commit 4ecc170179a60d7c00386759f1a8b2f5537adb0d
Author: Kirill Pashin <kento@kekto.ru>
Date:   Mon Oct 6 23:05:19 2025 +0300

    v0.0.1

diff --git a/batcher/batcher.go b/batcher/batcher.go
new file mode 100644
index 0000000..e497bc0
--- /dev/null
+++ b/batcher/batcher.go
@@ -0,0 +1,108 @@
+package batcher
+
+import (
+	"btchrr/models"
+	"errors"
+)
+
+// Batcher - encapsulates the batch size for splitting a slice into batches
+type Batcher struct {
+	batchSize    int
+	placeholders map[string]struct{}
+}
+
+// NewBatcher - Creates a new batcher instance with the specified batch size.
+// Returns an error if the batch size is invalid.
+func NewBatcher(batchSize int) (*Batcher, error) {
+	if batchSize <= 0 {
+		return nil, models.ErrInvalidBatchSize
+	}
+	b := &Batcher{
+		batchSize:    batchSize,
+		placeholders: make(map[string]struct{}),
+	}
+	for _, ph := range []string{"?", "$", ":", ":"} {
+		b.placeholders[ph] = struct{}{}
+	}
+	return b, nil
+}
+
+// BuildBatch - Builds a batch query from a single query
+func (b *Batcher) BuildBatches(singleQuery string, items []any) ([]models.BatchedQuery, error) {
+	batchedItems, err := b.batchItems(items)
+	if err != nil {
+		return []models.BatchedQuery{}, err
+	}
+
+	batches, err := b.BuildBatchQuery(singleQuery, b.batchSize, batchedItems)
+	if err != nil {
+		return []models.BatchedQuery{}, err
+	}
+
+	return batches, nil
+}
+
+// Batch - Splits the input slice into batches of the specified size.
+// Returns an error if the input slice is empty.
+func (b *Batcher) batchItems(items []any) ([][]any, error) {
+	if len(items) == 0 {
+		return nil, models.ErrNoItems
+	}
+
+	totalItems := len(items)
+	numOfBatches := (totalItems + b.batchSize - 1) / b.batchSize // round up
+
+	batches := make([][]any, 0, numOfBatches)
+
+	for i := 0; i < totalItems; i += b.batchSize {
+		end := i + b.batchSize
+		if end > totalItems {
+			end = totalItems
+		}
+		// Copy elements to avoid possible side effects if the original slice is modified
+		batch := make([]any, end-i)
+		copy(batch, items[i:end])
+		batches = append(batches, batch)
+	}
+
+	return batches, nil
+}
+
+// BuildBatchQuery - builds a batch query from a single query
+func (b *Batcher) BuildBatchQuery(singleQuery string, batchSize int, batchedItems [][]any) (batchedQueries []models.BatchedQuery, err error) {
+	placeholder, err := b.detectPlaceholders(singleQuery)
+	if err != nil {
+		return []models.BatchedQuery{}, err
+	}
+	
+	switch placeholder {
+	case "?":
+		return b.buildSqliteQuery(singleQuery, batchSize, batchedItems)
+	case "$":
+		return b.buildPostgresQuery(singleQuery, batchSize, batchedItems)
+	default:
+		return b.buildQueryWithNamedPlaceholders(singleQuery, batchSize, placeholder, batchedItems)
+	}
+}
+
+// detectPlaceholder определяет тип плейсхолдера в SQL-запросе, ищет плейсхолдеры окружённые пробелами (" ? ", " $ ", " : ")
+func (b *Batcher) detectPlaceholders(query string) (string, error) {
+	for _, s := range query {
+		if _, ok := b.placeholders[string(s)]; ok {
+			return string(s), nil
+		}
+	}
+	return "", models.ErrCannotDetectPlaceholder
+}
+
+func (b *Batcher) buildSqliteQuery(singleQuery string, batchSize int, batchedItems [][]any) (batchedQueries []models.BatchedQuery, err error) {
+	return []models.BatchedQuery{}, errors.New("not implemented")
+}
+
+func (b *Batcher) buildPostgresQuery(singleQuery string, batchSize int, batchedItems [][]any) (batchedQueries []models.BatchedQuery, err error) {
+	return []models.BatchedQuery{}, errors.New("not implemented")
+}
+
+func (b *Batcher) buildQueryWithNamedPlaceholders(singleQuery string, batchSize int, placeholder string, batchedItems [][]any) (batchedQueries []models.BatchedQuery, err error) {
+	return []models.BatchedQuery{}, errors.New("not implemented")
+}
diff --git a/btchrr.go b/btchrr.go
