feat(adapter): registry with detect filtering and duplicate guard

internal/adapter/registry.go

@@ -0,0 +1,60 @@
+package adapter
+
+import "fmt"
+
+// Registry holds adapters in registration order.
+type Registry struct {
+	byName map[string]Adapter
+	order  []string
+}
+
+// NewRegistry returns an empty Registry.
+func NewRegistry() *Registry {
+	return &Registry{byName: map[string]Adapter{}}
+}
+
+// Register adds a to the registry. Panics on duplicate name.
+func (r *Registry) Register(a Adapter) {
+	if _, exists := r.byName[a.Name()]; exists {
+		panic(fmt.Sprintf("adapter %q already registered", a.Name()))
+	}
+	r.byName[a.Name()] = a
+	r.order = append(r.order, a.Name())
+}
+
+// Names returns adapter names in registration order.
+func (r *Registry) Names() []string {
+	out := make([]string, len(r.order))
+	copy(out, r.order)
+	return out
+}
+
+// DetectedNames returns names of adapters whose Detect() returns true.
+func (r *Registry) DetectedNames() []string {
+	var out []string
+	for _, n := range r.order {
+		if r.byName[n].Detect() {
+			out = append(out, n)
+		}
+	}
+	return out
+}
+
+// Get returns the adapter for name and whether it was found.
+func (r *Registry) Get(name string) (Adapter, bool) {
+	a, ok := r.byName[name]
+	return a, ok
+}
+
+// All returns adapters in registration order.
+func (r *Registry) All() []Adapter {
+	out := make([]Adapter, 0, len(r.order))
+	for _, n := range r.order {
+		out = append(out, r.byName[n])
+	}
+	return out
+}
+
+// Default is the process-global registry used by main(). Tests should
+// construct their own Registry via NewRegistry to avoid global state.
+var Default = NewRegistry()