{- |
Module      : Main
Description : Integration tests for hcovguard executable
Copyright   : (c) Trevis Elser, 2026
License     : MIT
Maintainer  : oss@treviselser.com
-}
module Main
  ( main
  ) where

import qualified Data.ByteString.Lazy.Char8 as LBS8
import qualified Data.List as List
import qualified System.Directory as Directory
import qualified System.Environment as Environment
import qualified System.Exit as Exit
import qualified System.Process as Process
import qualified Test.Tasty as Tasty
import qualified Test.Tasty.Golden as Golden
import qualified Test.Tasty.HUnit as HUnit
import qualified Test.Tasty.Program as TastyProgram

main :: IO ()
main = do
  mExe <- getHcovguardExecutable
  case mExe of
    Nothing ->
      Tasty.defaultMain . HUnit.testCase "hcovguard executable" $
        HUnit.assertFailure
          "HCOVGUARD_EXE environment variable must be set to the path of the hcovguard executable"
    Just exe -> do
      exists <- Directory.doesFileExist exe
      if not exists
        then
          Tasty.defaultMain . HUnit.testCase "hcovguard executable" . HUnit.assertFailure $
            "HCOVGUARD_EXE points to non-existent file: " <> exe
        else Tasty.defaultMain (tests exe)

tests :: FilePath -> Tasty.TestTree
tests exe =
  Tasty.testGroup
    "Integration"
    [ Tasty.testGroup
        "CLI"
        [ TastyProgram.testProgram "help flag exits successfully" exe ["--help"] Nothing
        , TastyProgram.testProgram "version flag exits successfully" exe ["--version"] Nothing
        , TastyProgram.testProgram "render-man-page flag exits successfully" exe ["--render-man-page"] Nothing
        ]
    , Tasty.testGroup
        "Coverage checks"
        [ testCaseExitCode
            "passes when coverage meets thresholds"
            exe
            [ "-c"
            , "test/integration/fixtures/config-pass.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            Exit.ExitSuccess
        , testCaseExitCode
            "fails when coverage below thresholds"
            exe
            [ "-c"
            , "test/integration/fixtures/config-fail.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            (Exit.ExitFailure 1)
        , testCaseExitCode
            "ignores modules when configured"
            exe
            [ "-c"
            , "test/integration/fixtures/config-ignore.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            Exit.ExitSuccess
        , testCaseExitCode
            "matches modules with patterns"
            exe
            [ "-c"
            , "test/integration/fixtures/config-pattern.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            Exit.ExitSuccess
        , testCaseExitCode
            "passes with maximumUncovered when coverage is good"
            exe
            [ "-c"
            , "test/integration/fixtures/config-max-pass.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            Exit.ExitSuccess
        , testCaseExitCode
            "fails with maximumUncovered when too many uncovered"
            exe
            [ "-c"
            , "test/integration/fixtures/config-max-fail.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            (Exit.ExitFailure 1)
        , testCaseExitCode
            "passes with combined min and max thresholds"
            exe
            [ "-c"
            , "test/integration/fixtures/config-combined.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            Exit.ExitSuccess
        , testCaseExitCodeWithCwd
            "auto-discovers mix directories"
            exe
            [ "-c"
            , "config-pass.toml"
            , "-t"
            , "example.tix"
            , "--auto-discover"
            ]
            "test/integration/fixtures"
            Exit.ExitSuccess
        ]
    , Tasty.testGroup
        "Error handling"
        [ testCaseExitCode
            "fails when tix file not found"
            exe
            [ "-c"
            , "test/integration/fixtures/config-pass.toml"
            , "-t"
            , "test/integration/fixtures/nonexistent.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            (Exit.ExitFailure 1)
        , testCaseExitCode
            "fails when both module and pattern specified"
            exe
            [ "-c"
            , "test/integration/fixtures/config-invalid-both.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            (Exit.ExitFailure 1)
        , testCaseExitCode
            "fails when neither module nor pattern specified"
            exe
            [ "-c"
            , "test/integration/fixtures/config-invalid-neither.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            (Exit.ExitFailure 1)
        , testCaseExitCode
            "fails when no mix dirs and no auto-discover"
            exe
            [ "-c"
            , "test/integration/fixtures/config-pass.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            ]
            (Exit.ExitFailure 1)
        ]
    , Tasty.testGroup
        "Warnings"
        [ testCaseStderrContains
            "warns on unmatched pattern"
            exe
            [ "-c"
            , "test/integration/fixtures/config-unmatched.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            "[Hcovguard-8451]"
        ]
    , Tasty.testGroup
        "Output verification"
        [ testGoldenStdout
            "threshold failure output"
            exe
            [ "-c"
            , "test/integration/fixtures/config-fail.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            "test/integration/golden/config-fail.stdout.golden"
        , testGoldenStdout
            "maximum uncovered failure output"
            exe
            [ "-c"
            , "test/integration/fixtures/config-max-fail.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            "test/integration/golden/config-max-fail.stdout.golden"
        , testGoldenStderr
            "invalid config: both module and pattern"
            exe
            [ "-c"
            , "test/integration/fixtures/config-invalid-both.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            "test/integration/golden/config-invalid-both.stderr.golden"
        , testGoldenStderr
            "invalid config: neither module nor pattern"
            exe
            [ "-c"
            , "test/integration/fixtures/config-invalid-neither.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            "test/integration/golden/config-invalid-neither.stderr.golden"
        , testGoldenStderr
            "tix file not found"
            exe
            [ "-c"
            , "test/integration/fixtures/config-pass.toml"
            , "-t"
            , "test/integration/fixtures/nonexistent.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            "test/integration/golden/tix-not-found.stderr.golden"
        , testGoldenStderr
            "no mix dirs specified"
            exe
            [ "-c"
            , "test/integration/fixtures/config-pass.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            ]
            "test/integration/golden/no-mix-dirs.stderr.golden"
        , testGoldenStderr
            "unmatched pattern warning"
            exe
            [ "-c"
            , "test/integration/fixtures/config-unmatched.toml"
            , "-t"
            , "test/integration/fixtures/example.tix"
            , "-m"
            , "test/integration/fixtures/.hpc"
            ]
            "test/integration/golden/unmatched-pattern.stderr.golden"
        ]
    ]

