/******************************************************************************
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements OGRSQLiteViewLayer class, access to an existing
 *spatialite view. Author:   Even Rouault, <even dot rouault at spatialys.com>
 *
 ******************************************************************************
 * Copyright (c) 2011-2013, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "cpl_port.h"
#include "ogr_sqlite.h"
#include "ogrsqliteutility.h"

#include <cstdlib>
#include <cstring>
#include <set>
#include <string>

#include "cpl_conv.h"
#include "cpl_error.h"
#include "cpl_string.h"
#include "ogr_core.h"
#include "ogr_feature.h"
#include "ogr_geometry.h"
#include "sqlite3.h"

/************************************************************************/
/*                        OGRSQLiteViewLayer()                         */
/************************************************************************/

OGRSQLiteViewLayer::OGRSQLiteViewLayer(OGRSQLiteDataSource *poDSIn)
    : OGRSQLiteLayer(poDSIn)
{
}

/************************************************************************/
/*                        ~OGRSQLiteViewLayer()                        */
/************************************************************************/

OGRSQLiteViewLayer::~OGRSQLiteViewLayer()

{
    ClearStatement();
    CPLFree(m_pszViewName);
    CPLFree(m_pszEscapedTableName);
    CPLFree(m_pszEscapedUnderlyingTableName);
}

/************************************************************************/
/*                             Initialize()                             */
/************************************************************************/

CPLErr OGRSQLiteViewLayer::Initialize(const char *pszViewNameIn,
                                      const char *pszViewGeometry,
                                      const char *pszViewRowid,
                                      const char *pszUnderlyingTableName,
                                      const char *pszUnderlyingGeometryColumn)

{
    m_pszViewName = CPLStrdup(pszViewNameIn);
    SetDescription(m_pszViewName);

    m_osGeomColumn = pszViewGeometry;
    m_eGeomFormat = OSGF_SpatiaLite;

    CPLFree(m_pszFIDColumn);
    m_pszFIDColumn = CPLStrdup(pszViewRowid);

    m_osUnderlyingTableName = pszUnderlyingTableName;
    m_osUnderlyingGeometryColumn = pszUnderlyingGeometryColumn;
    m_poUnderlyingLayer = nullptr;

    m_pszEscapedTableName = CPLStrdup(SQLEscapeLiteral(m_pszViewName));
    m_pszEscapedUnderlyingTableName =
        CPLStrdup(SQLEscapeLiteral(pszUnderlyingTableName));

    return CE_None;
}

/************************************************************************/
/*                           GetLayerDefn()                             */
/************************************************************************/

OGRFeatureDefn *OGRSQLiteViewLayer::GetLayerDefn()
{
    if (m_poFeatureDefn)
        return m_poFeatureDefn;

    EstablishFeatureDefn();

    if (m_poFeatureDefn == nullptr)
    {
        m_bLayerDefnError = true;

        m_poFeatureDefn = new OGRSQLiteFeatureDefn(m_pszViewName);
        m_poFeatureDefn->Reference();
    }

    return m_poFeatureDefn;
}

/************************************************************************/
/*                        GetUnderlyingLayer()                          */
/************************************************************************/

OGRSQLiteLayer *OGRSQLiteViewLayer::GetUnderlyingLayer()
{
    if (m_poUnderlyingLayer == nullptr)
    {
        if (strchr(m_osUnderlyingTableName, '(') == nullptr)
        {
            CPLString osNewUnderlyingTableName;
            osNewUnderlyingTableName.Printf(
                "%s(%s)", m_osUnderlyingTableName.c_str(),
                m_osUnderlyingGeometryColumn.c_str());
            m_poUnderlyingLayer = cpl::down_cast<OGRSQLiteLayer *>(
                m_poDS->GetLayerByNameNotVisible(osNewUnderlyingTableName));
        }
        if (m_poUnderlyingLayer == nullptr)
            m_poUnderlyingLayer = cpl::down_cast<OGRSQLiteLayer *>(
                m_poDS->GetLayerByNameNotVisible(m_osUnderlyingTableName));
    }
    return m_poUnderlyingLayer;
}

/************************************************************************/
/*                            GetGeomType()                             */
/************************************************************************/

OGRwkbGeometryType OGRSQLiteViewLayer::GetGeomType()
{
    if (m_poFeatureDefn)
        return m_poFeatureDefn->GetGeomType();

    OGRSQLiteLayer *l_m_poUnderlyingLayer = GetUnderlyingLayer();
    if (l_m_poUnderlyingLayer)
        return l_m_poUnderlyingLayer->GetGeomType();

    return wkbUnknown;
}

/************************************************************************/
/*                         EstablishFeatureDefn()                       */
/************************************************************************/

