package application

import (
	"errors"
	"strings"
)

type AuthConfig struct {
	Required      bool
	Configured    bool
	SessionSecret string
}

func ParseAuthConfig(getenv func(string) string) (AuthConfig, error) {
	if getenv == nil {
		return AuthConfig{}, errors.New("auth config getenv is required")
	}

	sessionSecret := firstAuthEnv(getenv,
		"ZHINIAN_AUTH_SESSION_SECRET",
		"AUTH_SESSION_SECRET",
		"NEXTAUTH_SECRET",
	)
	hasSecret := sessionSecret != ""
	explicitRequired, hasExplicitRequired := authBool(getenv("ZHINIAN_AUTH_REQUIRED"))
	disabled, _ := authBool(getenv("ZHINIAN_AUTH_DISABLED"))

	required := getenv("NODE_ENV") == "production" || hasSecret
	if hasExplicitRequired {
		required = explicitRequired
	}
	if disabled {
		required = false
	}

	return AuthConfig{
		Required:      required,
		Configured:    (required || hasSecret) && hasSecret,
		SessionSecret: sessionSecret,
	}, nil
}

func firstAuthEnv(getenv func(string) string, names ...string) string {
	for _, name := range names {
		if value := strings.TrimSpace(getenv(name)); value != "" {
			return value
		}
	}
	return ""
}

func authBool(value string) (bool, bool) {
	switch strings.ToLower(strings.TrimSpace(value)) {
	case "1", "true", "yes", "on":
		return true, true
	case "0", "false", "no", "off":
		return false, true
	default:
		return false, false
	}
}