module GitPullSpec (spec) where

import Converge (RepoConfig (..), defaultRepoConfig, gitPull)
import qualified Data.Text as T
import System.Directory (createDirectory)
import System.Exit (ExitCode (..))
import System.FilePath ((</>))
import System.IO.Temp (withSystemTempDirectory)
import Test.Hspec
import TestHelper

spec :: Spec
spec = do
    describe "gitPull" $ do
        it "pulls changes from remote 'origin'" $ do
            logger <- testLogger
            withTempGitRepoWithRemote $ \local -> do
                -- Make a second commit on local and push to remote
                writeFile (local </> "upstream.txt") "pushed to remote"
                _ <- runGitIn local ["add", "upstream.txt"]
                _ <- runGitIn local ["commit", "-m", "second commit"]
                _ <- runGitIn local ["push", "origin", "main"]

                -- Rewind local to the initial commit (simulate being behind)
                _ <- runGitIn local ["reset", "--hard", "HEAD~1"]

                countBefore <- commitCount local
                countBefore `shouldBe` 1

                let cfg = defaultRepoConfig{rcPath = local}
                (code, _, _) <- gitPull logger cfg
                code `shouldBe` ExitSuccess

                countAfter <- commitCount local
                countAfter `shouldBe` 2

        it "rebases local commits on top of pulled changes" $ do
            logger <- testLogger
            withSystemTempDirectory "converge-test-rebase" $ \tmp -> do
                let remoteDir = tmp </> "remote.git"
                let localDir = tmp </> "local"

                -- Create directories before git init
                createDirectory remoteDir
                createDirectory localDir

                -- Create bare remote
                _ <- runGitIn remoteDir ["init", "--bare", "-b", "main"]

                -- Create local repo, push initial commit
                _ <- runGitIn localDir ["init", "-b", "main"]
                _ <- runGitIn localDir ["config", "user.name", "test"]
                _ <- runGitIn localDir ["config", "user.email", "test@test"]
                _ <- runGitIn localDir ["remote", "add", "origin", remoteDir]
                writeFile (localDir </> "initial.txt") "initial"
                _ <- runGitIn localDir ["add", "initial.txt"]
                _ <- runGitIn localDir ["commit", "-m", "initial commit"]
                _ <- runGitIn localDir ["push", "-u", "origin", "main"]

                -- Make a local-only commit (divergent from remote)
                writeFile (localDir </> "local.txt") "local-only change"
                _ <- runGitIn localDir ["add", "local.txt"]
                _ <- runGitIn localDir ["commit", "-m", "local commit"]

                -- Push a *different* commit to remote (from another clone)
                let otherDir = tmp </> "other"
                _ <- rawGit ["clone", remoteDir, otherDir]
                _ <- runGitIn otherDir ["config", "user.name", "test"]
                _ <- runGitIn otherDir ["config", "user.email", "test@test"]
                writeFile (otherDir </> "remote.txt") "remote-only change"
                _ <- runGitIn otherDir ["add", "remote.txt"]
                _ <- runGitIn otherDir ["commit", "-m", "remote commit"]
                _ <- runGitIn otherDir ["push", "origin", "main"]

                -- Pull with --rebase: local commits are rebased on top
                -- of the fetched remote commit, yielding a linear history.
                let cfg = defaultRepoConfig{rcPath = localDir}
                (code, _, _) <- gitPull logger cfg
                code `shouldBe` ExitSuccess
                -- Rebase produces linear history: 3 commits, no merge commit
                c <- commitCount localDir
                c `shouldBe` 3
                -- Verify no merge commits exist (each commit has exactly 1 parent)
                (_, logOut, _) <- runGitIn localDir ["log", "--format=%P", "--all"]
                let parentCounts = map (length . words) (lines (T.unpack logOut))
                parentCounts `shouldSatisfy` all (<= 1)