/**
 *    Copyright (C) 2014 MongoDB Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    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.  See the
 *    GNU Affero General Public License for more details.
 *
 *    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/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects
 *    for all of the code used other than as permitted herein. If you modify
 *    file(s) with this exception, you may extend this exception to your
 *    version of the file(s), but you are not obligated to do so. If you do not
 *    wish to do so, delete this exception statement from your version. If you
 *    delete this exception statement from all source files in the program,
 *    then also delete it in the license file.
 */

/**
 * This file tests db/exec/delete.cpp.
 */

#include <boost/scoped_ptr.hpp>

#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/database.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/exec/collection_scan.h"
#include "mongo/db/exec/delete.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/dbtests/dbtests.h"

namespace QueryStageDelete {

using boost::scoped_ptr;
using std::vector;

//
// Stage-specific tests.
//

class QueryStageDeleteBase {
public:
    QueryStageDeleteBase() : _client(&_txn) {
        Client::WriteContext ctx(&_txn, ns());

        for (size_t i = 0; i < numObj(); ++i) {
            BSONObjBuilder bob;
            bob.append("foo", static_cast<long long int>(i));
            _client.insert(ns(), bob.obj());
        }
    }

    virtual ~QueryStageDeleteBase() {
        Client::WriteContext ctx(&_txn, ns());
        _client.dropCollection(ns());
    }

    void remove(const BSONObj& obj) {
        _client.remove(ns(), obj);
    }

    void getLocs(Collection* collection,
                 CollectionScanParams::Direction direction,
                 vector<RecordId>* out) {
        WorkingSet ws;

        CollectionScanParams params;
        params.collection = collection;
        params.direction = direction;
        params.tailable = false;

        scoped_ptr<CollectionScan> scan(new CollectionScan(&_txn, params, &ws, NULL));
        while (!scan->isEOF()) {
            WorkingSetID id = WorkingSet::INVALID_ID;
            PlanStage::StageState state = scan->work(&id);
            if (PlanStage::ADVANCED == state) {
                WorkingSetMember* member = ws.get(id);
                verify(member->hasLoc());
                out->push_back(member->loc);
            }
        }
    }

    static size_t numObj() {
        return 50;
    }

    static const char* ns() {
        return "unittests.QueryStageDelete";
    }

protected:
    OperationContextImpl _txn;

private:
    DBDirectClient _client;
};

//
// Test invalidation for the delete stage.  Use the delete stage to delete some objects
// retrieved by a collscan, then invalidate the upcoming object, then expect the delete stage to
// skip over it and successfully delete the rest.
//
class QueryStageDeleteInvalidateUpcomingObject : public QueryStageDeleteBase {
public:
    void run() {
        Client::WriteContext ctx(&_txn, ns());

        Collection* coll = ctx.getCollection();

        // Get the RecordIds that would be returned by an in-order scan.
        vector<RecordId> locs;
        getLocs(coll, CollectionScanParams::FORWARD, &locs);

        // Configure the scan.
        CollectionScanParams collScanParams;
        collScanParams.collection = coll;
        collScanParams.direction = CollectionScanParams::FORWARD;
        collScanParams.tailable = false;

        // Configure the delete stage.
        DeleteStageParams deleteStageParams;
        deleteStageParams.isMulti = true;
        deleteStageParams.shouldCallLogOp = false;

        WorkingSet ws;
        DeleteStage deleteStage(&_txn,
                                deleteStageParams,
                                &ws,
                                coll,
                                new CollectionScan(&_txn, collScanParams, &ws, NULL));

        const DeleteStats* stats = static_cast<const DeleteStats*>(deleteStage.getSpecificStats());

        const size_t targetDocIndex = 10;

        while (stats->docsDeleted < targetDocIndex) {
            WorkingSetID id = WorkingSet::INVALID_ID;
            PlanStage::StageState state = deleteStage.work(&id);
            ASSERT_EQUALS(PlanStage::NEED_TIME, state);
        }

        // Remove locs[targetDocIndex];
        deleteStage.saveState();
        deleteStage.invalidate(&_txn, locs[targetDocIndex], INVALIDATION_DELETION);
        BSONObj targetDoc = coll->docFor(&_txn, locs[targetDocIndex]).value();
        ASSERT(!targetDoc.isEmpty());
        remove(targetDoc);
        deleteStage.restoreState(&_txn);

        // Remove the rest.
        while (!deleteStage.isEOF()) {
            WorkingSetID id = WorkingSet::INVALID_ID;
            PlanStage::StageState state = deleteStage.work(&id);
            invariant(PlanStage::NEED_TIME == state || PlanStage::IS_EOF == state);
        }

        ASSERT_EQUALS(numObj() - 1, stats->docsDeleted);
    }
};

class All : public Suite {
public:
    All() : Suite("query_stage_delete") {}

    void setupTests() {
        // Stage-specific tests below.
        add<QueryStageDeleteInvalidateUpcomingObject>();
    }
};

SuiteInstance<All> all;
}