/*
 * 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 "meta.h"

static int metaHandleEntry(SMeta *pMeta, const SMetaEntry *pME);
static int metaSaveToTbDb(SMeta *pMeta, const SMetaEntry *pME);
static int metaUpdateUidIdx(SMeta *pMeta, const SMetaEntry *pME);
static int metaUpdateNameIdx(SMeta *pMeta, const SMetaEntry *pME);
static int metaUpdateTtlIdx(SMeta *pMeta, const SMetaEntry *pME);
static int metaSaveToSkmDb(SMeta *pMeta, const SMetaEntry *pME);
static int metaUpdateCtbIdx(SMeta *pMeta, const SMetaEntry *pME);
static int metaUpdateTagIdx(SMeta *pMeta, const SMetaEntry *pCtbEntry);

int metaCreateSTable(SMeta *pMeta, int64_t version, SVCreateStbReq *pReq) {
  SMetaEntry  me = {0};
  int         kLen = 0;
  int         vLen = 0;
  const void *pKey = NULL;
  const void *pVal = NULL;
  void       *pBuf = NULL;
  int32_t     szBuf = 0;
  void       *p = NULL;
  SMetaReader mr = {0};

  // validate req
  metaReaderInit(&mr, pMeta, 0);
  if (metaGetTableEntryByName(&mr, pReq->name) == 0) {
// TODO: just for pass case
#if 0
    terrno = TSDB_CODE_TDB_TABLE_ALREADY_EXIST;
    metaReaderClear(&mr);
    return -1;
#else
    metaReaderClear(&mr);
    return 0;
#endif
  }
  metaReaderClear(&mr);

  // set structs
  me.version = version;
  me.type = TSDB_SUPER_TABLE;
  me.uid = pReq->suid;
  me.name = pReq->name;
  me.stbEntry.schema = pReq->schema;
  me.stbEntry.schemaTag = pReq->schemaTag;

  if (metaHandleEntry(pMeta, &me) < 0) goto _err;

  metaDebug("vgId:%d super table is created, name:%s uid: %" PRId64, TD_VID(pMeta->pVnode), pReq->name, pReq->suid);

  return 0;

_err:
  metaError("vgId:%d failed to create super table: %s uid: %" PRId64 " since %s", TD_VID(pMeta->pVnode), pReq->name,
            pReq->suid, tstrerror(terrno));
  return -1;
}

int metaDropSTable(SMeta *pMeta, int64_t verison, SVDropStbReq *pReq) {
  TBC        *pNameIdxc = NULL;
  TBC        *pUidIdxc = NULL;
  TBC        *pCtbIdxc = NULL;
  SCtbIdxKey *pCtbIdxKey;
  const void *pKey = NULL;
  int         nKey;
  const void *pData = NULL;
  int         nData;
  int         c, ret;

  // prepare uid idx cursor
  tdbTbcOpen(pMeta->pUidIdx, &pUidIdxc, &pMeta->txn);
  ret = tdbTbcMoveTo(pUidIdxc, &pReq->suid, sizeof(tb_uid_t), &c);
  if (ret < 0 || c != 0) {
    terrno = TSDB_CODE_VND_TB_NOT_EXIST;
    tdbTbcClose(pUidIdxc);
    goto _err;
  }

  // prepare name idx cursor
  tdbTbcOpen(pMeta->pNameIdx, &pNameIdxc, &pMeta->txn);
  ret = tdbTbcMoveTo(pNameIdxc, pReq->name, strlen(pReq->name) + 1, &c);
  if (ret < 0 || c != 0) {
    ASSERT(0);
  }

  tdbTbcDelete(pUidIdxc);
  tdbTbcDelete(pNameIdxc);
  tdbTbcClose(pUidIdxc);
  tdbTbcClose(pNameIdxc);

  // loop to drop each child table
  tdbTbcOpen(pMeta->pCtbIdx, &pCtbIdxc, &pMeta->txn);
  ret = tdbTbcMoveTo(pCtbIdxc, &(SCtbIdxKey){.suid = pReq->suid, .uid = INT64_MIN}, sizeof(SCtbIdxKey), &c);
  if (ret < 0 || (c < 0 && tdbTbcMoveToNext(pCtbIdxc) < 0)) {
    tdbTbcClose(pCtbIdxc);
    goto _exit;
  }

  for (;;) {
    tdbTbcGet(pCtbIdxc, &pKey, &nKey, NULL, NULL);
    pCtbIdxKey = (SCtbIdxKey *)pKey;

    if (pCtbIdxKey->suid > pReq->suid) break;

    // drop the child table (TODO)

    if (tdbTbcMoveToNext(pCtbIdxc) < 0) break;
  }

_exit:
  metaDebug("vgId:%d  super table %s uid:%" PRId64 " is dropped", TD_VID(pMeta->pVnode), pReq->name, pReq->suid);
  return 0;

