package ldap

import (
	"bytes"
	"testing"

	"github.com/vjeantet/goldap/message"
	ldap "github.com/vjeantet/ldapserver"

	pb "github.com/netauth/protocol"
)

// berBaseObjectSearch encodes a base-object search for a single entry
// with an arbitrary filter element. This is the shape HashiCorp Vault
// sends on every login to read the attributes of the bound user.
func berBaseObjectSearch(t *testing.T, baseDN string, filterElement []byte) []byte {
	t.Helper()

	search := berElement(0x63, // [APPLICATION 3] constructed
		berOctetString(baseDN),      // baseObject
		berElement(0x0a, []byte{0}), // scope: baseObject
		berElement(0x0a, []byte{0}), // derefAliases: never
		berInteger(0),               // sizeLimit
		berInteger(0),               // timeLimit
		berElement(0x01, []byte{0}), // typesOnly: false
		filterElement,               // filter
		berElement(0x30),            // empty attribute selection (all)
	)
	return berElement(0x30, berInteger(2), search)
}

// objectClassPresentFilter encodes the (objectClass=*) filter.
func objectClassPresentFilter() []byte { return berRawPresent("objectClass") }

// entryContains reports whether the encoded form of an entry contains
// an OCTET STRING holding exactly the given text.
func entryContains(t *testing.T, po message.ProtocolOp, text string) bool {
	t.Helper()

	m := message.NewLDAPMessageWithProtocolOp(po)
	m.SetMessageID(2)
	b, err := m.Write()
	if err != nil {
		t.Fatalf("encoding entry: %s", err)
	}
	// The value is encoded as a bare OCTET STRING with its exact
	// length, which avoids matching a substring of a longer value.
	want := []byte{0x04, byte(len(text))}
	want = append(want, text...)
	return bytes.Contains(b.Bytes(), want)
}

// entryHasAttribute encodes a SearchResultEntry and reports whether it
// carries the named attribute. goldap exposes no accessors for entry
// attributes, so the encoded form is inspected instead.
func entryHasAttribute(t *testing.T, po message.ProtocolOp, attr string) bool {
	t.Helper()
	return entryContains(t, po, attr)
}

// entryContainsDN reports whether an entry is recorded under the given
// distinguished name.
func entryContainsDN(t *testing.T, po message.ProtocolOp, dn string) bool {
	t.Helper()
	return entryContains(t, po, dn)
}

func vaultTestServer(c naClient) *server {
	s := boundTestServer(c)
	s.nc = []string{"dc=netauth", "dc=voidlinux", "dc=org"}
	return s
}

// vaultBind authenticates the fixture naming context so the search is
// not refused before it reaches the handler logic under test. The
// shared bind helper uses a different naming context and cannot be
// used here.
func vaultBind(t *testing.T, s *server) {
	t.Helper()
	s.handleBind(&recordingWriter{}, mustDecode(t,
		berBindRequest("uid=maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org", "hunter2")))
	if !s.bound(&ldap.Message{}) {
		t.Fatal("the fixture bind did not mark the connection bound")
	}
}

// A base-object search for a known entity returns exactly that entry
// terminated by a searchResDone. Vault reads the entity alias out of
// the returned attributes, so failing to answer this aborts login.
func TestBaseObjectSearchReturnsEntry(t *testing.T) {
	c := &fakeClient{
		entitySearchResults: []*pb.Entity{testEntity("maldridge", 1001)},
	}
	s := vaultTestServer(c)
	vaultBind(t, s)

	w := &recordingWriter{}
	s.handleSearchEntry(w, mustDecode(t, berBaseObjectSearch(t,
		"uid=maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org", objectClassPresentFilter())))

	if len(w.responses) != 2 {
		t.Fatalf("got %d responses, want 1 entry + 1 done", len(w.responses))
	}
	entry, ok := w.responses[0].(message.SearchResultEntry)
	if !ok {
		t.Fatalf("first response is %T, want SearchResultEntry", w.responses[0])
	}
	if _, ok := w.responses[1].(message.SearchResultDone); !ok {
		t.Errorf("second response is %T, want SearchResultDone", w.responses[1])
	}

	// Vault requires the DN it asked for, not one rebuilt from the
	// search base, and needs the userattr value to be present.
	if !entryContainsDN(t, entry, "uid=maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org") {
		t.Errorf("entry DN is not the requested DN")
	}
	for _, attr := range []string{"uid", "objectClass"} {
		if !entryHasAttribute(t, entry, attr) {
			t.Errorf("entry is missing the %q attribute", attr)
		}
	}
}

