// Изменено: 2026-04-09
// ReceiveMessageV1 — получает сообщения из очереди тенанта с поддержкой long polling.
// Ловушка #4: long polling держит соединение до 20 сек — не прерываем принудительно.
package gosqs

import (
"fmt"
"net/http"
"strings"
"time"

"github.com/google/uuid"

"shared-sqs/app/interfaces"
"shared-sqs/app/models"
"shared-sqs/app/utils"
"github.com/gorilla/mux"
log "github.com/sirupsen/logrus"
)

func ReceiveMessageV1(req *http.Request) (int, interfaces.AbstractResponseBody) {
requestBody := models.NewReceiveMessageRequest()
ok := utils.REQUEST_TRANSFORMER(requestBody, req, false)
if !ok {
log.Error("Invalid Request - ReceiveMessageV1")
return utils.CreateErrorResponseV1("InvalidParameterValue", true)
}

t := getTenantFromContext(req)
if t == nil {
return utils.CreateErrorResponseV1("InvalidClientTokenId", true)
}

maxNumberOfMessages := requestBody.MaxNumberOfMessages
if maxNumberOfMessages == 0 {
maxNumberOfMessages = 1
}

queueName := ""
if requestBody.QueueUrl == "" {
vars := mux.Vars(req)
queueName = vars["queueName"]
} else {
uriSegments := strings.Split(requestBody.QueueUrl, "/")
queueName = uriSegments[len(uriSegments)-1]
}

key := tenantQueueKey(t.AccessKey, queueName)

if _, ok := models.SyncQueues.Queues[key]; !ok {
return utils.CreateErrorResponseV1("QueueNotFound", true)
}

var messages []*models.ResultMessage
respStruct := models.ReceiveMessageResponse{}

waitTimeSeconds := requestBody.WaitTimeSeconds
if waitTimeSeconds == 0 {
models.SyncQueues.RLock()
waitTimeSeconds = models.SyncQueues.Queues[key].ReceiveMessageWaitTimeSeconds
models.SyncQueues.RUnlock()
}

// Long polling: ждём появления сообщения до waitTimeSeconds*10 итераций по 100ms
loops := waitTimeSeconds * 10
for loops > 0 {
models.SyncQueues.RLock()
_, queueFound := models.SyncQueues.Queues[key]
if !queueFound {
models.SyncQueues.RUnlock()
return utils.CreateErrorResponseV1("QueueNotFound", true)
}
messageFound := len(models.SyncQueues.Queues[key].Messages)-numberOfHiddenMessagesInQueue(*models.SyncQueues.Queues[key]) != 0
models.SyncQueues.RUnlock()
if !messageFound {
continueTimer := time.NewTimer(100 * time.Millisecond)
select {
case <-req.Context().Done():
continueTimer.Stop()
return http.StatusOK, models.ReceiveMessageResponse{
Xmlns:    models.BaseXmlns,
Result:   models.ReceiveMessageResult{},
Metadata: models.BaseResponseMetadata,
}
case <-continueTimer.C:
continueTimer.Stop()
}
loops--
} else {
break
}
}
log.Debugf("Getting Message from Queue:%s (tenant: %s)", queueName, t.ID)

models.SyncQueues.Lock()
defer models.SyncQueues.Unlock()

if len(models.SyncQueues.Queues[key].Messages) > 0 {
numMsg := 0
messages = make([]*models.ResultMessage, 0)
for i := range models.SyncQueues.Queues[key].Messages {
if numMsg >= maxNumberOfMessages {
break
}

if models.SyncQueues.Queues[key].Messages[i].ReceiptHandle != "" {
continue
}

msg := &models.SyncQueues.Queues[key].Messages[i]
if !msg.IsReadyForReceipt() {
continue
}

if models.SyncQueues.Queues[key].IsFIFO {
if models.SyncQueues.Queues[key].IsLocked(msg.GroupID) {
continue
}
models.SyncQueues.Queues[key].LockGroup(msg.GroupID)
}

randomId := uuid.NewString()
msg.ReceiptHandle = msg.Uuid + "#" + randomId
msg.ReceiptTime = time.Now().UTC()

if requestBody.VisibilityTimeout != 0 {
msg.VisibilityTimeout = time.Now().Add(time.Duration(requestBody.VisibilityTimeout) * time.Second)
} else {
msg.VisibilityTimeout = time.Now().Add(time.Duration(models.SyncQueues.Queues[key].VisibilityTimeout) * time.Second)
}

messages = append(messages, buildResultMessage(msg))
numMsg++
}

respStruct = models.ReceiveMessageResponse{
"http://queue.amazonaws.com/doc/2012-11-05/",
models.ReceiveMessageResult{Messages: messages},
models.ResponseMetadata{RequestId: "00000000-0000-0000-0000-000000000000"},
}
} else {
log.Warning("No messages in Queue:", queueName)
respStruct = models.ReceiveMessageResponse{
Xmlns:    "http://queue.amazonaws.com/doc/2012-11-05/",
Result:   models.ReceiveMessageResult{},
Metadata: models.ResponseMetadata{RequestId: "00000000-0000-0000-0000-000000000000"},
}
}

return http.StatusOK, respStruct
}

func buildResultMessage(m *models.SqsMessage) *models.ResultMessage {
return &models.ResultMessage{
MessageId:              m.Uuid,
Body:                   m.MessageBody,
ReceiptHandle:          m.ReceiptHandle,
MD5OfBody:              utils.GetMD5Hash(m.MessageBody),
MD5OfMessageAttributes: m.MD5OfMessageAttributes,
MessageAttributes:      m.MessageAttributes,
Attributes: map[string]string{
"ApproximateFirstReceiveTimestamp": fmt.Sprintf("%d", m.ReceiptTime.UnixNano()/int64(time.Millisecond)),
"SenderId":                         models.CurrentEnvironment.AccountID,
"ApproximateReceiveCount":          fmt.Sprintf("%d", m.NumberOfReceives+1),
"SentTimestamp":                    fmt.Sprintf("%d", time.Now().UTC().UnixNano()/int64(time.Millisecond)),
},
}
}