commit 2dd1fb91c7201fafaa4491f72b46c93df9f8988c
Author: Anton Zadvorny <thcheetah@gmail.com>
Date:   Sun Jan 7 08:40:41 2024 +0300

    Extract leaf package

diff --git a/.golangci.yml b/.golangci.yml
new file mode 100644
index 0000000..aa3c86b
--- /dev/null
+++ b/.golangci.yml
@@ -0,0 +1,52 @@
+run:
+  timeout: 5m
+  output:
+    format: tab
+
+linters-settings:
+  govet:
+    check-shadowing: true
+  golint:
+    min-confidence: 0.1
+  maligned:
+    suggest-new: true
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+  misspell:
+    locale: US
+  lll:
+    line-length: 140
+  gocritic:
+    enabled-tags:
+      - performance
+      - style
+      - experimental
+    disabled-checks:
+      - unnamedResult
+      - paramTypeCombine
+
+linters:
+  enable:
+    - megacheck
+    - revive
+    - govet
+    - unconvert
+    - megacheck
+    - unused
+    - gas
+    - gocyclo
+    - dupl
+    - misspell
+    - unparam
+    - typecheck
+    - ineffassign
+    - stylecheck
+    - gochecknoinits
+    - exportloopref
+    - gocritic
+    - nakedret
+    - gosimple
+    - prealloc
+  fast: false
+  disable-all: true
diff --git a/document.go b/document.go
new file mode 100644
index 0000000..4409d63
--- /dev/null
+++ b/document.go
@@ -0,0 +1,37 @@
+package leaf
+
+import (
+	"time"
+
+	"go.mongodb.org/mongo-driver/bson/primitive"
+)
+
+type Document interface {
+	ID() primitive.ObjectID
+	SetID(id primitive.ObjectID)
+
+	SetCreatedAt(ts time.Time)
+	SetUpdatedAt(ts time.Time)
+}
+
+type Base struct {
+	ObjectID  primitive.ObjectID `json:"id,omitempty" bson:"_id,omitempty" example:"507f1f77bcf86cd799439011"`
+	CreatedAt time.Time          `json:"created_at" bson:"created_at" format:"dateTime" example:"2020-01-01T00:00:00Z"`
+	UpdatedAt time.Time          `json:"updated_at" bson:"updated_at" format:"dateTime" example:"2020-01-01T00:00:00Z"`
+}
+
+func (s *Base) ID() primitive.ObjectID {
+	return s.ObjectID
+}
+
+func (s *Base) SetID(id primitive.ObjectID) {
+	s.ObjectID = id
+}
+
+func (s *Base) SetCreatedAt(ts time.Time) {
+	s.CreatedAt = ts
+}
+
+func (s *Base) SetUpdatedAt(ts time.Time) {
+	s.UpdatedAt = ts
+}
diff --git a/document_test.go b/document_test.go
new file mode 100644
index 0000000..3b4519c
--- /dev/null
+++ b/document_test.go
@@ -0,0 +1,51 @@
+package leaf
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+)
+
+func TestBaseInitialization(t *testing.T) {
+	id := primitive.NewObjectID()
+	now := time.Now()
+
+	base := Base{}
+	base.SetID(id)
+	base.SetCreatedAt(now)
+	base.SetUpdatedAt(now)
+
+	assert.Equal(t, id, base.ID())
+	assert.Equal(t, id, base.ObjectID)
+	assert.True(t, base.CreatedAt.Equal(now))
+	assert.True(t, base.UpdatedAt.Equal(now))
+}
+
+func TestBaseJSONMarshalling(t *testing.T) {
+	base := Base{}
+	base.SetID(primitive.NewObjectID())
+	base.SetCreatedAt(time.Now())
+	base.SetUpdatedAt(time.Now())
+
+	data, err := json.Marshal(base)
+	assert.NoError(t, err)
+	assert.True(t, json.Valid(data))
+}
+
+func TestBaseBSONMarshalling(t *testing.T) {
+	base := Base{}
+	base.SetID(primitive.NewObjectID())
+	base.SetCreatedAt(time.Now())
+	base.SetUpdatedAt(time.Now())
+
+	data, err := bson.Marshal(base)
+	assert.NoError(t, err)
+
+	var m bson.M
+	err = bson.Unmarshal(data, &m)
+	assert.NoError(t, err)
+}
diff --git a/filter.go b/filter.go
new file mode 100644
index 0000000..b030fa6
--- /dev/null
+++ b/filter.go
@@ -0,0 +1,84 @@
+package leaf
+
+var (