_err:
  metaError("vgId:%d failed to drop super table %s uid:%" PRId64 " since %s", TD_VID(pMeta->pVnode), pReq->name,
            pReq->suid, tstrerror(terrno));
  return -1;
}

int metaAlterSTable(SMeta *pMeta, int64_t version, SVCreateStbReq *pReq) {
  SMetaEntry  oStbEntry = {0};
  SMetaEntry  nStbEntry = {0};
  TBC        *pUidIdxc = NULL;
  TBC        *pTbDbc = NULL;
  const void *pData;
  int         nData;
  int64_t     oversion;
  SDecoder    dc = {0};
  int32_t     ret;
  int32_t     c;

  tdbTbcOpen(pMeta->pUidIdx, &pUidIdxc, &pMeta->txn);
  ret = tdbTbcMoveTo(pUidIdxc, &pReq->suid, sizeof(tb_uid_t), &c);
  if (ret < 0 || c) {
    ASSERT(0);
    return -1;
  }

  ret = tdbTbcGet(pUidIdxc, NULL, NULL, &pData, &nData);
  if (ret < 0) {
    ASSERT(0);
    return -1;
  }

  oversion = *(int64_t *)pData;

  tdbTbcOpen(pMeta->pTbDb, &pTbDbc, &pMeta->txn);
  ret = tdbTbcMoveTo(pTbDbc, &((STbDbKey){.uid = pReq->suid, .version = oversion}), sizeof(STbDbKey), &c);
  ASSERT(ret == 0 && c == 0);

  ret = tdbTbcGet(pTbDbc, NULL, NULL, &pData, &nData);
  ASSERT(ret == 0);

  oStbEntry.pBuf = taosMemoryMalloc(nData);
  memcpy(oStbEntry.pBuf, pData, nData);
  tDecoderInit(&dc, oStbEntry.pBuf, nData);
  metaDecodeEntry(&dc, &oStbEntry);

  nStbEntry.version = version;
  nStbEntry.type = TSDB_SUPER_TABLE;
  nStbEntry.uid = pReq->suid;
  nStbEntry.name = pReq->name;
  nStbEntry.stbEntry.schema = pReq->schema;
  nStbEntry.stbEntry.schemaTag = pReq->schemaTag;

  metaWLock(pMeta);
  // compare two entry
  if (oStbEntry.stbEntry.schema.sver != pReq->schema.sver) {
    if (oStbEntry.stbEntry.schema.nCols != pReq->schema.nCols) {
      metaSaveToSkmDb(pMeta, &nStbEntry);
    }
  }

  // if (oStbEntry.stbEntry.schemaTag.sver != pReq->schemaTag.sver) {
  //   // change tag schema
  // }

  // update table.db
  metaSaveToTbDb(pMeta, &nStbEntry);

  // update uid index
  tdbTbcUpsert(pUidIdxc, &pReq->suid, sizeof(tb_uid_t), &version, sizeof(version), 0);

  if (oStbEntry.pBuf) taosMemoryFree(oStbEntry.pBuf);
  metaULock(pMeta);
  tDecoderClear(&dc);
  tdbTbcClose(pTbDbc);
  tdbTbcClose(pUidIdxc);
  return 0;
}

int metaCreateTable(SMeta *pMeta, int64_t version, SVCreateTbReq *pReq) {
  SMetaEntry  me = {0};
  SMetaReader mr = {0};

  // validate message
  if (pReq->type != TSDB_CHILD_TABLE && pReq->type != TSDB_NORMAL_TABLE) {
    terrno = TSDB_CODE_INVALID_MSG;
    goto _err;
  }

  // validate req
  metaReaderInit(&mr, pMeta, 0);
  if (metaGetTableEntryByName(&mr, pReq->name) == 0) {
    pReq->uid = mr.me.uid;
    if (pReq->type == TSDB_CHILD_TABLE) {
      pReq->ctb.suid = mr.me.ctbEntry.suid;
    }
    terrno = TSDB_CODE_TDB_TABLE_ALREADY_EXIST;
    metaReaderClear(&mr);
    return -1;
  }
  metaReaderClear(&mr);

