package grpcapi

import (
	"context"
	"testing"

	gatewayv1 "galaxy/gateway/proto/galaxy/gateway/v1"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/metadata"
	"google.golang.org/grpc/status"
)

func TestParseExecuteCommandRequest(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name        string
		mutate      func(*gatewayv1.ExecuteCommandRequest)
		wantCode    codes.Code
		wantMessage string
		assertValid func(*testing.T, *gatewayv1.ExecuteCommandRequest, parsedEnvelope)
	}{
		{
			name:        "nil request",
			wantCode:    codes.InvalidArgument,
			wantMessage: "request envelope must not be nil",
		},
		{
			name: "empty protocol version",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.ProtocolVersion = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "protocol_version must not be empty",
		},
		{
			name: "empty device session id",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.DeviceSessionId = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "device_session_id must not be empty",
		},
		{
			name: "empty message type",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.MessageType = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "message_type must not be empty",
		},
		{
			name: "zero timestamp",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.TimestampMs = 0
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "timestamp_ms must be greater than zero",
		},
		{
			name: "empty request id",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.RequestId = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "request_id must not be empty",
		},
		{
			name: "empty payload bytes",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.PayloadBytes = nil
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "payload_bytes must not be empty",
		},
		{
			name: "empty payload hash",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.PayloadHash = nil
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "payload_hash must not be empty",
		},
		{
			name: "empty signature",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.Signature = nil
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "signature must not be empty",
		},
		{
			name: "unsupported protocol version",
			mutate: func(req *gatewayv1.ExecuteCommandRequest) {
				req.ProtocolVersion = "v2"
			},
			wantCode:    codes.FailedPrecondition,
			wantMessage: `unsupported protocol_version "v2"`,
		},
		{
			name:     "valid request",
			wantCode: codes.OK,
			assertValid: func(t *testing.T, req *gatewayv1.ExecuteCommandRequest, envelope parsedEnvelope) {
				t.Helper()

				assert.Equal(t, supportedProtocolVersion, envelope.ProtocolVersion)
				assert.Equal(t, req.GetDeviceSessionId(), envelope.DeviceSessionID)
				assert.Equal(t, req.GetMessageType(), envelope.MessageType)
				assert.Equal(t, req.GetTimestampMs(), envelope.TimestampMS)
				assert.Equal(t, req.GetRequestId(), envelope.RequestID)
				assert.Equal(t, req.GetTraceId(), envelope.TraceID)
				assert.Equal(t, req.GetPayloadBytes(), envelope.PayloadBytes)
				assert.Equal(t, req.GetPayloadHash(), envelope.PayloadHash)
				assert.Equal(t, req.GetSignature(), envelope.Signature)

				originalPayloadBytes := append([]byte(nil), req.GetPayloadBytes()...)
				originalPayloadHash := append([]byte(nil), req.GetPayloadHash()...)
				originalSignature := append([]byte(nil), req.GetSignature()...)

				envelope.PayloadBytes[0] = 'X'
				envelope.PayloadHash[0] = 'Y'
				envelope.Signature[0] = 'Z'

				assert.Equal(t, originalPayloadBytes, req.GetPayloadBytes())
				assert.Equal(t, originalPayloadHash, req.GetPayloadHash())
				assert.Equal(t, originalSignature, req.GetSignature())
			},
		},
	}

	for _, tt := range tests {
		tt := tt

		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			var req *gatewayv1.ExecuteCommandRequest
			if tt.name != "nil request" {
				req = newValidExecuteCommandRequest()
				if tt.mutate != nil {
					tt.mutate(req)
				}
			}

			envelope, err := parseExecuteCommandRequest(req)
			if tt.wantCode != codes.OK {
				require.Error(t, err)
				assert.Equal(t, tt.wantCode, status.Code(err))
				assert.Equal(t, tt.wantMessage, status.Convert(err).Message())
				return
			}

			require.NoError(t, err)
			require.NotNil(t, tt.assertValid)
			tt.assertValid(t, req, envelope)
		})
	}
}

