 [Node 12 []]
+                      , Node 9 [Node 18 [], Node 27 []]
+                      ])
+
 countingT :: Spec
 countingT = describe "The CountingT 'monad transformer'" $ do
   let nextTimes n = replicateM n next

From 9f6a8c106208b459f59d27b77f24d6c82f08b5c7 Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Wed, 28 Feb 2024 11:24:42 +0100
Subject: [PATCH 27/28] Improve TaskForest handling

---
 lib/LiBro/WebService.hs | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index 56374e8..fe117f4 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -29,6 +29,12 @@ data TaskTree   = TaskTree
   } deriving Generic
 instance ToJSON TaskTree
 
+convertTaskTree :: Tree Task -> TaskTree
+convertTaskTree (Node t ts) = TaskTree t (convertTasksForest ts)
+
+convertTasksForest :: Tasks -> TaskForest
+convertTasksForest = map convertTaskTree
+
 type LiBroAPI =
         "person"                        :> Get '[JSON]  [Person]
   :<|>  "person"  :> Capture "pid" Int  :> Get '[JSON]  PersonDetails
@@ -56,8 +62,7 @@ libroServer =     hPersonList
         hTaskTopLevelList = map rootLabel . tasks <$> runAction lsData
 
         hTaskFullForest :: LiBroHandler TaskForest
-        hTaskFullForest = map convert . tasks <$> runAction lsData
-          where convert (Node t sts) = TaskTree t (convert <$> sts)
+        hTaskFullForest = convertTasksForest . tasks <$> runAction lsData
 
 libroApi :: Proxy LiBroAPI
 libroApi = Proxy

From 2efbea64451d2b37f77316cdd3ae4cbca60e50ea Mon Sep 17 00:00:00 2001
From: Mirko Westermeier <mirko.westermeier@uni-muenster.de>
Date: Wed, 28 Feb 2024 11:43:49 +0100
Subject: [PATCH 28/28] Add task subtree endpoint

---
 lib/LiBro/WebService.hs      | 10 ++++++++++
 test/LiBro/WebServiceSpec.hs | 37 ++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/lib/LiBro/WebService.hs b/lib/LiBro/WebService.hs
index fe117f4..08d4710 100644
--- a/lib/LiBro/WebService.hs
+++ b/lib/LiBro/WebService.hs
@@ -2,6 +2,7 @@ module LiBro.WebService where
 
 import LiBro.Control
 import LiBro.Data
+import LiBro.Util
 import qualified Data.Map as M
 import Data.Tree
 import Data.Aeson
@@ -40,12 +41,14 @@ type LiBroAPI =
   :<|>  "person"  :> Capture "pid" Int  :> Get '[JSON]  PersonDetails
   :<|>  "task"                          :> Get '[JSON]  [Task]
   :<|>  "task"    :> "tree"             :> Get '[JSON]  TaskForest
+  :<|>  "task"    :> Capture "tid" Int  :> Get '[JSON]  TaskTree
 
 libroServer :: ServerT LiBroAPI LiBroHandler
 libroServer =     hPersonList
             :<|>  hPersonDetails
             :<|>  hTaskTopLevelList
             :<|>  hTaskFullForest
+            :<|>  hTaskDetails
   where
         hPersonList :: LiBroHandler [Person]
         hPersonList = M.elems . persons <$> runAction lsData
@@ -64,6 +67,13 @@ libroServer =     hPersonList
         hTaskFullForest :: LiBroHandler TaskForest
         hTaskFullForest = convertTasksForest . tasks <$> runAction lsData
 
+        hTaskDetails :: Int -> LiBroHandler TaskTree
+        hTaskDetails tId = do
+          result <- findSubtree ((== tId) . tid) . tasks <$> runAction lsData
+          case result of
+            Just tree -> return $ convertTaskTree tree
+            Nothing   -> throwError err404 {errBody = "Task not found"}
+
 libroApi :: Proxy LiBroAPI
 libroApi = Proxy
 
diff --git a/test/LiBro/WebServiceSpec.hs b/test/LiBro/WebServiceSpec.hs
index 84ca4e9..733fe9d 100644
--- a/test/LiBro/WebServiceSpec.hs
+++ b/test/LiBro/WebServiceSpec.hs
@@ -84,5 +84,42 @@ listings = describe "Simple data listing" $ with lws $ do
           ]|]
           {matchStatus = 200}
 
+    describe "Subforest of a given task" $ do
+
+      it "Task is a leaf" $ do
+        get "/task/37" `shouldRespondWith`
+          [json|{
+            "task": {"tid": 37, "title": "t37", "description": "d37", "assignees": [
+                {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+            ]},
+            "subTasks": []
+          }|]
+          {matchStatus = 200}
+
+      it "Task is an inner node" $ do
+        get "/task/17" `shouldRespondWith`
+          [json|{
+            "task": {"tid": 17, "title": "t17", "description": "d17", "assignees": [
+              {"pid": 1,  "name": "Foo Bar",  "email": "foo@bar.com"},
+              {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+            ]},
+            "subTasks": [
+              { "task": {"tid": 37, "title": "t37", "description": "d37", "assignees": [
+                  {"pid": 2,  "name": "Baz Quux", "email": "baz@quux.com"}
+                ]},
+                "subTasks": []
+              },
+              { "task": {"tid": 42, "title": "t42", "description": "d42", "assignees": []},
+                "subTasks": []
+              }
+            ]
+          }|]
+          {matchStatus = 200}
+
+      it "404 if task does not exist" $ do
+        get "/task/666" `shouldRespondWith`
+          "Task not found"
+          {matchStatus = 404}
+
   where lws = libro <$> initLiBroState cfg
         cfg = Config (def {directory = "test/storage-files/data"}) def