  // build SMetaEntry
  me.version = version;
  me.type = pReq->type;
  me.uid = pReq->uid;
  me.name = pReq->name;
  if (me.type == TSDB_CHILD_TABLE) {
    me.ctbEntry.ctime = pReq->ctime;
    me.ctbEntry.ttlDays = pReq->ttl;
    me.ctbEntry.suid = pReq->ctb.suid;
    me.ctbEntry.pTags = pReq->ctb.pTag;
  } else {
    me.ntbEntry.ctime = pReq->ctime;
    me.ntbEntry.ttlDays = pReq->ttl;
    me.ntbEntry.schema = pReq->ntb.schema;
    me.ntbEntry.ncid = me.ntbEntry.schema.pSchema[me.ntbEntry.schema.nCols - 1].colId + 1;
  }

  if (metaHandleEntry(pMeta, &me) < 0) goto _err;

  metaDebug("vgId:%d table %s uid %" PRId64 " is created, type:%" PRId8, TD_VID(pMeta->pVnode), pReq->name, pReq->uid,
            pReq->type);
  return 0;

_err:
  metaError("vgId:%d failed to create table:%s type:%s since %s", TD_VID(pMeta->pVnode), pReq->name,
            pReq->type == TSDB_CHILD_TABLE ? "child table" : "normal table", tstrerror(terrno));
  return -1;
}

int metaDropTable(SMeta *pMeta, int64_t version, SVDropTbReq *pReq, SArray *tbUids) {
  TBC        *pTbDbc = NULL;
  TBC        *pUidIdxc = NULL;
  TBC        *pNameIdxc = NULL;
  const void *pData;
  int         nData;
  tb_uid_t    uid;
  int64_t     tver;
  SMetaEntry  me = {0};
  SDecoder    coder = {0};
  int8_t      type;
  int64_t     ctime;
  tb_uid_t    suid;
  int         c = 0, ret;

  // search & delete the name idx
  tdbTbcOpen(pMeta->pNameIdx, &pNameIdxc, &pMeta->txn);
  ret = tdbTbcMoveTo(pNameIdxc, pReq->name, strlen(pReq->name) + 1, &c);
  if (ret < 0 || !tdbTbcIsValid(pNameIdxc) || c) {
    tdbTbcClose(pNameIdxc);
    terrno = TSDB_CODE_VND_TABLE_NOT_EXIST;
    return -1;
  }

  ret = tdbTbcGet(pNameIdxc, NULL, NULL, &pData, &nData);
  if (ret < 0) {
    ASSERT(0);
    return -1;
  }

  uid = *(tb_uid_t *)pData;

  tdbTbcDelete(pNameIdxc);
  tdbTbcClose(pNameIdxc);

  // search & delete uid idx
  tdbTbcOpen(pMeta->pUidIdx, &pUidIdxc, &pMeta->txn);
  ret = tdbTbcMoveTo(pUidIdxc, &uid, sizeof(uid), &c);
  if (ret < 0 || c != 0) {
    ASSERT(0);
    return -1;
  }

  ret = tdbTbcGet(pUidIdxc, NULL, NULL, &pData, &nData);
  if (ret < 0) {
    ASSERT(0);
    return -1;
  }

  tver = *(int64_t *)pData;
  tdbTbcDelete(pUidIdxc);
  tdbTbcClose(pUidIdxc);

  // search and get meta entry
  tdbTbcOpen(pMeta->pTbDb, &pTbDbc, &pMeta->txn);
  ret = tdbTbcMoveTo(pTbDbc, &(STbDbKey){.uid = uid, .version = tver}, sizeof(STbDbKey), &c);
  if (ret < 0 || c != 0) {
    ASSERT(0);
    return -1;
  }

  ret = tdbTbcGet(pTbDbc, NULL, NULL, &pData, &nData);
  if (ret < 0) {
    ASSERT(0);
    return -1;
  }

  // decode entry
  void *pDataCopy = taosMemoryMalloc(nData);  // remove the copy (todo)
  memcpy(pDataCopy, pData, nData);
  tDecoderInit(&coder, pDataCopy, nData);
  ret = metaDecodeEntry(&coder, &me);
  if (ret < 0) {
    ASSERT(0);
    return -1;
  }

  type = me.type;
  if (type == TSDB_CHILD_TABLE) {
    ctime = me.ctbEntry.ctime;
    suid = me.ctbEntry.suid;
    taosArrayPush(tbUids, &me.uid);
  } else if (type == TSDB_NORMAL_TABLE) {
    ctime = me.ntbEntry.ctime;
    suid = 0;
  } else {
    ASSERT(0);
  }

  taosMemoryFree(pDataCopy);
  tDecoderClear(&coder);
  tdbTbcClose(pTbDbc);

  if (type == TSDB_CHILD_TABLE) {
    // remove the pCtbIdx
    TBC *pCtbIdxc = NULL;
    tdbTbcOpen(pMeta->pCtbIdx, &pCtbIdxc, &pMeta->txn);

    ret = tdbTbcMoveTo(pCtbIdxc, &(SCtbIdxKey){.suid = suid, .uid = uid}, sizeof(SCtbIdxKey), &c);
    if (ret < 0 || c != 0) {
      ASSERT(0);
      return -1;
    }

    tdbTbcDelete(pCtbIdxc);
    tdbTbcClose(pCtbIdxc);

