{-# LANGUAGE CPP, OverloadedStrings, BangPatterns #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Haddock.Interface
-- Copyright   :  (c) Simon Marlow      2003-2006,
--                    David Waern       2006-2010,
--                    Mateusz Kowalczyk 2013
-- License     :  BSD-like
--
-- Maintainer  :  haddock@projects.haskell.org
-- Stability   :  experimental
-- Portability :  portable
--
-- This module typechecks Haskell modules using the GHC API and processes
-- the result to create 'Interface's. The typechecking and the 'Interface'
-- creation is interleaved, so that when a module is processed, the
-- 'Interface's of all previously processed modules are available. The
-- creation of an 'Interface' from a typechecked module is delegated to
-- "Haddock.Interface.Create".
--
-- When all modules have been typechecked and processed, information about
-- instances are attached to each 'Interface'. This task is delegated to
-- "Haddock.Interface.AttachInstances". Note that this is done as a separate
-- step because GHC can't know about all instances until all modules have been
-- typechecked.
--
-- As a last step a link environment is built which maps names to the \"best\"
-- places to link to in the documentation, and all 'Interface's are \"renamed\"
-- using this environment.
-----------------------------------------------------------------------------
module Haddock.Interface (
  processModules
) where


import Haddock.GhcUtils
import Haddock.InterfaceFile
import Haddock.Interface.Create
import Haddock.Interface.AttachInstances
import Haddock.Interface.Rename
import Haddock.Options hiding (verbosity)
import Haddock.Types
import Haddock.Utils

import Control.Monad
import Control.Exception (evaluate)
import Data.List
import qualified Data.Map as Map
import qualified Data.Set as Set
import Distribution.Verbosity
import Text.Printf

import GHC.Unit.Module.Env (mkModuleSet, emptyModuleSet, unionModuleSet, ModuleSet)
import GHC.Unit.Module.ModSummary
import GHC.Unit.Types
import GHC.Data.Graph.Directed
import GHC.Driver.Session hiding (verbosity)
import GHC hiding (verbosity)
import GHC.Driver.Env
import GHC.Data.FastString (unpackFS)
import GHC.Tc.Types (tcg_rdr_env)
import GHC.Types.Name (nameIsFromExternalPackage, nameOccName)
import GHC.Types.Name.Occurrence (isTcOcc)
import GHC.Types.Name.Reader (unQualOK, greMangledName, globalRdrEnvElts)
import GHC.Utils.Error (withTimingD)
import GHC.HsToCore.Docs

#if defined(mingw32_HOST_OS)
import System.IO
import GHC.IO.Encoding.CodePage (mkLocaleEncoding)
import GHC.IO.Encoding.Failure (CodingFailureMode(TransliterateCodingFailure))
#endif

-- | Create 'Interface's and a link environment by typechecking the list of
-- modules using the GHC API and processing the resulting syntax trees.
processModules
  :: Verbosity                  -- ^ Verbosity of logging to 'stdout'
  -> [String]                   -- ^ A list of file or module names sorted by
                                -- module topology
  -> [Flag]                     -- ^ Command-line flags
  -> [InterfaceFile]            -- ^ Interface files of package dependencies
  -> Ghc ([Interface], LinkEnv) -- ^ Resulting list of interfaces and renaming
                                -- environment
processModules verbosity modules flags extIfaces = do
#if defined(mingw32_HOST_OS)
  -- Avoid internal error: <stderr>: hPutChar: invalid argument (invalid character)' non UTF-8 Windows
  liftIO $ hSetEncoding stdout $ mkLocaleEncoding TransliterateCodingFailure
  liftIO $ hSetEncoding stderr $ mkLocaleEncoding TransliterateCodingFailure
#endif

  out verbosity verbose "Creating interfaces..."
  let instIfaceMap =  Map.fromList [ (instMod iface, iface) | ext <- extIfaces
                                   , iface <- ifInstalledIfaces ext ]
  (interfaces, ms) <- createIfaces verbosity modules flags instIfaceMap

  let exportedNames =
        Set.unions $ map (Set.fromList . ifaceExports) $
        filter (\i -> not $ OptHide `elem` ifaceOptions i) interfaces
      mods = Set.fromList $ map ifaceMod interfaces
  out verbosity verbose "Attaching instances..."
  interfaces' <- {-# SCC attachInstances #-}
                 withTimingD "attachInstances" (const ()) $ do
                   attachInstances (exportedNames, mods) interfaces instIfaceMap ms

  out verbosity verbose "Building cross-linking environment..."
  -- Combine the link envs of the external packages into one
  let extLinks  = Map.unions (map ifLinkEnv extIfaces)
      homeLinks = buildHomeLinks interfaces' -- Build the environment for the home
                                             -- package
      links     = homeLinks `Map.union` extLinks

  out verbosity verbose "Renaming interfaces..."
  let warnings = Flag_NoWarnings `notElem` flags
  dflags <- getDynFlags
  let (interfaces'', msgs) =
         runWriter $ mapM (renameInterface dflags links warnings) interfaces'
  liftIO $ mapM_ putStrLn msgs

  return (interfaces'', homeLinks)


--------------------------------------------------------------------------------
-- * Module typechecking and Interface creation
--------------------------------------------------------------------------------


createIfaces :: Verbosity -> [String] -> [Flag] -> InstIfaceMap -> Ghc ([Interface], ModuleSet)
createIfaces verbosity modules flags instIfaceMap = do
  -- Ask GHC to tell us what the module graph is
  targets <- mapM (\filePath -> guessTarget filePath Nothing) modules
  setTargets targets
  modGraph <- depanal [] False

