// Package gutil provides utility functions.
package gutil

import (
	"fmt"
	"gitee.com/micro-tools/wf/internal/empty"
	"gitee.com/micro-tools/wf/util/gconv"
	"reflect"
)

// Throw throws out an exception, which can be caught be TryCatch or recover.
func Throw(exception interface{}) {
	panic(exception)
}

// Try implements try... logistics using internal panic...recover.
// It returns error if any exception occurs, or else it returns nil.
func Try(try func()) (err error) {
	defer func() {
		if e := recover(); e != nil {
			err = fmt.Errorf(`%v`, e)
		}
	}()
	try()
	return
}

// TryCatch implements try...catch... logistics using internal panic...recover.
// It automatically calls function `catch` if any exception occurs ans passes the exception as an error.
func TryCatch(try func(), catch ...func(exception error)) {
	defer func() {
		if exception := recover(); exception != nil && len(catch) > 0 {
			if err, ok := exception.(error); ok {
				catch[0](err)
			} else {
				catch[0](fmt.Errorf(`%v`, exception))
			}
		}
	}()
	try()
}

// IsEmpty checks given `value` empty or not.
// It returns false if `value` is: integer(0), bool(false), slice/map(len=0), nil;
// or else returns true.
func IsEmpty(value interface{}) bool {
	return empty.IsEmpty(value)
}

// Keys retrieves and returns the keys from given map or struct.
func Keys(mapOrStruct interface{}) (keysOrAttrs []string) {
	keysOrAttrs = make([]string, 0)
	if m, ok := mapOrStruct.(map[string]interface{}); ok {
		for k, _ := range m {
			keysOrAttrs = append(keysOrAttrs, k)
		}
		return
	}
	var (
		reflectValue reflect.Value
		reflectKind  reflect.Kind
	)
	if v, ok := mapOrStruct.(reflect.Value); ok {
		reflectValue = v
	} else {
		reflectValue = reflect.ValueOf(mapOrStruct)
	}
	reflectKind = reflectValue.Kind()
	for reflectKind == reflect.Ptr {
		if !reflectValue.IsValid() || reflectValue.IsNil() {
			reflectValue = reflect.New(reflectValue.Type().Elem()).Elem()
			reflectKind = reflectValue.Kind()
		} else {
			reflectValue = reflectValue.Elem()
			reflectKind = reflectValue.Kind()
		}
	}
	switch reflectKind {
	case reflect.Map:
		for _, k := range reflectValue.MapKeys() {
			keysOrAttrs = append(keysOrAttrs, gconv.String(k.Interface()))
		}
	case reflect.Struct:
		var (
			fieldType   reflect.StructField
			reflectType = reflectValue.Type()
		)
		for i := 0; i < reflectValue.NumField(); i++ {
			fieldType = reflectType.Field(i)
			if fieldType.Anonymous {
				keysOrAttrs = append(keysOrAttrs, Keys(reflectValue.Field(i))...)
			} else {
				keysOrAttrs = append(keysOrAttrs, fieldType.Name)
			}
		}
	}
	return
}

// Values retrieves and returns the values from given map or struct.
func Values(mapOrStruct interface{}) (values []interface{}) {
	values = make([]interface{}, 0)
	if m, ok := mapOrStruct.(map[string]interface{}); ok {
		for _, v := range m {
			values = append(values, v)
		}
		return
	}
	var (
		reflectValue reflect.Value
		reflectKind  reflect.Kind
	)
	if v, ok := mapOrStruct.(reflect.Value); ok {
		reflectValue = v
	} else {
		reflectValue = reflect.ValueOf(mapOrStruct)
	}
	reflectKind = reflectValue.Kind()
	for reflectKind == reflect.Ptr {
		reflectValue = reflectValue.Elem()
		reflectKind = reflectValue.Kind()
	}
	switch reflectKind {
	case reflect.Map:
		for _, k := range reflectValue.MapKeys() {
			values = append(values, reflectValue.MapIndex(k).Interface())
		}
	case reflect.Struct:
		var (
			fieldType   reflect.StructField
			reflectType = reflectValue.Type()
		)
		for i := 0; i < reflectValue.NumField(); i++ {
			fieldType = reflectType.Field(i)
			if fieldType.Anonymous {
				values = append(values, Values(reflectValue.Field(i))...)
			} else {
				values = append(values, reflectValue.Field(i).Interface())
			}
		}
	}
	return
}