package main

import (
	"fmt"
	"sync"
	"time"

	"github.com/tinode/chat/server/logs"
	"github.com/tinode/chat/server/store"
	"github.com/tinode/chat/server/store/types"
	"github.com/tinode/chat/server/validate"
)

const registrationSMSConfigCacheTTL = 30 * time.Second

var registrationSMSConfigCache struct {
	sync.Mutex
	value     bool
	loaded    bool
	loadedAt  time.Time
	loadValue func() (bool, error)
}

func registrationSMSEnabled(now time.Time) bool {
	registrationSMSConfigCache.Lock()
	defer registrationSMSConfigCache.Unlock()
	if registrationSMSConfigCache.loaded && now.Sub(registrationSMSConfigCache.loadedAt) < registrationSMSConfigCacheTTL {
		return registrationSMSConfigCache.value
	}
	loader := registrationSMSConfigCache.loadValue
	if loader == nil {
		loader = func() (bool, error) {
			if store.RegistrationConfig == nil {
				return true, types.ErrUnsupported
			}
			return store.RegistrationConfig.SMSEnabled()
		}
	}
	value, err := loader()
	if err != nil {
		if registrationSMSConfigCache.loaded {
			logs.Warn.Println("registration SMS config read failed; using cached value:", err)
			return registrationSMSConfigCache.value
		}
		logs.Warn.Println("registration SMS config read failed; defaulting to enabled:", err)
		return true
	}
	registrationSMSConfigCache.value = value
	registrationSMSConfigCache.loaded = true
	registrationSMSConfigCache.loadedAt = now
	return value
}

func isValidIMInviteCode(value string) bool {
	if len(value) != 5 {
		return false
	}
	for i := range value {
		if (value[i] < 'A' || value[i] > 'Z') && (value[i] < 'a' || value[i] > 'z') {
			return false
		}
	}
	return true
}

var sendIMVerificationCode = func(tenantID types.TenantID, recipient, lang, scene, code string) error {
	if store.Store == nil {
		return types.ErrInternal
	}
	validatorImpl := store.Store.GetValidator("tel")
	sender, ok := validatorImpl.(validate.CodeSender)
	if !ok || !validatorImpl.IsInitialized() {
		return types.ErrUnsupported
	}
	if err := sender.SendCode(tenantID, recipient, lang, scene, code); err != nil {
		return fmt.Errorf("send verification code: %w", err)
	}
	return nil
}