    // remove tags from pTagIdx (todo)
  } else if (type == TSDB_NORMAL_TABLE) {
    // remove from pSkmDb
  } else {
    ASSERT(0);
  }

  // remove from ttl (todo)
  if (ctime > 0) {
  }

  return 0;
}

static int metaAlterTableColumn(SMeta *pMeta, int64_t version, SVAlterTbReq *pAlterTbReq) {
  void           *pVal = NULL;
  int             nVal = 0;
  const void     *pData = NULL;
  int             nData = 0;
  int             ret = 0;
  tb_uid_t        uid;
  int64_t         oversion;
  SSchema        *pColumn = NULL;
  SMetaEntry      entry = {0};
  SSchemaWrapper *pSchema;
  int             c;

  // search name index
  ret = tdbTbGet(pMeta->pNameIdx, pAlterTbReq->tbName, strlen(pAlterTbReq->tbName) + 1, &pVal, &nVal);
  if (ret < 0) {
    terrno = TSDB_CODE_VND_TABLE_NOT_EXIST;
    return -1;
  }

  uid = *(tb_uid_t *)pVal;
  tdbFree(pVal);
  pVal = NULL;

  // search uid index
  TBC *pUidIdxc = NULL;

  tdbTbcOpen(pMeta->pUidIdx, &pUidIdxc, &pMeta->txn);
  tdbTbcMoveTo(pUidIdxc, &uid, sizeof(uid), &c);
  ASSERT(c == 0);

  tdbTbcGet(pUidIdxc, NULL, NULL, &pData, &nData);
  oversion = *(int64_t *)pData;

  // search table.db
  TBC *pTbDbc = NULL;

  tdbTbcOpen(pMeta->pTbDb, &pTbDbc, &pMeta->txn);
  tdbTbcMoveTo(pTbDbc, &((STbDbKey){.uid = uid, .version = oversion}), sizeof(STbDbKey), &c);
  ASSERT(c == 0);
  tdbTbcGet(pTbDbc, NULL, NULL, &pData, &nData);

  // get table entry
  SDecoder dc = {0};
  entry.pBuf = taosMemoryMalloc(nData);
  memcpy(entry.pBuf, pData, nData);
  tDecoderInit(&dc, entry.pBuf, nData);
  ret = metaDecodeEntry(&dc, &entry);
  ASSERT(ret == 0);

  if (entry.type != TSDB_NORMAL_TABLE) {
    terrno = TSDB_CODE_VND_INVALID_TABLE_ACTION;
    goto _err;
  }

  // search the column to add/drop/update
  pSchema = &entry.ntbEntry.schema;
  int32_t iCol = 0;
  for (;;) {
    pColumn = NULL;

    if (iCol >= pSchema->nCols) break;
    pColumn = &pSchema->pSchema[iCol];

    if (strcmp(pColumn->name, pAlterTbReq->colName) == 0) break;
    iCol++;
  }

  entry.version = version;
  int      tlen;
  SSchema *pNewSchema = NULL;
  switch (pAlterTbReq->action) {
    case TSDB_ALTER_TABLE_ADD_COLUMN:
      if (pColumn) {
        terrno = TSDB_CODE_VND_COL_ALREADY_EXISTS;
        goto _err;
      }
      pSchema->sver++;
      pSchema->nCols++;
      pNewSchema = taosMemoryMalloc(sizeof(SSchema) * pSchema->nCols);
      memcpy(pNewSchema, pSchema->pSchema, sizeof(SSchema) * (pSchema->nCols - 1));
      pSchema->pSchema = pNewSchema;
      pSchema->pSchema[entry.ntbEntry.schema.nCols - 1].bytes = pAlterTbReq->bytes;
      pSchema->pSchema[entry.ntbEntry.schema.nCols - 1].type = pAlterTbReq->type;
      pSchema->pSchema[entry.ntbEntry.schema.nCols - 1].flags = pAlterTbReq->flags;
      pSchema->pSchema[entry.ntbEntry.schema.nCols - 1].colId = entry.ntbEntry.ncid++;
      strcpy(pSchema->pSchema[entry.ntbEntry.schema.nCols - 1].name, pAlterTbReq->colName);
      break;
    case TSDB_ALTER_TABLE_DROP_COLUMN:
      if (pColumn == NULL) {
        terrno = TSDB_CODE_VND_TABLE_COL_NOT_EXISTS;
        goto _err;
      }
      if (pColumn->colId == 0) {
        terrno = TSDB_CODE_VND_INVALID_TABLE_ACTION;
        goto _err;
      }
      pSchema->sver++;
      tlen = (pSchema->nCols - iCol - 1) * sizeof(SSchema);
      if (tlen) {
        memmove(pColumn, pColumn + 1, tlen);
      }
      pSchema->nCols--;
      break;
    case TSDB_ALTER_TABLE_UPDATE_COLUMN_BYTES:
      if (pColumn == NULL) {
        terrno = TSDB_CODE_VND_TABLE_COL_NOT_EXISTS;
        goto _err;
      }
      if (!IS_VAR_DATA_TYPE(pColumn->type) || pColumn->bytes > pAlterTbReq->colModBytes) {
        terrno = TSDB_CODE_VND_INVALID_TABLE_ACTION;
        goto _err;
      }
      pSchema->sver++;
      pColumn->bytes = pAlterTbReq->colModBytes;
      break;
    case TSDB_ALTER_TABLE_UPDATE_COLUMN_NAME:
      if (pColumn == NULL) {
        terrno = TSDB_CODE_VND_TABLE_COL_NOT_EXISTS;
        goto _err;
      }
      pSchema->sver++;
      strcpy(pColumn->name, pAlterTbReq->colNewName);
      break;
  }

