package xorm

import (
	"errors"
	"fmt"
	"os"
	"reflect"
	"runtime"
	"sync"

	"github.com/lunny/xorm/core"
	_ "github.com/lunny/xorm/dialects"
	_ "github.com/lunny/xorm/drivers"
)

const (
	Version string = "0.3.1"
)

func close(engine *Engine) {
	engine.Close()
}

// new a db manager according to the parameter. Currently support four
// drivers
func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
	driver := core.QueryDriver(driverName)
	if driver == nil {
		return nil, errors.New(fmt.Sprintf("Unsupported driver name: %v", driverName))
	}

	uri, err := driver.Parse(driverName, dataSourceName)
	if err != nil {
		return nil, err
	}

	dialect := core.QueryDialect(uri.DbType)
	if dialect == nil {
		return nil, errors.New(fmt.Sprintf("Unsupported dialect type: %v", uri.DbType))
	}

	err = dialect.Init(uri, driverName, dataSourceName)
	if err != nil {
		return nil, err
	}

	engine := &Engine{DriverName: driverName,
		DataSourceName: dataSourceName, dialect: dialect,
		tableCachers: make(map[reflect.Type]Cacher)}

	engine.SetMapper(SnakeMapper{})

	engine.Filters = dialect.Filters()

	engine.Tables = make(map[reflect.Type]*core.Table)
	engine.mutex = &sync.Mutex{}
	engine.TagIdentifier = "xorm"

	engine.Logger = os.Stdout

	//engine.Pool = NewSimpleConnectPool()
	//engine.Pool = NewNoneConnectPool()
	//engine.Cacher = NewLRUCacher()
	err = engine.SetPool(NewSysConnectPool())
	runtime.SetFinalizer(engine, close)
	return engine, err
}