/*
 * 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/>.
 */

#define _DEFAULT_SOURCE
#include "mndShow.h"

#define SHOW_STEP_SIZE 100

static SShowObj *mndCreateShowObj(SMnode *pMnode, SShowReq *pReq);
static void      mndFreeShowObj(SShowObj *pShow);
static SShowObj *mndAcquireShowObj(SMnode *pMnode, int64_t showId);
static void      mndReleaseShowObj(SShowObj *pShow, bool forceRemove);
static int32_t   mndProcessShowReq(SNodeMsg *pReq);
static int32_t   mndProcessRetrieveReq(SNodeMsg *pReq);
static bool      mndCheckRetrieveFinished(SShowObj *pShow);
static int32_t   mndProcessRetrieveSysTableReq(SNodeMsg *pReq);

int32_t mndInitShow(SMnode *pMnode) {
  SShowMgmt *pMgmt = &pMnode->showMgmt;

  pMgmt->cache = taosCacheInit(TSDB_DATA_TYPE_INT, 5, true, (__cache_free_fn_t)mndFreeShowObj, "show");
  if (pMgmt->cache == NULL) {
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    mError("failed to alloc show cache since %s", terrstr());
    return -1;
  }

  mndSetMsgHandle(pMnode, TDMT_MND_SHOW, mndProcessShowReq);
  mndSetMsgHandle(pMnode, TDMT_MND_SHOW_RETRIEVE, mndProcessRetrieveReq);
  mndSetMsgHandle(pMnode, TDMT_MND_SYSTABLE_RETRIEVE, mndProcessRetrieveSysTableReq);
  return 0;
}

void mndCleanupShow(SMnode *pMnode) {
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  if (pMgmt->cache != NULL) {
    taosCacheCleanup(pMgmt->cache);
    pMgmt->cache = NULL;
  }
}

static SShowObj *mndCreateShowObj(SMnode *pMnode, SShowReq *pReq) {
  SShowMgmt *pMgmt = &pMnode->showMgmt;

  int64_t showId = atomic_add_fetch_64(&pMgmt->showId, 1);
  if (showId == 0) atomic_add_fetch_64(&pMgmt->showId, 1);

  int32_t  size = sizeof(SShowObj) + pReq->payloadLen;
  SShowObj showObj = {0};
  showObj.id = showId;
  showObj.pMnode = pMnode;
  showObj.type = pReq->type;
  showObj.payloadLen = pReq->payloadLen;
  memcpy(showObj.db, pReq->db, TSDB_DB_FNAME_LEN);
  memcpy(showObj.payload, pReq->payload, pReq->payloadLen);

  int32_t   keepTime = tsShellActivityTimer * 6 * 1000;
  SShowObj *pShow = taosCachePut(pMgmt->cache, &showId, sizeof(int64_t), &showObj, size, keepTime);
  if (pShow == NULL) {
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    mError("show:0x%" PRIx64 ", failed to put into cache since %s", showId, terrstr());
    return NULL;
  }

  mTrace("show:0x%" PRIx64 ", is created, data:%p", showId, pShow);
  return pShow;
}

static void mndFreeShowObj(SShowObj *pShow) {
  SMnode    *pMnode = pShow->pMnode;
  SShowMgmt *pMgmt = &pMnode->showMgmt;

  ShowFreeIterFp freeFp = pMgmt->freeIterFps[pShow->type];
  if (freeFp != NULL) {
    if (pShow->pIter != NULL) {
      (*freeFp)(pMnode, pShow->pIter);
    }
  }

  mTrace("show:0x%" PRIx64 ", is destroyed, data:%p", pShow->id, pShow);
}

static SShowObj *mndAcquireShowObj(SMnode *pMnode, int64_t showId) {
  SShowMgmt *pMgmt = &pMnode->showMgmt;

