package git

import (
	"context"
	"errors"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"testing"
)

func TestDiscoverRepositoryRoot(t *testing.T) {
	repo := newRemoteFixture(t)
	child := filepath.Join(repo.work, "child")
	if err := os.Mkdir(child, 0755); err != nil {
		t.Fatal(err)
	}
	alias := filepath.Join(t.TempDir(), "alias")
	if err := os.Symlink(repo.work, alias); err != nil {
		t.Fatal(err)
	}
	worktree := filepath.Join(t.TempDir(), "worktree")
	gitRun(t, repo.work, "worktree", "add", "--detach", worktree)
	for _, tc := range []struct{ dir, want string }{{repo.work, repo.work}, {child, repo.work}, {alias, repo.work}, {worktree, worktree}} {
		root, found, err := DiscoverRepositoryRoot(context.Background(), tc.dir)
		want, e := filepath.EvalSymlinks(tc.want)
		if e != nil {
			t.Fatal(e)
		}
		if err != nil || !found || root != want {
			t.Fatalf("Discover(%s) = %q, %t, %v; want %q", tc.dir, root, found, err, want)
		}
	}
	standalone := t.TempDir()
	if root, found, err := DiscoverRepositoryRoot(context.Background(), standalone); err != nil || found || root != "" {
		t.Fatalf("standalone = %q, %t, %v", root, found, err)
	}
	if _, err := RepositoryRoot(context.Background(), standalone); err == nil {
		t.Fatal("strict lookup accepted standalone")
	}
	broken := t.TempDir()
	if err := os.WriteFile(filepath.Join(broken, ".git"), []byte("gitdir: missing\n"), 0600); err != nil {
		t.Fatal(err)
	}
	if _, found, err := DiscoverRepositoryRoot(context.Background(), broken); err == nil || found {
		t.Fatalf("broken marker: found %t, error %v", found, err)
	}
	if _, found, err := DiscoverRepositoryRoot(context.Background(), filepath.Join(standalone, "missing")); err == nil || found {
		t.Fatalf("missing directory: found %t, error %v", found, err)
	}
}

func TestNoRepositoryDiagnostic(t *testing.T) {
	for _, tc := range []struct {
		message string
		want    bool
	}{
		{"fatal: not a git repository (or any of the parent directories): .git\n", true},
		{"fatal: not a git repository (or any parent up to mount point /some path)\nStopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).\n", true},
		{"fatal: not a git repository: '/bad'", false},
		{"fatal: detected dubious ownership in repository", false},
	} {
		if got := noRepositoryDiagnostic(tc.message); got != tc.want {
			t.Errorf("diagnostic %q = %t", tc.message, got)
		}
	}
}

func TestDiscoverRepositoryRootFailures(t *testing.T) {
	dir := t.TempDir()
	bin := t.TempDir()
	script := "#!/bin/sh\nprintf '%s\\n' 'fatal: detected dubious ownership in repository' >&2\nexit 128\n"
	if err := os.WriteFile(filepath.Join(bin, "git"), []byte(script), 0755); err != nil {
		t.Fatal(err)
	}
	t.Setenv("PATH", bin)
	_, found, err := DiscoverRepositoryRoot(context.Background(), dir)
	var exitErr *exec.ExitError
	if found || !errors.As(err, &exitErr) || exitErr.ExitCode() != 128 || !strings.Contains(err.Error(), "dubious ownership") {
		t.Fatalf("found %t, error %v", found, err)
	}
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if _, _, err := DiscoverRepositoryRoot(ctx, dir); !errors.Is(err, context.Canceled) {
		t.Fatalf("cancellation = %v", err)
	}
}

func TestDiscoverRepositoryRootWithoutGit(t *testing.T) {
	repo := newRemoteFixture(t)
	standalone := t.TempDir()
	t.Setenv("PATH", t.TempDir())
	if _, found, err := DiscoverRepositoryRoot(context.Background(), standalone); found || err != nil {
		t.Fatalf("standalone: found %t, error %v", found, err)
	}
	if _, found, err := DiscoverRepositoryRoot(context.Background(), repo.work); found || !errors.Is(err, exec.ErrNotFound) {
		t.Fatalf("checkout: found %t, error %v", found, err)
	}
	broken := t.TempDir()
	if err := os.WriteFile(filepath.Join(broken, ".git"), []byte("broken"), 0600); err != nil {
		t.Fatal(err)
	}
	if _, found, err := DiscoverRepositoryRoot(context.Background(), broken); found || !errors.Is(err, exec.ErrNotFound) {
		t.Fatalf("broken marker: found %t, error %v", found, err)
	}
	t.Setenv("GIT_DIR", "invalid")
	if _, found, err := DiscoverRepositoryRoot(context.Background(), standalone); found || !errors.Is(err, exec.ErrNotFound) {
		t.Fatalf("explicit context: found %t, error %v", found, err)
	}
}