Beginning of refactor

Start a refactor to better organize the code in this repo. This change
also begins addressing error reporting stuff described in #23, #47, and
#46. It also adds rudimentary timing information so we know how long
different phases take.

elm-make.cabal

@@ -40,14 +40,14 @@ Executable elm-make
         Main.hs
 
     other-modules:
-        Arguments,
-        Build,
-        CrawlPackage,
-        CrawlProject,
-        Generate,
-        LoadInterfaces,
+        Flags,
         Path,
         Paths_elm_make,
+        Pipeline.Compile,
+        Pipeline.Crawl,
+        Pipeline.Crawl.Package,
+        Pipeline.Generate,
+        Pipeline.Plan,
         Report,
         TheMasterPlan,
         Utils.File,
@@ -68,4 +68,5 @@ Executable elm-make
         filepath,
         mtl >= 2.2.1 && < 3,
         optparse-applicative >=0.11 && <0.12,
+        time,
         text

src/BuildManager.hs

@@ -0,0 +1,203 @@
+{-# OPTIONS_GHC -Wall #-}
+module BuildManager where
+
+import Control.Monad.Except (ExceptT, runExceptT)
+import Control.Monad.State (StateT, liftIO, runStateT)
+import qualified Control.Monad.State as State
+import qualified Data.Time.Clock.POSIX as Time
+import qualified Elm.Compiler as Compiler
+import qualified Elm.Compiler.Module as Module
+import qualified Elm.Package.Name as Pkg
+import qualified Elm.Package.Paths as Path
+import System.FilePath ((</>))
+
+import qualified Report
+import qualified TheMasterPlan as TMP
+
+
+-- CONFIGURATION
+
+data Config = Config
+    { _artifactDirectory :: FilePath
+    , _files :: [FilePath]
+    , _output :: Output
+    , _autoYes :: Bool
+    , _reportType :: Report.Type
+    , _warn :: Bool
+    , _docs :: Maybe FilePath
+    }
+
+
+data Output
+    = Html FilePath
+    | JS FilePath
+
+
+outputFilePath :: Config -> FilePath
+outputFilePath config =
+  case _output config of
+    Html file -> file
+    JS file -> file
+
+
+artifactDirectory :: FilePath
+artifactDirectory =
+    Path.stuffDirectory </> "build-artifacts"
+
+
+-- RUN A BUILD
+
+type Task a =
+  ExceptT Error (StateT [Phase] IO) a
+
+
+run :: Task a -> IO (Either Error (a, Timeline))
+run task =
+  do  result <-
+          runStateT (runExceptT (phase "elm-make" task)) []
+      case result of
+        (Right answer, [Phase _ start phases end]) ->
+            return (Right (answer, Timeline start phases end))
+
+        (Left err, _) ->
+            return (Left err)
+
+
+-- TIMELINE
+
+data Timeline = Timeline
+    { _start :: Time.POSIXTime
+    , _phases :: [Phase]
+    , _end :: Time.POSIXTime
+    }
+
+
+data Phase = Phase
+    { _tag :: String
+    , _start_ :: Time.POSIXTime
+    , _subphases :: [Phase]
+    , _end_ :: Time.POSIXTime
+    }
+
+
+phase :: String -> Task a -> Task a
+phase name task =
+  do  phasesSoFar <- State.get
+      State.put []
+      start <- liftIO Time.getPOSIXTime
+      result <- task
+      end <- liftIO Time.getPOSIXTime
+      State.modify' (\phases -> Phase name start (reverse phases) end : phasesSoFar)
+      return result
+
+
+timelineToString :: Timeline -> String
+timelineToString (Timeline start phases end) =
+  let
+    duration = end - start
+  in
+    "\nOverall time: " ++ show duration ++ "\n"
+    ++ concatMap (phaseToString duration 1) phases
+    ++ "\n"
+
+
+phaseToString :: Time.POSIXTime -> Int -> Phase -> String
+phaseToString overallDuration indent (Phase tag start subphases end) =
+  let
+    duration = end - start
+    percent = truncate (100 * duration / overallDuration) :: Int
+  in
+    '\n' : replicate (indent * 4) ' ' ++ show percent ++ "% - " ++ tag
+    ++ concatMap (phaseToString duration (indent + 1)) subphases
+
+
+-- ERRORS
+
+data Error
+    = BadFlags
+    | CompilerErrors FilePath String [Compiler.Error]
+    | CorruptedArtifact FilePath
+    | Cycle [TMP.CanonicalModule]
+    | PackageProblem String
+    | MissingPackage Pkg.Name
+    | ModuleNotFound Module.Name (Maybe Module.Name)
+    | ModuleDuplicates
+        { _name :: Module.Name
+        , _parent :: Maybe Module.Name
+        , _local :: [FilePath]
+        , _foreign :: [Pkg.Name]
+        }
+    | ModuleName
+        { _path :: FilePath
+        , _expectedName :: Module.Name
+        , _actualName :: Module.Name
+        }
+
+
+errorToString :: Error -> String
+errorToString err =
+  case err of
+    BadFlags ->
+        error "TODO bad flags"
+
+    CompilerErrors _ _ _ ->
+        error "TODO"
+
+    CorruptedArtifact filePath ->
+        concat
+          [ "Error reading build artifact ", filePath, "\n"
+          , "    The file was generated by a previous build and may be outdated or corrupt.\n"
+          , "    Please remove the file and try again."
+          ]
+
+    Cycle moduleCycle ->
+        "Your dependencies form a cycle:\n\n"
+        ++ error "TODO" moduleCycle
+        ++ "\nYou may need to move some values to a new module to get rid of the cycle."
+
+    PackageProblem msg ->
+        msg
+
+    MissingPackage name ->
+        error "TODO" name
+
+    ModuleNotFound name maybeParent ->
+        unlines
+        [ "Error when searching for modules" ++ toContext maybeParent ++ ":"
+        , "    Could not find module '" ++ Module.nameToString name ++ "'"
+        , ""
+        , "Potential problems could be:"
+        , "  * Misspelled the module name"
+        , "  * Need to add a source directory or new dependency to " ++ Path.description
+        ]
+
+    ModuleDuplicates name maybeParent filePaths pkgs ->
+        "Error when searching for modules" ++ toContext maybeParent ++ ".\n" ++
+        "Found multiple modules named '" ++ Module.nameToString name ++ "'\n" ++
+        "Modules with that name were found in the following locations:\n\n" ++
+        concatMap (\str -> "    " ++ str ++ "\n") (paths ++ packages)
+      where
+        packages =
+            map ("package " ++) (map Pkg.toString pkgs)
+
+        paths =
+            map ("directory " ++) filePaths
+
+    ModuleName path nameFromPath nameFromSource ->
+        unlines
+          [ "The module name is messed up for " ++ path
+          , "    According to the file's name it should be " ++ Module.nameToString nameFromPath
+          , "    According to the source code it should be " ++ Module.nameToString nameFromSource
+          , "Which is it?"
+          ]
+
+
+toContext :: Maybe Module.Name -> String
+toContext maybeParent =
+  case maybeParent of
+    Nothing ->
+        " exposed by " ++ Path.description
+
+    Just parent ->
+        " imported by module '" ++ Module.nameToString parent ++ "'"
+