ollie/backend/new.go

package backend

import (
	"fmt"
	"os"
)

// NewWithName constructs a Backend for the given backend name.
// If name is empty, falls back to backends.conf default, then OLLIE_BACKEND env.
func NewWithName(name string) (Backend, error) {
	cfg := loadConfig()
	if name == "" {
		name = cfg.Default
	}
	if name == "" {
		name = os.Getenv("OLLIE_BACKEND")
	}
	if name == "" {
		return nil, fmt.Errorf("no backend specified: set 'backend' in backends.conf, OLLIE_BACKEND, or pass backend= to the session")
	}
	return newBackendFromConfig(name, cfg)
}

func newBackend(which string) (Backend, error) {
	return newBackendFromConfig(which, loadConfig())
}

func newBackendFromConfig(which string, cfg configFile) (Backend, error) {
	bc := cfg.Backends[which]

	switch which {
	case "ollama":
		host := bc.Host
		if host == "" {
			host = os.Getenv("OLLAMA_HOST")
		}
		b, err := NewOllama(host)
		if err != nil {
			return nil, err
		}
		if bc.Model != "" {
			b.SetModel(bc.Model)
		}
		return b, nil

	case "openai":
		url := bc.URL
		if url == "" {
			url = os.Getenv("OLLIE_OPENAI_URL")
		}
		key := bc.Key
		if key == "" {
			key = os.Getenv("OLLIE_OPENAI_KEY")
		}
		if key == "" {
			return nil, fmt.Errorf("openai: key required (backends.conf [openai] key= or OLLIE_OPENAI_KEY)")
		}
		b, err := NewOpenAI("openai", url, key)
		if err != nil {
			return nil, err
		}
		if bc.Model != "" {
			b.SetModel(bc.Model)
		}
		return b, nil

	case "openrouter":
		url := bc.URL
		if url == "" {
			url = os.Getenv("OLLIE_OPENAI_URL")
		}
		if url == "" {
			url = "https://openrouter.ai/api"
		}
		key := bc.Key
		if key == "" {
			key = os.Getenv("OLLIE_OPENAI_KEY")
		}
		if key == "" {
			return nil, fmt.Errorf("openrouter: key required (backends.conf [openrouter] key= or OLLIE_OPENAI_KEY)")
		}
		b, err := NewOpenAI("openrouter", url, key)
		if err != nil {
			return nil, err
		}
		if bc.Model != "" {
			b.SetModel(bc.Model)
		}
		return b, nil

	case "anthropic":
		key := bc.Key
		if key == "" {
			key = os.Getenv("OLLIE_ANTHROPIC_KEY")
		}
		if key == "" {
			return nil, fmt.Errorf("anthropic: key required (backends.conf [anthropic] key= or OLLIE_ANTHROPIC_KEY)")
		}
		b, err := NewAnthropic(key)
		if err != nil {
			return nil, err
		}
		if bc.Model != "" {
			b.SetModel(bc.Model)
		}
		return b, nil

	case "copilot":
		token := bc.Key
		if token == "" {
			token = os.Getenv("OLLIE_COPILOT_TOKEN")
		}
		if token == "" {
			return nil, fmt.Errorf("copilot: key required (backends.conf [copilot] key= or OLLIE_COPILOT_TOKEN)")
		}
		b, err := NewCopilot(token)
		if err != nil {
			return nil, err
		}
		if bc.Model != "" {
			b.SetModel(bc.Model)
		}
		return b, nil

	case "kiro", "codewhisperer":
		token := bc.Key
		if token == "" {
			token = os.Getenv("OLLIE_KIRO_TOKEN")
		}
		b, err := NewCodeWhisperer(token)
		if err != nil {
			return nil, err
		}
		if bc.Model != "" {
			b.SetModel(bc.Model)
		}
		return b, nil

	case "gemini":
		key := bc.Key
		if key == "" {
			key = os.Getenv("OLLIE_GEMINI_KEY")
		}
		if key == "" {
			return nil, fmt.Errorf("gemini: key required (backends.conf [gemini] key= or OLLIE_GEMINI_KEY)")
		}
		b, err := NewGemini(key)
		if err != nil {
			return nil, err
		}
		if bc.Model != "" {
			b.SetModel(bc.Model)
		}
		return b, nil

	default:
		return nil, fmt.Errorf("unknown backend %q (supported: ollama, openai, openrouter, anthropic, copilot, kiro, gemini)", which)
	}
}

// Backends returns the list of supported backend names.
func Backends() []string {
	return []string{"ollama", "openai", "openrouter", "anthropic", "copilot", "kiro", "gemini"}
}