  SShowObj *pShow = taosCacheAcquireByKey(pMgmt->cache, &showId, sizeof(showId));
  if (pShow == NULL) {
    mError("show:0x%" PRIx64 ", already destroyed", showId);
    return NULL;
  }

  mTrace("show:0x%" PRIx64 ", acquired from cache, data:%p", pShow->id, pShow);
  return pShow;
}

static void mndReleaseShowObj(SShowObj *pShow, bool forceRemove) {
  if (pShow == NULL) return;
  mTrace("show:0x%" PRIx64 ", released from cache, data:%p force:%d", pShow->id, pShow, forceRemove);

  // A bug in tcache.c
  forceRemove = 0;

  SMnode    *pMnode = pShow->pMnode;
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  taosCacheRelease(pMgmt->cache, (void **)(&pShow), forceRemove);
}

static int32_t mndProcessShowReq(SNodeMsg *pReq) {
  SMnode    *pMnode = pReq->pNode;
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  int32_t    code = -1;
  SShowReq   showReq = {0};
  SShowRsp   showRsp = {0};

  if (tDeserializeSShowReq(pReq->rpcMsg.pCont, pReq->rpcMsg.contLen, &showReq) != 0) {
    terrno = TSDB_CODE_INVALID_MSG;
    goto SHOW_OVER;
  }

  if (showReq.type <= TSDB_MGMT_TABLE_START || showReq.type >= TSDB_MGMT_TABLE_MAX) {
    terrno = TSDB_CODE_MND_INVALID_MSG_TYPE;
    goto SHOW_OVER;
  }

  ShowMetaFp metaFp = pMgmt->metaFps[showReq.type];
  if (metaFp == NULL) {
    terrno = TSDB_CODE_MND_INVALID_MSG_TYPE;
    goto SHOW_OVER;
  }

  SShowObj *pShow = mndCreateShowObj(pMnode, &showReq);
  if (pShow == NULL) {
    goto SHOW_OVER;
  }

  showRsp.showId = pShow->id;
  showRsp.tableMeta.pSchemas = calloc(TSDB_MAX_COLUMNS, sizeof(SSchema));
  if (showRsp.tableMeta.pSchemas == NULL) {
    mndReleaseShowObj(pShow, true);
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    goto SHOW_OVER;
  }

  code = (*metaFp)(pReq, pShow, &showRsp.tableMeta);
  mDebug("show:0x%" PRIx64 ", get meta finished, numOfRows:%d cols:%d showReq.type:%s, result:%s", pShow->id,
         pShow->numOfRows, pShow->numOfColumns, mndShowStr(showReq.type), tstrerror(code));

  if (code == 0) {
    int32_t bufLen = tSerializeSShowRsp(NULL, 0, &showRsp);
    void   *pBuf = rpcMallocCont(bufLen);
    tSerializeSShowRsp(pBuf, bufLen, &showRsp);
    pReq->rspLen = bufLen;
    pReq->pRsp = pBuf;
    mndReleaseShowObj(pShow, false);
  } else {
    mndReleaseShowObj(pShow, true);
  }

SHOW_OVER:
  if (code != 0) {
    mError("failed to process show-meta req since %s", terrstr());
  }

  tFreeSShowReq(&showReq);
  tFreeSShowRsp(&showRsp);
  return code;
}

static int32_t mndProcessRetrieveReq(SNodeMsg *pReq) {
  SMnode    *pMnode = pReq->pNode;
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  int32_t    rowsToRead = 0;
  int32_t    size = 0;
  int32_t    rowsRead = 0;

  SRetrieveTableReq retrieveReq = {0};
  if (tDeserializeSRetrieveTableReq(pReq->rpcMsg.pCont, pReq->rpcMsg.contLen, &retrieveReq) != 0) {
    terrno = TSDB_CODE_INVALID_MSG;
    return -1;
  }

  SShowObj *pShow = mndAcquireShowObj(pMnode, retrieveReq.showId);
  if (pShow == NULL) {
    terrno = TSDB_CODE_MND_INVALID_SHOWOBJ;
    mError("failed to process show-retrieve req:%p since %s", pShow, terrstr());
    return -1;
  }

