package di

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

	"git.loafle.net/loafer/annotation-go"
	"git.loafle.net/loafer/di-go/annotations"
	luReflect "git.loafle.net/loafer/util-go/reflect"
)

func init() {
	registry = newRegistry()
}

// Regist is interface
type Regist interface {
	RegisterType(t reflect.Type)
	RegisterResource(name string, resource interface{}) error

	GetInstance(t reflect.Type) (interface{}, error)
	GetInstances(ts []reflect.Type) ([]interface{}, error)
	GetInstanceByName(name string) (interface{}, error)
	GetInstancesByAnnotationType(t reflect.Type) ([]interface{}, error)

	GetTypeAnnotation(instanceType reflect.Type, annotationType reflect.Type) annotation.Annotation
	GetMethodAnnotation(instanceType reflect.Type, annotationType reflect.Type, methodName string) annotation.Annotation
	GetMethodAnnotations(instanceType reflect.Type, annotationType reflect.Type) map[string]annotation.Annotation
}

// Registry is struct
type Registry struct {
	definitionByType map[reflect.Type]*TypeDefinition
	definitionByName map[string]*TypeDefinition
	instanceByType   map[reflect.Type]interface{}
	resourceByName   map[string]interface{}
}

var registry Regist

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

	return r
}

// RegisterType is function
func RegisterType(t reflect.Type) {
	pc, _, _, ok := runtime.Caller(1)
	details := runtime.FuncForPC(pc)
	if ok && details != nil {
		log.Printf("called from %s", details.Name())
	}

	registry.RegisterType(t)
}

func (r *Registry) RegisterType(t reflect.Type) {
	if nil == t {
		log.Panicf("DI: t[reflect.Type] is nil")
	}
	if !luReflect.IsTypeKind(t, reflect.Struct, true) {
		log.Panicf("DI: t[reflect.Type] must be specified but is %v", t)
	}

	td, err := r.buildDefinition(t)
	if nil != err {
		log.Panicf("DI: %v", err)
	}

	if _, ok := r.definitionByType[td.Type]; ok {
		log.Panicf("DI: The type[%s] of Component is exist already", td.FullName)
	}
	r.definitionByType[td.Type] = td

	name := td.TypeName

	if a := td.GetTypeAnnotationByType(annotations.ComponentAnnotationType, true); nil != a {
		ca := a.(*annotations.ComponentAnnotation)
		if "" != strings.Trim(ca.Name, " ") {
			name = ca.Name
		}
	}

	if eTD, ok := r.definitionByName[name]; ok {
		log.Panicf("DI: The name[%s] of Component is exist already type[%s]", name, eTD.FullName)
	}
	r.definitionByName[name] = td
}

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

	return nil
}

// GetInstance returns instance of type
// t must be pointer of struct
func GetInstance(t reflect.Type) (interface{}, error) {
	return registry.GetInstance(t)
}
func (r *Registry) GetInstance(t reflect.Type) (instance interface{}, err error) {
	if nil == t {
		return nil, fmt.Errorf("DI: t[reflect.Type] is nil")
	}

	if reflect.Ptr != t.Kind() {
		return nil, fmt.Errorf("DI: t[reflect.Type] must be pointer of struct")
	}

	if reflect.Struct != t.Elem().Kind() {
		return nil, fmt.Errorf("DI: t[reflect.Type] must be pointer of struct")
	}

	var (
		td   *TypeDefinition
		comV interface{}
		ok   bool
	)

	rt, _, _ := luReflect.GetTypeInfo(t)
	if td, ok = r.definitionByType[t]; !ok {
		if td, err = r.buildDefinition(t); nil != err {
			return nil, fmt.Errorf("DI: %v", err)
		}
	}

	if comV, ok = r.instanceByType[td.RealType]; ok {
		return comV, nil
	}

	v := reflect.New(rt)
	rv := v.Elem()

	instance = v.Interface()
	r.instanceByType[td.RealType] = instance
	err = nil
	defer func() {
		if nil != err {
			instance = nil
			delete(r.instanceByType, td.RealType)
		}
	}()

	var (
		annotation annotation.Annotation
		fV         interface{}
	)

	for _, fd := range td.Fields {
		f := rv.FieldByName(fd.FieldName)

		if !f.IsValid() {
			err = fmt.Errorf("DI: Field[%s] is not valid", fd.FieldName)
			return
		}
		if !f.CanSet() {
			err = fmt.Errorf("DI: Field[%s] can not set", fd.FieldName)
			return
		}

		if annotation = fd.GetAnnotationByType(annotations.InjectAnnotationType, false); nil != annotation {
			if fV, err = r.GetInstance(fd.Type); nil != err {
				return
			}
		}

		if annotation = fd.GetAnnotationByType(annotations.ResourceAnnotationType, false); nil != annotation {
			n := annotation.(*annotations.ResourceAnnotation).Name
			if "" == n {
				n = fd.FieldName
			}
			if fV, err = r.GetInstanceByName(n); nil != err {
				return
			}
		}

		if nil != err {
			return
		}
		f.Set(reflect.ValueOf(fV))
	}

	return
}

func GetInstanceByName(name string) (interface{}, error) {
	return registry.GetInstanceByName(name)
}
func (r *Registry) GetInstanceByName(name string) (interface{}, error) {
	v, ok := r.resourceByName[name]
	if ok {
		return v, nil
	}

	td, ok := r.definitionByName[name]
	if !ok {
		return nil, fmt.Errorf("DI: Instance[%s] is not exist", name)
	}

	v, err := r.GetInstance(td.Type)
	if nil != err {
		return nil, fmt.Errorf("DI: Instance[%s] is not exist -> %s", name, err.Error())
	}