+	FilterAll = FilterDocument{}
+)
+
+const (
+	OperatorEq     Operator = "$eq"
+	OperatorNe     Operator = "$ne"
+	OperatorGt     Operator = "$gt"
+	OperatorGte    Operator = "$gte"
+	OperatorLt     Operator = "$lt"
+	OperatorLte    Operator = "$lte"
+	OperatorIn     Operator = "$in"
+	OperatorNin    Operator = "$nin"
+	OperatorExists Operator = "$exists"
+	OperatorRegex  Operator = "$regex"
+)
+
+type M map[Operator]any
+type Operator string
+type FilterDocument map[string]M
+
+func Eq[T any](field string, value T) FilterDocument {
+	return createSelector(field, OperatorEq, value)
+}
+
+func Ne[T any](field string, value T) FilterDocument {
+	return createSelector(field, OperatorNe, value)
+}
+
+func Gt[T any](field string, value T) FilterDocument {
+	return createSelector(field, OperatorGt, value)
+}
+
+func Gte[T any](field string, value T) FilterDocument {
+	return createSelector(field, OperatorGte, value)
+}
+
+func Lt[T any](field string, value T) FilterDocument {
+	return createSelector(field, OperatorLt, value)
+}
+
+func Lte[T any](field string, value T) FilterDocument {
+	return createSelector(field, OperatorLte, value)
+}
+
+func In[T any](field string, value []T) FilterDocument {
+	return createSelector(field, OperatorIn, value)
+}
+
+func Nin[T any](field string, value []T) FilterDocument {
+	return createSelector(field, OperatorNin, value)
+}
+
+func Exists(field string, value bool) FilterDocument {
+	return createSelector(field, OperatorExists, value)
+}
+
+func Regex(field string, value string) FilterDocument {
+	return createSelector(field, OperatorRegex, value)
+}
+
+func createSelector(field string, operator Operator, value any) FilterDocument {
+	return FilterDocument{field: M{operator: value}}
+}
+
+func Filter(docs ...FilterDocument) FilterDocument {
+	query := FilterDocument{}
+	for _, doc := range docs {
+		for field, operators := range doc {
+			if _, ok := query[field]; !ok {
+				query[field] = operators
+				continue
+			}
+
+			for op, value := range operators {
+				query[field][op] = value
+			}
+		}
+	}
+
+	return query
+}
diff --git a/filter_test.go b/filter_test.go
new file mode 100644
index 0000000..4de96f2
--- /dev/null
+++ b/filter_test.go
@@ -0,0 +1,56 @@
+package leaf
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFilter(t *testing.T) {
+	t.Run("merge two filter documents", func(t *testing.T) {
+		doc1 := Filter(
+			Gt("field1", 1),
+			Lt("field2", 10),
+		)
+
+		doc2 := Filter(
+			Ne("field1", 2),
+			Eq("field3", "test"),
+		)
+
+		expected := FilterDocument{
+			"field1": {"$gt": 1, "$ne": 2},
+			"field2": {"$lt": 10},
+			"field3": {"$eq": "test"},
+		}
+
+		assert.Equal(t, expected, Filter(doc1, doc2))
+	})
+
+	t.Run("merge three filter documents", func(t *testing.T) {
+		doc1 := Filter(
+			Gt("field1", 1),
+			Lt("field2", 10),
+		)
+
+		doc2 := Filter(
+			Ne("field1", 2),
+			Eq("field3", "test"),
+		)
+
+		doc3 := Filter(
+			Gt("field1", 5),
+			Ne("field2", 5),
+			Eq("field4", "hello"),
+		)
+
+		expected := FilterDocument{
+			"field1": {"$gt": 5, "$ne": 2},
+			"field2": {"$lt": 10, "$ne": 5},
+			"field3": {"$eq": "test"},
+			"field4": {"$eq": "hello"},
+		}
+
+		assert.Equal(t, expected, Filter(doc1, doc2, doc3))
+	})
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..a97c8b7
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,28 @@
+module go.pkg.cx/leaf
+
+go 1.21
+
+require (
+	github.com/rs/zerolog v1.31.0
