package llm

import (
	"context"
	"fmt"

	"github.com/enmanuel/agents/internal/config"
	coretypes "github.com/enmanuel/agents/pkg/llm"
)

// FromConfig builds a CompleteFunc from an LLMProviderCfg.
func FromConfig(cfg config.LLMProviderCfg) (coretypes.CompleteFunc, error) {
	switch cfg.Provider {
	case "anthropic":
		return NewAnthropicComplete(cfg.APIKeyEnv, cfg.BaseURL), nil
	case "openai":
		return NewOpenAIComplete(cfg.APIKeyEnv, cfg.BaseURL), nil
	case "ollama":
		base := cfg.BaseURL
		if base == "" {
			base = "http://localhost:11434/v1"
		}
		return NewOpenAIComplete("OLLAMA_API_KEY", base), nil
	default:
		return nil, fmt.Errorf("unknown LLM provider: %s", cfg.Provider)
	}
}

// WithFallback wraps primary with a fallback CompleteFunc.
// If primary returns an error, fallback is tried.
func WithFallback(primary, fallback coretypes.CompleteFunc) coretypes.CompleteFunc {
	return func(ctx context.Context, req coretypes.CompletionRequest) (coretypes.CompletionResponse, error) {
		resp, err := primary(ctx, req)
		if err != nil {
			return fallback(ctx, req)
		}
		return resp, nil
	}
}