CPLErr OGRSQLiteViewLayer::EstablishFeatureDefn()
{
    sqlite3 *hDB = m_poDS->GetDB();
    sqlite3_stmt *hColStmt = nullptr;

    OGRSQLiteLayer *l_m_poUnderlyingLayer = GetUnderlyingLayer();
    if (l_m_poUnderlyingLayer == nullptr)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Cannot find underlying layer %s for view %s",
                 m_osUnderlyingTableName.c_str(), m_pszViewName);
        return CE_Failure;
    }
    if (!l_m_poUnderlyingLayer->IsTableLayer())
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Underlying layer %s for view %s is not a regular table",
                 m_osUnderlyingTableName.c_str(), m_pszViewName);
        return CE_Failure;
    }

    int nUnderlyingLayerGeomFieldIndex =
        l_m_poUnderlyingLayer->GetLayerDefn()->GetGeomFieldIndex(
            m_osUnderlyingGeometryColumn);
    if (nUnderlyingLayerGeomFieldIndex < 0)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Underlying layer %s for view %s has not expected geometry "
                 "column name %s",
                 m_osUnderlyingTableName.c_str(), m_pszViewName,
                 m_osUnderlyingGeometryColumn.c_str());
        return CE_Failure;
    }

    m_bHasSpatialIndex =
        l_m_poUnderlyingLayer->HasSpatialIndex(nUnderlyingLayerGeomFieldIndex);

    /* -------------------------------------------------------------------- */
    /*      Get the column definitions for this table.                      */
    /* -------------------------------------------------------------------- */
    hColStmt = nullptr;
    const char *pszSQL = CPLSPrintf("SELECT \"%s\", * FROM '%s' LIMIT 1",
                                    SQLEscapeName(m_pszFIDColumn).c_str(),
                                    m_pszEscapedTableName);

    int rc = sqlite3_prepare_v2(hDB, pszSQL, -1, &hColStmt, nullptr);
    if (rc != SQLITE_OK)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Unable to query table %s for column definitions : %s.",
                 m_pszViewName, sqlite3_errmsg(hDB));

        return CE_Failure;
    }

    rc = sqlite3_step(hColStmt);
    if (rc != SQLITE_DONE && rc != SQLITE_ROW)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "In Initialize(): sqlite3_step(%s):\n  %s", pszSQL,
                 sqlite3_errmsg(hDB));
        sqlite3_finalize(hColStmt);
        return CE_Failure;
    }

    /* -------------------------------------------------------------------- */
    /*      Collect the rest of the fields.                                 */
    /* -------------------------------------------------------------------- */
    std::set<CPLString> aosGeomCols;
    std::set<CPLString> aosIgnoredCols;
    aosGeomCols.insert(m_osGeomColumn);
    BuildFeatureDefn(m_pszViewName, false, hColStmt, &aosGeomCols,
                     aosIgnoredCols);
    sqlite3_finalize(hColStmt);

    /* -------------------------------------------------------------------- */
    /*      Set the properties of the geometry column.                      */
    /* -------------------------------------------------------------------- */
    if (m_poFeatureDefn->GetGeomFieldCount() != 0)
    {
        OGRSQLiteGeomFieldDefn *poSrcGeomFieldDefn =
            l_m_poUnderlyingLayer->myGetLayerDefn()->myGetGeomFieldDefn(
                nUnderlyingLayerGeomFieldIndex);
        OGRSQLiteGeomFieldDefn *poGeomFieldDefn =
            m_poFeatureDefn->myGetGeomFieldDefn(0);
        poGeomFieldDefn->SetType(poSrcGeomFieldDefn->GetType());
        poGeomFieldDefn->SetSpatialRef(poSrcGeomFieldDefn->GetSpatialRef());
        poGeomFieldDefn->m_nSRSId = poSrcGeomFieldDefn->m_nSRSId;
        if (m_eGeomFormat != OSGF_None)
            poGeomFieldDefn->m_eGeomFormat = m_eGeomFormat;
    }

    return CE_None;
}

/************************************************************************/
/*                           ResetStatement()                           */
/************************************************************************/

OGRErr OGRSQLiteViewLayer::ResetStatement()

{
    CPLString osSQL;