+	github.com/stretchr/testify v1.8.4
+	go.mongodb.org/mongo-driver v1.13.1
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/golang/snappy v0.0.1 // indirect
+	github.com/klauspost/compress v1.13.6 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.19 // indirect
+	github.com/montanaflynn/stats v0.0.0-20171201202039-1bf9dbcd8cbe // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/xdg-go/pbkdf2 v1.0.0 // indirect
+	github.com/xdg-go/scram v1.1.2 // indirect
+	github.com/xdg-go/stringprep v1.0.4 // indirect
+	github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d // indirect
+	golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d // indirect
+	golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4 // indirect
+	golang.org/x/sys v0.12.0 // indirect
+	golang.org/x/text v0.7.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..da95aed
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,77 @@
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
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+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/index.go b/index.go
new file mode 100644
index 0000000..0553bc3
--- /dev/null
+++ b/index.go
@@ -0,0 +1,98 @@
+package leaf
+
+import (
+	"context"
+
+	"github.com/rs/zerolog"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	driver "go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+)
+
+func ensureIndexes(ctx context.Context, collection *driver.Collection, models []driver.IndexModel, createIndexes bool, logger *zerolog.Logger) error {
+	existing, err := indexNames(ctx, collection)
+	if err != nil {
+		return err
+	}
+
+	indexes := filterIndexes(models, existing, logger)
+	if len(indexes) < 1 {
+		return nil
+	}
+
+	if !createIndexes {
+		for _, im := range indexes {
+			logger.Warn().Str("name", *im.Options.Name).Msg("index declared but not present")
+		}
+
+		return nil
+	}
+
+	_, err = collection.Indexes().CreateMany(ctx, indexes)
+	if err != nil {
+		return err
+	}
+
+	for _, im := range indexes {
+		logger.Info().Str("name", *im.Options.Name).Msg("index created")
+	}
+
+	return nil
+}
+
+func indexNames(ctx context.Context, collection *driver.Collection) (map[string]struct{}, error) {
+	cursor, err := collection.Indexes().List(ctx)
+	if err != nil {
+		return nil, err
+	}
+	defer cursor.Close(ctx)
+
+	names := make(map[string]struct{})
+	for cursor.Next(ctx) {
+		var idx bson.M
+		if err := cursor.Decode(&idx); err != nil {
+			continue
+		}
+
+		name, ok := idx["name"].(string)
+		if !ok {
+			continue
+		}
+
+		names[name] = struct{}{}
+	}
+
+	return names, nil
+}
+
+func filterIndexes(models []driver.IndexModel, names map[string]struct{}, logger *zerolog.Logger) []driver.IndexModel {
+	var filtered []driver.IndexModel
+	for _, im := range models {
+		if im.Options.Name == nil {
+			logger.Warn().Interface("keys", im.Keys).Msg("must specify index name explicitly")
+			continue
+		}
+
+		if _, ok := names[*im.Options.Name]; !ok {
+			filtered = append(filtered, im)
+		}
+	}
+
+	return filtered
+}
+
+func withTimestampIndexes(models []driver.IndexModel) []driver.IndexModel {
+	tsModels := []driver.IndexModel{
+		{
+			Keys:    bson.D{primitive.E{Key: "created_at", Value: 1}},
+			Options: options.Index().SetName("created_at_1"),
+		},
+		{
+			Keys:    bson.D{primitive.E{Key: "updated_at", Value: 1}},
+			Options: options.Index().SetName("updated_at_1"),
+		},
+	}
+
+	return append(models, tsModels...)