	return v, nil
}

// GetInstances returns instance of annotated
// n must be name of registered annotation
func GetInstances(ts []reflect.Type) ([]interface{}, error) {
	return registry.GetInstances(ts)
}
func (r *Registry) GetInstances(ts []reflect.Type) ([]interface{}, error) {
	var (
		i   interface{}
		err error
	)
	instances := make([]interface{}, 0)
	for _, t := range ts {
		if i, err = r.GetInstance(t); nil != err {
			return nil, err
		}
		instances = append(instances, i)
	}

	return instances, nil
}

func GetInstancesByAnnotationType(t reflect.Type) ([]interface{}, error) {
	return registry.GetInstancesByAnnotationType(t)
}
func (r *Registry) GetInstancesByAnnotationType(t reflect.Type) ([]interface{}, error) {
	var (
		i   interface{}
		err error
	)
	instances := make([]interface{}, 0)

	for _, td := range r.definitionByType {
		if nil != td.GetTypeAnnotationByType(t, true) {
			if i, err = r.GetInstance(td.Type); nil != err {
				return nil, err
			}
			instances = append(instances, i)
		}
	}

	return instances, nil
}

func GetTypeAnnotation(instanceType reflect.Type, annotationType reflect.Type) annotation.Annotation {
	return registry.GetTypeAnnotation(instanceType, annotationType)
}
func (r *Registry) GetTypeAnnotation(instanceType reflect.Type, annotationType reflect.Type) annotation.Annotation {
	def, ok := r.definitionByType[instanceType]
	if !ok {
		return nil
	}

	return def.GetTypeAnnotationByType(annotationType, false)
}
func GetMethodAnnotation(instanceType reflect.Type, annotationType reflect.Type, methodName string) annotation.Annotation {
	return registry.GetMethodAnnotation(instanceType, annotationType, methodName)
}
func (r *Registry) GetMethodAnnotation(instanceType reflect.Type, annotationType reflect.Type, methodName string) annotation.Annotation {
	def, ok := r.definitionByType[instanceType]
	if !ok {
		return nil
	}

	return def.GetMethodAnnotationByType(annotationType, methodName)
}

func GetMethodAnnotations(instanceType reflect.Type, annotationType reflect.Type) map[string]annotation.Annotation {
	return registry.GetMethodAnnotations(instanceType, annotationType)
}
func (r *Registry) GetMethodAnnotations(instanceType reflect.Type, annotationType reflect.Type) map[string]annotation.Annotation {
	def, ok := r.definitionByType[instanceType]
	if !ok {
		return nil
	}

	return def.GetMethodAnnotationsByType(annotationType)
}

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

	rt, pkgName, tName := luReflect.GetTypeInfo(t)
	td := &TypeDefinition{}
	td.FullName = FullName(pkgName, tName)
	td.PkgName = pkgName
	td.TypeName = tName
	td.Type = t
	td.RealType = rt
	td.Fields = make([]*FieldDefinition, 0)

	parseFields(rt, td)

	return td, nil
}

func parseFields(t reflect.Type, td *TypeDefinition) {
	// fields := make([]*FieldDefinition, 0)
	rt, _, _ := luReflect.GetTypeInfo(t)
	if reflect.Struct != rt.Kind() {
		return
	}

	for i := 0; i < rt.NumField(); i++ {
		f := rt.Field(i)

		if f.Anonymous {
			if parseAnonymousField(&f, td) {
				continue
			}
			parseFields(f.Type, td)
		} else {
			if parseMethodAnnotation(&f, td) {
				continue
			}
			as, err := annotation.Parse(f.Tag)
			if nil != err {
				return
			}
			if nil != as && 0 < len(as) {
				fRT, fPkgName, fTName := luReflect.GetTypeInfo(f.Type)

				fd := &FieldDefinition{
					FieldName:   f.Name,
					PkgName:     fPkgName,
					TypeName:    fTName,
					Type:        f.Type,
					RealType:    fRT,
					Annotations: as,
				}
				td.Fields = append(td.Fields, fd)
			}
		}
	}
}

func parseAnonymousField(f *reflect.StructField, td *TypeDefinition) bool {
	if parseTypeAnnotation(f, td) {
		return true
	}
	return false
}

func parseTypeAnnotation(f *reflect.StructField, td *TypeDefinition) bool {
	// if !haveEmbeddingOf(cda.TypeAnnotationType, f.Type) {
	// 	return
	// }
	if annotation.TypeAnnotationType != f.Type {
		return false
	}

	as, err := annotation.Parse(f.Tag)
	if nil != err {
		return false
	}

	if nil != as && 0 < len(as) {
		td.TypeAnnotations = as
		return true
	}
	return false
}

func parseMethodAnnotation(f *reflect.StructField, td *TypeDefinition) bool {
	if annotation.MethodAnnotationType != f.Type {
		return false
	}

	as, err := annotation.Parse(f.Tag)
	if nil != err {
		return false
	}

	if nil != as && 0 < len(as) {
		if nil == td.MethodAnnotations {
			td.MethodAnnotations = make(map[string]map[reflect.Type]annotation.Annotation, 0)
		}
		td.MethodAnnotations[f.Name[1:]] = as
		return true
	}
	return false
}

func haveEmbeddingOf(t reflect.Type, target reflect.Type) bool {
	if t == target {
		return true
	}

	rt, _, _ := luReflect.GetTypeInfo(target)
	if reflect.Struct != rt.Kind() {
		return false
	}

	for i := 0; i < rt.NumField(); i++ {
		f := rt.Field(i)

		if f.Anonymous {
			if haveEmbeddingOf(t, f.Type) {
				return true
			}
		}
	}
	return false
}