Add plain text document state

data/plaintextdocstate.go

@@ -0,0 +1,61 @@
+package data
+
+import (
+	"fmt"
+
+	"github.com/anytypeio/go-anytype-infrastructure-experiments/data/pb"
+	"github.com/gogo/protobuf/proto"
+)
+
+type PlainTextDocumentState struct {
+	LastChangeId string
+	Text         string
+}
+
+func NewPlainTextDocumentState(text string, id string) *PlainTextDocumentState {
+	return &PlainTextDocumentState{
+		LastChangeId: id,
+		Text:         text,
+	}
+}
+
+func (p *PlainTextDocumentState) ApplyChange(change []byte, id string) (DocumentState, error) {
+	var changesData pb.PlainTextChangeData
+	err := proto.Unmarshal(change, &changesData)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, content := range changesData.GetContent() {
+		err = p.applyChange(content)
+		if err != nil {
+			return nil, err
+		}
+	}
+	p.LastChangeId = id
+	return p, nil
+}
+
+func (p *PlainTextDocumentState) applyChange(ch *pb.PlainTextChangeContent) error {
+	switch {
+	case ch.GetTextAppend() != nil:
+		text := ch.GetTextAppend().GetText()
+		p.Text += text
+	}
+	return nil
+}
+
+type PlainTextDocumentStateProvider struct{}
+
+func (p *PlainTextDocumentStateProvider) ProvideFromInitialChange(change []byte, id string) (DocumentState, error) {
+	var changesData pb.PlainTextChangeData
+	err := proto.Unmarshal(change, &changesData)
+	if err != nil {
+		return nil, err
+	}
+
+	if changesData.GetSnapshot() == nil {
+		return nil, fmt.Errorf("could not create state from empty snapshot")
+	}
+	return NewPlainTextDocumentState(changesData.GetSnapshot().GetText(), id), nil
+}