mcp-captcharesolver/internal/config/config.go

// Package config loads and validates the MCP server configuration from env vars.
package config

import (
	"fmt"
	"os"
	"strconv"
	"time"
)

// Config is the validated runtime configuration. Fields are ordered
// largest-alignment-first to satisfy the fieldalignment linter.
type Config struct {
	Provider    string
	BaseURL     string
	APIKey      string
	Model       string
	AudioModel  string
	LogLevel    string
	Temperature float64
	Timeout     time.Duration
	MaxTokens   int
}

var validProviders = map[string]bool{
	"anthropic": true, "openai": true, "openai-compatible": true, "gemini": true,
}

// Load reads CAPTCHA_LLM_* env vars and returns a validated Config.
func Load() (Config, error) {
	c := Config{
		Provider:   os.Getenv("CAPTCHA_LLM_PROVIDER"),
		BaseURL:    os.Getenv("CAPTCHA_LLM_BASE_URL"),
		APIKey:     os.Getenv("CAPTCHA_LLM_API_KEY"),
		Model:      os.Getenv("CAPTCHA_LLM_MODEL"),
		AudioModel: os.Getenv("CAPTCHA_LLM_AUDIO_MODEL"),
		LogLevel:   envOr("CAPTCHA_LOG_LEVEL", "info"),
		MaxTokens:  1024,
		Timeout:    60 * time.Second,
	}
	if !validProviders[c.Provider] {
		return Config{}, fmt.Errorf("CAPTCHA_LLM_PROVIDER must be one of anthropic|openai|openai-compatible|gemini, got %q", c.Provider)
	}
	if c.APIKey == "" && c.BaseURL == "" {
		return Config{}, fmt.Errorf("CAPTCHA_LLM_API_KEY is required (or set CAPTCHA_LLM_BASE_URL for a keyless local endpoint)")
	}
	if c.Model == "" {
		return Config{}, fmt.Errorf("CAPTCHA_LLM_MODEL is required")
	}
	if v := os.Getenv("CAPTCHA_LLM_TEMPERATURE"); v != "" {
		f, err := strconv.ParseFloat(v, 64)
		if err != nil {
			return Config{}, fmt.Errorf("CAPTCHA_LLM_TEMPERATURE: %w", err)
		}
		c.Temperature = f
	}
	if v := os.Getenv("CAPTCHA_LLM_MAX_TOKENS"); v != "" {
		n, err := strconv.Atoi(v)
		if err != nil {
			return Config{}, fmt.Errorf("CAPTCHA_LLM_MAX_TOKENS: %w", err)
		}
		c.MaxTokens = n
	}
	if v := os.Getenv("CAPTCHA_LLM_TIMEOUT"); v != "" {
		d, err := time.ParseDuration(v)
		if err != nil {
			return Config{}, fmt.Errorf("CAPTCHA_LLM_TIMEOUT: %w", err)
		}
		c.Timeout = d
	}
	return c, nil
}

func envOr(key, def string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return def
}