package safeio

import (
	"errors"
	"os"
	"path/filepath"
	"runtime"
	"testing"
)

func TestReadCanonicalRegularRejectsFinalAndParentSymlinks(t *testing.T) {
	temporaryRoot, err := filepath.EvalSymlinks(os.TempDir())
	if err != nil {
		t.Fatal(err)
	}
	root, err := os.MkdirTemp(temporaryRoot, "thothctl-safeio-")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = os.RemoveAll(root) })

	realDirectory := filepath.Join(root, "real")
	if err := os.Mkdir(realDirectory, 0o700); err != nil {
		t.Fatal(err)
	}
	realFile := filepath.Join(realDirectory, "secret")
	if err := os.WriteFile(realFile, []byte("secret"), 0o600); err != nil {
		t.Fatal(err)
	}

	parentLink := filepath.Join(root, "parent-link")
	symlinkOrSkip(t, realDirectory, parentLink)
	if _, err := ReadCanonicalRegular(filepath.Join(parentLink, "secret"), 1024); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("parent symlink error = %v, want ErrUnsafeFile", err)
	}

	finalLink := filepath.Join(root, "final-link")
	symlinkOrSkip(t, realFile, finalLink)
	if _, err := ReadCanonicalRegular(finalLink, 1024); !errors.Is(err, ErrUnsafeFile) {
		t.Fatalf("final symlink error = %v, want ErrUnsafeFile", err)
	}
}

func symlinkOrSkip(t *testing.T, target, link string) {
	t.Helper()
	if err := os.Symlink(target, link); err != nil {
		if runtime.GOOS == "windows" && errors.Is(err, os.ErrPermission) {
			t.Skip("Windows symlink privilege is unavailable")
		}
		t.Fatal(err)
	}
}