    ClearStatement();

    m_iNextShapeId = 0;

    osSQL.Printf("SELECT \"%s\", * FROM '%s' %s",
                 SQLEscapeName(m_pszFIDColumn).c_str(), m_pszEscapedTableName,
                 m_osWHERE.c_str());

    const int rc =
        sqlite3_prepare_v2(m_poDS->GetDB(), osSQL,
                           static_cast<int>(osSQL.size()), &m_hStmt, nullptr);

    if (rc == SQLITE_OK)
    {
        return OGRERR_NONE;
    }

    CPLError(CE_Failure, CPLE_AppDefined,
             "In ResetStatement(): sqlite3_prepare_v2(%s):\n  %s",
             osSQL.c_str(), sqlite3_errmsg(m_poDS->GetDB()));
    m_hStmt = nullptr;
    return OGRERR_FAILURE;
}

/************************************************************************/
/*                           GetNextFeature()                           */
/************************************************************************/

OGRFeature *OGRSQLiteViewLayer::GetNextFeature()

{
    if (HasLayerDefnError())
        return nullptr;

    return OGRSQLiteLayer::GetNextFeature();
}

/************************************************************************/
/*                             GetFeature()                             */
/************************************************************************/

OGRFeature *OGRSQLiteViewLayer::GetFeature(GIntBig nFeatureId)

{
    if (HasLayerDefnError())
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      If we don't have an explicit FID column, just read through      */
    /*      the result set iteratively to find our target.                  */
    /* -------------------------------------------------------------------- */
    if (m_pszFIDColumn == nullptr)
        return OGRSQLiteLayer::GetFeature(nFeatureId);

    /* -------------------------------------------------------------------- */
    /*      Setup explicit query statement to fetch the record we want.     */
    /* -------------------------------------------------------------------- */
    CPLString osSQL;

    ClearStatement();

    m_iNextShapeId = nFeatureId;

    osSQL.Printf("SELECT \"%s\", * FROM '%s' WHERE \"%s\" = " CPL_FRMT_GIB,
                 SQLEscapeName(m_pszFIDColumn).c_str(), m_pszEscapedTableName,
                 SQLEscapeName(m_pszFIDColumn).c_str(), nFeatureId);

    CPLDebug("OGR_SQLITE", "exec(%s)", osSQL.c_str());

    const int rc =
        sqlite3_prepare_v2(m_poDS->GetDB(), osSQL,
                           static_cast<int>(osSQL.size()), &m_hStmt, nullptr);
    if (rc != SQLITE_OK)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "In GetFeature(): sqlite3_prepare_v2(%s):\n  %s",
                 osSQL.c_str(), sqlite3_errmsg(m_poDS->GetDB()));

        return nullptr;
    }
    /* -------------------------------------------------------------------- */
    /*      Get the feature if possible.                                    */
    /* -------------------------------------------------------------------- */
    OGRFeature *poFeature = GetNextRawFeature();

    ResetReading();

    return poFeature;
}

/************************************************************************/
/*                         SetAttributeFilter()                         */
/************************************************************************/

OGRErr OGRSQLiteViewLayer::SetAttributeFilter(const char *pszQuery)

{
    if (pszQuery == nullptr)
        m_osQuery = "";
    else
        m_osQuery = pszQuery;

    BuildWhere();

    ResetReading();

    return OGRERR_NONE;
}

/************************************************************************/
/*                          SetSpatialFilter()                          */
/************************************************************************/

void OGRSQLiteViewLayer::SetSpatialFilter(OGRGeometry *poGeomIn)

{
    if (InstallFilter(poGeomIn))
    {
        BuildWhere();

        ResetReading();
    }
}

/************************************************************************/
/*                           GetSpatialWhere()                          */
/************************************************************************/

CPLString OGRSQLiteViewLayer::GetSpatialWhere(int iGeomCol,
                                              OGRGeometry *poFilterGeom)
{
    if (HasLayerDefnError() || m_poFeatureDefn == nullptr || iGeomCol < 0 ||
        iGeomCol >= m_poFeatureDefn->GetGeomFieldCount())
        return "";

    if (poFilterGeom != nullptr && m_bHasSpatialIndex)
    {
        OGREnvelope sEnvelope;

        poFilterGeom->getEnvelope(&sEnvelope);

        /* We first check that the spatial index table exists */
        if (!m_bHasCheckedSpatialIndexTable)
        {
            m_bHasCheckedSpatialIndexTable = true;
            char **papszResult = nullptr;
            int nRowCount = 0;
            int nColCount = 0;
            char *pszErrMsg = nullptr;

