feat: implement memory state backend with key group assignment and value state interface

3 files changed, 42 insertions, 0 deletions

diff --git a/core/hash.go b/core/hash.go
new file mode 100644
index 0000000..af15546
--- /dev/null
+++ b/core/hash.go
@@ -0,0 +1,19 @@
+package core
+
+import "hash/fnv"
+
+const DefaultMaxParallelism = 128
+
+func AssignToKeyGroup(key string, maxParallelism int) int {
+
+	if maxParallelism <= 0 {
+		maxParallelism = DefaultMaxParallelism
+	}
+
+	// hash
+	h := fnv.New32a()
+	h.Write([]byte(key))
+	hash := h.Sum32()
+
+	return int(hash % uint32(maxParallelism))
+}
diff --git a/core/state.go b/core/state.go
new file mode 100644
index 0000000..d6d7847
--- /dev/null
+++ b/core/state.go
@@ -0,0 +1,10 @@
+package core
+
+import "context"
+
+// ValueState is for client side using to update state
+type ValueState[T any] interface {
+	Value(ctx context.Context) (T, error)
+	Update(ctx context.Context, newVal T) (T, error)
+	Clear(ctx context.Context) error
+}
diff --git a/core/state_backend.go b/core/state_backend.go
new file mode 100644
index 0000000..219bb63
--- /dev/null
+++ b/core/state_backend.go
@@ -0,0 +1,13 @@
+package core
+
+import "context"
+
+type StateBackend interface {
+	// SetCurrentKey will perform in Memory
+	SetCurrentKey(key string) error
+	// GetCurrentKey will perform in Memory
+	GetCurrentKey() string
+
+	// GetValueState will perform in disk
+	GetValueState(ctx context.Context, key string) (ValueState[any], error)
+}