  entry.version = version;

  // do actual write
  metaWLock(pMeta);

  // save to table db
  metaSaveToTbDb(pMeta, &entry);

  tdbTbcUpsert(pUidIdxc, &entry.uid, sizeof(tb_uid_t), &version, sizeof(version), 0);

  metaSaveToSkmDb(pMeta, &entry);

  metaULock(pMeta);

  if (pNewSchema) taosMemoryFree(pNewSchema);
  tDecoderClear(&dc);
  tdbTbcClose(pTbDbc);
  tdbTbcClose(pUidIdxc);
  return 0;

_err:
  tDecoderClear(&dc);
  tdbTbcClose(pTbDbc);
  tdbTbcClose(pUidIdxc);
  return -1;
}

static int metaUpdateTableTagVal(SMeta *pMeta, int64_t version, SVAlterTbReq *pAlterTbReq) {
  SMetaEntry  ctbEntry = {0};
  SMetaEntry  stbEntry = {0};
  void       *pVal = NULL;
  int         nVal = 0;
  int         ret;
  int         c;
  tb_uid_t    uid;
  int64_t     oversion;
  const void *pData = NULL;
  int         nData = 0;

  // search name index
  ret = tdbTbGet(pMeta->pNameIdx, pAlterTbReq->tbName, strlen(pAlterTbReq->tbName) + 1, &pVal, &nVal);
  if (ret < 0) {
    terrno = TSDB_CODE_VND_TABLE_NOT_EXIST;
    return -1;
  }

  uid = *(tb_uid_t *)pVal;
  tdbFree(pVal);
  pVal = NULL;

  // search uid index
  TBC *pUidIdxc = NULL;

  tdbTbcOpen(pMeta->pUidIdx, &pUidIdxc, &pMeta->txn);
  tdbTbcMoveTo(pUidIdxc, &uid, sizeof(uid), &c);
  ASSERT(c == 0);

  tdbTbcGet(pUidIdxc, NULL, NULL, &pData, &nData);
  oversion = *(int64_t *)pData;

  // search table.db
  TBC     *pTbDbc = NULL;
  SDecoder dc1 = {0};
  SDecoder dc2 = {0};

  /* get ctbEntry */
  tdbTbcOpen(pMeta->pTbDb, &pTbDbc, &pMeta->txn);
  tdbTbcMoveTo(pTbDbc, &((STbDbKey){.uid = uid, .version = oversion}), sizeof(STbDbKey), &c);
  ASSERT(c == 0);
  tdbTbcGet(pTbDbc, NULL, NULL, &pData, &nData);

  ctbEntry.pBuf = taosMemoryMalloc(nData);
  memcpy(ctbEntry.pBuf, pData, nData);
  tDecoderInit(&dc1, ctbEntry.pBuf, nData);
  metaDecodeEntry(&dc1, &ctbEntry);

  /* get stbEntry*/
  tdbTbGet(pMeta->pUidIdx, &ctbEntry.ctbEntry.suid, sizeof(tb_uid_t), &pVal, &nVal);
  tdbTbGet(pMeta->pTbDb, &((STbDbKey){.uid = ctbEntry.ctbEntry.suid, .version = *(int64_t *)pVal}), sizeof(STbDbKey),
           (void **)&stbEntry.pBuf, &nVal);
  tdbFree(pVal);
  tDecoderInit(&dc2, stbEntry.pBuf, nVal);
  metaDecodeEntry(&dc2, &stbEntry);

