Add base

ceen.go

@@ -0,0 +1,105 @@
+package ceen
+
+import (
+	"fmt"
+	"github.com/kjuulh/ceen/codec"
+	"github.com/kjuulh/ceen/id"
+	"github.com/kjuulh/ceen/types"
+	"github.com/nats-io/nats.go"
+)
+
+type Ceen struct {
+	nc    *nats.Conn
+	js    nats.JetStreamContext
+	types *types.Registry
+	id    id.ID
+}
+
+type ceenOption func(o *Ceen) error
+
+func (f ceenOption) addOption(o *Ceen) error {
+	return f(o)
+}
+
+type CeenOption interface {
+	addOption(o *Ceen) error
+}
+
+func TypeRegistry(types *types.Registry) CeenOption {
+	return ceenOption(func(o *Ceen) error {
+		o.types = types
+		return nil
+	})
+}
+
+func (c *Ceen) EventStore(name string) (*EventStore, error) {
+	return &EventStore{name: name, c: c}, nil
+}
+
+func (c *Ceen) UnpackEvent(msg *nats.Msg) (*Event, error) {
+	eventType := msg.Header.Get(eventTypeHdr)
+	codecName := msg.Header.Get(eventCodecHdr)
+	var (
+		data any
+		err  error
+	)
+
+	codc, ok := codec.Codecs[codecName]
+	if !ok {
+		return nil, fmt.Errorf("%w: %s", codec.ErrCodecNotRegistered, codecName)
+	}
+
+	if c.types == nil {
+		var b []byte
+		err = codc.Unmarshal(msg.Data, &b)
+		data = b
+	} else {
+		var v any
+		v, err = c.types.Init(eventType)
+		if err == nil {
+			err = codc.Unmarshal(msg.Data, v)
+			data = v
+		}
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	var seq uint64
+	if msg.Reply != "" {
+		md, err := msg.Metadata()
+		if err != nil {
+			return nil, fmt.Errorf("unpack: failed to get metadata: %s", err)
+		}
+		seq = md.Sequence.Stream
+	}
+
+	return &Event{
+		ID:       msg.Header.Get(nats.MsgIdHdr),
+		Type:     msg.Header.Get(eventTypeHdr),
+		Data:     data,
+		Subject:  msg.Subject,
+		Sequence: seq,
+	}, nil
+}
+
+func New(nc *nats.Conn, options ...CeenOption) (*Ceen, error) {
+	js, err := nc.JetStream()
+	if err != nil {
+		return nil, err
+	}
+
+	c := &Ceen{
+		nc: nc,
+		js: js,
+		id: id.NUID,
+	}
+
+	for _, o := range options {
+		if err := o.addOption(c); err != nil {
+			return nil, err
+		}
+	}
+
+	return c, nil
+}