/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "chpp/clients.h"

#include <inttypes.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

#include "chpp/app.h"
#ifdef CHPP_CLIENT_ENABLED_GNSS
#include "chpp/clients/gnss.h"
#endif
#ifdef CHPP_CLIENT_ENABLED_LOOPBACK
#include "chpp/clients/loopback.h"
#endif
#ifdef CHPP_CLIENT_ENABLED_WIFI
#include "chpp/clients/wifi.h"
#endif
#ifdef CHPP_CLIENT_ENABLED_WWAN
#include "chpp/clients/wwan.h"
#endif
#include "chpp/macros.h"
#include "chpp/memory.h"
#include "chpp/platform/log.h"
#include "chpp/time.h"
#include "chpp/transport.h"

/************************************************
 *  Prototypes
 ***********************************************/

/************************************************
 *  Private Functions
 ***********************************************/

/************************************************
 *  Public Functions
 ***********************************************/

void chppRegisterCommonClients(struct ChppAppState *context) {
  UNUSED_VAR(context);

#ifdef CHPP_CLIENT_ENABLED_LOOPBACK
  if (context->clientServiceSet.loopbackClient) {
    chppLoopbackClientInit(context);
  }
#endif

#ifdef CHPP_CLIENT_ENABLED_WWAN
  if (context->clientServiceSet.wwanClient) {
    chppRegisterWwanClient(context);
  }
#endif

#ifdef CHPP_CLIENT_ENABLED_WIFI
  if (context->clientServiceSet.wifiClient) {
    chppRegisterWifiClient(context);
  }
#endif

#ifdef CHPP_CLIENT_ENABLED_GNSS
  if (context->clientServiceSet.gnssClient) {
    chppRegisterGnssClient(context);
  }
#endif
}

void chppDeregisterCommonClients(struct ChppAppState *context) {
  UNUSED_VAR(context);

#ifdef CHPP_CLIENT_ENABLED_LOOPBACK
  if (context->clientServiceSet.loopbackClient) {
    chppLoopbackClientDeinit();
  }
#endif

#ifdef CHPP_CLIENT_ENABLED_WWAN
  if (context->clientServiceSet.wwanClient) {
    chppDeregisterWwanClient(context);
  }
#endif

#ifdef CHPP_CLIENT_ENABLED_WIFI
  if (context->clientServiceSet.wifiClient) {
    chppDeregisterWifiClient(context);
  }
#endif

#ifdef CHPP_CLIENT_ENABLED_GNSS
  if (context->clientServiceSet.gnssClient) {
    chppDeregisterGnssClient(context);
  }
#endif
}

void chppClientInit(struct ChppClientState *clientContext, uint8_t handle) {
  clientContext->handle = handle;
  chppMutexInit(&clientContext->responseMutex);
  chppConditionVariableInit(&clientContext->responseCondVar);
}

void chppClientDeinit(struct ChppClientState *clientContext) {
  chppConditionVariableDeinit(&clientContext->responseCondVar);
  chppMutexDeinit(&clientContext->responseMutex);
}

void chppRegisterClient(struct ChppAppState *appContext, void *clientContext,
                        const struct ChppClient *newClient) {
  CHPP_NOT_NULL(newClient);

  if (appContext->registeredClientCount >= CHPP_MAX_REGISTERED_CLIENTS) {
    CHPP_LOGE("Cannot register new client # %" PRIu8 ". Already hit maximum",
              appContext->registeredClientCount);

  } else {
    appContext->registeredClients[appContext->registeredClientCount] =
        newClient;
    appContext->registeredClientContexts[appContext->registeredClientCount] =
        clientContext;

    char uuidText[CHPP_SERVICE_UUID_STRING_LEN];
    chppUuidToStr(newClient->descriptor.uuid, uuidText);
    CHPP_LOGI("Registered client # %" PRIu8 " with UUID=%s, version=%" PRIu8
              ".%" PRIu8 ".%" PRIu16 ", min_len=%" PRIuSIZE,
              appContext->registeredClientCount, uuidText,
              newClient->descriptor.version.major,
              newClient->descriptor.version.minor,
              newClient->descriptor.version.patch, newClient->minLength);

    appContext->registeredClientCount++;
  }
}

struct ChppAppHeader *chppAllocClientRequest(
    struct ChppClientState *clientState, size_t len) {
  CHPP_ASSERT(len >= CHPP_APP_MIN_LEN_HEADER_WITH_TRANSACTION);

