{-# LANGUAGE CPP #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE Trustworthy #-}

-- |
-- Module      : Criterion.Report
-- Copyright   : (c) 2009-2014 Bryan O'Sullivan
--
-- License     : BSD-style
-- Maintainer  : bos@serpentine.com
-- Stability   : experimental
-- Portability : GHC
--
-- Reporting functions.

module Criterion.Report
    (
      formatReport
    , report
    , tidyTails
    -- * Rendering helper functions
    , TemplateException(..)
    , loadTemplate
    , includeFile
    , getTemplateDir
    , vector
    , vector2
    ) where

import Control.Exception (Exception, IOException, throwIO)
import Control.Monad (mplus, unless)
import Control.Monad.IO.Class (MonadIO(liftIO))
import Control.Monad.Reader (ask)
import Criterion.Monad (Criterion)
import Criterion.Types
import Data.Aeson (ToJSON (..), Value(..), object, (.=), Value, encode)
import Data.Data (Data, Typeable)
import Data.Foldable (forM_)
import GHC.Generics (Generic)
import Paths_criterion (getDataFileName)
import Statistics.Function (minMax)
import Statistics.Types (confidenceInterval, confidenceLevel, confIntCL, estError)
import System.Directory (doesFileExist)
import System.FilePath ((</>), (<.>), isPathSeparator)
import System.IO (hPutStrLn, stderr)
import Text.Microstache (Key (..), MustacheWarning (..), Node (..), Template (..),
                         compileMustacheText, displayMustacheWarning, renderMustacheW)
import Prelude ()
import Prelude.Compat
import qualified Control.Exception as E
import qualified Data.Text as T
import qualified Data.Text.Lazy.Encoding as TLE
import qualified Data.Text.IO as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.Lazy.IO as TL
import qualified Data.Vector.Generic as G
import qualified Data.Vector.Unboxed as U

#if defined(EMBED)
import Criterion.EmbeddedData (dataFiles, jQueryContents, flotContents,
                               flotErrorbarsContents, flotNavigateContents)
import qualified Data.ByteString.Lazy as BL
import qualified Data.Text.Encoding as TE
#else
import qualified Language.Javascript.Flot as Flot
import qualified Language.Javascript.JQuery as JQuery
#endif

-- | Trim long flat tails from a KDE plot.
tidyTails :: KDE -> KDE
tidyTails KDE{..} = KDE { kdeType   = kdeType
                        , kdeValues = G.slice front winSize kdeValues
                        , kdePDF    = G.slice front winSize kdePDF
                        }
  where tiny     = uncurry subtract (minMax kdePDF) * 0.005
        omitTiny = G.length . G.takeWhile ((<= tiny) . abs)
        front    = omitTiny kdePDF
        back     = omitTiny . G.reverse $ kdePDF
        winSize  = G.length kdePDF - front - back

-- | Return the path to the template and other files used for
-- generating reports.
--
-- When the @-fembed-data-files@ @Cabal@ flag is enabled, this simply
-- returns the empty path.
getTemplateDir :: IO FilePath
#if defined(EMBED)
getTemplateDir = pure ""
#else
getTemplateDir = getDataFileName "templates"
#endif

-- | Write out a series of 'Report' values to a single file, if
-- configured to do so.
report :: [Report] -> Criterion ()
report reports = do
  Config{..} <- ask
  forM_ reportFile $ \name -> liftIO $ do
    td <- getTemplateDir
    tpl <- loadTemplate [td,"."] template
    TL.writeFile name =<< formatReport reports tpl

-- | Format a series of 'Report' values using the given Mustache template.
formatReport :: [Report]
             -> TL.Text    -- ^ Mustache template.
             -> IO TL.Text
formatReport reports templateName = do
    template0 <- case compileMustacheText "tpl" templateName of
        Left err -> fail (show err) -- TODO: throw a template exception?
        Right x -> return x

    jQuery            <- jQueryFileContents
    flot              <- flotFileContents
    flotErrorbars     <- flotErrorbarsFileContents
    flotNavigate      <- flotNavigateFileContents
    jQueryCriterionJS <- readDataFile ("js" </> "jquery.criterion.js")
    criterionCSS      <- readDataFile "criterion.css"

