--src/Core.hs

data Pipeline
    = Pipeline
        { steps :: [Step]
        }
    deriving (Eq, Show)

data Step 
    = Step
        { name :: StepName 
        , commands :: [String]
        , image :: Image
        }
        deriving (Eq, Show)

data Build
    = Build
        { pipeline :: Pipeline
        , state :: BuildState
        }
    deriving (Eq, Show)

data BuildState 
    = BuildReady
    | BuildRunning
    | BuildFinished BuildResult
    deriving (Eq, Show)

data BuildResult
    = BuildSucceeded
    | BuildFailed
    deriving (Eq, Show)

newtype StepName = StepName String
    deriving (Eq, Show)

newtype Image = Image String
    deriving (Eq, Show)

-- test/Spec.hs

-- Helper functions
makeStep :: String -> String -> [String] -> Step
makeStep name image commands
    = Step
        { name = StepName name
        , image = Image image
        , commands = commands
        }

makePipeline :: [Step] -> Pipeline
makePipeline steps =
    Pipeline { steps = steps }

-- Test values
testPipeline :: Pipeline
testPipeline = makePipeline
    [ makeStep "First step" "ubuntu" ["date"]
    , makeStep "Second step" "ubuntu" ["uname -r"]
    ]

testBuild :: Build
testBuild = Build
    { pipeline = testPipeline
    , state = BuildReady
    }

main :: IO ()
main = do
  putStrLn (show testBuild)