// The alias Vault derives comes from the attribute the entry carries,
// so an entity whose NetAuth ID differs in case from the requested DN
// must still resolve.
func TestBaseObjectSearchIsCaseInsensitive(t *testing.T) {
	c := &fakeClient{entitySearchResults: []*pb.Entity{testEntity("maldridge", 1001)}}
	s := vaultTestServer(c)
	vaultBind(t, s)

	w := &recordingWriter{}
	s.handleSearchEntry(w, mustDecode(t, berBaseObjectSearch(t,
		"uid=Maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org", objectClassPresentFilter())))

	if code := resultCode(t, w.responses[len(w.responses)-1]); code != ldap.LDAPResultSuccess {
		t.Fatalf("result code is %d, want success", code)
	}
	if len(w.responses) != 2 {
		t.Errorf("got %d responses, want the entry plus a done", len(w.responses))
	}
}

// A base-object search for an unknown name returns noSuchObject rather
// than an empty success, so clients can tell the difference.
func TestBaseObjectSearchUnknownEntity(t *testing.T) {
	s := vaultTestServer(&fakeClient{})
	vaultBind(t, s)

	w := &recordingWriter{}
	s.handleSearchEntry(w, mustDecode(t, berBaseObjectSearch(t,
		"uid=ghost,ou=entities,dc=netauth,dc=voidlinux,dc=org", objectClassPresentFilter())))

	if len(w.responses) != 1 {
		t.Fatalf("got %d responses, want only a done", len(w.responses))
	}
	if code := resultCode(t, w.responses[0]); code != ldap.LDAPResultNoSuchObject {
		t.Errorf("result code is %d, want %d (noSuchObject)", code, ldap.LDAPResultNoSuchObject)
	}
}

// RFC 4511: a base-object search whose entry does not match the filter
// succeeds with zero entries.
func TestBaseObjectSearchFilterMismatch(t *testing.T) {
	c := &fakeClient{entitySearchResults: []*pb.Entity{testEntity("maldridge", 1001)}}
	s := vaultTestServer(c)
	vaultBind(t, s)

	w := &recordingWriter{}
	s.handleSearchEntry(w, mustDecode(t, berBaseObjectSearch(t,
		"uid=maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org",
		berRawEquality("uid", "someoneelse"))))

	if len(w.responses) != 1 {
		t.Fatalf("got %d responses, want only a done", len(w.responses))
	}
	if code := resultCode(t, w.responses[0]); code != ldap.LDAPResultSuccess {
		t.Errorf("result code is %d, want success with no entries", code)
	}
}

func TestBaseObjectSearchRequiresBind(t *testing.T) {
	s := vaultTestServer(&fakeClient{})

	w := &recordingWriter{}
	s.handleSearchEntry(w, mustDecode(t, berBaseObjectSearch(t,
		"uid=maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org", objectClassPresentFilter())))

	if code := resultCode(t, w.responses[len(w.responses)-1]); code != ldap.LDAPResultInsufficientAccessRights {
		t.Errorf("result code is %d, want %d (insufficientAccessRights)",
			code, ldap.LDAPResultInsufficientAccessRights)
	}
}

// A base-object search on a DN that is neither an entity nor a group
// (the naming context itself, an ou) is refused without ever reaching
// NetAuth.
func TestBaseObjectSearchOnContainerDN(t *testing.T) {
	c := &fakeClient{entitySearchResults: []*pb.Entity{testEntity("maldridge", 1001)}}
	s := vaultTestServer(c)
	vaultBind(t, s)

	w := &recordingWriter{}
	s.handleSearchEntry(w, mustDecode(t, berBaseObjectSearch(t,
		"ou=entities,dc=netauth,dc=voidlinux,dc=org", objectClassPresentFilter())))

	if len(c.entitySearchResults) == 0 {
		t.Error("the fake client should still hold its fixture data")
	}
	if code := resultCode(t, w.responses[len(w.responses)-1]); code != ldap.LDAPResultNoSuchObject {
		t.Errorf("result code is %d, want %d (noSuchObject)", code, ldap.LDAPResultNoSuchObject)
	}
	if len(w.responses) != 1 {
		t.Errorf("got %d responses, want only a done", len(w.responses))
	}
}

