{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE OverloadedStrings #-}

-- | Reporting on performance, potentially checking versus a canned results.
module Perf.Report
  ( Format (..),
    parseFormat,
    Header (..),
    parseHeader,
    CompareLevels (..),
    defaultCompareLevels,
    parseCompareLevels,
    ReportConfig (..),
    defaultReportConfig,
    parseReportConfig,
    writeResult,
    readResult,
    CompareResult (..),
    compareNote,
    outercalate,
    reportGolden,
    reportOrg2D,
    Golden (..),
    parseGolden,
    report,
  )
where

import Control.Monad
import Data.Bool
import Data.Foldable
import Data.FormatN hiding (format)
import qualified Data.List as List
import Data.Map.Merge.Strict
import qualified Data.Map.Strict as Map
import Data.Text (Text)
import qualified Data.Text as Text
import qualified Data.Text.IO as Text
import GHC.Generics
import Options.Applicative
import Text.Printf hiding (parseFormat)

-- | Type of format for report
data Format = OrgMode | ConsoleMode deriving (Eq, Show, Generic)

-- | Command-line parser for 'Format'
parseFormat :: Format -> Parser Format
parseFormat f =
  flag' OrgMode (long "orgmode" <> help "report using orgmode table format")
    <|> flag' ConsoleMode (long "console" <> help "report using plain table format")
    <|> pure f

-- | Whether to include header information.
data Header = Header | NoHeader deriving (Eq, Show, Generic)

-- | Command-line parser for 'Header'
parseHeader :: Header -> Parser Header
parseHeader h =
  flag' Header (long "header" <> help "include headers")
    <|> flag' NoHeader (long "noheader" <> help "dont include headers")
    <|> pure h

-- | Levels of geometric difference in compared performance that triggers reporting.
data CompareLevels = CompareLevels {errorLevel :: Double, warningLevel :: Double, improvedLevel :: Double} deriving (Eq, Show)

-- |
-- >>> defaultCompareLevels
-- CompareLevels {errorLevel = 0.2, warningLevel = 5.0e-2, improvedLevel = 5.0e-2}
defaultCompareLevels :: CompareLevels
defaultCompareLevels = CompareLevels 0.2 0.05 0.05

-- | Command-line parser for 'CompareLevels'
parseCompareLevels :: CompareLevels -> Parser CompareLevels
parseCompareLevels c =
  CompareLevels
    <$> option auto (value (errorLevel c) <> long "error" <> help "error level")
    <*> option auto (value (warningLevel c) <> long "warning" <> help "warning level")
    <*> option auto (value (improvedLevel c) <> long "improved" <> help "improved level")

-- | Report configuration options
data ReportConfig = ReportConfig
  { format :: Format,
    includeHeader :: Header,
    levels :: CompareLevels
  }
  deriving (Eq, Show, Generic)

-- |
-- >>> defaultReportConfig
-- ReportConfig {format = ConsoleMode, includeHeader = Header, levels = CompareLevels {errorLevel = 0.2, warningLevel = 5.0e-2, improvedLevel = 5.0e-2}}
defaultReportConfig :: ReportConfig
defaultReportConfig = ReportConfig ConsoleMode Header defaultCompareLevels

-- | Parse 'ReportConfig' command line options.
parseReportConfig :: ReportConfig -> Parser ReportConfig
parseReportConfig c =
  ReportConfig
    <$> parseFormat (format c)
    <*> parseHeader (includeHeader c)
    <*> parseCompareLevels (levels c)

-- | Write results to file
writeResult :: FilePath -> Map.Map [Text] Double -> IO ()
writeResult f m = writeFile f (show m)

-- | Read results from file
readResult :: FilePath -> IO (Map.Map [Text] Double)
readResult f = do
  a <- readFile f
  pure (read a)

-- | Comparison data between two results.
data CompareResult = CompareResult {oldResult :: Maybe Double, newResult :: Maybe Double, noteResult :: Text} deriving (Show, Eq)

-- | Compare two results and produce some notes given level triggers.
compareNote :: (Ord a) => CompareLevels -> Map.Map a Double -> Map.Map a Double -> Map.Map a CompareResult
compareNote cfg x y =
  merge
    (mapMissing (\_ x' -> CompareResult Nothing (Just x') "new result"))
    (mapMissing (\_ x' -> CompareResult (Just x') Nothing "old result not found"))
    ( zipWithMatched
        ( \_ x' y' ->
            CompareResult (Just x') (Just y') (note' x' y')
        )
    )
    x
    y
  where
    note' x' y'
      | y' / x' > 1 + errorLevel cfg = "degraded"
      | y' / x' > 1 + warningLevel cfg = "slightly-degraded"
      | y' / x' < (1 - improvedLevel cfg) = "improvement"
      | otherwise = ""

