v0.2.0 transitioned to api-only, extended and improved features, docs and tests added

internal/core/state.go

@@ -0,0 +1,35 @@
+// FILE: internal/core/core.go
+package core
+
+type State int
+
+const (
+	StateOngoing State = iota
+	StatePending       // Computer is calculating a move
+	StateStuck         // Computer is calculating a move
+	StateWhiteWins
+	StateBlackWins
+	StateDraw
+	StateStalemate
+)
+
+func (s State) String() string {
+	switch s {
+	case StatePending:
+		return "pending"
+	case StateStuck:
+		return "stuck"
+	case StateWhiteWins:
+		return "white wins"
+	case StateBlackWins:
+		return "black wins"
+	case StateDraw:
+		return "draw"
+	case StateStalemate:
+		return "stalemate"
+	case StateOngoing:
+		return "ongoing"
+	default:
+		return "unknown"
+	}
+}