package host

import (
	"golang.org/x/sys/unix"
	"os"
	"path/filepath"
	"testing"

	"github.com/carlosframework/platform/internal/rootstate"
)

func TestPlan14ProofBindingProvenance(t *testing.T) {
	if !plan14RootFixture(t) {
		return
	}
	for _, attack := range []string{"nonroot owner", "writable parent", "writable file", "symlink", "rename", "erasure"} {
		t.Run(attack, func(t *testing.T) {
			e, rt, _, source := plan14ProofFixture(t)
			path := source.sys.(*fakeUnits).shows[0].FragmentPath
			makeProofAncestorsPublic(t, path)
			makeProofAncestorsPublic(t, source.sys.(*fakeUnits).exe[7])
			source.openFile = rootstate.OpenTrustedFile
			baseline, err := source.resolve(t.Context(), rt)
			if err != nil {
				t.Fatalf("trusted baseline: %v", err)
			}
			switch attack {
			case "nonroot owner":
				if err := unix.Mount("/foreign", path, "", unix.MS_BIND, ""); err != nil {
					t.Fatal(err)
				}
				t.Cleanup(func() { _ = unix.Unmount(path, 0) })
			case "writable parent":
				if err := os.Chmod(filepath.Dir(path), 0777); err != nil {
					t.Fatal(err)
				}
			case "writable file":
				if err := os.Chmod(path, 0666); err != nil {
					t.Fatal(err)
				}
			case "symlink":
				if err := os.Rename(path, path+".real"); err != nil {
					t.Fatal(err)
				}
				if err := os.Symlink(path+".real", path); err != nil {
					t.Fatal(err)
				}
			case "erasure":
				if err := os.Remove(path); err != nil {
					t.Fatal(err)
				}
			case "rename":
				raw, err := os.ReadFile(path)
				if err != nil {
					t.Fatal(err)
				}
				if err := os.Rename(path, path+".old"); err != nil {
					t.Fatal(err)
				}
				if err := os.WriteFile(path, raw, 0644); err != nil {
					t.Fatal(err)
				}
			}
			if attack == "rename" {
				current, err := source.resolve(t.Context(), rt)
				if err != nil {
					t.Fatal(err)
				}
				if current.Source == baseline.Source {
					t.Fatal("replacement retained identity")
				}
				if _, err := source.prepareRollback(t.Context(), baseline); err == nil {
					t.Fatal("replacement accepted captured identity")
				}
			} else if _, err := source.resolve(t.Context(), rt); err == nil {
				t.Fatal("mutation accepted")
			}
			_ = e
		})
	}
}