new file mode 100644
index 0000000..15d9baa
--- /dev/null
+++ b/btchrr.go
@@ -0,0 +1,91 @@
+package Btchrr
+
+import (
+	"btchrr/batcher"
+	"btchrr/dbadapter"
+	"context"
+	"database/sql"
+
+	"btchrr/models"
+)
+
+// Btchrr - main struct for the package
+type Btchrr struct {
+	batcher     *batcher.Batcher
+	executor    Executor
+}
+
+// Executor - interface for the sql execution
+type Executor interface {
+	Exec(ctx context.Context, query models.BatchedQuery) (sql.Result, error)
+	CheckQuery(query string) error
+}
+
+// AggregatedResult - aggregated result from all batches
+type AggregatedResult struct {
+	rowsAffected int64
+	lastInsertId int64
+}
+
+func (r *AggregatedResult) LastInsertId() (int64, error) {
+	return r.lastInsertId, nil
+}
+
+func (r *AggregatedResult) RowsAffected() (int64, error) {
+	return r.rowsAffected, nil
+}
+
+// NewBtchrr - creates a new Btchrr instance
+func NewBtchrr(batchSize int, db *sql.DB) (*Btchrr, error) {
+	batcher, err := batcher.NewBatcher(batchSize)
+	if err != nil {
+		return nil, err
+	}
+
+	dbAdapter := dbadapter.NewSQLAdapter(db)
+
+	return &Btchrr{
+		batcher:     batcher,
+		executor:    dbAdapter,
+	}, nil
+}
+
+// Exec - accepts a query for single item, items and executes it in batches
+func (b *Btchrr) Exec(ctx context.Context, query string, items []any) (sql.Result, error) {
+	err := b.executor.CheckQuery(query)
+	if err != nil {
+		return nil, err
+	}
+
+	batches, err := b.batcher.BuildBatches(query, items)
+	if err != nil {
+		return nil, err
+	}
+
+	var totalRowsAffected int64
+	var lastInsertId int64
+
+	// Execute SQL query for each batch (transforming single-item query to batch query)
+	for _, batch := range batches {
+
+		result, err := b.executor.Exec(ctx, batch)
+		if err != nil {
+			return nil, err
+		}
+
+		// Суммируем результаты от всех батчей
+		rowsAffected, _ := result.RowsAffected()
+		totalRowsAffected += rowsAffected
+
+		// Берем последний InsertId
+		insertId, _ := result.LastInsertId()
+		if insertId > 0 {
+			lastInsertId = insertId
+		}
+	}
+
+	return &AggregatedResult{
+		rowsAffected: totalRowsAffected,
+		lastInsertId: lastInsertId,
+	}, nil
+}
diff --git a/dbadapter/sql_adapter.go b/dbadapter/sql_adapter.go
new file mode 100644
index 0000000..e59747a
--- /dev/null
+++ b/dbadapter/sql_adapter.go
@@ -0,0 +1,32 @@
+package dbadapter
+
+import (
+	"context"
+	"database/sql"
+
+	"btchrr/models"
+)
+
+type DBAdapter struct {
+	db *sql.DB
+}
+
+func NewSQLAdapter(db *sql.DB) *DBAdapter {
+	return &DBAdapter{db: db}
+}
+
+func (a *DBAdapter) Exec(ctx context.Context, batchedQuery models.BatchedQuery) (sql.Result, error) {
+	res, err := a.db.ExecContext(ctx, string(batchedQuery))
+
+	return res, err
+}
+
+// CheckQuery - checks if the query is valid
+func (a *DBAdapter) CheckQuery(query string) error {
+	stmt, err := a.db.Prepare(query) 
+	if err != nil {
+    return err
+	}
+	stmt.Close()
+	return nil
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..d8d5414
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module btchrr
+
+go 1.25.1
diff --git a/models/models.go b/models/models.go
new file mode 100644
index 0000000..85a3a23
--- /dev/null
+++ b/models/models.go
@@ -0,0 +1,12 @@
+package models
+
+import "errors"
+
+var (
+	ErrNoItems                 = errors.New("no items recieved, batch is empty")
+	ErrInvalidBatchSize        = errors.New("batch size must be greater than zero")
+	ErrCannotDetectPlaceholder = errors.New("cannot detect placeholder in query")
+)
+
+// BatchedQuery - single batch query
+type BatchedQuery string
diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..ea24a27
--- /dev/null
+++ b/readme.md
@@ -0,0 +1,110 @@
+# Btchrr
+
+A Go package for automatic batching of database operations with query transformation and result aggregation.
