/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "streamInt.h"

int32_t tEncodeStreamCheckpointSourceReq(SEncoder* pEncoder, const SStreamCheckpointSourceReq* pReq) {
  if (tStartEncode(pEncoder) < 0) return -1;
  if (tEncodeI64(pEncoder, pReq->streamId) < 0) return -1;
  if (tEncodeI64(pEncoder, pReq->checkpointId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->taskId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->nodeId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->mnodeId) < 0) return -1;
  if (tEncodeI64(pEncoder, pReq->expireTime) < 0) return -1;
  tEndEncode(pEncoder);
  return pEncoder->pos;
}

int32_t tDecodeStreamCheckpointSourceReq(SDecoder* pDecoder, SStreamCheckpointSourceReq* pReq) {
  if (tStartDecode(pDecoder) < 0) return -1;
  if (tDecodeI64(pDecoder, &pReq->streamId) < 0) return -1;
  if (tDecodeI64(pDecoder, &pReq->checkpointId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pReq->taskId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pReq->nodeId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pReq->mnodeId) < 0) return -1;
  if (tDecodeI64(pDecoder, &pReq->expireTime) < 0) return -1;
  tEndDecode(pDecoder);
  return 0;
}

int32_t tEncodeStreamCheckpointSourceRsp(SEncoder* pEncoder, const SStreamCheckpointSourceRsp* pRsp) {
  if (tStartEncode(pEncoder) < 0) return -1;
  if (tEncodeI64(pEncoder, pRsp->streamId) < 0) return -1;
  if (tEncodeI64(pEncoder, pRsp->checkpointId) < 0) return -1;
  if (tEncodeI32(pEncoder, pRsp->taskId) < 0) return -1;
  if (tEncodeI32(pEncoder, pRsp->nodeId) < 0) return -1;
  if (tEncodeI64(pEncoder, pRsp->expireTime) < 0) return -1;
  tEndEncode(pEncoder);
  return pEncoder->pos;
}

int32_t tDecodeStreamCheckpointSourceRsp(SDecoder* pDecoder, SStreamCheckpointSourceRsp* pRsp) {
  if (tStartDecode(pDecoder) < 0) return -1;
  if (tDecodeI64(pDecoder, &pRsp->streamId) < 0) return -1;
  if (tDecodeI64(pDecoder, &pRsp->checkpointId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pRsp->taskId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pRsp->nodeId) < 0) return -1;
  if (tDecodeI64(pDecoder, &pRsp->expireTime) < 0) return -1;
  tEndDecode(pDecoder);
  return 0;
}

int32_t tEncodeStreamCheckpointReadyMsg(SEncoder* pEncoder, const SStreamCheckpointReadyMsg* pReq) {
  if (tStartEncode(pEncoder) < 0) return -1;
  if (tEncodeI64(pEncoder, pReq->streamId) < 0) return -1;
  if (tEncodeI64(pEncoder, pReq->checkpointId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->downstreamTaskId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->downstreamNodeId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->upstreamTaskId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->upstreamNodeId) < 0) return -1;
  if (tEncodeI32(pEncoder, pReq->childId) < 0) return -1;
  tEndEncode(pEncoder);
  return pEncoder->pos;
}

int32_t tDecodeStreamCheckpointReadyMsg(SDecoder* pDecoder, SStreamCheckpointReadyMsg* pRsp) {
  if (tStartDecode(pDecoder) < 0) return -1;
  if (tDecodeI64(pDecoder, &pRsp->streamId) < 0) return -1;
  if (tDecodeI64(pDecoder, &pRsp->checkpointId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pRsp->downstreamTaskId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pRsp->downstreamNodeId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pRsp->upstreamTaskId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pRsp->upstreamNodeId) < 0) return -1;
  if (tDecodeI32(pDecoder, &pRsp->childId) < 0) return -1;
  tEndDecode(pDecoder);
  return 0;
}

static int32_t streamAlignCheckpoint(SStreamTask* pTask) {
  int32_t num = taosArrayGetSize(pTask->pUpstreamInfoList);
  int64_t old = atomic_val_compare_exchange_32(&pTask->checkpointAlignCnt, 0, num);
  if (old == 0) {
    qDebug("s-task:%s set initial align upstream num:%d", pTask->id.idStr, num);
  }

  return atomic_sub_fetch_32(&pTask->checkpointAlignCnt, 1);
}

static int32_t appendCheckpointIntoInputQ(SStreamTask* pTask, int32_t checkpointType) {
  SStreamDataBlock* pChkpoint = taosAllocateQitem(sizeof(SStreamDataBlock), DEF_QITEM, sizeof(SSDataBlock));
  if (pChkpoint == NULL) {
    return TSDB_CODE_OUT_OF_MEMORY;
  }

  pChkpoint->type = checkpointType;