            CPLString osSQL;
            osSQL.Printf(
                "SELECT name FROM sqlite_master "
                "WHERE name='idx_%s_%s'",
                m_pszEscapedUnderlyingTableName,
                SQLEscapeLiteral(m_osUnderlyingGeometryColumn).c_str());

            int rc =
                sqlite3_get_table(m_poDS->GetDB(), osSQL.c_str(), &papszResult,
                                  &nRowCount, &nColCount, &pszErrMsg);

            if (rc != SQLITE_OK)
            {
                CPLError(CE_Failure, CPLE_AppDefined, "Error: %s", pszErrMsg);
                sqlite3_free(pszErrMsg);
                m_bHasSpatialIndex = false;
            }
            else
            {
                if (nRowCount != 1)
                {
                    m_bHasSpatialIndex = false;
                }

                sqlite3_free_table(papszResult);
            }
        }

        if (m_bHasSpatialIndex)
        {
            return FormatSpatialFilterFromRTree(
                poFilterGeom,
                CPLSPrintf("\"%s\"", SQLEscapeName(m_pszFIDColumn).c_str()),
                m_pszEscapedUnderlyingTableName,
                SQLEscapeLiteral(m_osUnderlyingGeometryColumn).c_str());
        }
        else
        {
            CPLDebug("SQLITE",
                     "Count not find idx_%s_%s layer. Disabling spatial index",
                     m_pszEscapedUnderlyingTableName,
                     m_osUnderlyingGeometryColumn.c_str());
        }
    }

    if (poFilterGeom != nullptr && m_poDS->IsSpatialiteLoaded())
    {
        return FormatSpatialFilterFromMBR(
            poFilterGeom,
            SQLEscapeName(
                m_poFeatureDefn->GetGeomFieldDefn(iGeomCol)->GetNameRef())
                .c_str());
    }

    return "";
}

/************************************************************************/
/*                             BuildWhere()                             */
/*                                                                      */
/*      Build the WHERE statement appropriate to the current set of     */
/*      criteria (spatial and attribute queries).                       */
/************************************************************************/

void OGRSQLiteViewLayer::BuildWhere()

{
    m_osWHERE = "";

    CPLString osSpatialWHERE =
        GetSpatialWhere(m_iGeomFieldFilter, m_poFilterGeom);
    if (!osSpatialWHERE.empty())
    {
        m_osWHERE = "WHERE ";
        m_osWHERE += osSpatialWHERE;
    }

    if (!m_osQuery.empty())
    {
        if (m_osWHERE.empty())
        {
            m_osWHERE = "WHERE ";
            m_osWHERE += m_osQuery;
        }
        else
        {
            m_osWHERE += " AND (";
            m_osWHERE += m_osQuery;
            m_osWHERE += ")";
        }
    }
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRSQLiteViewLayer::TestCapability(const char *pszCap)

{
    if (HasLayerDefnError())
        return FALSE;

    if (EQUAL(pszCap, OLCFastFeatureCount))
        return m_poFilterGeom == nullptr || m_osGeomColumn.empty() ||
               m_bHasSpatialIndex;

    else if (EQUAL(pszCap, OLCFastSpatialFilter))
        return m_bHasSpatialIndex;

    else
        return OGRSQLiteLayer::TestCapability(pszCap);
}

/************************************************************************/
/*                          GetFeatureCount()                           */
/*                                                                      */
/*      If a spatial filter is in effect, we turn control over to       */
/*      the generic counter.  Otherwise we return the total count.      */
/*      Eventually we should consider implementing a more efficient     */
/*      way of counting features matching a spatial query.              */
/************************************************************************/

GIntBig OGRSQLiteViewLayer::GetFeatureCount(int bForce)

{
    if (HasLayerDefnError())
        return 0;

    if (!TestCapability(OLCFastFeatureCount))
        return OGRSQLiteLayer::GetFeatureCount(bForce);

    /* -------------------------------------------------------------------- */
    /*      Form count SQL.                                                 */
    /* -------------------------------------------------------------------- */
    const char *pszSQL = CPLSPrintf("SELECT count(*) FROM '%s' %s",
                                    m_pszEscapedTableName, m_osWHERE.c_str());

    /* -------------------------------------------------------------------- */
    /*      Execute.                                                        */
    /* -------------------------------------------------------------------- */
    char **papszResult, *pszErrMsg;
    int nRowCount, nColCount;
    int nResult = -1;

    if (sqlite3_get_table(m_poDS->GetDB(), pszSQL, &papszResult, &nColCount,
                          &nRowCount, &pszErrMsg) != SQLITE_OK)
        return -1;

    if (nRowCount == 1 && nColCount == 1)
        nResult = atoi(papszResult[1]);

    sqlite3_free_table(papszResult);

    return nResult;
}