package config

import (
	"os"
	"strings"
)

// Config 承载直播 SFU 分流 Demo 的运行参数。
// 优先级：环境变量 > 默认值。Cloudflare Realtime 为主 SFU，SRS 为本地对照后端。
type Config struct {
	HTTPPort      string
	GRPCPort      string
	ProviderOrder string // 逗号分隔的后端顺序，如 "cloudflare,srs"

	SRSBaseURL   string
	SRSApp       string
	SRSSecret    string
	SRSCandidate string

	CFAppID     string
	CFAppSecret string
	CFBaseURL   string
	CFStunURL   string

	TokenSecret   string
	TokenRequired bool
}

func Load() *Config {
	c := &Config{
		HTTPPort:      getenv("HTTP_PORT", "8088"),
		GRPCPort:      getenv("GRPC_PORT", "9090"),
		ProviderOrder: getenv("SFU_PROVIDER", "cloudflare,srs"),

		SRSBaseURL:   getenv("SRS_API_BASE", "http://localhost:1985"),
		SRSApp:       getenv("SRS_APP", "live"),
		SRSSecret:    getenv("SRS_SECRET", ""),
		SRSCandidate: getenv("SRS_CANDIDATE", "127.0.0.1"),

		CFAppID:     getenv("CF_APP_ID", ""),
		CFAppSecret: getenv("CF_APP_SECRET", ""),
		CFBaseURL:   getenv("CF_BASE_URL", "https://rtc.live.cloudflare.com/v1"),
		CFStunURL:   getenv("CF_STUN_URL", "stun:stun.cloudflare.com:3478"),

		TokenSecret:   getenv("DEMO_TOKEN_SECRET", ""),
		TokenRequired: getenv("SFU_TOKEN_REQUIRED", "0") == "1",
	}
	if c.TokenSecret == "" {
		c.TokenSecret = "insecure-demo-secret-change-me"
	}
	return c
}

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

// ProviderList 返回去重、保序的后端名列表。
func (c *Config) ProviderList() []string {
	parts := strings.Split(c.ProviderOrder, ",")
	out := make([]string, 0, len(parts))
	seen := make(map[string]struct{}, len(parts))
	for _, p := range parts {
		p = strings.TrimSpace(strings.ToLower(p))
		if p == "" || p == "both" || p == "all" {
			if p == "both" || p == "all" {
				for _, b := range []string{"cloudflare", "srs"} {
					if _, ok := seen[b]; !ok {
						seen[b] = struct{}{}
						out = append(out, b)
					}
				}
			}
			continue
		}
		if _, ok := seen[p]; !ok {
			seen[p] = struct{}{}
			out = append(out, p)
		}
	}
	return out
}