Count method

app/main.go

@@ -89,6 +89,21 @@ func doList(db *gorm.DB) {
 	}
 }
 
+func doCount(db *gorm.DB) {
+	repo := repository.RepoBase[models.Cert]{}
+	repo.Init(db, nil)
+
+	filter := CertFilter{
+		Alive: &TRUE,
+	}
+
+	count, err := repo.Count(filter)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf(">>> count: %d\n", count)
+}
+
 func doGet(db *gorm.DB) {
 	repo := repository.RepoBase[models.Cert]{}
 	repo.Init(db, nil)
@@ -130,8 +145,9 @@ func main() {
 
 	db := db.InitDB()
 
-	doMagic(db)
+	// doMagic(db)
 	// doList(db)
+	doCount(db)
 	// doGet(db)
 	// doExists(db)
 	// inheritance.DoInheritanceTest()

app/repository/method_count.go

@@ -0,0 +1,32 @@
+package repository
+
+import (
+	"repo-pattern/app/repository/smartfilter"
+
+	"gorm.io/gorm/schema"
+)
+
+type CountMethod[T schema.Tabler] struct {
+	repo *RepoBase[T]
+}
+
+func (m *CountMethod[T]) Init(repo *RepoBase[T]) {
+	m.repo = repo
+}
+
+func (m CountMethod[T]) Count(filter interface{}) (int64, error) {
+	var (
+		model T
+		count int64
+	)
+
+	query := m.repo.dbConn.Model(model)
+
+	query, err := smartfilter.ToQuery(model, filter, query)
+	if err != nil {
+		return 0, err
+	}
+
+	query.Count(&count)
+	return count, nil
+}

app/repository/method_count_test.go

@@ -0,0 +1,60 @@
+package repository
+
+import (
+	"fmt"
+	"regexp"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCountMethod(t *testing.T) {
+	t.Run("Count without filter", func(t *testing.T) {
+		sqldb, db, mock := NewMockDB()
+		defer sqldb.Close()
+
+		repo := RepoBase[MyModel]{}
+		repo.Init(db, nil)
+
+		filter := MyModelFilter{}
+
+		sql := "SELECT count(*) FROM my_models"
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql)))
+
+		result, err := repo.Count(filter)
+		assert.Equal(t, result, int64(0))
+		assert.Nil(t, err)
+
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("there were unfulfilled expectations: %s", err)
+		}
+	})
+
+	t.Run("Count with filter", func(t *testing.T) {
+		sqldb, db, mock := NewMockDB()
+		defer sqldb.Close()
+
+		repo := RepoBase[MyModel]{}
+		repo.Init(db, nil)
+
+		id1 := uuid.New()
+		id2 := uuid.New()
+		id3 := uuid.New()
+		filter := MyModelFilter{
+			Ids: &[]uuid.UUID{id1, id2, id3},
+		}
+
+		sql := "SELECT count(*) FROM my_models WHERE my_models.id IN ($1,$2,$3)"
+		mock.ExpectQuery(fmt.Sprintf("^%s$", regexp.QuoteMeta(sql))).
+			WithArgs(id1, id2, id3)
+
+		result, err := repo.Count(filter)
+		assert.Equal(t, result, int64(0))
+		assert.Nil(t, err)
+
+		if err := mock.ExpectationsWereMet(); err != nil {
+			t.Errorf("there were unfulfilled expectations: %s", err)
+		}
+	})
+}

app/repository/method_list_test.go

@@ -44,6 +44,7 @@ func (m MyModel) TableName() string {
 
 type MyModelFilter struct {
 	Id    *uuid.UUID   `filterfield:"field=id,operator=EQ"`
+	Ids   *[]uuid.UUID `filterfield:"field=id,operator=IN"`
 	Value *string      `filterfield:"field=value,operator=EQ"`
 	Count *int         `filterfield:"field=count,operator=GT"`
 }

app/repository/repository.go

@@ -20,10 +20,11 @@ type RepoBase[T schema.Tabler] struct {
 	ListMethod[T]
 	GetMethod[T]
 	ExistsMethod[T]
+	CountMethod[T]
 	methods []MethodInitInterface[T]
 }
 
-func (repo *RepoBase[T]) InitMethods(dbConn *gorm.DB) {
+func (repo *RepoBase[T]) InitMethods() {
 	for _, method := range repo.methods {
 		method.Init(repo)
 	}
@@ -41,6 +42,11 @@ func (m *RepoBase[T]) Init(dbConn *gorm.DB, options *RepoOptions) {
 		}
 	}
 
-	m.methods = []MethodInitInterface[T]{&m.ListMethod, &m.GetMethod, &m.ExistsMethod}
+	m.methods = []MethodInitInterface[T]{
-	m.InitMethods(dbConn)
+		&m.ListMethod,
+		&m.GetMethod,
+		&m.ExistsMethod,
+		&m.CountMethod,
+	}
+	m.InitMethods()
 }