/**
 *    Copyright (C) 2021-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    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
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    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 Server Side 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.
 */

#pragma once

#include <boost/optional.hpp>

#include "mongo/bson/timestamp.h"
#include "mongo/db/commands/tenant_migration_donor_cmds_gen.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/optime.h"
#include "mongo/executor/task_executor.h"

namespace mongo {

/**
 * Tenant access blocking interface used by TenantMigrationDonorAccessBlocker and
 * TenantMigrationRecipientAccessBlocker.
 */
class TenantMigrationAccessBlocker {
public:
    /**
     * The blocker type determines the context in which the access blocker is used.
     */
    enum class BlockerType { kDonor, kRecipient };

    TenantMigrationAccessBlocker(BlockerType type, const UUID& migrationId)
        : _type(type), _migrationId(migrationId) {}
    virtual ~TenantMigrationAccessBlocker() = default;

    //
    // Called by all writes and reads against the database.
    //

    virtual Status checkIfCanWrite(Timestamp writeTs) = 0;
    virtual Status waitUntilCommittedOrAborted(OperationContext* opCtx) = 0;


    virtual Status checkIfLinearizableReadWasAllowed(OperationContext* opCtx) = 0;
    virtual SharedSemiFuture<void> getCanReadFuture(OperationContext* opCtx,
                                                    StringData command) = 0;

    //
    // Called by index build user threads before acquiring an index build slot, and again right
    // after registering the build.
    //
    virtual Status checkIfCanBuildIndex() = 0;

    /**
     * Checks if opening a new change stream should block.
     */
    virtual Status checkIfCanOpenChangeStream() = 0;

    /**
     * Checks if getMores for change streams should fail.
     */
    virtual Status checkIfCanGetMoreChangeStream() = 0;

    // We suspend TTL deletions at the recipient side to avoid the race when a document is updated
    // at the donor side, which may prevent it from being garbage collected by TTL, while the
    // recipient side document is deleted by the TTL. The donor side update will fail to propagate
    // to the recipient because of non-existing recipient side document. There is no necessity to
    // suspend TTL at the donor side, as the writes are blocked by checking the other related
    // methods in this class.
    virtual bool checkIfShouldBlockTTL() const = 0;

    /**
     * If the given opTime is the commit or abort opTime and the completion promise has not been
     * fulfilled, calls _onMajorityCommitCommitOpTime or _onMajorityCommitAbortOpTime to transition
     * out of blocking and fulfill the promise.
     */
    virtual void onMajorityCommitPointUpdate(repl::OpTime opTime) = 0;

    virtual void appendInfoForServerStatus(BSONObjBuilder* builder) const = 0;

    /**
     * Returns structured info.
     */
    BSONObj getDebugInfo() const {
        return BSON("migrationId" << _migrationId.toString());
    }

    /**
     * Updates the runtime statistics for the number of tenant migration errors that have been
     * thrown based on the given status.
     */
    virtual void recordTenantMigrationError(Status status) = 0;

    /**
     * Returns the type of access blocker.
     */
    BlockerType getType() {
        return _type;
    }

    /**
     * Returns the migration id of access blocker.
     */
    const UUID& getMigrationId() const {
        return _migrationId;
    }

private:
    const BlockerType _type;
    const UUID _migrationId;
};

}  // namespace mongo