  -- Visit modules in that order
  let sortedMods = flattenSCCs $ topSortModuleGraph False modGraph Nothing
  out verbosity normal "Haddock coverage:"
  (ifaces, _, !ms) <- foldM f ([], Map.empty, emptyModuleSet) sortedMods
  return (reverse ifaces, ms)
  where
    f (ifaces, ifaceMap, !ms) modSummary = do
      x <- {-# SCC processModule #-}
           withTimingD "processModule" (const ()) $ do
             processModule verbosity modSummary flags ifaceMap instIfaceMap
      return $ case x of
        Just (iface, ms') -> ( iface:ifaces
                             , Map.insert (ifaceMod iface) iface ifaceMap
                             , unionModuleSet ms ms' )
        Nothing           -> ( ifaces
                             , ifaceMap
                             , ms ) -- Boot modules don't generate ifaces.


processModule :: Verbosity -> ModSummary -> [Flag] -> IfaceMap -> InstIfaceMap -> Ghc (Maybe (Interface, ModuleSet))
processModule verbosity modsum flags modMap instIfaceMap = do
  out verbosity verbose $ "Checking module " ++ moduleString (ms_mod modsum) ++ "..."
  tm <- {-# SCC "parse/typecheck/load" #-} loadModule =<< typecheckModule =<< parseModule modsum

  case isBootSummary modsum of
    IsBoot ->
      return Nothing
    NotBoot -> do
      unit_state <- hsc_units <$> getSession
      out verbosity verbose "Creating interface..."
      (interface, msgs) <- {-# SCC createIterface #-}
                          withTimingD "createInterface" (const ()) $ do
                            runWriterGhc $ createInterface tm unit_state flags modMap instIfaceMap

      -- We need to keep track of which modules were somehow in scope so that when
      -- Haddock later looks for instances, it also looks in these modules too.
      --
      -- See https://github.com/haskell/haddock/issues/469.
      hsc_env <- getSession
      let new_rdr_env = tcg_rdr_env . fst . GHC.tm_internals_ $ tm
          home_unit = hsc_home_unit hsc_env
          !mods = mkModuleSet [ nameModule name
                              | gre <- globalRdrEnvElts new_rdr_env
                              , let name = greMangledName gre
                              , nameIsFromExternalPackage home_unit name
                              , isTcOcc (nameOccName name)   -- Types and classes only
                              , unQualOK gre ]               -- In scope unqualified

      liftIO $ mapM_ putStrLn (nub msgs)
      dflags <- getDynFlags
      let (haddockable, haddocked) = ifaceHaddockCoverage interface
          percentage = round (fromIntegral haddocked * 100 / fromIntegral haddockable :: Double) :: Int
          modString = moduleString (ifaceMod interface)
          coverageMsg = printf " %3d%% (%3d /%3d) in '%s'" percentage haddocked haddockable modString
          header = case ifaceDoc interface of
            Documentation Nothing _ -> False
            _ -> True
          undocumentedExports = [ formatName s n | ExportDecl { expItemDecl = L s n
                                                              , expItemMbDoc = (Documentation Nothing _, _)
                                                              } <- ifaceExportItems interface ]
            where
              formatName :: SrcSpan -> HsDecl GhcRn -> String
              formatName loc n = p (getMainDeclBinder n) ++ case loc of
                RealSrcSpan rss _ -> " (" ++ unpackFS (srcSpanFile rss) ++ ":" ++ show (srcSpanStartLine rss) ++ ")"
                _ -> ""

              p [] = ""
              p (x:_) = let n = pretty dflags x
                            ms = modString ++ "."
                        in if ms `isPrefixOf` n
                           then drop (length ms) n
                           else n

      when (OptHide `notElem` ifaceOptions interface) $ do
        out verbosity normal coverageMsg
        when (Flag_NoPrintMissingDocs `notElem` flags
              && not (null undocumentedExports && header)) $ do
          out verbosity normal "  Missing documentation for:"
          unless header $ out verbosity normal "    Module header"
          mapM_ (out verbosity normal . ("    " ++)) undocumentedExports
      interface' <- liftIO $ evaluate interface
      return (Just (interface', mods))


--------------------------------------------------------------------------------
-- * Building of cross-linking environment
--------------------------------------------------------------------------------


-- | Build a mapping which for each original name, points to the "best"
-- place to link to in the documentation.  For the definition of
-- "best", we use "the module nearest the bottom of the dependency
-- graph which exports this name", not including hidden modules.  When
-- there are multiple choices, we pick a random one.
--
-- The interfaces are passed in in topologically sorted order, but we start
-- by reversing the list so we can do a foldl.
buildHomeLinks :: [Interface] -> LinkEnv
buildHomeLinks ifaces = foldl upd Map.empty (reverse ifaces)
  where
    upd old_env iface
      | OptHide    `elem` ifaceOptions iface = old_env
      | OptNotHome `elem` ifaceOptions iface =
        foldl' keep_old old_env exported_names
      | otherwise = foldl' keep_new old_env exported_names
      where
        exported_names = ifaceVisibleExports iface ++ map getName (ifaceInstances iface)
        mdl            = ifaceMod iface
        keep_old env n = Map.insertWith (\_ old -> old) n mdl env
        keep_new env n = Map.insert n mdl env