/*
 * 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 (tEncodeSEpSet(pEncoder, &pReq->mgmtEps) < 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 (tDecodeSEpSet(pDecoder, &pReq->mgmtEps) < 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);

  taosMemoryFree(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.
  taosThreadMutexLock(&pTask->lock);

  pTask->status.taskStatus = TASK_STATUS__CK;
  pTask->checkpointingId = pReq->checkpointId;
  pTask->checkpointNotReadyTasks = streamTaskGetNumOfDownstream(pTask);

  // 2. let's dispatch checkpoint msg to downstream task directly and do nothing else. put the checkpoint block into
  //    inputQ, to make sure all blocks with less version have been handled by this task already.
  int32_t code = appendCheckpointIntoInputQ(pTask, STREAM_INPUT__CHECKPOINT_TRIGGER);
  taosThreadMutexUnlock(&pTask->lock);

  return code;
}

static int32_t continueDispatchCheckpointBlock(SStreamDataBlock* pBlock, SStreamTask* pTask) {
  pBlock->srcTaskId = pTask->id.taskId;
  pBlock->srcVgId = pTask->pMeta->vgId;

  int32_t code = taosWriteQitem(pTask->outputInfo.queue->queue, pBlock);
  if (code == 0) {
    streamDispatchStreamBlock(pTask);
  } else {
    streamFreeQitem((SStreamQueueItem*)pBlock);
  }

  return code;
}

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

  const char* id = pTask->id.idStr;
  int32_t code = TSDB_CODE_SUCCESS;

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

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

  { // todo: remove this when the pipeline checkpoint generating is used.
    SStreamMeta* pMeta = pTask->pMeta;
    taosWLockLatch(&pMeta->lock);
    if (pMeta->chkptNotReadyTasks == 0) {
      pMeta->chkptNotReadyTasks = taosArrayGetSize(pMeta->pTaskList);
    }

    taosWUnLockLatch(&pMeta->lock);
  }

  //todo fix race condition: set the status and append checkpoint block
  int32_t taskLevel = pTask->info.taskLevel;
  if (taskLevel == TASK_LEVEL__SOURCE) {
    if (pTask->outputInfo.type == TASK_OUTPUT__FIXED_DISPATCH || pTask->outputInfo.type == TASK_OUTPUT__SHUFFLE_DISPATCH) {
      qDebug("s-task:%s set childIdx:%d, and add checkpoint block into outputQ", id, pTask->info.selfChildId);
      continueDispatchCheckpointBlock(pBlock, pTask);
    } else {  // only one task exists, no need to dispatch downstream info
      streamProcessCheckpointReadyMsg(pTask);
      streamFreeQitem((SStreamQueueItem*)pBlock);
    }
  } else if (taskLevel == TASK_LEVEL__SINK || taskLevel == TASK_LEVEL__AGG) {
    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",
             id, pTask->info.selfChildId, notReady, num);
      streamFreeQitem((SStreamQueueItem*)pBlock);
      return code;
    }

    if (taskLevel == TASK_LEVEL__SINK) {
      pTask->status.taskStatus = TASK_STATUS__CK_READY;
      qDebug("s-task:%s process checkpoint block, all %d upstreams sent checkpoint msgs, send ready msg to upstream",
             id, num);
      streamFreeQitem((SStreamQueueItem*)pBlock);
    } else {
      qDebug(
          "s-task:%s process checkpoint block, all %d upstreams sent checkpoint msgs, dispatch checkpoint msg "
          "downstream", id, 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
      code = continueDispatchCheckpointBlock(pBlock, pTask);
    }
  }

  return code;
}

/**
 * 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 streamSaveAllTaskStatus(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));

    int8_t prev = p->status.taskStatus;
    ASSERT(p->chkInfo.checkpointId < p->checkpointingId && p->checkpointingId == checkpointId);

    p->chkInfo.checkpointId = p->checkpointingId;
    p->status.taskStatus = TASK_STATUS__NORMAL;

    // save the task
    streamMetaSaveTask(pMeta, p);
    streamTaskOpenAllUpstreamInput(p);   // open inputQ for all upstream tasks
    qDebug("vgId:%d s-task:%s level:%d commit task status after checkpoint completed, checkpointId:%" PRId64
           ", Ver(saved):%" PRId64 " currentVer:%" PRId64 ", status to be normal, prev:%s",
           pMeta->vgId, p->id.idStr, p->info.taskLevel, 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;
}

int32_t streamTaskBuildCheckpoint(SStreamTask* pTask) {
  int32_t code = 0;

  if (pTask->status.taskStatus == TASK_STATUS__CK_READY) {
    // check for all tasks, and do generate the vnode-wide checkpoint data.
    SStreamMeta* pMeta = pTask->pMeta;
    int32_t      remain = atomic_sub_fetch_32(&pMeta->chkptNotReadyTasks, 1);
    ASSERT(remain >= 0);

    if (remain == 0) {  // all tasks are in TASK_STATUS__CK_READY state
      streamBackendDoCheckpoint(pMeta, pTask->checkpointingId);
      streamSaveAllTaskStatus(pMeta, pTask->checkpointingId);

      qDebug("vgId:%d vnode wide checkpoint completed, save all tasks status, checkpointId:%" PRId64, pMeta->vgId,
             pTask->checkpointingId);
    } else {
      qDebug("vgId:%d vnode wide tasks not reach checkpoint ready status, not ready:%d/%d", pMeta->vgId, remain,
             (int32_t)taosArrayGetSize(pMeta->pTaskList));
    }

    // send check point response to upstream task
    if (pTask->info.taskLevel == TASK_LEVEL__SOURCE) {
      code = streamTaskSendCheckpointSourceRsp(pTask);
    } else {
      code = streamTaskSendCheckpointReadyMsg(pTask);
    }

    if (code != TSDB_CODE_SUCCESS) {
      // todo: let's retry send rsp to upstream/mnode
      qError("s-task:%s failed to send checkpoint rsp to upstream, checkpointId:%" PRId64 ", code:%s",
             pTask->id.idStr, pTask->checkpointingId, tstrerror(code));
    }
  }

  return code;
}