func TestParseSubscribeEventsRequest(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name        string
		mutate      func(*gatewayv1.SubscribeEventsRequest)
		wantCode    codes.Code
		wantMessage string
		assertValid func(*testing.T, *gatewayv1.SubscribeEventsRequest, parsedEnvelope)
	}{
		{
			name:        "nil request",
			wantCode:    codes.InvalidArgument,
			wantMessage: "request envelope must not be nil",
		},
		{
			name: "empty protocol version",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.ProtocolVersion = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "protocol_version must not be empty",
		},
		{
			name: "empty device session id",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.DeviceSessionId = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "device_session_id must not be empty",
		},
		{
			name: "empty message type",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.MessageType = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "message_type must not be empty",
		},
		{
			name: "zero timestamp",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.TimestampMs = 0
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "timestamp_ms must be greater than zero",
		},
		{
			name: "empty request id",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.RequestId = ""
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "request_id must not be empty",
		},
		{
			name: "empty payload hash",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.PayloadHash = nil
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "payload_hash must not be empty",
		},
		{
			name: "empty signature",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.Signature = nil
			},
			wantCode:    codes.InvalidArgument,
			wantMessage: "signature must not be empty",
		},
		{
			name: "unsupported protocol version",
			mutate: func(req *gatewayv1.SubscribeEventsRequest) {
				req.ProtocolVersion = "v2"
			},
			wantCode:    codes.FailedPrecondition,
			wantMessage: `unsupported protocol_version "v2"`,
		},
		{
			name:     "valid request with empty payload bytes",
			wantCode: codes.OK,
			assertValid: func(t *testing.T, req *gatewayv1.SubscribeEventsRequest, envelope parsedEnvelope) {
				t.Helper()

				assert.Empty(t, req.GetPayloadBytes())
				assert.Empty(t, envelope.PayloadBytes)
				assert.Equal(t, req.GetPayloadHash(), envelope.PayloadHash)
				assert.Equal(t, req.GetSignature(), envelope.Signature)
			},
		},
	}

	for _, tt := range tests {
		tt := tt

		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			var req *gatewayv1.SubscribeEventsRequest
			if tt.name != "nil request" {
				req = newValidSubscribeEventsRequest()
				if tt.mutate != nil {
					tt.mutate(req)
				}
			}

			envelope, err := parseSubscribeEventsRequest(req)
			if tt.wantCode != codes.OK {
				require.Error(t, err)
				assert.Equal(t, tt.wantCode, status.Code(err))
				assert.Equal(t, tt.wantMessage, status.Convert(err).Message())
				return
			}

			require.NoError(t, err)
			require.NotNil(t, tt.assertValid)
			tt.assertValid(t, req, envelope)
		})
	}
}

func TestEnvelopeValidatingServiceExecuteCommandRejectsInvalidRequestBeforeDelegate(t *testing.T) {
	t.Parallel()

	delegate := &recordingEdgeGatewayService{}
	service := newEnvelopeValidatingService(delegate)

	_, err := service.ExecuteCommand(context.Background(), &gatewayv1.ExecuteCommandRequest{})
	require.Error(t, err)

	assert.Equal(t, codes.InvalidArgument, status.Code(err))
	assert.Zero(t, delegate.executeCalls)
}

func TestEnvelopeValidatingServiceSubscribeEventsRejectsInvalidRequestBeforeDelegate(t *testing.T) {
	t.Parallel()

	delegate := &recordingEdgeGatewayService{}
	service := newEnvelopeValidatingService(delegate)

	err := service.SubscribeEvents(&gatewayv1.SubscribeEventsRequest{}, stubGatewayEventStream{})
	require.Error(t, err)

	assert.Equal(t, codes.InvalidArgument, status.Code(err))
	assert.Zero(t, delegate.subscribeCalls)
}

func TestEnvelopeValidatingServiceExecuteCommandAttachesParsedEnvelope(t *testing.T) {
	t.Parallel()