  ShowRetrieveFp retrieveFp = pMgmt->retrieveFps[pShow->type];
  if (retrieveFp == NULL) {
    mndReleaseShowObj(pShow, false);
    terrno = TSDB_CODE_MSG_NOT_PROCESSED;
    mError("show:0x%" PRIx64 ", failed to retrieve data since %s", pShow->id, terrstr());
    return -1;
  }

  mDebug("show:0x%" PRIx64 ", start retrieve data, numOfReads:%d numOfRows:%d type:%s", pShow->id, pShow->numOfReads,
         pShow->numOfRows, mndShowStr(pShow->type));

  if (mndCheckRetrieveFinished(pShow)) {
    mDebug("show:0x%" PRIx64 ", read finished, numOfReads:%d numOfRows:%d", pShow->id, pShow->numOfReads,
           pShow->numOfRows);
    pShow->numOfReads = pShow->numOfRows;
  }

  if ((retrieveReq.free & TSDB_QUERY_TYPE_FREE_RESOURCE) != TSDB_QUERY_TYPE_FREE_RESOURCE) {
    rowsToRead = pShow->numOfRows - pShow->numOfReads;
  }

  /* return no more than 100 tables in one round trip */
  if (rowsToRead > SHOW_STEP_SIZE) rowsToRead = SHOW_STEP_SIZE;

  /*
   * the actual number of table may be larger than the value of pShow->numOfRows, if a query is
   * issued during a continuous create table operation. Therefore, rowToRead may be less than 0.
   */
  if (rowsToRead < 0) rowsToRead = 0;
  size = pShow->rowSize * rowsToRead;

  size += SHOW_STEP_SIZE;
  SRetrieveTableRsp *pRsp = rpcMallocCont(size);
  if (pRsp == NULL) {
    mndReleaseShowObj(pShow, false);
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    mError("show:0x%" PRIx64 ", failed to retrieve data since %s", pShow->id, terrstr());
    return -1;
  }

  // if free flag is set, client wants to clean the resources
  if ((retrieveReq.free & TSDB_QUERY_TYPE_FREE_RESOURCE) != TSDB_QUERY_TYPE_FREE_RESOURCE) {
    rowsRead = (*retrieveFp)(pReq, pShow, pRsp->data, rowsToRead);
  }

  mDebug("show:0x%" PRIx64 ", stop retrieve data, rowsRead:%d rowsToRead:%d", pShow->id, rowsRead, rowsToRead);

  pRsp->numOfRows = htonl(rowsRead);
  pRsp->precision = TSDB_TIME_PRECISION_MILLI;  // millisecond time precision

  pReq->pRsp = pRsp;
  pReq->rspLen = size;

  if (rowsRead == 0 || rowsToRead == 0 || (rowsRead == rowsToRead && pShow->numOfRows == pShow->numOfReads)) {
    pRsp->completed = 1;
    mDebug("show:0x%" PRIx64 ", retrieve completed", pShow->id);
    mndReleaseShowObj(pShow, true);
  } else {
    mDebug("show:0x%" PRIx64 ", retrieve not completed yet", pShow->id);
    mndReleaseShowObj(pShow, false);
  }

  return TSDB_CODE_SUCCESS;
}

static int32_t mndProcessRetrieveSysTableReq(SNodeMsg *pReq) {
  SMnode    *pMnode = pReq->pNode;
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  int32_t    rowsToRead = 0;
  int32_t    size = 0;
  int32_t    rowsRead = 0;

  SRetrieveTableReq retrieveReq = {0};
  if (tDeserializeSRetrieveTableReq(pReq->rpcMsg.pCont, pReq->rpcMsg.contLen, &retrieveReq) != 0) {
    terrno = TSDB_CODE_INVALID_MSG;
    return -1;
  }