-- | Like intercalate, but on the outside as well.
outercalate :: Text -> [Text] -> Text
outercalate c ts = c <> Text.intercalate c ts <> c

-- | Report to a console, comparing the measurement versus a canned file.
reportGolden :: ReportConfig -> FilePath -> Map.Map [Text] Double -> IO ()
reportGolden cfg f m = do
  mOrig <- readResult f
  let n = compareNote (levels cfg) mOrig m
  reportToConsole $ formatCompare (format cfg) (includeHeader cfg) n

-- | Org-mode style header.
formatOrgHeader :: Map.Map [Text] a -> [Text] -> [Text]
formatOrgHeader m ts =
  [ outercalate "|" ((("label" <>) . Text.pack . show <$> [1 .. labelCols]) <> ts),
    outercalate "|" (replicate (labelCols + 1) "---")
  ]
  where
    labelCols = maximum $ length <$> Map.keys m

-- | Console-style header information.
formatConsoleHeader :: Map.Map [Text] a -> [Text] -> [Text]
formatConsoleHeader m ts =
  [mconcat $ Text.pack . printf "%-20s" <$> ((("label" <>) . Text.pack . show <$> [1 .. labelCols]) <> ts), mempty]
  where
    labelCols = maximum $ length <$> Map.keys m

-- | Format a comparison.
formatCompare :: Format -> Header -> Map.Map [Text] CompareResult -> [Text]
formatCompare f h m =
  case f of
    OrgMode ->
      bool [] (formatOrgHeader m ["old_result", "new_result", "status"]) (h == Header)
        <> Map.elems (Map.mapWithKey (\k a -> outercalate "|" (k <> compareReport a)) m)
    ConsoleMode ->
      bool [] (formatConsoleHeader m ["old_result", "new_result", "status"]) (h == Header)
        <> Map.elems (Map.mapWithKey (\k a -> Text.pack . mconcat $ printf "%-20s" <$> (k <> compareReport a)) m)
  where
    compareReport (CompareResult x y n) =
      [ maybe mempty (expt (Just 3)) x,
        maybe mempty (expt (Just 3)) y,
        n
      ]

-- | Format a result in org-mode style
formatOrg :: Header -> Map.Map [Text] Text -> [Text]
formatOrg h m =
  bool [] (formatOrgHeader m ["results"]) (h == Header)
    <> Map.elems (Map.mapWithKey (\k a -> outercalate "|" (k <> [a])) m)

-- | Format a result in console-style
formatConsole :: Header -> Map.Map [Text] Text -> [Text]
formatConsole h m =
  bool [] (formatConsoleHeader m ["results"]) (h == Header)
    <> Map.elems (Map.mapWithKey (\k a -> Text.pack . mconcat $ printf "%-20s" <$> (k <> [a])) m)

-- | Format a result as a table.
reportOrg2D :: Map.Map [Text] Text -> IO ()
reportOrg2D m = do
  let rs = List.nub ((List.!! 1) . fst <$> Map.toList m)
  let cs = List.nub ((List.!! 0) . fst <$> Map.toList m)
  Text.putStrLn ("||" <> Text.intercalate "|" rs <> "|")
  mapM_
    ( \c ->
        Text.putStrLn
          ( "|"
              <> c
              <> "|"
              <> Text.intercalate "|" ((\r -> m Map.! [c, r]) <$> rs)
              <> "|"
          )
    )
    cs

reportToConsole :: [Text] -> IO ()
reportToConsole xs = traverse_ Text.putStrLn xs

-- | Golden file options.
data Golden = Golden {golden :: FilePath, check :: Bool, record :: Bool} deriving (Generic, Eq, Show)

-- | Parse command-line golden file options.
parseGolden :: String -> Parser Golden
parseGolden def =
  Golden
    <$> option str (Options.Applicative.value ("other/" <> def <> ".perf") <> long "golden" <> short 'g' <> help "golden file name")
    <*> switch (long "check" <> short 'c' <> help "check versus a golden file")
    <*> switch (long "record" <> short 'r' <> help "record the result to a golden file")

-- | Report results
report :: ReportConfig -> Golden -> [Text] -> Map.Map [Text] [Double] -> IO ()
report cfg g labels m = do
  bool
    (reportToConsole (formatIn (format cfg) (includeHeader cfg) (expt (Just 3) <$> m')))
    (reportGolden cfg (golden g) m')
    (check g)
  when
    (record g)
    (writeResult (golden g) m')
  where
    m' = Map.fromList $ mconcat $ (\(ks, xss) -> zipWith (\x l -> (ks <> [l], x)) xss labels) <$> Map.toList m

-- | Format a result given 'Format' and 'Header' preferences.
formatIn :: Format -> Header -> Map.Map [Text] Text -> [Text]
formatIn f h = case f of
  OrgMode -> formatOrg h
  ConsoleMode -> formatConsole h