package grpc

import (
	"context"
	"errors"
	"net"
	"reflect"
	"testing"
	"time"

	hav1 "gitea.nik4nao.com/nik/home-services/gen/ha/v1"
	"gitea.nik4nao.com/nik/home-services/ha-gateway/internal/core/domain"
	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/status"
	"google.golang.org/grpc/test/bufconn"
)

type mockEntityService struct {
	getStateFunc   func(ctx context.Context, id domain.EntityID) (*domain.EntityState, error)
	listStatesFunc func(ctx context.Context, ids []domain.EntityID, domainFilter string) ([]*domain.EntityState, error)
}

func (m *mockEntityService) GetState(ctx context.Context, id domain.EntityID) (*domain.EntityState, error) {
	if m.getStateFunc == nil {
		return nil, nil
	}
	return m.getStateFunc(ctx, id)
}

func (m *mockEntityService) ListStates(ctx context.Context, ids []domain.EntityID, domainFilter string) ([]*domain.EntityState, error) {
	if m.listStatesFunc == nil {
		return nil, nil
	}
	return m.listStatesFunc(ctx, ids, domainFilter)
}

func TestEntityGRPCGetState(t *testing.T) {
	now := time.Date(2026, 4, 9, 10, 0, 0, 0, time.UTC)

	tests := []struct {
		name     string
		err      error
		wantCode codes.Code
	}{
		{name: "happy path", wantCode: codes.OK},
		{name: "not found maps to codes.NotFound", err: ErrNotFound, wantCode: codes.NotFound},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var gotID domain.EntityID
			conn := newEntityTestClientConn(t, &mockEntityService{
				getStateFunc: func(ctx context.Context, id domain.EntityID) (*domain.EntityState, error) {
					gotID = id
					if tt.err != nil {
						return nil, tt.err
					}
					return &domain.EntityState{
						EntityID:    "light.kitchen",
						State:       "on",
						Attributes:  map[string]string{"friendly_name": "Kitchen"},
						LastChanged: now,
						LastUpdated: now,
					}, nil
				},
			})
			client := hav1.NewEntityServiceClient(conn)

			resp, err := client.GetState(context.Background(), &hav1.GetStateRequest{EntityId: "light.kitchen"})
			if status.Code(err) != tt.wantCode {
				t.Fatalf("status code = %v, want %v", status.Code(err), tt.wantCode)
			}
			if tt.wantCode != codes.OK {
				return
			}
			if gotID != "light.kitchen" {
				t.Fatalf("GetState id = %q, want %q", gotID, "light.kitchen")
			}
			if resp.GetState().GetEntityId() != "light.kitchen" {
				t.Fatalf("response state = %#v", resp.GetState())
			}
		})
	}
}

func TestEntityGRPCListStates(t *testing.T) {
	now := time.Date(2026, 4, 9, 10, 0, 0, 0, time.UTC)

	tests := []struct {
		name     string
		err      error
		wantCode codes.Code
	}{
		{name: "happy path", wantCode: codes.OK},
		{name: "error maps to codes.Internal", err: errors.New("boom"), wantCode: codes.Internal},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var gotIDs []domain.EntityID
			var gotDomain string
			conn := newEntityTestClientConn(t, &mockEntityService{
				listStatesFunc: func(ctx context.Context, ids []domain.EntityID, domainFilter string) ([]*domain.EntityState, error) {
					gotIDs = append([]domain.EntityID(nil), ids...)
					gotDomain = domainFilter
					if tt.err != nil {
						return nil, tt.err
					}
					return []*domain.EntityState{
						{
							EntityID:    "light.kitchen",
							State:       "on",
							Attributes:  map[string]string{"friendly_name": "Kitchen"},
							LastChanged: now,
							LastUpdated: now,
						},
						{
							EntityID:    "light.desk",
							State:       "off",
							Attributes:  map[string]string{"friendly_name": "Desk"},
							LastChanged: now,
							LastUpdated: now,
						},
					}, nil
				},
			})
			client := hav1.NewEntityServiceClient(conn)

			resp, err := client.ListStates(context.Background(), &hav1.ListStatesRequest{
				EntityIds: []string{"light.kitchen", "light.desk"},
				Domain:    "light",
			})
			if status.Code(err) != tt.wantCode {
				t.Fatalf("status code = %v, want %v", status.Code(err), tt.wantCode)
			}
			if tt.wantCode != codes.OK {
				return
			}

			wantIDs := []domain.EntityID{"light.kitchen", "light.desk"}
			if !reflect.DeepEqual(gotIDs, wantIDs) {
				t.Fatalf("ListStates ids = %#v, want %#v", gotIDs, wantIDs)
			}
			if gotDomain != "light" {
				t.Fatalf("ListStates domain = %q, want %q", gotDomain, "light")
			}
			if len(resp.GetStates()) != 2 {
				t.Fatalf("len(states) = %d, want 2", len(resp.GetStates()))
			}
		})
	}
}

func newEntityTestClientConn(t *testing.T, svc *mockEntityService) *grpc.ClientConn {
	t.Helper()

	lis := bufconn.Listen(testBufSize)
	server := grpc.NewServer()
	hav1.RegisterEntityServiceServer(server, NewEntityGRPC(svc))
	go func() {
		_ = server.Serve(lis)
	}()
	t.Cleanup(func() {
		server.Stop()
		_ = lis.Close()
	})

	conn, err := grpc.DialContext(
		context.Background(),
		"bufnet",
		grpc.WithContextDialer(func(ctx context.Context, s string) (net.Conn, error) {
			return lis.Dial()
		}),
		grpc.WithTransportCredentials(insecure.NewCredentials()),
	)
	if err != nil {
		t.Fatalf("grpc.DialContext() error = %v", err)
	}
	t.Cleanup(func() {
		_ = conn.Close()
	})
	return conn
}