// Package proto provides a proto codec
package proto

import (
	pb "go.unistack.org/micro-proto/v3/codec"
	"go.unistack.org/micro/v3/codec"
	rutil "go.unistack.org/micro/v3/util/reflect"
	"google.golang.org/protobuf/proto"
)

var (
	DefaultMarshalOptions = proto.MarshalOptions{
		AllowPartial: false,
	}

	DefaultUnmarshalOptions = proto.UnmarshalOptions{
		DiscardUnknown: false,
		AllowPartial:   false,
	}
)

type protoCodec struct {
	opts codec.Options
}

type protoCodecV2 struct {
	opts codec.Options
}

var (
	_ codec.Codec   = (*protoCodec)(nil)
	_ codec.CodecV2 = (*protoCodecV2)(nil)
)

func (c *protoCodec) Marshal(v interface{}, opts ...codec.Option) ([]byte, error) {
	if v == nil {
		return nil, nil
	}

	options := c.opts
	for _, o := range opts {
		o(&options)
	}

	if options.Flatten {
		if nv, nerr := rutil.StructFieldByTag(v, options.TagName, "flatten"); nerr == nil {
			v = nv
		}
	}

	switch m := v.(type) {
	case *codec.Frame:
		return m.Data, nil
	case *pb.Frame:
		return m.Data, nil
	case proto.Message:
		marshalOptions := DefaultMarshalOptions
		if options.Context != nil {
			if f, ok := options.Context.Value(marshalOptionsKey{}).(proto.MarshalOptions); ok {
				marshalOptions = f
			}
		}
		return marshalOptions.Marshal(m)
	default:
		return nil, codec.ErrInvalidMessage
	}
}

func (c *protoCodec) Unmarshal(d []byte, v interface{}, opts ...codec.Option) error {
	if v == nil || len(d) == 0 {
		return nil
	}

	options := c.opts
	for _, o := range opts {
		o(&options)
	}

	if options.Flatten {
		if nv, nerr := rutil.StructFieldByTag(v, options.TagName, "flatten"); nerr == nil {
			v = nv
		}
	}

	switch m := v.(type) {
	case *codec.Frame:
		m.Data = d
		return nil
	case *pb.Frame:
		m.Data = d
		return nil
	case proto.Message:
		unmarshalOptions := DefaultUnmarshalOptions
		if options.Context != nil {
			if f, ok := options.Context.Value(marshalOptionsKey{}).(proto.UnmarshalOptions); ok {
				unmarshalOptions = f
			}
		}
		return unmarshalOptions.Unmarshal(d, m)
	default:
		return codec.ErrInvalidMessage
	}
}

func (c *protoCodec) String() string {
	return "proto"
}

func NewCodec(opts ...codec.Option) codec.Codec {
	return &protoCodec{opts: codec.NewOptions(opts...)}
}

func (c *protoCodecV2) Marshal(d []byte, v interface{}, opts ...codec.Option) ([]byte, error) {
	if v == nil {
		return nil, nil
	}

	options := c.opts
	for _, o := range opts {
		o(&options)
	}

	if options.Flatten {
		if nv, nerr := rutil.StructFieldByTag(v, options.TagName, "flatten"); nerr == nil {
			v = nv
		}
	}

	switch m := v.(type) {
	case *codec.Frame:
		return m.Data, nil
	case *pb.Frame:
		return m.Data, nil
	case proto.Message:
		marshalOptions := DefaultMarshalOptions
		if options.Context != nil {
			if f, ok := options.Context.Value(marshalOptionsKey{}).(proto.MarshalOptions); ok {
				marshalOptions = f
			}
		}
		return marshalOptions.MarshalAppend(d[:0], m)
	default:
		return nil, codec.ErrInvalidMessage
	}
}

func (c *protoCodecV2) Unmarshal(d []byte, v interface{}, opts ...codec.Option) error {
	if v == nil || len(d) == 0 {
		return nil
	}

	options := c.opts
	for _, o := range opts {
		o(&options)
	}

	if options.Flatten {
		if nv, nerr := rutil.StructFieldByTag(v, options.TagName, "flatten"); nerr == nil {
			v = nv
		}
	}

	switch m := v.(type) {
	case *codec.Frame:
		m.Data = d
		return nil
	case *pb.Frame:
		m.Data = d
		return nil
	case proto.Message:
		unmarshalOptions := DefaultUnmarshalOptions
		if options.Context != nil {
			if f, ok := options.Context.Value(marshalOptionsKey{}).(proto.UnmarshalOptions); ok {
				unmarshalOptions = f
			}
		}
		return unmarshalOptions.Unmarshal(d, m)
	default:
		return codec.ErrInvalidMessage
	}
}

func (c *protoCodecV2) String() string {
	return "proto"
}

func NewCodecV2(opts ...codec.Option) codec.CodecV2 {
	return &protoCodecV2{opts: codec.NewOptions(opts...)}
}