#ifndef __M_EXCHANGE_H__
#define __M_EXCHANGE_H__
#include "../mqcommon/mq_logger.hpp"
#include "../mqcommon/mq_helper.hpp"
#include "../mqcommon/mq_msg.pb.h"
#include <google/protobuf/map.h>
#include <iostream>
#include <unordered_map>
#include <mutex>

namespace bitmq
{
    // 1. 定义交换机类
    struct Exchange
    {
        using ptr = std::shared_ptr<Exchange>;
        // 1. 交换机名称
        std::string name;
        // 2. 交换机类型
        ExchangeType type;
        // 3. 交换机持久化标志
        bool durable;
        // 4. 是否自动删除标志
        bool auto_delete;
        // 5. 其他参数
        google::protobuf::Map<std::string, std::string> args;

        // 无参对象也要定义
        Exchange() {}
        Exchange(const std::string &ename,
                 ExchangeType etype,
                 bool edurable,
                 bool eauto_delete,
                 const google::protobuf::Map<std::string, std::string> &eargs) : name(ename), type(etype), durable(edurable),
                                                                              auto_delete(eauto_delete), args(eargs) {}
        // args存储键值对，在存储数据库的时候，会组织一个格式字符串进行存储 key=val&key=val....

        // 内部解析str_args字符串，将内容存储到成员中
        void setArgs(const std::string &str_args)
        {
            // key=val&key=val
            std::vector<std::string> sub_args;
            StrHelper::split(str_args, "&", sub_args);
            for (auto &str : sub_args)
            {
                size_t pos = str.find("=");
                std::string key = str.substr(0, pos);
                std::string val = str.substr(pos + 1);
                args[key] = val;
            }
        }

        // 将args中的内容进行序列化后，返回一个字符串
        std::string getArgs()
        {
            std::string result;
            for (auto start = args.begin(); start != args.end(); ++start)
            {
                result += start->first + "=" + start->second + "&";
            }
            return result;
        }
    };

    using ExchangeMap = std::unordered_map<std::string, Exchange::ptr>;
    // 2. 定义交换机数据持久化管理类--数据存储在sqlite数据库中
    class ExchangeMapper
    {
    public:
        ExchangeMapper(const std::string &dbfile) : _sql_helper(dbfile)
        {
            std::string path = FileHelper::parentDirectory(dbfile);
            FileHelper::createDirectory(path);
            assert(_sql_helper.open());
            createTable();
        }
        void createTable()
        {
#define CREATE_TABLE "create table if not exists exchange_table\
            (name varchar(32) primary key,\
            type int,\
            durable int,\
            auto_delete int, args varchar(128));"
            bool ret = _sql_helper.exec(CREATE_TABLE, nullptr, nullptr);
            if (ret == false)
            {
                DLOG("创建交换机数据库表失败！！");
                abort(); // 直接异常退出程序
            }
        }
        void removeTable()
        {
#define DROP_TABLE "drop table if exists exchange_table;"
            bool ret = _sql_helper.exec(DROP_TABLE, nullptr, nullptr);
            if (ret == false)
            {
                DLOG("删除交换机数据库表失败！！");
                abort(); // 直接异常退出程序
            }
        }
        bool insert(Exchange::ptr &exp)
        {
            std::stringstream ss;
            ss << "insert into exchange_table values(";
            ss << "'" << exp->name << "', ";
            ss << exp->type << ", ";
            ss << exp->durable << ", ";
            ss << exp->auto_delete << ", ";
            ss << "'" << exp->getArgs() << "');";
            return _sql_helper.exec(ss.str(), nullptr, nullptr);
        }
        void remove(const std::string &name)
        {
            std::stringstream ss;
            ss << "delete from exchange_table where name=";
            ss << "'" << name << "';";
            _sql_helper.exec(ss.str(), nullptr, nullptr);
        }

        ExchangeMap recovery()
        {
            ExchangeMap result;
            std::string sql = "select name, type, durable, auto_delete, args from exchange_table;";
            _sql_helper.exec(sql, selectCallback, &result);
            return result;
        }

    private:
        static int selectCallback(void *arg, int numcol, char **row, char **fields)
        {
            ExchangeMap *result = (ExchangeMap *)arg;
            auto exp = std::make_shared<Exchange>();
            exp->name = row[0];
            exp->type = (bitmq::ExchangeType)std::stoi(row[1]);
            exp->durable = (bool)std::stoi(row[2]);
            exp->auto_delete = (bool)std::stoi(row[3]);
            if (row[4])
                exp->setArgs(row[4]);
            result->insert(std::make_pair(exp->name, exp));
            return 0;
        }

    private:
        SqliteHelper _sql_helper;
    };

    // 3. 定义交换机数据内存管理类
    class ExchangeManager
    {
    public:
        using ptr = std::shared_ptr<ExchangeManager>;
        ExchangeManager(const std::string &dbfile) : _mapper(dbfile)
        {
            _exchanges = _mapper.recovery();
        }

        // 声明交换机
        bool declareExchange(const std::string &name,
                             ExchangeType type, bool durable, bool auto_delete,
                             const google::protobuf::Map<std::string, std::string> &args)
        {
            std::unique_lock<std::mutex> lock(_mutex);
            auto it = _exchanges.find(name);
            if (it != _exchanges.end())
            {
                // 如果交换机已经存在，那就直接返回，不需要重复新增。
                return true;
            }
            auto exp = std::make_shared<Exchange>(name, type, durable, auto_delete, args);
            if (durable == true)
            {
                bool ret = _mapper.insert(exp);
                if (ret == false)
                    return false;
            }
            _exchanges.insert(std::make_pair(name, exp));
            return true;
        }

        //删除交换机
        void deleteExchange(const std::string &name) {
            std::unique_lock<std::mutex> lock(_mutex);
            auto it = _exchanges.find(name);
            if (it == _exchanges.end()) {
                return;
            }
            if(it->second->durable == true) _mapper.remove(name);
            _exchanges.erase(name);
        }
        //获取指定交换机对象
        Exchange::ptr selectExchange(const std::string &name) {
            std::unique_lock<std::mutex> lock(_mutex);
            auto it = _exchanges.find(name);
            if (it == _exchanges.end()) {
                return Exchange::ptr();
            }
            return it->second;
        }
        //判断交换机是否存在
        bool exists(const std::string &name) {
            std::unique_lock<std::mutex> lock(_mutex);
            auto it = _exchanges.find(name);
            if (it == _exchanges.end()) {
                return false;
            }
            return true;
        }
        size_t size() {
            std::unique_lock<std::mutex> lock(_mutex);
            return _exchanges.size();
        }
        //清理所有交换机数据
        void clear() {
            std::unique_lock<std::mutex> lock(_mutex);
            _mapper.removeTable();
            _exchanges.clear();
        }
        
    private:
        std::mutex _mutex;
        ExchangeMapper _mapper;
        std::unordered_map<std::string, Exchange::ptr> _exchanges;
    };
}
#endif