package ldap

import (
	"reflect"
	"testing"

	"github.com/hashicorp/go-hclog"
	"github.com/vjeantet/goldap/message"
	ldap "github.com/vjeantet/ldapserver"
)

// recordingWriter captures everything written to it so tests can
// assert on the exact sequence of responses a handler produces.
type recordingWriter struct {
	responses []message.ProtocolOp
}

func (w *recordingWriter) Write(po message.ProtocolOp) {
	w.responses = append(w.responses, po)
}

func testLogger() hclog.Logger { return hclog.NewNullLogger() }

func TestGuardRecoversPanic(t *testing.T) {
	s := &server{l: testLogger()}

	h := s.guard(func(w ldap.ResponseWriter, m *ldap.Message) {
		panic("boom")
	})

	w := &recordingWriter{}
	h(w, mustDecode(t, berSearchRequest("ou=entities,dc=netauth,dc=example,dc=com")))

	if len(w.responses) != 1 {
		t.Fatalf("got %d responses, want 1", len(w.responses))
	}
	if _, ok := w.responses[0].(message.SearchResultDone); !ok {
		t.Errorf("response is %T, want message.SearchResultDone", w.responses[0])
	}
	if code := resultCode(t, w.responses[0]); code != ldap.LDAPResultOperationsError {
		t.Errorf("result code is %d, want %d", code, ldap.LDAPResultOperationsError)
	}
}

func TestGuardSilentAfterPartialWrite(t *testing.T) {
	s := &server{l: testLogger()}

	h := s.guard(func(w ldap.ResponseWriter, m *ldap.Message) {
		w.Write(ldap.NewSearchResultEntry("cn=test"))
		panic("boom")
	})

	w := &recordingWriter{}
	h(w, mustDecode(t, berSearchRequest("ou=entities,dc=netauth,dc=example,dc=com")))

	if len(w.responses) != 1 {
		t.Errorf("got %d responses, want 1", len(w.responses))
	}
	if _, ok := w.responses[0].(message.SearchResultEntry); !ok {
		t.Errorf("response is %T, want the partial entry only", w.responses[0])
	}
}

func TestGuardPassesThrough(t *testing.T) {
	s := &server{l: testLogger()}

	h := s.guard(func(w ldap.ResponseWriter, m *ldap.Message) {
		w.Write(ldap.NewSearchResultDoneResponse(ldap.LDAPResultSuccess))
	})

	w := &recordingWriter{}
	h(w, &ldap.Message{})

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

// TestResultForRequestPairing is the regression test for the client
// hang: an LDAP client only accepts the result type that pairs with
// the request it sent and silently discards anything else, so a
// mismatched type leaves it waiting for a done message forever.
func TestResultForRequestPairing(t *testing.T) {
	tests := []struct {
		name string
		op   message.ProtocolOp
		want string
	}{
		{"search", message.SearchRequest{}, "SearchResultDone"},
		{"bind", message.BindRequest{}, "BindResponse"},
		{"extended", message.ExtendedRequest{}, "ExtendedResponse"},
		{"compare", message.CompareRequest{}, "CompareResponse"},
		{"add", message.AddRequest{}, "AddResponse"},
		{"delete", message.DelRequest("cn=x,dc=example,dc=com"), "DelResponse"},
		{"modify", message.ModifyRequest{}, "ModifyResponse"},
		{"modifyDN", message.ModifyDNRequest{}, "ModifyDNResponse"},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			res, ok := resultForRequest(tc.op, ldap.LDAPResultUnwillingToPerform, "nope")
			if !ok {
				t.Fatal("no result produced for a request that needs one")
			}
			if got := reflect.TypeOf(res).Name(); got != tc.want {
				t.Errorf("result type is %s, want %s", got, tc.want)
			}
		})
	}

	// Abandon is never answered, so it must produce nothing rather
	// than an unsolicited result.
	if res, ok := resultForRequest(message.AbandonRequest(1), ldap.LDAPResultSuccess, ""); ok {
		t.Errorf("abandon produced %T, want no response", res)
	}
}

// TestSearchResultDoneWireTag pins the search reply to the
// searchResDone application tag (5). A reply carrying any other tag,
// including the bare LDAPResult universal SEQUENCE, is ignored by
// clients and hangs them.
func TestSearchResultDoneWireTag(t *testing.T) {
	res, ok := resultForRequest(message.SearchRequest{}, ldap.LDAPResultUnwillingToPerform, "nope")
	if !ok {
		t.Fatal("no result produced for a search request")
	}

	m := message.NewLDAPMessageWithProtocolOp(res)
	m.SetMessageID(2)
	b, err := m.Write()
	if err != nil {
		t.Fatalf("encoding response: %s", err)
	}
	raw := b.Bytes()

	// Descend from the LDAPMessage SEQUENCE into the protocolOp.
	off := 0
	if _, off, err = message.ParseTagAndLength(raw, off); err != nil {
		t.Fatalf("message tag: %s", err)
	}
	var id message.TagAndLength
	if id, off, err = message.ParseTagAndLength(raw, off); err != nil {
		t.Fatalf("messageID tag: %s", err)
	}
	off += id.Length
	op, _, err := message.ParseTagAndLength(raw, off)
	if err != nil {
		t.Fatalf("protocolOp tag: %s", err)
	}
	if op.Class != 1 || op.Tag != 5 {
		t.Errorf("protocolOp is class %d tag %d, want APPLICATION (1) tag 5", op.Class, op.Tag)
	}
}