Refactor and remove sqlite and replace with MySQL

internal/storage/mysql/db.go

@@ -0,0 +1,78 @@
+package storage
+
+import (
+	"database/sql"
+	"embed"
+	"fmt"
+	"log"
+	"os"
+
+	_ "github.com/go-sql-driver/mysql"
+	"github.com/golang-migrate/migrate/v4"
+	"github.com/golang-migrate/migrate/v4/database/mysql"
+	iofs "github.com/golang-migrate/migrate/v4/source/iofs"
+)
+
+//go:embed migrations/*.sql
+var migrationFiles embed.FS
+
+var DB *sql.DB
+
+// InitDB connects to MySQL, runs migrations, and returns the DB handle.
+func InitDB() *sql.DB {
+	cfg := getDSNFromEnv()
+
+	db, err := sql.Open("mysql", cfg)
+	if err != nil {
+		log.Fatalf("❌ Failed to connect to MySQL: %v", err)
+	}
+
+	if err := db.Ping(); err != nil {
+		log.Fatalf("❌ MySQL not reachable: %v", err)
+	}
+
+	if err := runMigrations(db); err != nil {
+		log.Fatalf("❌ Migration failed: %v", err)
+	}
+
+	DB = db
+	return db
+}
+
+// runMigrations applies any pending .sql files in migrations/
+func runMigrations(db *sql.DB) error {
+	driver, err := mysql.WithInstance(db, &mysql.Config{})
+	if err != nil {
+		return err
+	}
+
+	src, err := iofs.New(migrationFiles, "migrations")
+	if err != nil {
+		return err
+	}
+
+	m, err := migrate.NewWithInstance("iofs", src, "mysql", driver)
+	if err != nil {
+		return err
+	}
+
+	err = m.Up()
+	if err == migrate.ErrNoChange {
+		log.Println("✅ Database schema up to date.")
+		return nil
+	}
+	return err
+}
+
+func getDSNFromEnv() string {
+	user := os.Getenv("DB_USER")
+	pass := os.Getenv("DB_PASS")
+	host := os.Getenv("DB_HOST") // e.g. localhost or 127.0.0.1
+	port := os.Getenv("DB_PORT") // e.g. 3306
+	name := os.Getenv("DB_NAME") // e.g. synlotto
+	params := "parseTime=true&multiStatements=true"
+
+	dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s?%s",
+		user, pass, host, port, name, params)
+	return dsn
+}