  SSDataBlock* pBlock = taosMemoryCalloc(1, sizeof(SSDataBlock));
  if (pBlock == NULL) {
    taosFreeQitem(pChkpoint);
    return TSDB_CODE_OUT_OF_MEMORY;
  }

  pBlock->info.type = STREAM_CHECKPOINT;
  pBlock->info.version = pTask->checkpointingId;
  pBlock->info.rows = 1;
  pBlock->info.childId = pTask->info.selfChildId;

  pChkpoint->blocks = taosArrayInit(4, sizeof(SSDataBlock));//pBlock;
  taosArrayPush(pChkpoint->blocks, pBlock);

  if (tAppendDataToInputQueue(pTask, (SStreamQueueItem*)pChkpoint) < 0) {
    taosFreeQitem(pChkpoint);
    return TSDB_CODE_OUT_OF_MEMORY;
  }

  streamSchedExec(pTask);
  return TSDB_CODE_SUCCESS;
}

int32_t streamProcessCheckpointSourceReq(SStreamTask* pTask, SStreamCheckpointSourceReq* pReq) {
  ASSERT(pTask->info.taskLevel == TASK_LEVEL__SOURCE);

  // 1. set task status to be prepared for check point, no data are allowed to put into inputQ.
  pTask->status.taskStatus = TASK_STATUS__CK;
  pTask->checkpointingId = pReq->checkpointId;
  pTask->checkpointNotReadyTasks = 1;

  // 2. let's dispatch checkpoint msg to downstream task directly and do nothing else.
  // 2. put the checkpoint block into inputQ, to make sure all blocks with less version have been handled by this task already.
  return appendCheckpointIntoInputQ(pTask, STREAM_INPUT__CHECKPOINT_TRIGGER);
}

int32_t streamProcessCheckpointBlock(SStreamTask* pTask, SStreamDataBlock* pBlock) {
  SSDataBlock* pDataBlock = taosArrayGet(pBlock->blocks, 0);
  int64_t checkpointId = pDataBlock->info.version;

  // set the task status
  pTask->checkpointingId = checkpointId;
  pTask->status.taskStatus = TASK_STATUS__CK;

  //todo fix race condition: set the status and append checkpoint block
  int32_t taskLevel = pTask->info.taskLevel;
  if (taskLevel == TASK_LEVEL__SOURCE) {
    if (pTask->outputType == TASK_OUTPUT__FIXED_DISPATCH || pTask->outputType == TASK_OUTPUT__SHUFFLE_DISPATCH) {
      pBlock->srcTaskId = pTask->id.taskId;
      pBlock->srcVgId = pTask->pMeta->vgId;

      qDebug("s-task:%s set childIdx:%d, and add checkpoint block into outputQ", pTask->id.idStr,
             pTask->info.selfChildId);

      int32_t code = taosWriteQitem(pTask->outputQueue->queue, pBlock);
      if (code != 0) {  // todo failed to add it into the output queue, free it.
        return code;
      }

      streamFreeQitem((SStreamQueueItem*)pBlock);
      streamDispatchStreamBlock(pTask);
    } else {  // only one task exists
      streamProcessCheckpointReadyMsg(pTask);
    }
  } else if (taskLevel == TASK_LEVEL__SINK) {
    // todo: sink node needs alignment??
    ASSERT(pTask->status.taskStatus == TASK_STATUS__CK);
    pTask->status.taskStatus = TASK_STATUS__CK_READY;

    // update the child Id for downstream tasks
    streamAddCheckpointReadyMsg(pTask, pBlock->srcTaskId, pTask->info.selfChildId, checkpointId);
    qDebug("s-task:%s sink task do checkpoint ready, send ready msg to upstream", pTask->id.idStr);
  } else {
    ASSERT(taosArrayGetSize(pTask->pUpstreamInfoList) > 0);

    // update the child Id for downstream tasks
    streamAddCheckpointReadyMsg(pTask, pBlock->srcTaskId, pTask->info.selfChildId, checkpointId);

