/**
 *    Copyright (C) 2013-2014 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 PlanExecutor forced yielding, ClientCursor::registerExecutor, and
 * ClientCursor::deregisterExecutor.
 */

#include "mongo/client/dbclientcursor.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/database.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/exec/collection_scan.h"
#include "mongo/db/exec/plan_stage.h"
#include "mongo/db/service_context.h"
#include "mongo/db/json.h"
#include "mongo/db/matcher/expression_parser.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/query/plan_executor.h"
#include "mongo/dbtests/dbtests.h"

namespace ExecutorRegistry {

    using std::auto_ptr;

    class ExecutorRegistryBase {
    public:
        ExecutorRegistryBase()
            : _client(&_opCtx)
        {
            _ctx.reset(new OldClientWriteContext(&_opCtx, ns()));
            _client.dropCollection(ns());

            for (int i = 0; i < N(); ++i) {
                _client.insert(ns(), BSON("foo" << i));
            }
        }

        /**
         * Return a plan executor that is going over the collection in ns().
         */
        PlanExecutor* getCollscan() {
            auto_ptr<WorkingSet> ws(new WorkingSet());
            CollectionScanParams params;
            params.collection = collection();
            params.direction = CollectionScanParams::FORWARD;
            params.tailable = false;
            auto_ptr<CollectionScan> scan(new CollectionScan(&_opCtx, params, ws.get(), NULL));

            // Create a plan executor to hold it
            CanonicalQuery* cq;
            ASSERT(CanonicalQuery::canonicalize(ns(), BSONObj(), &cq).isOK());
            PlanExecutor* exec;
            // Takes ownership of 'ws', 'scan', and 'cq'.
            Status status = PlanExecutor::make(&_opCtx,
                                               ws.release(),
                                               scan.release(),
                                               cq,
                                               _ctx->db()->getCollection(ns()),
                                               PlanExecutor::YIELD_MANUAL,
                                               &exec);
            ASSERT_OK(status);
            return exec;
        }

        void registerExecutor( PlanExecutor* exec ) {
            WriteUnitOfWork wuow(&_opCtx);
            _ctx->db()->getOrCreateCollection(&_opCtx, ns())
                      ->getCursorManager()
                      ->registerExecutor(exec);
            wuow.commit();
        }

        void deregisterExecutor( PlanExecutor* exec ) {
            WriteUnitOfWork wuow(&_opCtx);
            _ctx->db()->getOrCreateCollection(&_opCtx, ns())
                      ->getCursorManager()
                      ->deregisterExecutor(exec);
            wuow.commit();
        }

        int N() { return 50; }

        Collection* collection() {
            return _ctx->db()->getCollection(ns());
        }

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

        // Order of these is important for initialization
        OperationContextImpl _opCtx;
        auto_ptr<OldClientWriteContext> _ctx;
        DBDirectClient _client;
    };


    // Test that a registered runner receives invalidation notifications.
    class ExecutorRegistryDiskLocInvalid : public ExecutorRegistryBase {
    public:
        void run() {
            if ( supportsDocLocking() ) {
                return;
            }

            auto_ptr<PlanExecutor> run(getCollscan());
            BSONObj obj;

            // Read some of it.
            for (int i = 0; i < 10; ++i) {
                ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
                ASSERT_EQUALS(i, obj["foo"].numberInt());
            }

            // Register it.
            run->saveState();
            registerExecutor(run.get());
            // At this point it's safe to yield.  forceYield would do that.  Let's now simulate some
            // stuff going on in the yield.

            // Delete some data, namely the next 2 things we'd expect.
            _client.remove(ns(), BSON("foo" << 10));
            _client.remove(ns(), BSON("foo" << 11));

            // At this point, we're done yielding.  We recover our lock.

            // Unregister the runner.
            deregisterExecutor(run.get());

            // And clean up anything that happened before.
            run->restoreState(&_opCtx);

            // Make sure that the runner moved forward over the deleted data.  We don't see foo==10
            // or foo==11.
            for (int i = 12; i < N(); ++i) {
                ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
                ASSERT_EQUALS(i, obj["foo"].numberInt());
            }

            ASSERT_EQUALS(PlanExecutor::IS_EOF, run->getNext(&obj, NULL));
        }
    };

    // Test that registered runners are killed when their collection is dropped.
    class ExecutorRegistryDropCollection : public ExecutorRegistryBase {
    public:
        void run() {
            auto_ptr<PlanExecutor> run(getCollscan());
            BSONObj obj;

            // Read some of it.
            for (int i = 0; i < 10; ++i) {
                ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
                ASSERT_EQUALS(i, obj["foo"].numberInt());
            }