  SShowObj* pShow = NULL;

  if (retrieveReq.showId == 0) {
    SShowReq req = {0};
    req.type = retrieveReq.type;
    strncpy(req.db, retrieveReq.db, tListLen(req.db));

    pShow = mndCreateShowObj(pMnode, &req);
    if (pShow == NULL) {
      terrno = TSDB_CODE_OUT_OF_MEMORY;
      mError("failed to process show-meta req since %s", terrstr());
      return -1;
    }

    STableMetaRsp *meta = (STableMetaRsp *)taosHashGet(pMnode->infosMeta, retrieveReq.tb, strlen(retrieveReq.tb));
    pShow->numOfRows = 100;

    int32_t offset = 0;
    for(int32_t i = 0; i < meta->numOfColumns; ++i) {
      pShow->numOfColumns = meta->numOfColumns;
      pShow->offset[i] = offset;

      int32_t bytes = meta->pSchemas[i].bytes;
      pShow->rowSize += bytes;
      pShow->bytes[i] = bytes;
      offset += bytes;
    }
  } else {
    pShow = mndAcquireShowObj(pMnode, retrieveReq.showId);
    if (pShow == NULL) {
      terrno = TSDB_CODE_MND_INVALID_SHOWOBJ;
      mError("failed to process show-retrieve req:%p since %s", pShow, terrstr());
      return -1;
    }
  }

  ShowRetrieveFp retrieveFp = pMgmt->retrieveFps[pShow->type];
  if (retrieveFp == NULL) {
    mndReleaseShowObj((SShowObj*) pShow, false);
    terrno = TSDB_CODE_MSG_NOT_PROCESSED;
    mError("show:0x%" PRIx64 ", failed to retrieve data since %s", pShow->id, terrstr());
    return -1;
  }

  mDebug("show:0x%" PRIx64 ", start retrieve data, numOfReads:%d numOfRows:%d type:%s", pShow->id, pShow->numOfReads,
         pShow->numOfRows, mndShowStr(pShow->type));

  if (mndCheckRetrieveFinished((SShowObj*) pShow)) {
    mDebug("show:0x%" PRIx64 ", read finished, numOfReads:%d numOfRows:%d", pShow->id, pShow->numOfReads,
           pShow->numOfRows);
    pShow->numOfReads = pShow->numOfRows;
  }

  if ((retrieveReq.free & TSDB_QUERY_TYPE_FREE_RESOURCE) != TSDB_QUERY_TYPE_FREE_RESOURCE) {
    rowsToRead = pShow->numOfRows - pShow->numOfReads;
  }

  /* return no more than 100 tables in one round trip */
  if (rowsToRead > SHOW_STEP_SIZE) rowsToRead = SHOW_STEP_SIZE;

  /*
   * the actual number of table may be larger than the value of pShow->numOfRows, if a query is
   * issued during a continuous create table operation. Therefore, rowToRead may be less than 0.
   */
  if (rowsToRead < 0) rowsToRead = 0;
  size = pShow->rowSize * rowsToRead;

  size += SHOW_STEP_SIZE;
  SRetrieveMetaTableRsp *pRsp = rpcMallocCont(size);
  if (pRsp == NULL) {
    mndReleaseShowObj((SShowObj*) pShow, false);
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    mError("show:0x%" PRIx64 ", failed to retrieve data since %s", pShow->id, terrstr());
    return -1;
  }

  pRsp->handle = htobe64(pShow->id);