-- | Get the hcovguard executable path from environment variable
getHcovguardExecutable :: IO (Maybe FilePath)
getHcovguardExecutable = Environment.lookupEnv "HCOVGUARD_EXE"

-- | Test a program invocation and check its exit code
testCaseExitCode :: String -> FilePath -> [String] -> Exit.ExitCode -> Tasty.TestTree
testCaseExitCode name exe args expectedExitCode =
  HUnit.testCase name $ do
    (exitCode, _, _) <- Process.readProcessWithExitCode exe args ""
    exitCode HUnit.@?= expectedExitCode

-- | Test a program invocation with a custom working directory
testCaseExitCodeWithCwd ::
  String -> FilePath -> [String] -> FilePath -> Exit.ExitCode -> Tasty.TestTree
testCaseExitCodeWithCwd name exe args workDir expectedExitCode =
  HUnit.testCase name $ do
    let process = (Process.proc exe args){Process.cwd = Just workDir}
    (exitCode, _, _) <- Process.readCreateProcessWithExitCode process ""
    exitCode HUnit.@?= expectedExitCode

-- | Golden test comparing stdout output against a golden file
testGoldenStdout :: String -> FilePath -> [String] -> FilePath -> Tasty.TestTree
testGoldenStdout name exe args goldenFile =
  Golden.goldenVsStringDiff
    name
    (\ref new -> ["diff", "-u", ref, new])
    goldenFile
    (fmap (LBS8.pack . snd3) (Process.readProcessWithExitCode exe args ""))

-- | Golden test comparing stderr output against a golden file
testGoldenStderr :: String -> FilePath -> [String] -> FilePath -> Tasty.TestTree
testGoldenStderr name exe args goldenFile =
  Golden.goldenVsStringDiff
    name
    (\ref new -> ["diff", "-u", ref, new])
    goldenFile
    (fmap (LBS8.pack . thd3) (Process.readProcessWithExitCode exe args ""))

-- | Extract the second element of a triple
snd3 :: (a, b, c) -> b
snd3 (_, b, _) = b

-- | Extract the third element of a triple
thd3 :: (a, b, c) -> c
thd3 (_, _, c) = c

-- | Test that stderr contains a specific substring
testCaseStderrContains :: String -> FilePath -> [String] -> String -> Tasty.TestTree
testCaseStderrContains name exe args expectedSubstr =
  HUnit.testCase name $ do
    (_, _, stderr) <- Process.readProcessWithExitCode exe args ""
    HUnit.assertBool
      ("Expected stderr to contain: " <> expectedSubstr <> "\nActual stderr: " <> stderr)
      (expectedSubstr `List.isInfixOf` stderr)