            // Save state and register.
            run->saveState();
            registerExecutor(run.get());

            // Drop a collection that's not ours.
            _client.dropCollection("unittests.someboguscollection");

            // Unregister and restore state.
            deregisterExecutor(run.get());
            run->restoreState(&_opCtx);

            ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
            ASSERT_EQUALS(10, obj["foo"].numberInt());

            // Save state and register.
            run->saveState();
            registerExecutor(run.get());

            // Drop our collection.
            _client.dropCollection(ns());

            // Unregister and restore state.
            deregisterExecutor(run.get());
            run->restoreState(&_opCtx);

            // PlanExecutor was killed.
            ASSERT_EQUALS(PlanExecutor::DEAD, run->getNext(&obj, NULL));
        }
    };

    // Test that registered runners are killed when all indices are dropped on the collection.
    class ExecutorRegistryDropAllIndices : public ExecutorRegistryBase {
    public:
        void run() {
            auto_ptr<PlanExecutor> run(getCollscan());
            BSONObj obj;

            ASSERT_OK(dbtests::createIndex(&_opCtx, ns(), BSON("foo" << 1)));

            // Read some of it.
            for (int i = 0; i < 10; ++i) {
                ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
                ASSERT_EQUALS(i, obj["foo"].numberInt());
            }

            // Save state and register.
            run->saveState();
            registerExecutor(run.get());

            // Drop all indices.
            _client.dropIndexes(ns());

            // Unregister and restore state.
            deregisterExecutor(run.get());
            run->restoreState(&_opCtx);

            // PlanExecutor was killed.
            ASSERT_EQUALS(PlanExecutor::DEAD, run->getNext(&obj, NULL));
        }
    };

    // Test that registered runners are killed when an index is dropped on the collection.
    class ExecutorRegistryDropOneIndex : public ExecutorRegistryBase {
    public:
        void run() {
            auto_ptr<PlanExecutor> run(getCollscan());
            BSONObj obj;

            ASSERT_OK(dbtests::createIndex(&_opCtx, ns(), BSON("foo" << 1)));

            // Read some of it.
            for (int i = 0; i < 10; ++i) {
                ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
                ASSERT_EQUALS(i, obj["foo"].numberInt());
            }

            // Save state and register.
            run->saveState();
            registerExecutor(run.get());

            // Drop a specific index.
            _client.dropIndex(ns(), BSON("foo" << 1));

            // Unregister and restore state.
            deregisterExecutor(run.get());
            run->restoreState(&_opCtx);

            // PlanExecutor was killed.
            ASSERT_EQUALS(PlanExecutor::DEAD, run->getNext(&obj, NULL));
        }
    };

    // Test that registered runners are killed when their database is dropped.
    class ExecutorRegistryDropDatabase : public ExecutorRegistryBase {
    public:
        void run() {
            auto_ptr<PlanExecutor> run(getCollscan());
            BSONObj obj;

            // Read some of it.
            for (int i = 0; i < 10; ++i) {
                ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
                ASSERT_EQUALS(i, obj["foo"].numberInt());
            }

            // Save state and register.
            run->saveState();
            registerExecutor(run.get());

            // Drop a DB that's not ours.  We can't have a lock at all to do this as dropping a DB
            // requires a "global write lock."
            _ctx.reset();
            _client.dropDatabase("somesillydb");
            _ctx.reset(new OldClientWriteContext(&_opCtx, ns()));

            // Unregister and restore state.
            deregisterExecutor(run.get());
            run->restoreState(&_opCtx);

            ASSERT_EQUALS(PlanExecutor::ADVANCED, run->getNext(&obj, NULL));
            ASSERT_EQUALS(10, obj["foo"].numberInt());

            // Save state and register.
            run->saveState();
            registerExecutor(run.get());

            // Drop our DB.  Once again, must give up the lock.
            _ctx.reset();
            _client.dropDatabase("unittests");
            _ctx.reset(new OldClientWriteContext(&_opCtx, ns()));

            // Unregister and restore state.
            deregisterExecutor(run.get());
            run->restoreState(&_opCtx);
            _ctx.reset();

            // PlanExecutor was killed.
            ASSERT_EQUALS(PlanExecutor::DEAD, run->getNext(&obj, NULL));
        }
    };

    // TODO: Test that this works with renaming a collection.

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

        void setupTests() {
            add<ExecutorRegistryDiskLocInvalid>();
            add<ExecutorRegistryDropCollection>();
            add<ExecutorRegistryDropAllIndices>();
            add<ExecutorRegistryDropOneIndex>();
            add<ExecutorRegistryDropDatabase>();
        }
    };

    SuiteInstance<All> executorRegistryAll;

}  // namespace ExecutorRegistry