package config

import (
	"errors"
	"os"
)

// Config holds runtime configuration for the Discord bot process.
type Config struct {
	DiscordToken  string
	GuildID       string
	HAGatewayAddr string
	TLSDir        string
	OTELEndpoint  string
	LogLevel      string
	LogFormat     string
}

// Load reads Discord bot configuration from environment variables.
func Load() (*Config, error) {
	token := os.Getenv("DISCORD_TOKEN")
	if token == "" {
		return nil, errors.New("DISCORD_TOKEN is required but not set")
	}

	addr := os.Getenv("HA_GATEWAY_ADDR")
	if addr == "" {
		return nil, errors.New("HA_GATEWAY_ADDR is required but not set")
	}

	return &Config{
		DiscordToken:  token,
		GuildID:       os.Getenv("GUILD_ID"),
		HAGatewayAddr: addr,
		TLSDir:        os.Getenv("TLS_DIR"),
		OTELEndpoint:  os.Getenv("OTEL_ENDPOINT"),
		LogLevel:      getenvDefault("LOG_LEVEL", "info"),
		LogFormat:     getenvDefault("LOG_FORMAT", "json"),
	}, nil
}

// getenvDefault keeps config loading concise for optional variables with defaults.
func getenvDefault(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}