package registry

import (
	"fmt"
	"log"
	"reflect"

	cda "git.loafle.net/commons_go/di/annotation"
	cdur "git.loafle.net/commons_go/di/util/reflect"
)

func init() {
	registry = newRegistry()
}

var registry ComponentRegistry

type ComponentRegistry interface {
	RegisterType(t reflect.Type, ca *cda.ComponentAnnotation) error

	GetInstance(t reflect.Type) (interface{}, error)
	GetInstanceByName(name string) (interface{}, error)
}

func newRegistry() ComponentRegistry {
	r := &defaultComponentRegistry{}
	r.definitionsByType = make(map[reflect.Type]*TypeDefinition, 0)
	r.definitionByName = make(map[string]*TypeDefinition, 0)

	return r
}

type defaultComponentRegistry struct {
	definitionsByType map[reflect.Type]*TypeDefinition

	definitionByName map[string]*TypeDefinition
}

func RegisterType(t reflect.Type, ca *cda.ComponentAnnotation) error {
	return registry.RegisterType(t, ca)
}
func (cr *defaultComponentRegistry) RegisterType(t reflect.Type, ca *cda.ComponentAnnotation) error {
	if nil == t {
		return fmt.Errorf("DI: t[reflect.Type] is nil")
	}
	if !cdur.IsTypeKind(t, reflect.Struct, true) {
		return fmt.Errorf("DI: t[reflect.Type] must be specified but is %v", t)
	}

	td, err := cr.buildDefinition(t)
	if nil != err {
		return err
	}

	cr.definitionsByType[td.RealType] = td

	if nil != ca {
		if nil != ca.Names && 0 < len(ca.Names) {
			for _, n := range ca.Names {
				cr.definitionByName[n] = td
			}
		}
	}

	return nil
}

func GetInstance(t reflect.Type) (interface{}, error) {
	return registry.GetInstance(t)
}
func (cr *defaultComponentRegistry) GetInstance(t reflect.Type) (interface{}, error) {
	if nil == t {
		return nil, fmt.Errorf("DI: t[reflect.Type] is nil")
	}
	var err error
	cd, ok := cr.definitionsByType[t]
	if !ok {
		cd, err = cr.buildDefinition(t)
		if nil != err {
			return nil, err
		}
	}
	log.Printf("%v", cd)

	return nil, nil
}

func GetInstanceByName(name string) (interface{}, error) {
	return registry.GetInstanceByName(name)
}
func (cr *defaultComponentRegistry) GetInstanceByName(name string) (interface{}, error) {

	return nil, nil
}

func (cr *defaultComponentRegistry) buildDefinition(t reflect.Type) (*TypeDefinition, error) {
	if nil == t {
		return nil, fmt.Errorf("DI: t[reflect.Type] is nil")
	}

	rt, pkgName, tName := cdur.GetTypeInfo(t)
	cd := &TypeDefinition{}
	cd.PkgName = pkgName
	cd.TypeName = tName
	cd.Type = t
	cd.RealType = rt

	nf := rt.NumField()
	if 0 < nf {
		fields := make(map[string]*FieldDefinition)
		for i := 0; i < nf; i++ {
			f := rt.Field(i)
			as, err := cda.ParseAnnotation(f.Tag)
			if nil != err {
				return nil, err
			}
			if nil != as && 0 < len(as) {
				fRT, fPkgName, fTName := cdur.GetTypeInfo(f.Type)

				fd := &FieldDefinition{
					PkgName:     fPkgName,
					TypeName:    fTName,
					Type:        f.Type,
					RealType:    fRT,
					Annotations: as,
				}
				fields[f.Name] = fd
			}
		}

		if 0 < len(fields) {
			cd.Fields = fields
		}
	}

	return cd, nil
}