First working version

internal/database/client.go

@@ -0,0 +1,67 @@
+package database
+
+import (
+	"database/sql"
+	"fmt"
+
+	_ "github.com/lib/pq"
+)
+
+// Client represents a database connection
+type Client struct {
+	db     *sql.DB
+	schema string
+}
+
+// Config holds database connection parameters
+type Config struct {
+	Host     string
+	Port     int
+	Database string
+	Schema   string
+	User     string
+	Password string
+}
+
+// NewClient creates a new database client
+func NewClient(cfg Config) (*Client, error) {
+	connStr := fmt.Sprintf(
+		"host=%s port=%d user=%s password=%s dbname=%s sslmode=disable",
+		cfg.Host, cfg.Port, cfg.User, cfg.Password, cfg.Database,
+	)
+
+	db, err := sql.Open("postgres", connStr)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open database: %w", err)
+	}
+
+	if err := db.Ping(); err != nil {
+		db.Close()
+		return nil, fmt.Errorf("failed to connect to database: %w", err)
+	}
+
+	return &Client{
+		db:     db,
+		schema: cfg.Schema,
+	}, nil
+}
+
+// Close closes the database connection
+func (c *Client) Close() error {
+	return c.db.Close()
+}
+
+// TableExists checks if a table exists in the schema
+func (c *Client) TableExists(tableName string) (bool, error) {
+	query := `
+		SELECT EXISTS (
+			SELECT 1
+			FROM information_schema.tables
+			WHERE table_schema = $1 AND table_name = $2
+		)
+	`
+
+	var exists bool
+	err := c.db.QueryRow(query, c.schema, tableName).Scan(&exists)
+	return exists, err
+}