  SSchemaWrapper *pTagSchema = &stbEntry.stbEntry.schemaTag;
  SSchema        *pColumn = NULL;
  int32_t         iCol = 0;
  for (;;) {
    pColumn = NULL;

    if (iCol >= pTagSchema->nCols) break;
    pColumn = &pTagSchema->pSchema[iCol];

    if (strcmp(pColumn->name, pAlterTbReq->tagName) == 0) break;
    iCol++;
  }

  if (pColumn == NULL) {
    terrno = TSDB_CODE_VND_TABLE_COL_NOT_EXISTS;
    goto _err;
  }

  if (iCol == 0) {
    // TODO : need to update tag index
  }
  ctbEntry.version = version;
  if(pTagSchema->nCols == 1 && pTagSchema->pSchema[0].type == TSDB_DATA_TYPE_JSON){
    ctbEntry.ctbEntry.pTags = taosMemoryMalloc(pAlterTbReq->nTagVal);
    if(ctbEntry.ctbEntry.pTags == NULL){
      terrno = TSDB_CODE_OUT_OF_MEMORY;
      goto _err;
    }
    memcpy((void*)ctbEntry.ctbEntry.pTags, pAlterTbReq->pTagVal, pAlterTbReq->nTagVal);
  }else{
    SKVRowBuilder kvrb = {0};
    const SKVRow  pOldTag = (const SKVRow)ctbEntry.ctbEntry.pTags;
    SKVRow        pNewTag = NULL;

    tdInitKVRowBuilder(&kvrb);
    for (int32_t i = 0; i < pTagSchema->nCols; i++) {
      SSchema *pCol = &pTagSchema->pSchema[i];
      if (iCol == i) {
        tdAddColToKVRow(&kvrb, pCol->colId, pAlterTbReq->pTagVal, pAlterTbReq->nTagVal);
      } else {
        void *p = tdGetKVRowValOfCol(pOldTag, pCol->colId);
        if (p) {
          if (IS_VAR_DATA_TYPE(pCol->type)) {
            tdAddColToKVRow(&kvrb, pCol->colId, p, varDataTLen(p));
          } else {
            tdAddColToKVRow(&kvrb, pCol->colId, p, pCol->bytes);
          }
        }
      }
    }

    ctbEntry.ctbEntry.pTags = tdGetKVRowFromBuilder(&kvrb);
    tdDestroyKVRowBuilder(&kvrb);
  }

  // save to table.db
  metaSaveToTbDb(pMeta, &ctbEntry);

  // save to uid.idx
  tdbTbUpsert(pMeta->pUidIdx, &ctbEntry.uid, sizeof(tb_uid_t), &version, sizeof(version), &pMeta->txn);

  tDecoderClear(&dc1);
  tDecoderClear(&dc2);
  if (ctbEntry.ctbEntry.pTags) taosMemoryFree((void*)ctbEntry.ctbEntry.pTags);
  if (ctbEntry.pBuf) taosMemoryFree(ctbEntry.pBuf);
  if (stbEntry.pBuf) tdbFree(stbEntry.pBuf);
  tdbTbcClose(pTbDbc);
  tdbTbcClose(pUidIdxc);
  return 0;

_err:
  tDecoderClear(&dc1);
  tDecoderClear(&dc2);
  if (ctbEntry.pBuf) taosMemoryFree(ctbEntry.pBuf);
  if (stbEntry.pBuf) tdbFree(stbEntry.pBuf);
  tdbTbcClose(pTbDbc);
  tdbTbcClose(pUidIdxc);
  return -1;
}

static int metaUpdateTableOptions(SMeta *pMeta, int64_t version, SVAlterTbReq *pAlterTbReq) {
  // TODO
  ASSERT(0);
  return 0;
}

int metaAlterTable(SMeta *pMeta, int64_t version, SVAlterTbReq *pReq) {
  switch (pReq->action) {
    case TSDB_ALTER_TABLE_ADD_COLUMN:
    case TSDB_ALTER_TABLE_DROP_COLUMN:
    case TSDB_ALTER_TABLE_UPDATE_COLUMN_BYTES:
    case TSDB_ALTER_TABLE_UPDATE_COLUMN_NAME:
      return metaAlterTableColumn(pMeta, version, pReq);
    case TSDB_ALTER_TABLE_UPDATE_TAG_VAL:
      return metaUpdateTableTagVal(pMeta, version, pReq);
    case TSDB_ALTER_TABLE_UPDATE_OPTIONS:
      return metaUpdateTableOptions(pMeta, version, pReq);
    default:
      terrno = TSDB_CODE_VND_INVALID_TABLE_ACTION;
      return -1;
      break;
  }
}

static int metaSaveToTbDb(SMeta *pMeta, const SMetaEntry *pME) {
  STbDbKey tbDbKey;
  void    *pKey = NULL;
  void    *pVal = NULL;
  int      kLen = 0;
  int      vLen = 0;
  SEncoder coder = {0};