    -- includes, only top level
    templates <- getTemplateDir
    template <- includeTemplate (includeFile [templates]) template0

    let context = object
            [ "json"                .= reports
            , "report"              .= map inner reports
            , "js-jquery"           .= jQuery
            , "js-flot"             .= flot
            , "js-flot-errorbars"   .= flotErrorbars
            , "js-flot-navigate"    .= flotNavigate
            , "jquery-criterion-js" .= jQueryCriterionJS
            , "criterion-css"       .= criterionCSS
            ]

    let (warnings, formatted) = renderMustacheW template context
    -- If there were any issues during mustache template rendering, make sure
    -- to inform the user. See #127.
    forM_ warnings $ \warning -> do
      -- The one thing we choose not to warn about is substituting in the `json`
      -- key. The reason is that `json` is used in:
      --
      --   var reports = {{{json}}};
      --
      -- So `json` represents a raw JavaScript array. This is a bit skeevy by
      -- mustache conventions, but redesigning the template to avoid this
      -- warning would be more work than just substituting the array directly.
      unless (warning == MustacheDirectlyRenderedValue (Key ["json"])) $
        mapM_ (hPutStrLn stderr)
         [ "criterion: warning:"
         , "  " ++ displayMustacheWarning warning
         , ""
         ]
    return formatted
  where
    jQueryFileContents, flotFileContents :: IO T.Text
#if defined(EMBED)
    jQueryFileContents        = pure $ TE.decodeUtf8 jQueryContents
    flotFileContents          = pure $ TE.decodeUtf8 flotContents
    flotErrorbarsFileContents = pure $ TE.decodeUtf8 flotErrorbarsContents
    flotNavigateFileContents  = pure $ TE.decodeUtf8 flotNavigateContents
#else
    jQueryFileContents        = T.readFile =<< JQuery.file
    flotFileContents          = T.readFile =<< Flot.file Flot.Flot
    flotErrorbarsFileContents = T.readFile =<< Flot.file Flot.FlotErrorbars
    flotNavigateFileContents  = T.readFile =<< Flot.file Flot.FlotNavigate
#endif

    readDataFile :: FilePath -> IO T.Text
    readDataFile fp =
      (T.readFile =<< getDataFileName ("templates" </> fp))
#if defined(EMBED)
      `E.catch` \(e :: IOException) ->
        maybe (throwIO e)
              (pure . TE.decodeUtf8)
              (lookup fp dataFiles)
#endif

    includeTemplate :: (FilePath -> IO T.Text) -> Template -> IO Template
    includeTemplate f Template {..} = fmap
        (Template templateActual)
        (traverse (traverse (includeNode f)) templateCache)

    includeNode :: (FilePath -> IO T.Text) -> Node -> IO Node
    includeNode f (Section (Key ["include"]) [TextBlock fp]) =
        fmap TextBlock (f (T.unpack fp))
    includeNode _ n = return n

    -- Merge Report with it's analysis and outliers
    merge :: ToJSON a => a -> Value -> Value
    merge x y = case toJSON x of
        Object x' -> case y of
            Object y' -> Object (x' <> y')
            _         -> y
        _         -> y

    inner r@Report {..} = merge reportAnalysis $ merge reportOutliers $ object
        [ "name"                  .= reportName
        , "json"                  .= TLE.decodeUtf8 (encode r)
        , "number"                .= reportNumber
        , "iters"                 .= vector "x" iters
        , "times"                 .= vector "x" times
        , "cycles"                .= vector "x" cycles
        , "kdetimes"              .= vector "x" kdeValues
        , "kdepdf"                .= vector "x" kdePDF
        , "kde"                   .= vector2 "time" "pdf" kdeValues kdePDF
        , "anMeanConfidenceLevel" .= anMeanConfidenceLevel
        , "anMeanLowerBound"      .= anMeanLowerBound
        , "anMeanUpperBound"      .= anMeanUpperBound
        , "anStdDevLowerBound"    .= anStdDevLowerBound
        , "anStdDevUpperBound"    .= anStdDevUpperBound
        ]
      where
        [KDE{..}]          = reportKDEs
        SampleAnalysis{..} = reportAnalysis

        iters  = measure measIters reportMeasured
        times  = measure measTime reportMeasured
        cycles = measure measCycles reportMeasured
        anMeanConfidenceLevel
               = confidenceLevel $ confIntCL $ estError anMean
        (anMeanLowerBound, anMeanUpperBound)
               = confidenceInterval anMean
        (anStdDevLowerBound, anStdDevUpperBound)
               = confidenceInterval anStdDev

