package config

import (
	"os"
	"strings"
	"time"
)

// 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。
// 默认 DB 使用 Turso 嵌入式 (libSQL file) 持久化房间拓扑；同时支持 JWT/Casbin 登录。
type Config struct {
	HTTPPort      string
	GRPCPort      string
	ProviderOrder string // 逗号分隔的后端顺序，如 "cloudflare,srs"

	SRSBaseURL   string
	SRSHttpURL   string
	SRSApp       string
	SRSSecret    string
	SRSCandidate string

	CFAppID     string
	CFAppSecret string
	CFBaseURL   string
	CFStunURL   string

	TokenSecret   string
	TokenRequired bool

	JWTSecret    string
	JWTTTL       time.Duration
	AuthModel    string
	AuthPolicy   string
	AuthUserFile string
	AllowRegister bool

	DatabaseURL string // TURSO_DATABASE_URL 或 DATABASE_URL，默认 file:./data/live-sfu.db
	AuthToken   string // 兼容远程 Turso，嵌入模式可为空
}

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"),
		SRSHttpURL:   getenv("SRS_HTTP_BASE", "http://localhost:8080"),
		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",

		JWTSecret:     getenv("JWT_SECRET", ""),
		JWTTTL:        parseDuration(getenv("JWT_TTL", "2h"), 2*time.Hour),
		AuthModel:     getenv("CASBIN_MODEL", "internal/auth/model.conf"),
		AuthPolicy:    getenv("CASBIN_POLICY", "internal/auth/policy.csv"),
		AuthUserFile:  getenv("AUTH_USER_FILE", "data/users.json"),
		AllowRegister: getenv("ALLOW_REGISTER", "1") == "1",

		DatabaseURL: getenv("TURSO_DATABASE_URL", "file:./data/live-sfu.db?cache=shared&_journal_mode=WAL"),
		AuthToken:   getenv("TURSO_AUTH_TOKEN", ""),
	}
	if c.TokenSecret == "" {
		c.TokenSecret = "insecure-demo-secret-change-me"
	}
	if c.JWTSecret == "" {
		c.JWTSecret = c.TokenSecret
		if c.JWTSecret == "" {
			c.JWTSecret = "insecure-jwt-secret-change-me"
		}
	}
	if c.DatabaseURL == "file:./data/live-sfu.db?cache=shared&_journal_mode=WAL" {
		if v := os.Getenv("DATABASE_URL"); v != "" {
			c.DatabaseURL = v
		} else if v := os.Getenv("LIBSQL_URL"); v != "" {
			c.DatabaseURL = v
		}
	}
	if c.AuthToken == "" {
		if v := os.Getenv("TURSO_AUTH_TOKEN"); v != "" {
			c.AuthToken = v
		} else if v := os.Getenv("LIBSQL_AUTH_TOKEN"); v != "" {
			c.AuthToken = v
		}
	}
	return c
}

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

func parseDuration(s string, def time.Duration) time.Duration {
	if s == "" {
		return def
	}
	if d, err := time.ParseDuration(s); err == nil {
		return d
	}
	return def
}

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
}

func (c *Config) DSN() string {
	if c.AuthToken != "" && strings.HasPrefix(c.DatabaseURL, "libsql://") && !strings.Contains(c.DatabaseURL, "authToken") {
		sep := "?"
		if strings.Contains(c.DatabaseURL, "?") {
			sep = "&"
		}
		return c.DatabaseURL + sep + "authToken=" + c.AuthToken
	}
	return c.DatabaseURL
}

func (c *Config) IsRemoteTurso() bool {
	return strings.HasPrefix(c.DatabaseURL, "libsql://") || strings.HasPrefix(c.DatabaseURL, "https://")
}