  // if free flag is set, client wants to clean the resources
  if ((retrieveReq.free & TSDB_QUERY_TYPE_FREE_RESOURCE) != TSDB_QUERY_TYPE_FREE_RESOURCE) {
    rowsRead = (*retrieveFp)(pReq, (SShowObj*) pShow, pRsp->data, rowsToRead);
  }

  mDebug("show:0x%" PRIx64 ", stop retrieve data, rowsRead:%d rowsToRead:%d", pShow->id, rowsRead, rowsToRead);

  pRsp->numOfRows = htonl(rowsRead);
  pRsp->precision = TSDB_TIME_PRECISION_MILLI;  // millisecond time precision

  pReq->pRsp = pRsp;
  pReq->rspLen = size;

  if (rowsRead == 0 || rowsToRead == 0 || (rowsRead == rowsToRead && pShow->numOfRows == pShow->numOfReads)) {
    pRsp->completed = 1;
    mDebug("show:0x%" PRIx64 ", retrieve completed", pShow->id);
    mndReleaseShowObj((SShowObj*) pShow, true);
  } else {
    mDebug("show:0x%" PRIx64 ", retrieve not completed yet", pShow->id);
    mndReleaseShowObj((SShowObj*) pShow, false);
  }

  return TSDB_CODE_SUCCESS;
}

char *mndShowStr(int32_t showType) {
  switch (showType) {
    case TSDB_MGMT_TABLE_ACCT:
      return "show accounts";
    case TSDB_MGMT_TABLE_USER:
      return "show users";
    case TSDB_MGMT_TABLE_DB:
      return "show databases";
    case TSDB_MGMT_TABLE_TABLE:
      return "show tables";
    case TSDB_MGMT_TABLE_DNODE:
      return "show dnodes";
    case TSDB_MGMT_TABLE_MNODE:
      return "show mnodes";
    case TSDB_MGMT_TABLE_QNODE:
      return "show qnodes";
    case TSDB_MGMT_TABLE_SNODE:
      return "show snodes";
    case TSDB_MGMT_TABLE_BNODE:
      return "show bnodes";
    case TSDB_MGMT_TABLE_VGROUP:
      return "show vgroups";
    case TSDB_MGMT_TABLE_STB:
      return "show stables";
    case TSDB_MGMT_TABLE_MODULE:
      return "show modules";
    case TSDB_MGMT_TABLE_QUERIES:
      return "show queries";
    case TSDB_MGMT_TABLE_STREAMS:
      return "show streams";
    case TSDB_MGMT_TABLE_VARIABLES:
      return "show configs";
    case TSDB_MGMT_TABLE_CONNS:
      return "show connections";
    case TSDB_MGMT_TABLE_TRANS:
      return "show trans";
    case TSDB_MGMT_TABLE_GRANTS:
      return "show grants";
    case TSDB_MGMT_TABLE_VNODES:
      return "show vnodes";
    case TSDB_MGMT_TABLE_CLUSTER:
      return "show cluster";
    case TSDB_MGMT_TABLE_STREAMTABLES:
      return "show streamtables";
    case TSDB_MGMT_TABLE_TP:
      return "show topics";
    case TSDB_MGMT_TABLE_FUNC:
      return "show functions";
    default:
      return "undefined";
  }
}

static bool mndCheckRetrieveFinished(SShowObj *pShow) {
  if (pShow->pIter == NULL && pShow->numOfReads != 0) {
    return true;
  }
  return false;
}

void mndVacuumResult(char *data, int32_t numOfCols, int32_t rows, int32_t capacity, SShowObj *pShow) {
  if (rows < capacity) {
    for (int32_t i = 0; i < numOfCols; ++i) {
      memmove(data + pShow->offset[i] * rows, data + pShow->offset[i] * capacity, pShow->bytes[i] * rows);
    }
  }
}

void mndAddShowMetaHandle(SMnode *pMnode, EShowType showType, ShowMetaFp fp) {
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  pMgmt->metaFps[showType] = fp;
}

void mndAddShowRetrieveHandle(SMnode *pMnode, EShowType showType, ShowRetrieveFp fp) {
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  pMgmt->retrieveFps[showType] = fp;
}

void mndAddShowFreeIterHandle(SMnode *pMnode, EShowType showType, ShowFreeIterFp fp) {
  SShowMgmt *pMgmt = &pMnode->showMgmt;
  pMgmt->freeIterFps[showType] = fp;
}
