package grpcapi

import (
	"context"
	"testing"
	"time"

	"galaxy/gateway/internal/app"
	"galaxy/gateway/internal/config"
	"galaxy/gateway/internal/session"
	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/credentials/insecure"
	"google.golang.org/grpc/status"
)

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

	server, runGateway := newTestGateway(t, ServerDependencies{})
	defer runGateway.stop(t)

	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	defer func() {
		require.NoError(t, conn.Close())
	}()

	client := gatewayv1.NewEdgeGatewayClient(conn)
	_, err := client.ExecuteCommand(context.Background(), &gatewayv1.ExecuteCommandRequest{})
	require.Error(t, err)
	assert.Equal(t, codes.InvalidArgument, status.Code(err))
}

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

	server, runGateway := newTestGateway(t, ServerDependencies{})
	defer runGateway.stop(t)

	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	defer func() {
		require.NoError(t, conn.Close())
	}()

	client := gatewayv1.NewEdgeGatewayClient(conn)
	err := subscribeEventsError(t, context.Background(), client, &gatewayv1.SubscribeEventsRequest{})
	require.Error(t, err)
	assert.Equal(t, codes.InvalidArgument, status.Code(err))
}

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

	server, runGateway := newTestGateway(t, ServerDependencies{})
	defer runGateway.stop(t)

	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	defer func() {
		require.NoError(t, conn.Close())
	}()

	client := gatewayv1.NewEdgeGatewayClient(conn)
	_, err := client.ExecuteCommand(context.Background(), &gatewayv1.ExecuteCommandRequest{
		ProtocolVersion: "v2",
		DeviceSessionId: "device-session-123",
		MessageType:     "fleet.move",
		TimestampMs:     123456789,
		RequestId:       "request-123",
		PayloadBytes:    []byte("payload"),
		PayloadHash:     []byte("hash"),
		Signature:       []byte("signature"),
	})
	require.Error(t, err)
	assert.Equal(t, codes.FailedPrecondition, status.Code(err))
	assert.Equal(t, `unsupported protocol_version "v2"`, status.Convert(err).Message())
}

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

	server, runGateway := newTestGateway(t, ServerDependencies{
		SessionCache: staticSessionCache{
			lookupFunc: func(context.Context, string) (session.Record, error) {
				return newActiveSessionRecord(), nil
			},
		},
		ReplayStore: staticReplayStore{},
	})
	defer runGateway.stop(t)

	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	defer func() {
		require.NoError(t, conn.Close())
	}()

	client := gatewayv1.NewEdgeGatewayClient(conn)
	_, err := client.ExecuteCommand(context.Background(), newValidExecuteCommandRequest())
	require.Error(t, err)
	assert.Equal(t, codes.Unimplemented, status.Code(err))
}

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

	server, runGateway := newTestGateway(t, ServerDependencies{
		SessionCache: staticSessionCache{
			lookupFunc: func(context.Context, string) (session.Record, error) {
				return newActiveSessionRecord(), nil
			},
		},
	})
	defer runGateway.stop(t)

	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	defer func() {
		require.NoError(t, conn.Close())
	}()

	client := gatewayv1.NewEdgeGatewayClient(conn)
	_, err := client.ExecuteCommand(context.Background(), newValidExecuteCommandRequest())
	require.Error(t, err)
	assert.Equal(t, codes.Unavailable, status.Code(err))
	assert.Equal(t, "replay store is unavailable", status.Convert(err).Message())
}

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

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	server, runGateway := newTestGateway(t, ServerDependencies{
		SessionCache: staticSessionCache{
			lookupFunc: func(context.Context, string) (session.Record, error) {
				return newActiveSessionRecord(), nil
			},
		},
		ReplayStore: staticReplayStore{},
	})
	defer runGateway.stop(t)