  // set key and value
  tbDbKey.version = pME->version;
  tbDbKey.uid = pME->uid;

  pKey = &tbDbKey;
  kLen = sizeof(tbDbKey);

  int32_t ret = 0;
  tEncodeSize(metaEncodeEntry, pME, vLen, ret);
  if (ret < 0) {
    goto _err;
  }

  pVal = taosMemoryMalloc(vLen);
  if (pVal == NULL) {
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    goto _err;
  }

  tEncoderInit(&coder, pVal, vLen);

  if (metaEncodeEntry(&coder, pME) < 0) {
    goto _err;
  }

  tEncoderClear(&coder);

  // write to table.db
  if (tdbTbInsert(pMeta->pTbDb, pKey, kLen, pVal, vLen, &pMeta->txn) < 0) {
    goto _err;
  }

  taosMemoryFree(pVal);
  return 0;

_err:
  taosMemoryFree(pVal);
  return -1;
}

static int metaUpdateUidIdx(SMeta *pMeta, const SMetaEntry *pME) {
  return tdbTbInsert(pMeta->pUidIdx, &pME->uid, sizeof(tb_uid_t), &pME->version, sizeof(int64_t), &pMeta->txn);
}

static int metaUpdateNameIdx(SMeta *pMeta, const SMetaEntry *pME) {
  return tdbTbInsert(pMeta->pNameIdx, pME->name, strlen(pME->name) + 1, &pME->uid, sizeof(tb_uid_t), &pMeta->txn);
}

static int metaUpdateTtlIdx(SMeta *pMeta, const SMetaEntry *pME) {
  int32_t    ttlDays;
  int64_t    ctime;
  STtlIdxKey ttlKey;

  if (pME->type == TSDB_CHILD_TABLE) {
    ctime = pME->ctbEntry.ctime;
    ttlDays = pME->ctbEntry.ttlDays;
  } else if (pME->type == TSDB_NORMAL_TABLE) {
    ctime = pME->ntbEntry.ctime;
    ttlDays = pME->ntbEntry.ttlDays;
  } else {
    ASSERT(0);
  }

  if (ttlDays <= 0) return 0;

  ttlKey.dtime = ctime + ttlDays * 24 * 60 * 60;
  ttlKey.uid = pME->uid;

  return tdbTbInsert(pMeta->pTtlIdx, &ttlKey, sizeof(ttlKey), NULL, 0, &pMeta->txn);
}

static int metaUpdateCtbIdx(SMeta *pMeta, const SMetaEntry *pME) {
  SCtbIdxKey ctbIdxKey = {.suid = pME->ctbEntry.suid, .uid = pME->uid};
  return tdbTbInsert(pMeta->pCtbIdx, &ctbIdxKey, sizeof(ctbIdxKey), NULL, 0, &pMeta->txn);
}

static int metaCreateTagIdxKey(tb_uid_t suid, int32_t cid, const void *pTagData, int8_t type, tb_uid_t uid,
                               STagIdxKey **ppTagIdxKey, int32_t *nTagIdxKey) {
  int32_t nTagData = 0;

  if (pTagData) {
    if (IS_VAR_DATA_TYPE(type)) {
      nTagData = varDataTLen(pTagData);
    } else {
      nTagData = tDataTypes[type].bytes;
    }
  }
  *nTagIdxKey = sizeof(STagIdxKey) + nTagData + sizeof(tb_uid_t);

  *ppTagIdxKey = (STagIdxKey *)taosMemoryMalloc(*nTagIdxKey);
  if (*ppTagIdxKey == NULL) {
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    return -1;
  }

  (*ppTagIdxKey)->suid = suid;
  (*ppTagIdxKey)->cid = cid;
  (*ppTagIdxKey)->isNull = (pTagData == NULL) ? 1 : 0;
  (*ppTagIdxKey)->type = type;
  if (nTagData) memcpy((*ppTagIdxKey)->data, pTagData, nTagData);
  *(tb_uid_t *)((*ppTagIdxKey)->data + nTagData) = uid;

  return 0;
}

static void metaDestroyTagIdxKey(STagIdxKey *pTagIdxKey) {
  if (pTagIdxKey) taosMemoryFree(pTagIdxKey);
}

static int metaUpdateTagIdx(SMeta *pMeta, const SMetaEntry *pCtbEntry) {
  void          *pData = NULL;
  int            nData = 0;
  STbDbKey       tbDbKey = {0};
  SMetaEntry     stbEntry = {0};
  STagIdxKey    *pTagIdxKey = NULL;
  int32_t        nTagIdxKey;
  const SSchema *pTagColumn;       // = &stbEntry.stbEntry.schema.pSchema[0];
  const void    *pTagData = NULL;  //
  SDecoder       dc = {0};