    // there are still some upstream tasks not send checkpoint request, do nothing and wait for then
    int32_t notReady = streamAlignCheckpoint(pTask);
    int32_t num = taosArrayGetSize(pTask->pUpstreamInfoList);
    if (notReady > 0) {
      qDebug("s-task:%s received checkpoint block, idx:%d, %d upstream tasks not send checkpoint info yet, total:%d",
             pTask->id.idStr, pTask->info.selfChildId, notReady, num);
      return 0;
    }

    qDebug(
        "s-task:%s receive one checkpoint block, all %d upstream sent checkpoint msgs, dispatch checkpoint msg to "
        "downstream",
        pTask->id.idStr, num);

    // set the needed checked downstream tasks, only when all downstream tasks do checkpoint complete, this task
    // can start local checkpoint procedure
    pTask->checkpointNotReadyTasks = streamTaskGetNumOfDownstream(pTask);

    // if all upstreams are ready for generating checkpoint, set the status to be TASK_STATUS__CK_READY
    // put the checkpoint block into inputQ, to make sure all blocks with less version have been handled by this task
    // already. And then, dispatch check point msg to all downstream tasks

    {
      pBlock->srcTaskId = pTask->id.taskId;
      pBlock->srcVgId = pTask->pMeta->vgId;

      ASSERT(pTask->outputType == TASK_OUTPUT__FIXED_DISPATCH || pTask->outputType == TASK_OUTPUT__SHUFFLE_DISPATCH);
      int32_t code = taosWriteQitem(pTask->outputQueue->queue, pBlock);
      if (code != 0) {  // todo failed to add it into the output queue, free it.
        return code;
      }

      streamFreeQitem((SStreamQueueItem*)pBlock);
      streamDispatchStreamBlock(pTask);
    }
  }

  return 0;
}

/**
 * All down stream tasks have successfully completed the check point task.
 * Current stream task is allowed to start to do checkpoint things in ASYNC model.
 */
int32_t streamProcessCheckpointReadyMsg(SStreamTask* pTask) {
  ASSERT(pTask->info.taskLevel == TASK_LEVEL__SOURCE || pTask->info.taskLevel == TASK_LEVEL__AGG);

  // only when all downstream tasks are send checkpoint rsp, we can start the checkpoint procedure for the agg task
  int32_t notReady = atomic_sub_fetch_32(&pTask->checkpointNotReadyTasks, 1);
  ASSERT(notReady >= 0);

  if (notReady == 0) {
    qDebug("s-task:%s all downstream tasks have completed the checkpoint, start to do checkpoint for current task",
           pTask->id.idStr);
    appendCheckpointIntoInputQ(pTask, STREAM_INPUT__CHECKPOINT);
  } else {
    int32_t total = streamTaskGetNumOfDownstream(pTask);
    qDebug("s-task:%s %d/%d downstream tasks are not ready, wait", pTask->id.idStr, notReady, total);
  }

  return 0;
}

int32_t streamSaveTasks(SStreamMeta* pMeta, int64_t checkpointId) {
  taosWLockLatch(&pMeta->lock);

  for (int32_t i = 0; i < taosArrayGetSize(pMeta->pTaskList); ++i) {
    uint32_t*    pTaskId = taosArrayGet(pMeta->pTaskList, i);
    SStreamTask* p = *(SStreamTask**)taosHashGet(pMeta->pTasks, pTaskId, sizeof(*pTaskId));

    ASSERT(p->chkInfo.checkpointId < p->checkpointingId && p->checkpointingId == checkpointId);
    p->chkInfo.checkpointId = p->checkpointingId;

    int8_t prev = p->status.taskStatus;
    p->status.taskStatus = TASK_STATUS__NORMAL;

    streamMetaSaveTask(pMeta, p);
    qDebug("vgId:%d s-task:%s commit task status after checkpoint completed, checkpointId:%" PRId64 ", ver:%" PRId64
           " currentVer:%" PRId64 ", status to be normal, prev:%s",
           pMeta->vgId, p->id.idStr, checkpointId, p->chkInfo.checkpointVer, p->chkInfo.currentVer,
           streamGetTaskStatusStr(prev));
  }

  if (streamMetaCommit(pMeta) < 0) {
    taosWUnLockLatch(&pMeta->lock);
    qError("vgId:%d failed to commit stream meta after do checkpoint, checkpointId:%" PRId64 ", since %s", pMeta->vgId,
           checkpointId, terrstr());
    return -1;
  } else {
    taosWUnLockLatch(&pMeta->lock);
    qInfo("vgId:%d commit stream meta after do checkpoint, checkpointId:%" PRId64 " DONE", pMeta->vgId, checkpointId);
  }

  return TSDB_CODE_SUCCESS;
}