	want := newValidExecuteCommandRequest()
	delegate := &recordingEdgeGatewayService{
		executeCommandFunc: func(ctx context.Context, req *gatewayv1.ExecuteCommandRequest) (*gatewayv1.ExecuteCommandResponse, error) {
			envelope, ok := parsedEnvelopeFromContext(ctx)
			require.True(t, ok)
			assert.Equal(t, want.GetRequestId(), envelope.RequestID)
			assert.Equal(t, want.GetDeviceSessionId(), envelope.DeviceSessionID)
			assert.Equal(t, want.GetMessageType(), envelope.MessageType)
			assert.Equal(t, want.GetPayloadBytes(), envelope.PayloadBytes)
			return &gatewayv1.ExecuteCommandResponse{RequestId: req.GetRequestId()}, nil
		},
	}
	service := newEnvelopeValidatingService(delegate)

	response, err := service.ExecuteCommand(context.Background(), want)
	require.NoError(t, err)

	assert.Equal(t, want.GetRequestId(), response.GetRequestId())
	assert.Equal(t, 1, delegate.executeCalls)
}

func TestEnvelopeValidatingServiceSubscribeEventsAttachesParsedEnvelope(t *testing.T) {
	t.Parallel()

	want := newValidSubscribeEventsRequest()
	delegate := &recordingEdgeGatewayService{
		subscribeEventsFunc: func(req *gatewayv1.SubscribeEventsRequest, stream grpc.ServerStreamingServer[gatewayv1.GatewayEvent]) error {
			envelope, ok := parsedEnvelopeFromContext(stream.Context())
			require.True(t, ok)
			assert.Equal(t, want.GetRequestId(), envelope.RequestID)
			assert.Equal(t, want.GetDeviceSessionId(), envelope.DeviceSessionID)
			assert.Equal(t, want.GetMessageType(), envelope.MessageType)
			assert.Equal(t, want.GetPayloadHash(), envelope.PayloadHash)
			assert.Equal(t, want.GetSignature(), envelope.Signature)
			return nil
		},
	}
	service := newEnvelopeValidatingService(delegate)

	err := service.SubscribeEvents(want, stubGatewayEventStream{})
	require.NoError(t, err)

	assert.Equal(t, 1, delegate.subscribeCalls)
}

type recordingEdgeGatewayService struct {
	gatewayv1.UnimplementedEdgeGatewayServer

	executeCalls        int
	subscribeCalls      int
	executeCommandFunc  func(context.Context, *gatewayv1.ExecuteCommandRequest) (*gatewayv1.ExecuteCommandResponse, error)
	subscribeEventsFunc func(*gatewayv1.SubscribeEventsRequest, grpc.ServerStreamingServer[gatewayv1.GatewayEvent]) error
}

func (s *recordingEdgeGatewayService) ExecuteCommand(ctx context.Context, req *gatewayv1.ExecuteCommandRequest) (*gatewayv1.ExecuteCommandResponse, error) {
	s.executeCalls++
	if s.executeCommandFunc != nil {
		return s.executeCommandFunc(ctx, req)
	}

	return &gatewayv1.ExecuteCommandResponse{}, nil
}

func (s *recordingEdgeGatewayService) SubscribeEvents(req *gatewayv1.SubscribeEventsRequest, stream grpc.ServerStreamingServer[gatewayv1.GatewayEvent]) error {
	s.subscribeCalls++
	if s.subscribeEventsFunc != nil {
		return s.subscribeEventsFunc(req, stream)
	}

	return nil
}

type stubGatewayEventStream struct {
	grpc.ServerStream
	ctx context.Context
}

func (s stubGatewayEventStream) Send(*gatewayv1.GatewayEvent) error {
	return nil
}

func (s stubGatewayEventStream) SetHeader(metadata.MD) error {
	return nil
}

func (s stubGatewayEventStream) SendHeader(metadata.MD) error {
	return nil
}

func (s stubGatewayEventStream) SetTrailer(metadata.MD) {}

func (s stubGatewayEventStream) Context() context.Context {
	if s.ctx == nil {
		return context.Background()
	}

	return s.ctx
}

func (s stubGatewayEventStream) SendMsg(any) error {
	return nil
}

func (s stubGatewayEventStream) RecvMsg(any) error {
	return nil
}