	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	defer func() {
		require.NoError(t, conn.Close())
	}()

	client := gatewayv1.NewEdgeGatewayClient(conn)
	stream, err := client.SubscribeEvents(ctx, newValidSubscribeEventsRequest())
	require.NoError(t, err)

	event := recvBootstrapEvent(t, stream)
	assertServerTimeBootstrapEvent(t, event, newTestResponseSignerPublicKey(), "request-123", "trace-123", testCurrentTime.UnixMilli())

	recvResult := make(chan error, 1)
	go func() {
		_, recvErr := stream.Recv()
		recvResult <- recvErr
	}()

	require.Never(t, func() bool {
		select {
		case <-recvResult:
			return true
		default:
			return false
		}
	}, 100*time.Millisecond, 10*time.Millisecond, "stream closed before cancellation")

	cancel()

	var recvErr error
	require.Eventually(t, func() bool {
		select {
		case recvErr = <-recvResult:
			return true
		default:
			return false
		}
	}, time.Second, 10*time.Millisecond, "stream did not stop after client cancellation")
	require.Error(t, recvErr)
	assert.Equal(t, codes.Canceled, status.Code(recvErr))
}

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

	server, runGateway := newTestGateway(t, ServerDependencies{
		SessionCache: staticSessionCache{
			lookupFunc: func(context.Context, string) (session.Record, error) {
				return newActiveSessionRecord(), nil
			},
		},
	})
	defer runGateway.stop(t)

	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	defer func() {
		require.NoError(t, conn.Close())
	}()

	client := gatewayv1.NewEdgeGatewayClient(conn)
	err := subscribeEventsError(t, context.Background(), client, newValidSubscribeEventsRequest())
	require.Error(t, err)
	assert.Equal(t, codes.Unavailable, status.Code(err))
	assert.Equal(t, "replay store is unavailable", status.Convert(err).Message())
}

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

	server, runGateway := newTestGateway(t, ServerDependencies{})
	addr := waitForListenAddr(t, server)
	conn := dialGatewayClient(t, addr)
	require.NoError(t, conn.Close())

	runGateway.stop(t)

	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
	defer cancel()

	_, err := grpc.DialContext(
		ctx,
		addr,
		grpc.WithTransportCredentials(insecure.NewCredentials()),
		grpc.WithBlock(),
	)
	require.Error(t, err)
}

type runningGateway struct {
	cancel   context.CancelFunc
	resultCh chan error
}

func newTestGateway(t *testing.T, deps ServerDependencies) (*Server, runningGateway) {
	t.Helper()

	grpcCfg := config.DefaultAuthenticatedGRPCConfig()
	grpcCfg.Addr = "127.0.0.1:0"
	grpcCfg.FreshnessWindow = testFreshnessWindow

	return newTestGatewayWithGRPCConfig(t, grpcCfg, deps)
}

func newTestGatewayWithGRPCConfig(t *testing.T, grpcCfg config.AuthenticatedGRPCConfig, deps ServerDependencies) (*Server, runningGateway) {
	t.Helper()

	cfg := config.Config{
		ShutdownTimeout:   time.Second,
		AuthenticatedGRPC: grpcCfg,
	}

	if deps.Clock == nil {
		deps.Clock = fixedClock{now: testCurrentTime}
	}
	if deps.ResponseSigner == nil {
		deps.ResponseSigner = newTestResponseSigner()
	}
	if deps.Router == nil && deps.Service != nil {
		deps.Router = executeCommandAdapterRouter{service: deps.Service}
	}

	server := NewServer(cfg.AuthenticatedGRPC, deps)
	application := app.New(cfg, server)

	ctx, cancel := context.WithCancel(context.Background())
	resultCh := make(chan error, 1)
	go func() {
		resultCh <- application.Run(ctx)
	}()

	return server, runningGateway{
		cancel:   cancel,
		resultCh: resultCh,
	}
}

func (g runningGateway) stop(t *testing.T) {
	t.Helper()

	g.cancel()

	var err error
	require.Eventually(t, func() bool {
		select {
		case err = <-g.resultCh:
			return true
		default:
			return false
		}
	}, 2*time.Second, 10*time.Millisecond, "gateway did not stop after cancellation")
	require.NoError(t, err)
}

func waitForListenAddr(t *testing.T, server *Server) string {
	t.Helper()

	var addr string
	require.Eventually(t, func() bool {
		addr = server.listenAddr()
		return addr != ""
	}, time.Second, 10*time.Millisecond, "server did not start listening")
	return addr
}

func dialGatewayClient(t *testing.T, addr string) *grpc.ClientConn {
	t.Helper()

	ctx, cancel := context.WithTimeout(context.Background(), time.Second)
	defer cancel()

	conn, err := grpc.DialContext(
		ctx,
		addr,
		grpc.WithTransportCredentials(insecure.NewCredentials()),
		grpc.WithBlock(),
	)
	require.NoError(t, err)

	return conn
}