{-# LANGUAGE RecordWildCards #-}

module Trace.Hpc.Lcov.Report (
  LcovReport (..),
  FileReport (..),
  FunctionReport (..),
  BranchReport (..),
  LineReport (..),
  writeReport,
  showReport,
) where

import Data.List (intercalate)
import Trace.Hpc.Util (Hash)

-- http://ltp.sourceforge.net/coverage/lcov/geninfo.1.php
newtype LcovReport = LcovReport [FileReport]

data FileReport = FileReport
  { fileReportLocation :: FilePath
  , fileReportFunctions :: [FunctionReport] -- anything top level is considered a function
  , fileReportBranches :: [BranchReport]
  , fileReportLines :: [LineReport]
  }
  deriving (Show, Eq)

data FunctionReport = FunctionReport
  { functionReportLine :: Int
  , functionReportName :: String
  , functionReportHits :: Integer
  }
  deriving (Show, Eq)

data BranchReport = BranchReport
  { branchReportLine :: Int
  , branchReportHash :: Hash
  , branchReportTrueHits :: Integer
  , branchReportFalseHits :: Integer
  }
  deriving (Show, Eq)

data LineReport = LineReport
  { lineReportLine :: Int
  , lineReportHits :: Integer
  }
  deriving (Show, Eq)

writeReport :: FilePath -> LcovReport -> IO ()
writeReport fp = writeFile fp . showReport

showReport :: LcovReport -> String
showReport (LcovReport fileReports) = unlines $ concatMap generateFileReport fileReports
  where
    generateFileReport FileReport{..} =
      concat
        [ [line "TN" []]
        , [line "SF" [fileReportLocation]]
        , map showFunctionDefinition fileReportFunctions
        , map showFunctionHits fileReportFunctions
        , [line "FNF" [show $ length fileReportFunctions]]
        , [line "FNH" [countHits functionReportHits fileReportFunctions]]
        , concatMap generateBranchReport fileReportBranches
        , [line "BRF" [show $ length fileReportBranches * 2]] -- multiplying by 2 for true and false branches
        , [line "BRH" [countHits branchReportHits fileReportBranches]]
        , map showLineReport fileReportLines
        , [line "LF" [show $ length fileReportLines]]
        , [line "LH" [countHits lineReportHits fileReportLines]]
        , ["end_of_record"]
        ]

    showFunctionDefinition FunctionReport{..} = line "FN" [show functionReportLine, functionReportName]

    showFunctionHits FunctionReport{..} = line "FNDA" [show functionReportHits, functionReportName]

    generateBranchReport BranchReport{..} =
      let mkBranchLine branchNum hits =
            line
              "BRDA"
              [ show branchReportLine
              , show branchReportHash
              , show (branchNum :: Int)
              , show hits
              ]
       in [mkBranchLine 0 branchReportTrueHits, mkBranchLine 1 branchReportFalseHits]

    showLineReport LineReport{..} = line "DA" [show lineReportLine, show lineReportHits]

    {- Helpers -}

    line :: String -> [String] -> String
    line label info = label ++ ":" ++ intercalate "," info

    countHits :: (a -> Integer) -> [a] -> String
    countHits f = show . length . filter ((> 0) . f)

    branchReportHits BranchReport{..} = branchReportTrueHits + branchReportFalseHits