-- | Render the elements of a vector.
--
-- It will substitute each value in the vector for @x@ in the
-- following Mustache template:
--
-- > {{#foo}}
-- >  {{x}}
-- > {{/foo}}
vector :: (G.Vector v a, ToJSON a) =>
          T.Text                -- ^ Name to use when substituting.
       -> v a
       -> Value
{-# SPECIALIZE vector :: T.Text -> U.Vector Double -> Value #-}
vector name v = toJSON . map val . G.toList $ v where
    val i = object [ name .= i ]

-- | Render the elements of two vectors.
vector2 :: (G.Vector v a, G.Vector v b, ToJSON a, ToJSON b) =>
           T.Text               -- ^ Name for elements from the first vector.
        -> T.Text               -- ^ Name for elements from the second vector.
        -> v a                  -- ^ First vector.
        -> v b                  -- ^ Second vector.
        -> Value
{-# SPECIALIZE vector2 :: T.Text -> T.Text -> U.Vector Double -> U.Vector Double
                       -> Value #-}
vector2 name1 name2 v1 v2 = toJSON $ zipWith val (G.toList v1) (G.toList v2) where
    val i j = object
        [ name1 .= i
        , name2 .= j
        ]

-- | Attempt to include the contents of a file based on a search path.
-- Returns 'B.empty' if the search fails or the file could not be read.
--
-- Intended for preprocessing Mustache files, e.g. replacing sections
--
-- @
-- {{#include}}file.txt{{/include}
-- @
--
-- with file contents.
includeFile :: (MonadIO m) =>
               [FilePath]       -- ^ Directories to search.
            -> FilePath         -- ^ Name of the file to search for.
            -> m T.Text
{-# SPECIALIZE includeFile :: [FilePath] -> FilePath -> IO T.Text #-}
includeFile searchPath name = liftIO $ foldr go (return T.empty) searchPath
    where go dir next = do
            let path = dir </> name
            T.readFile path `E.catch` \(_::IOException) -> next

-- | A problem arose with a template.
data TemplateException =
    TemplateNotFound FilePath   -- ^ The template could not be found.
    deriving (Eq, Read, Show, Typeable, Data, Generic)

instance Exception TemplateException

-- | Load a Mustache template file.
--
-- If the name is an absolute or relative path, the search path is
-- /not/ used, and the name is treated as a literal path.
--
-- If the @-fembed-data-files@ @Cabal@ flag is enabled, this also checks
-- the embedded @data-files@ from @criterion.cabal@.
--
-- This function throws a 'TemplateException' if the template could
-- not be found, or an 'IOException' if no template could be loaded.
loadTemplate :: [FilePath]      -- ^ Search path.
             -> FilePath        -- ^ Name of template file.
             -> IO TL.Text
loadTemplate paths name
    | any isPathSeparator name = readFileCheckEmbedded name
    | otherwise                = go Nothing paths
  where go me (p:ps) = do
          let cur = p </> name <.> "tpl"
          x <- doesFileExist' cur
          if x
            then readFileCheckEmbedded cur `E.catch` \e -> go (me `mplus` Just e) ps
            else go me ps
        go (Just e) _ = throwIO (e::IOException)
        go _        _ = throwIO . TemplateNotFound $ name

        doesFileExist' :: FilePath -> IO Bool
        doesFileExist' fp = do
          e <- doesFileExist fp
          pure $ e
#if defined(EMBED)
                 || (fp `elem` map fst dataFiles)
#endif

-- A version of 'readFile' that falls back on the embedded 'dataFiles'
-- from @criterion.cabal@.
readFileCheckEmbedded :: FilePath -> IO TL.Text
readFileCheckEmbedded fp =
  TL.readFile fp
#if defined(EMBED)
  `E.catch` \(e :: IOException) ->
    maybe (throwIO e)
          (pure . TLE.decodeUtf8 . BL.fromStrict)
          (lookup fp dataFiles)
#endif
