package registry

import (
	"fmt"
	"log"
	"reflect"
	"runtime"
	"strings"

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

func init() {
	registry = newRegistry()
}

var registry ComponentRegistry

type ComponentRegistry interface {
	RegisterType(t reflect.Type, ca *cda.ComponentAnnotation)
	RegisterResource(name string, resource interface{}) error

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

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

	return r
}

type defaultComponentRegistry struct {
	definitionByType map[reflect.Type]*TypeDefinition
	definitionByName map[string]*TypeDefinition
	resourceByName   map[string]interface{}
}

func RegisterType(t reflect.Type, ca *cda.ComponentAnnotation) {
	pc, _, _, ok := runtime.Caller(1)
	details := runtime.FuncForPC(pc)
	if ok && details != nil {
		log.Printf("called from %s\n", details.Name())
	}

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

	td, err := cr.buildDefinition(t)
	if nil != err {
		logging.Logger().Panic(fmt.Sprintf("DI: %v", err))
	}

	if _, ok := cr.definitionByType[td.RealType]; ok {
		logging.Logger().Panic(fmt.Sprintf("DI: The type[%s] of Component is exist already", td.FullName))
	}
	cr.definitionByType[td.RealType] = td

	name := ""
	if nil != ca && "" != strings.Trim(ca.Name, " ") {
		name = ca.Name
	} else {
		name = td.TypeName
	}

	if eTD, ok := cr.definitionByName[name]; ok {
		logging.Logger().Panic(fmt.Sprintf("DI: The name[%s] of Component is exist already type[%s]", name, eTD.FullName))
	}
	cr.definitionByName[name] = td
}

func RegisterResource(name string, resource interface{}) error {
	return registry.RegisterResource(name, resource)
}
func (cr *defaultComponentRegistry) RegisterResource(name string, resource interface{}) error {
	if _, ok := cr.resourceByName[name]; ok {
		return fmt.Errorf("DI: Resource[%s] is already exist", name)
	}
	cr.resourceByName[name] = resource

	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

	rt, _, _ := cdur.GetTypeInfo(t)
	td, ok := cr.definitionByType[rt]
	if !ok {
		td, err = cr.buildDefinition(t)
		if nil != err {
			return nil, err
		}
	}

	v := reflect.New(rt)
	i := v.Interface()

	for f, fd := range td.Fields {

	}

	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("t[reflect.Type] is nil")
	}

	rt, pkgName, tName := cdur.GetTypeInfo(t)
	td := &TypeDefinition{}
	td.FullName = FullName(pkgName, tName)
	td.PkgName = pkgName
	td.TypeName = tName
	td.Type = t
	td.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) {
			td.Fields = fields
		}
	}

	return td, nil
}