// Group DNs are served the same way entity DNs are.
func TestBaseObjectSearchGroup(t *testing.T) {
	c := &fakeClient{
		groupSearchResults:  []*pb.Group{testGroup("admins", 42)},
		groupMembersResults: map[string][]*pb.Entity{"admins": {testEntity("maldridge", 1001)}},
	}
	s := vaultTestServer(c)
	vaultBind(t, s)

	w := &recordingWriter{}
	s.handleSearchEntry(w, mustDecode(t, berBaseObjectSearch(t,
		"cn=admins,ou=groups,dc=netauth,dc=voidlinux,dc=org", objectClassPresentFilter())))

	if len(w.responses) != 2 {
		t.Fatalf("got %d responses, want 1 entry + 1 done", len(w.responses))
	}
	entry, ok := w.responses[0].(message.SearchResultEntry)
	if !ok {
		t.Fatalf("first response is %T, want SearchResultEntry", w.responses[0])
	}
	if !entryHasAttribute(t, entry, "cn") {
		t.Error("group entry is missing the cn attribute")
	}
	if !entryHasAttribute(t, entry, "member") {
		t.Error("group entry is missing the member attribute")
	}
}

// The single-entry handler is reached through the real mux, and adding
// it must not widen what other searches are accepted: an empty base or
// a stale base DN at subtree scope is still refused.
func TestBaseObjectSearchRouting(t *testing.T) {
	c := &fakeClient{entitySearchResults: []*pb.Entity{testEntity("maldridge", 1001)}}
	s := New(WithLogger(testLogger()), WithNetAuth(c))
	if err := s.SetDomain("voidlinux.org"); err != nil {
		t.Fatal(err)
	}
	fc := &fakeConn{}
	s.conn = func(*ldap.Message) connection { return fc }

	bind := &recordingWriter{}
	s.ServeLDAP(bind, mustDecode(t,
		berBindRequest("uid=maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org", "hunter2")))
	if code := resultCode(t, bind.responses[len(bind.responses)-1]); code != ldap.LDAPResultSuccess {
		t.Fatalf("bind result code is %d, want success", code)
	}

	entry := &recordingWriter{}
	s.ServeLDAP(entry, mustDecode(t, berBaseObjectSearch(t,
		"uid=maldridge,ou=entities,dc=netauth,dc=voidlinux,dc=org", objectClassPresentFilter())))
	if len(entry.responses) != 2 {
		t.Fatalf("got %d responses through the mux, want 1 entry + 1 done", len(entry.responses))
	}
	if _, ok := entry.responses[0].(message.SearchResultEntry); !ok {
		t.Errorf("first response is %T, want SearchResultEntry", entry.responses[0])
	}

	for _, base := range []string{"", "ou=entities,dc=netauth,dc=example,dc=com"} {
		w := &recordingWriter{}
		s.ServeLDAP(w, mustDecode(t, berSearchRequest(base)))
		if len(w.responses) != 1 {
			t.Fatalf("base %q: got %d responses, want only a done", base, len(w.responses))
		}
		if code := resultCode(t, w.responses[0]); code != ldap.LDAPResultUnwillingToPerform {
			t.Errorf("base %q: result code is %d, want %d (unwillingToPerform)",
				base, code, ldap.LDAPResultUnwillingToPerform)
		}
	}
}

func TestEntryFromDN(t *testing.T) {
	s := vaultTestServer(&fakeClient{})

	ok := map[string]entryKind{
		"uid=jsmith,ou=entities,dc=netauth,dc=voidlinux,dc=org": kindEntity,
		"cn=admins,ou=groups,dc=netauth,dc=voidlinux,dc=org":    kindGroup,
		"uid=jsmith,ou=ENTITIES,dc=netauth,dc=voidlinux,dc=org": kindEntity,
	}
	for dn, want := range ok {
		ref, err := s.entryFromDN(message.LDAPDN(dn))
		if err != nil {
			t.Errorf("entryFromDN(%q): %s", dn, err)
			continue
		}
		if ref.kind != want {
			t.Errorf("entryFromDN(%q) kind is %v, want %v", dn, ref.kind, want)
		}
	}

	bad := []string{
		"",
		"uid=jsmith",
		"uid=jsmith,ou=entities",
		"ou=entities,dc=netauth,dc=voidlinux,dc=org",
		"cn=admins,ou=entities,dc=netauth,dc=voidlinux,dc=org",
		"uid=jsmith,ou=entities,dc=netauth,dc=example,dc=com",
	}
	for _, dn := range bad {
		if ref, err := s.entryFromDN(message.LDAPDN(dn)); err == nil {
			t.Errorf("entryFromDN(%q) accepted a non-entry DN (%+v)", dn, ref)
		}
	}
}