+
+## Features
+
+- ✅ Automatic splitting of items into batches of specified size
+- ✅ SQL query transformation from single-item to batch queries
+- ✅ Batch query execution with result aggregation
+- ✅ Support for any SQL database through `Executor` interface
+- ✅ Database-specific placeholder support (PostgreSQL, MySQL, SQLite, etc.)
+- ✅ Error handling and input validation
+
+## Usage
+
+### PostgreSQL Example
+
+```go
+package main
+
+import (
+    "context"
+    "database/sql"
+    "log"
+    "your-project/btchrr"  // Path to your package in the project
+)
+
+func main() {
+    // Database connection
+    db, err := sql.Open("postgres", "connection_string")
+    if err != nil {
+        log.Fatal(err)
+    }
+    defer db.Close()
+
+    // Create Btchrr instance with batch size 100 and PostgreSQL placeholder
+    btchrr, err := btchrr.NewBtchrr(100, db, "$1")
+    if err != nil {
+        log.Fatal(err)
+    }
+
+    // Prepare data for insertion
+    items := []any{"John", "Jane", "Bob", "Alice", "Charlie"}
+
+    // Execute query with automatic batching
+    ctx := context.Background()
+    result, err := btchrr.Exec(ctx, "INSERT INTO users (name) VALUES ($1)", items)
+    if err != nil {
+        log.Fatal(err)
+    }
+
+    // Get aggregated results
+    rowsAffected, _ := result.RowsAffected()
+    lastId, _ := result.LastInsertId()
+
+    log.Printf("Rows affected: %d, Last ID: %d", rowsAffected, lastId)
+}
+```
+
+### MySQL/SQLite Example
+
+```go
+// For MySQL or SQLite, use "?" placeholder
+btchrr, err := btchrr.NewBtchrr(100, db, "?")
+
+// Query will be transformed from:
+// "INSERT INTO users (name) VALUES (?)"
+// To:
+// "INSERT INTO users (name) VALUES (?, ?, ?)"
+```
+
+## API
+
+### NewBtchrr(batchSize int, db *sql.DB, placeholder string) (*Btchrr, error)
+
+Creates a new Btchrr instance with specified batch size, database connection, and placeholder format.
+
+**Parameters:**
+
+- `batchSize` - batch size (must be > 0)
+- `db` - database connection
+- `placeholder` - database-specific placeholder ("?" for MySQL/SQLite, "$1" for PostgreSQL)
+
+**Returns:**
+
+- `*Btchrr` - Btchrr instance
+- `error` - creation error
+
+### Exec(ctx context.Context, query string, items []any) (sql.Result, error)
+
+Executes SQL query for each batch and returns aggregated result.
+
+**Parameters:**
+
+- `ctx` - execution context
+- `query` - SQL query for single item
+- `items` - slice of items to process
+
+**Returns:**
+
+- `sql.Result` - aggregated result from all batches
+- `error` - execution error
+
+## Future Plans
+
+- [ ] Support for GORM, sqlx, ent, go-pg, pgx
+- [ ] Dynamic batch size based on item count
+- [ ] Transaction support
+- [ ] Performance metrics
+- [ ] Transaction support