+}
diff --git a/objectid.go b/objectid.go
new file mode 100644
index 0000000..8d9cbd7
--- /dev/null
+++ b/objectid.go
@@ -0,0 +1,23 @@
+package leaf
+
+import (
+	"go.mongodb.org/mongo-driver/bson/primitive"
+)
+
+func ObjectIDFromHex(hex string) primitive.ObjectID {
+	id, err := primitive.ObjectIDFromHex(hex)
+	if err != nil {
+		return primitive.NilObjectID
+	}
+
+	return id
+}
+
+func ObjectIDFromHexSlice(hexSlice []string) []primitive.ObjectID {
+	ids := make([]primitive.ObjectID, len(hexSlice))
+	for i := range hexSlice {
+		ids[i] = ObjectIDFromHex(hexSlice[i])
+	}
+
+	return ids
+}
diff --git a/objectid_test.go b/objectid_test.go
new file mode 100644
index 0000000..9213f10
--- /dev/null
+++ b/objectid_test.go
@@ -0,0 +1,40 @@
+package leaf
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+)
+
+func TestObjectIDFromHex(t *testing.T) {
+	t.Run("valid hex", func(t *testing.T) {
+		hex := "507f1f77bcf86cd799439011"
+		id, err := primitive.ObjectIDFromHex(hex)
+
+		assert.NoError(t, err)
+		assert.Equal(t, id, ObjectIDFromHex(hex))
+	})
+
+	t.Run("invalid hex", func(t *testing.T) {
+		hex := "invalidhex"
+		assert.Equal(t, primitive.NilObjectID, ObjectIDFromHex(hex))
+	})
+}
+
+func TestObjectIDFromHexSlice(t *testing.T) {
+	t.Run("valid hex slice", func(t *testing.T) {
+		hex := []string{"507f1f77bcf86cd799439011", "507f1f77bcf86cd799439012"}
+		ids := make([]primitive.ObjectID, len(hex))
+		for i := range hex {
+			ids[i], _ = primitive.ObjectIDFromHex(hex[i])
+		}
+
+		assert.Equal(t, ids, ObjectIDFromHexSlice(hex))
+	})
+
+	t.Run("invalid hex slice", func(t *testing.T) {
+		hex := []string{"invalidhex", "invalidhex"}
+		assert.Equal(t, []primitive.ObjectID{primitive.NilObjectID, primitive.NilObjectID}, ObjectIDFromHexSlice(hex))
+	})
+}
diff --git a/repository.go b/repository.go
new file mode 100644
index 0000000..cd9400a
--- /dev/null
+++ b/repository.go
@@ -0,0 +1,118 @@
+package leaf
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/rs/zerolog"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/bson/primitive"
+	driver "go.mongodb.org/mongo-driver/mongo"
+	"go.mongodb.org/mongo-driver/mongo/options"
+)
+
+type RepositoryInterface[T Document] interface {
+	Find(ctx context.Context, filter interface{}, opts ...*options.FindOptions) ([]T, error)
+	FindOne(ctx context.Context, filter interface{}, opts ...*options.FindOneOptions) (T, error)
+	FindByID(ctx context.Context, id string, opts ...*options.FindOneOptions) (T, error)
+
+	Create(ctx context.Context, data T, opts ...*options.InsertOneOptions) (T, error)
+
+	Update(ctx context.Context, data T, opts ...*options.UpdateOptions) (T, error)
+	UpdateOne(ctx context.Context, filter interface{}, data T, opts ...*options.UpdateOptions) (T, error)
+
+	Delete(ctx context.Context, data T, opts ...*options.DeleteOptions) error
+	DeleteOne(ctx context.Context, filter interface{}, opts ...*options.DeleteOptions) error
+
+	CountDocuments(ctx context.Context, filter interface{}, opts ...*options.CountOptions) (int, error)
+}
+
+type Repository[T Document] struct {
+	collection *driver.Collection
+	indexes    []driver.IndexModel
+}
+
+func NewRepository[T Document](collection *driver.Collection, indexes []driver.IndexModel) *Repository[T] {
+	return &Repository[T]{collection: collection, indexes: withTimestampIndexes(indexes)}
+}
+
+func (s *Repository[T]) Find(ctx context.Context, filter interface{}, opts ...*options.FindOptions) ([]T, error) {
+	cursor, err := s.collection.Find(ctx, filter, opts...)