  // get super table
  tdbTbGet(pMeta->pUidIdx, &pCtbEntry->ctbEntry.suid, sizeof(tb_uid_t), &pData, &nData);
  tbDbKey.uid = pCtbEntry->ctbEntry.suid;
  tbDbKey.version = *(int64_t *)pData;
  tdbTbGet(pMeta->pTbDb, &tbDbKey, sizeof(tbDbKey), &pData, &nData);

  tDecoderInit(&dc, pData, nData);
  metaDecodeEntry(&dc, &stbEntry);

  pTagColumn = &stbEntry.stbEntry.schemaTag.pSchema[0];
  pTagData = tdGetKVRowValOfCol((const SKVRow)pCtbEntry->ctbEntry.pTags, pTagColumn->colId);

  // update tag index
#ifdef USE_INVERTED_INDEX
  tb_uid_t suid = pCtbEntry->ctbEntry.suid;
  tb_uid_t tuid = pCtbEntry->uid;

  SIndexMultiTerm *tmGroup = indexMultiTermCreate();

  SIndexTerm *tm = indexTermCreate(suid, ADD_VALUE, pTagColumn->type, pTagColumn->name, sizeof(pTagColumn->name),
                                   pTagData, pTagData == NULL ? 0 : strlen(pTagData));
  indexMultiTermAdd(tmGroup, tm);
  int ret = indexPut((SIndex *)pMeta->pTagIvtIdx, tmGroup, tuid);
  indexMultiTermDestroy(tmGroup);
#else
  if (metaCreateTagIdxKey(pCtbEntry->ctbEntry.suid, pTagColumn->colId, pTagData, pTagColumn->type, pCtbEntry->uid,
                          &pTagIdxKey, &nTagIdxKey) < 0) {
    return -1;
  }
  tdbTbInsert(pMeta->pTagIdx, pTagIdxKey, nTagIdxKey, NULL, 0, &pMeta->txn);
  metaDestroyTagIdxKey(pTagIdxKey);
#endif
  tDecoderClear(&dc);
  tdbFree(pData);
  return 0;
}

static int metaSaveToSkmDb(SMeta *pMeta, const SMetaEntry *pME) {
  SEncoder              coder = {0};
  void                 *pVal = NULL;
  int                   vLen = 0;
  int                   rcode = 0;
  SSkmDbKey             skmDbKey = {0};
  const SSchemaWrapper *pSW;

  if (pME->type == TSDB_SUPER_TABLE) {
    pSW = &pME->stbEntry.schema;
  } else if (pME->type == TSDB_NORMAL_TABLE) {
    pSW = &pME->ntbEntry.schema;
  } else {
    ASSERT(0);
  }

  skmDbKey.uid = pME->uid;
  skmDbKey.sver = pSW->sver;

  // encode schema
  int32_t ret = 0;
  tEncodeSize(tEncodeSSchemaWrapper, pSW, vLen, ret);
  if (ret < 0) return -1;
  pVal = taosMemoryMalloc(vLen);
  if (pVal == NULL) {
    rcode = -1;
    terrno = TSDB_CODE_OUT_OF_MEMORY;
    goto _exit;
  }

  tEncoderInit(&coder, pVal, vLen);
  tEncodeSSchemaWrapper(&coder, pSW);

  if (tdbTbInsert(pMeta->pSkmDb, &skmDbKey, sizeof(skmDbKey), pVal, vLen, &pMeta->txn) < 0) {
    rcode = -1;
    goto _exit;
  }

_exit:
  taosMemoryFree(pVal);
  tEncoderClear(&coder);
  return rcode;
}

static int metaHandleEntry(SMeta *pMeta, const SMetaEntry *pME) {
  metaWLock(pMeta);

  // save to table.db
  if (metaSaveToTbDb(pMeta, pME) < 0) goto _err;

  // update uid.idx
  if (metaUpdateUidIdx(pMeta, pME) < 0) goto _err;

  // update name.idx
  if (metaUpdateNameIdx(pMeta, pME) < 0) goto _err;

  if (pME->type == TSDB_CHILD_TABLE) {
    // update ctb.idx
    if (metaUpdateCtbIdx(pMeta, pME) < 0) goto _err;

    // update tag.idx
    if (metaUpdateTagIdx(pMeta, pME) < 0) goto _err;
  } else {
    // update schema.db
    if (metaSaveToSkmDb(pMeta, pME) < 0) goto _err;
  }

  if (pME->type != TSDB_SUPER_TABLE) {
    if (metaUpdateTtlIdx(pMeta, pME) < 0) goto _err;
  }

  metaULock(pMeta);
  return 0;

_err:
  metaULock(pMeta);
  return -1;
}