  struct ChppAppHeader *result = chppMalloc(len);
  if (result != NULL) {
    result->handle = clientState->handle;
    result->type = CHPP_MESSAGE_TYPE_CLIENT_REQUEST;
    result->transaction = clientState->transaction;

    clientState->transaction++;
  }
  return result;
}

struct ChppAppHeader *chppAllocClientRequestCommand(
    struct ChppClientState *clientState, uint16_t command) {
  struct ChppAppHeader *result =
      chppAllocClientRequest(clientState, sizeof(struct ChppAppHeader));

  if (result != NULL) {
    result->command = command;
  }
  return result;
}

void chppClientTimestampRequest(struct ChppRequestResponseState *rRState,
                                struct ChppAppHeader *requestHeader) {
  if (rRState->responseTime == CHPP_TIME_NONE &&
      rRState->requestTime != CHPP_TIME_NONE) {
    CHPP_LOGE("Sending duplicate request with transaction ID = %" PRIu8
              " while prior request with transaction ID = %" PRIu8
              " was outstanding from t = %" PRIu64,
              requestHeader->transaction, rRState->transaction,
              rRState->requestTime);
  }
  rRState->requestTime = chppGetCurrentTimeNs();
  rRState->responseTime = CHPP_TIME_NONE;
  rRState->transaction = requestHeader->transaction;
}

bool chppClientTimestampResponse(struct ChppRequestResponseState *rRState,
                                 struct ChppAppHeader *responseHeader) {
  uint64_t previousResponseTime = rRState->responseTime;
  rRState->responseTime = chppGetCurrentTimeNs();

  if (rRState->requestTime == CHPP_TIME_NONE) {
    CHPP_LOGE("Received response at t = %" PRIu64
              " with no prior outstanding request",
              rRState->responseTime);

  } else if (previousResponseTime != CHPP_TIME_NONE) {
    rRState->responseTime = chppGetCurrentTimeNs();
    CHPP_LOGW("Received additional response at t = %" PRIu64
              " for request at t = %" PRIu64 " (RTT = %" PRIu64 ")",
              rRState->responseTime, rRState->responseTime,
              rRState->responseTime - rRState->requestTime);

  } else {
    CHPP_LOGI("Received initial response at t = %" PRIu64
              " for request at t = %" PRIu64 " (RTT = %" PRIu64 ")",
              rRState->responseTime, rRState->responseTime,
              rRState->responseTime - rRState->requestTime);
  }

  // TODO: Also check for timeout
  if (responseHeader->transaction != rRState->transaction) {
    CHPP_LOGE(
        "Received a response at t = %" PRIu64 " with transaction ID = %" PRIu8
        " for a different outstanding request with transaction ID = %" PRIu8,
        rRState->responseTime, responseHeader->transaction,
        rRState->transaction);
    return false;
  } else {
    return true;
  }
}

bool chppSendTimestampedRequestOrFail(struct ChppClientState *clientState,
                                      struct ChppRequestResponseState *rRState,
                                      void *buf, size_t len) {
  CHPP_ASSERT(len >= CHPP_APP_MIN_LEN_HEADER_WITH_TRANSACTION);
  chppClientTimestampRequest(rRState, buf);
  return chppEnqueueTxDatagramOrFail(clientState->appContext->transportContext,
                                     buf, len);
}

bool chppSendTimestampedRequestAndWait(struct ChppClientState *clientState,
                                       struct ChppRequestResponseState *rRState,
                                       void *buf, size_t len) {
  return chppSendTimestampedRequestAndWaitTimeout(
      clientState, rRState, buf, len, DEFAULT_CLIENT_REQUEST_TIMEOUT_NS);
}

bool chppSendTimestampedRequestAndWaitTimeout(
    struct ChppClientState *clientState,
    struct ChppRequestResponseState *rRState, void *buf, size_t len,
    uint64_t timeoutNs) {
  chppMutexLock(&clientState->responseMutex);

  bool result =
      chppSendTimestampedRequestOrFail(clientState, rRState, buf, len);
  if (result) {
    clientState->responseReady = false;
    while (result && !clientState->responseReady) {
      result = chppConditionVariableTimedWait(&clientState->responseCondVar,
                                              &clientState->responseMutex,
                                              timeoutNs);
    }
    if (!clientState->responseReady) {
      CHPP_LOGE("Timeout waiting on service response after %" PRIu64 " ms",
                timeoutNs / CHPP_NSEC_PER_MSEC);
      result = false;
    }
  }

  chppMutexUnlock(&clientState->responseMutex);

  return result;
}