+	if err != nil {
+		return nil, repositoryError(s.collection, "Find", err)
+	}
+	defer cursor.Close(ctx)
+
+	var data []T
+	if err := cursor.All(ctx, &data); err != nil {
+		return nil, repositoryError(s.collection, "Find", err)
+	}
+
+	return data, nil
+}
+
+func (s *Repository[T]) FindOne(ctx context.Context, filter interface{}, opts ...*options.FindOneOptions) (T, error) {
+	var data T
+	if err := s.collection.FindOne(ctx, filter, opts...).Decode(&data); err != nil {
+		return data, repositoryError(s.collection, "FindOne", err)
+	}
+
+	return data, nil
+}
+
+func (s *Repository[T]) FindByID(ctx context.Context, id string, opts ...*options.FindOneOptions) (T, error) {
+	return s.FindOne(ctx, bson.M{"_id": ObjectIDFromHex(id)}, opts...)
+}
+
+func (s *Repository[T]) Create(ctx context.Context, data T, opts ...*options.InsertOneOptions) (T, error) {
+	data.SetCreatedAt(time.Now().UTC())
+	data.SetUpdatedAt(time.Now().UTC())
+
+	res, err := s.collection.InsertOne(ctx, data, opts...)
+	if err != nil {
+		return data, repositoryError(s.collection, "Create", err)
+	}
+
+	data.SetID(res.InsertedID.(primitive.ObjectID))
+	return data, nil
+}
+
+func (s *Repository[T]) Update(ctx context.Context, data T, opts ...*options.UpdateOptions) (T, error) {
+	return s.UpdateOne(ctx, bson.M{"_id": data.ID()}, data, opts...)
+}
+
+func (s *Repository[T]) UpdateOne(ctx context.Context, filter interface{}, data T, opts ...*options.UpdateOptions) (T, error) {
+	data.SetUpdatedAt(time.Now().UTC())
+
+	if _, err := s.collection.UpdateOne(ctx, filter, bson.M{"$set": data}, opts...); err != nil {
+		return data, repositoryError(s.collection, "UpdateOne", err)
+	}
+
+	return data, nil
+}
+
+func (s *Repository[T]) Delete(ctx context.Context, data T, opts ...*options.DeleteOptions) error {
+	return s.DeleteOne(ctx, bson.M{"_id": data.ID()}, opts...)
+}
+
+func (s *Repository[T]) DeleteOne(ctx context.Context, filter interface{}, opts ...*options.DeleteOptions) error {
+	if _, err := s.collection.DeleteOne(ctx, filter, opts...); err != nil {
+		return repositoryError(s.collection, "DeleteOne", err)
+	}
+
+	return nil
+}
+
+func (s *Repository[T]) CountDocuments(ctx context.Context, filter interface{}, opts ...*options.CountOptions) (int, error) {
+	count, err := s.collection.CountDocuments(ctx, filter, opts...)
+	return int(count), err
+}
+
+func (s *Repository[T]) EnsureIndexes(ctx context.Context, createIndexes bool, logger *zerolog.Logger) error {
+	return ensureIndexes(ctx, s.collection, s.indexes, createIndexes, logger)
+}
+
+func repositoryError(collection *driver.Collection, op string, err error) error {
+	return fmt.Errorf("%s.%s: %v", collection.Name(), op, err)
+}