// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

#pragma once

#include <deque>

#include <map>

#include <memory>

#include <mutex>

#include <sstream>

#include <string>

#include <utility>

#include "common/status.h"

#include "service/http/http_handler_with_auth.h"

#include "storage/tablet/tablet.h"

#include "util/threadpool.h"

namespace doris {

class DataDir;

class HttpRequest;

class ExecEnv;

class StorageEngine;

// Migrate a tablet from a disk to another.

class TabletMigrationAction : public HttpHandlerWithAuth {

public:

    TabletMigrationAction(ExecEnv* exec_env, StorageEngine& engine, TPrivilegeHier::type hier,

                          TPrivilegeType::type type)

            : HttpHandlerWithAuth(exec_env, hier, type), _engine(engine) {

        _init_migration_action();

    }

    ~TabletMigrationAction() override = default;

    void handle(HttpRequest* req) override;

    void _init_migration_action();

    Status _execute_tablet_migration(TabletSharedPtr tablet, DataDir* dest_store);

    Status _check_param(HttpRequest* req, int64_t& tablet_id, unsigned long& schema_hash,

                        std::string& dest_disk, std::string& goal);

    Status _check_migrate_request(int64_t tablet_id, unsigned long schema_hash,

                                  std::string dest_disk, TabletSharedPtr& tablet,

                                  DataDir** dest_store);

private:

    StorageEngine& _engine;

    std::unique_ptr<ThreadPool> _migration_thread_pool;

    struct MigrationTask {

        MigrationTask(int64_t tablet_id, unsigned long schema_hash)

                : _tablet_id(tablet_id), _schema_hash(schema_hash) {}

        MigrationTask(int64_t tablet_id, unsigned long schema_hash, std::string dest_disk)

                : _tablet_id(tablet_id), _schema_hash(schema_hash), _dest_disk(dest_disk) {}

        bool operator<(const MigrationTask& right) const {

            if (_tablet_id != right._tablet_id) {

                return _tablet_id < right._tablet_id;

            } else if (_schema_hash != right._schema_hash) {

                return _schema_hash < right._schema_hash;

            } else {

                return false;

            }

        }

        std::string to_string() const {

            std::stringstream ss;

            ss << "MigrationTask: tablet_id=" << _tablet_id << ", schema_hash=" << _schema_hash

               << ", dest_disk=" << _dest_disk;

            return ss.str();

        }

        int64_t _tablet_id;

        unsigned long _schema_hash;

        std::string _dest_disk;

    };

    std::mutex _migration_status_mutex;

    std::map<MigrationTask, std::string> _migration_tasks;

    std::deque<std::pair<MigrationTask, Status>> _finished_migration_tasks;

};

} // namespace doris