feat: add provider interface and registry

internal/provider/provider.go

@@ -0,0 +1,69 @@
+package provider
+
+// Provider defines the interface for a transcription/LLM service provider
+type Provider interface {
+	Name() string
+	RequiresAPIKey() bool
+	ValidateAPIKey(key string) bool
+	SupportsTranscription() bool
+	SupportsLLM() bool
+	DefaultTranscriptionModel() string
+	DefaultLLMModel() string
+	TranscriptionModels() []string
+	LLMModels() []string
+}
+
+// ProviderConfig holds configuration for a single provider
+type ProviderConfig struct {
+	APIKey string `toml:"api_key"`
+}
+
+var registry = make(map[string]Provider)
+
+func init() {
+	Register(&OpenAIProvider{})
+	Register(&GroqProvider{})
+	Register(&MistralProvider{})
+	Register(&ElevenLabsProvider{})
+}
+
+// Register adds a provider to the registry
+func Register(p Provider) {
+	registry[p.Name()] = p
+}
+
+// GetProvider returns a provider by name, or nil if not found
+func GetProvider(name string) Provider {
+	return registry[name]
+}
+
+// ListProviders returns all registered provider names
+func ListProviders() []string {
+	names := make([]string, 0, len(registry))
+	for name := range registry {
+		names = append(names, name)
+	}
+	return names
+}
+
+// ListProvidersWithTranscription returns providers that support transcription
+func ListProvidersWithTranscription() []string {
+	var names []string
+	for name, p := range registry {
+		if p.SupportsTranscription() {
+			names = append(names, name)
+		}
+	}
+	return names
+}
+
+// ListProvidersWithLLM returns providers that support LLM
+func ListProvidersWithLLM() []string {
+	var names []string
+	for name, p := range registry {
+		if p.SupportsLLM() {
+			names = append(names, name)
+		}
+	}
+	return names
+}