package codec

import (
	"fmt"
	"reflect"
	"time"
)

//解码器
type Decoder struct {
	DefDecoder func(buf []byte, v interface{}) error //默认编码 扩展自定义编码方式
}

func (this *Decoder) Decoder(buf []byte, v interface{}) error {
	switch v := v.(type) {
	case nil:
		return fmt.Errorf("decoder: Decoder(nil)")
	case *string:
		*v = BytesToString(buf)
		return nil
	case *[]byte:
		*v = buf
		return nil
	case *int:
		*v = BytesToInt(buf)
		return nil
	case *int8:
		*v = BytesToInt8(buf)
		return nil
	case *int16:
		*v = BytesToInt16(buf)
		return nil
	case *int32:
		*v = BytesToInt32(buf)
		return nil
	case *int64:
		*v = BytesToInt64(buf)
		return nil
	case *uint:
		*v = BytesToUInt(buf)
		return nil
	case *uint8:
		*v = BytesToUInt8(buf)
		return nil
	case *uint16:
		*v = BytesToUInt16(buf)
		return nil
	case *uint32:
		*v = BytesToUInt32(buf)
		return nil
	case *uint64:
		*v = BytesToUInt64(buf)
		return nil
	case *float32:
		*v = BytesToFloat32(buf)
		return nil
	case *float64:
		*v = BytesToFloat64(buf)
		return nil
	case *bool:
		*v = BytesToBool(buf)
		return nil
	case *time.Time:
		var err error
		*v, err = time.Parse(time.RFC3339Nano, BytesToString(buf))
		return err
	case *time.Duration:
		*v = time.Duration(BytesToInt64(buf))
		return nil
	default:
		if this.DefDecoder != nil {
			return this.DefDecoder(buf, v)
		} else {
			return fmt.Errorf(
				"decoder: can't marshal %T (implement decoder.DefDecoder)", v)
		}
	}
}

func (this *Decoder) DecoderMap(data map[string]string, v interface{}) error {
	vof := reflect.ValueOf(v)
	if !vof.IsValid() {
		return fmt.Errorf("Decoder: DecoderMap(nil)")
	}
	if vof.Kind() != reflect.Ptr && vof.Kind() != reflect.Map && vof.Kind() != reflect.Slice {
		return fmt.Errorf("Decoder: DecoderMap(non-pointer %T)", v)
	}
	if vof.Kind() == reflect.Map {
		kt, vt := vof.Type().Key(), vof.Type().Elem()
		for k, v := range data {
			key := reflect.New(kt).Elem()
			if key.Kind() != reflect.Ptr {
				if err := this.Decoder(StringToBytes(k), key.Addr().Interface()); err != nil {
					return fmt.Errorf("Decoder: Decoder(non-pointer %T) err:%v", key, err)
				}
			} else {
				if err := this.Decoder(StringToBytes(k), key.Addr()); err != nil {
					return fmt.Errorf("Decoder: Decoder(non-pointer %T) err:%v", key, err)
				}
			}
			value := reflect.New(vt).Elem()
			if value.Kind() != reflect.Ptr {
				if err := this.Decoder(StringToBytes(v), value.Addr().Interface()); err != nil {
					return fmt.Errorf("Decoder: Decoder(non-pointer %T) err:%v", value, err)
				}
			} else {
				value.Interface()
				if err := this.Decoder(StringToBytes(v), value.Addr().Interface()); err != nil {
					return fmt.Errorf("Decoder: Decoder(non-pointer %T) err:%v", value, err)
				}
			}
			vof.SetMapIndex(key, value)
		}
	} else if vof.Kind() == reflect.Ptr {
		elem := vof.Elem()
		relType := elem.Type()
		for i := 0; i < relType.NumField(); i++ {
			fieldInfo := relType.Field(i)
			tag := fieldInfo.Tag
			name := tag.Get("json")
			if len(name) == 0 {
				name = fieldInfo.Name
			}
			if value, ok := data[name]; ok {
				v := reflect.New(fieldInfo.Type).Elem()
				if fieldInfo.Type.Kind() != reflect.Ptr {
					if err := this.Decoder(StringToBytes(value), v.Addr().Interface()); err != nil {
						return fmt.Errorf("Decoder: Decoder(non-pointer %T) err:%v", value, err)
					}
					elem.FieldByName(fieldInfo.Name).Set(v)
				} else {
					if err := this.Decoder(StringToBytes(value), v); err != nil {
						return fmt.Errorf("Decoder: Decoder(non-pointer %T) err:%v", value, err)
					}
					elem.FieldByName(fieldInfo.Name).Set(v)
				}
			}
		}
	}
	return nil
}