package store

import (
	"fmt"
	"os"
	"sync"

	"gorm.io/driver/postgres"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
)

const DB_TYPE string = "DB_TYPE"
const DB_CONNECTION_SETTINGS string = "DB_CONNECTION_SETTINGS"
const MAX_ACCOUNT_INDEX int = 4294967295

var db *gorm.DB
var once sync.Once

func Init() (*gorm.DB, error) {

	dbType, isDbTypePresent := os.LookupEnv(DB_TYPE)
	dbConn, isDbConnPresent := os.LookupEnv(DB_CONNECTION_SETTINGS)
	if !isDbConnPresent || !isDbTypePresent {
		return nil, fmt.Errorf("missing environment variables: %s=%s, %s=%s", DB_CONNECTION_SETTINGS, dbConn, DB_TYPE, dbType)
	}

	if db != nil {
		return db, nil
	}
	fmt.Println("dbType: ", dbType)
	fmt.Println("dbConn: ", dbConn)
	var _err error
	once.Do(func() {
		var dialect gorm.Dialector
		switch dbType {
		case "sqlite":
			dialect = sqlite.Open(dbConn)
		case "postgres":
			dialect = postgres.Open(dbConn)
		default:
			_err = fmt.Errorf("unknown database type: %s", dbType)
			return
		}
		_db, err := gorm.Open(dialect, &gorm.Config{})
		if err != nil {
			_err = err
			return
		}

		db = _db
		db.AutoMigrate(&TronAccount{})
		db.AutoMigrate(&EthereumAccount{})
		db.AutoMigrate(&Webhook{})
	})
	if _err != nil {
		return nil, _err
	}
	return db, nil
}