1 files changed, 73 insertions, 0 deletions
diff --git a/entities/bug/operation.go b/entities/bug/operation.go
new file mode 100644
index 00000000..a02fc780
--- /dev/null
+++ b/entities/bug/operation.go
@@ -0,0 +1,73 @@
+package bug
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/MichaelMure/git-bug/entity"
+	"github.com/MichaelMure/git-bug/entity/dag"
+)
+
+const (
+	_ dag.OperationType = iota
+	CreateOp
+	SetTitleOp
+	AddCommentOp
+	SetStatusOp
+	LabelChangeOp
+	EditCommentOp
+	NoOpOp
+	SetMetadataOp
+)
+
+// Operation define the interface to fulfill for an edit operation of a Bug
+type Operation interface {
+	dag.Operation
+
+	// Apply the operation to a Snapshot to create the final state
+	Apply(snapshot *Snapshot)
+}
+
+// make sure that package external operations do conform to our interface
+var _ Operation = &dag.NoOpOperation[*Snapshot]{}
+var _ Operation = &dag.SetMetadataOperation[*Snapshot]{}
+
+func operationUnmarshaller(raw json.RawMessage, resolvers entity.Resolvers) (dag.Operation, error) {
+	var t struct {
+		OperationType dag.OperationType `json:"type"`
+	}
+
+	if err := json.Unmarshal(raw, &t); err != nil {
+		return nil, err
+	}
+
+	var op dag.Operation
+
+	switch t.OperationType {
+	case AddCommentOp:
+		op = &AddCommentOperation{}
+	case CreateOp:
+		op = &CreateOperation{}
+	case EditCommentOp:
+		op = &EditCommentOperation{}
+	case LabelChangeOp:
+		op = &LabelChangeOperation{}
+	case NoOpOp:
+		op = &dag.NoOpOperation[*Snapshot]{}
+	case SetMetadataOp:
+		op = &dag.SetMetadataOperation[*Snapshot]{}
+	case SetStatusOp:
+		op = &SetStatusOperation{}
+	case SetTitleOp:
+		op = &SetTitleOperation{}
+	default:
+		panic(fmt.Sprintf("unknown operation type %v", t.OperationType))
+	}
+
+	err := json.Unmarshal(raw, &op)
+	if err != nil {
+		return nil, err
+	}
+
+	return op, nil
+}