ylib/include/db/mysql.h

#pragma once

#include <vector>
#include <string>
#include <queue>
#include <memory>
#include <sstream>
#include <unordered_map>
#ifndef _WIN32 
#include <stddef.h>
#endif
#include "base/define.h"
#include "base/error.h"
#include "base/buffer.h"
#include "util/json.h"
#include "util/pool.hpp"

namespace ylib::mysql
{
    class pool;
    class result;
    class conn;
    class prepare_statement;

    // 与 MySQL Connector/C++ sql::DataType 数值对齐
    enum class field_type : int {
        UNKNOWN = 0,
        BIT,
        TINYINT,
        SMALLINT,
        MEDIUMINT,
        INTEGER,
        BIGINT,
        REAL,
        DOUBLE,
        DECIMAL,
        NUMERIC,
        CHAR,
        BINARY,
        VARCHAR,
        VARBINARY,
        LONGVARCHAR,
        LONGVARBINARY,
        TIMESTAMP,
        DATE,
        TIME,
        YEAR,
        GEOMETRY,
        ENUM,
        SET,
        SQLNULL,
        JSON
    };

    struct field {
        uint32 index = 0; // 列下标，从 1 开始
        std::string name;
        field_type type = field_type::UNKNOWN;
        bool is_unsigned = false;
    };

    // 单列取值：从 ResultSet 读出后独立保存
    class data {
    public:
        data() = default;

        bool is_null() const { return m_hold == hold::null; }
        field_type type() const { return m_type; }

        int32 to_int32() const;
        uint32 to_uint32() const;
        int64 to_int64() const;
        uint64 to_uint64() const;
        bool to_boolean() const;
        double to_double() const;
        std::string to_string() const;
        ylib::buffer to_blob() const;

        friend class result;
        friend class row;
    private:
        enum class hold {
            null,
            i64,
            u64,
            f64,
            boolean,
            str,
            blob
        };

        hold m_hold = hold::null;
        field_type m_type = field_type::UNKNOWN;
        int64 m_i64 = 0;
        uint64 m_u64 = 0;
        double m_f64 = 0;
        bool m_bool = false;
        std::string m_str;
        ylib::buffer m_blob;
    };

    // 整行数据：支持按索引 / 字段名取值，并可转为 json 对象
    class row {
    public:
        row() = default;

        size_t size() const { return m_values.size(); }
        bool empty() const { return m_values.empty(); }
        bool has(const std::string& name) const;

        // 列下标从 1 开始
        const data& get(uint32 index) const;
        const data& get(const std::string& name) const;
        const data& operator[](uint32 index) const { return get(index); }
        const data& operator[](const std::string& name) const { return get(name); }

        const field& field_info(uint32 index) const;
        const std::vector<field>& fields() const { return m_fields; }

        ylib::json to_json() const;

        friend class result;
    private:
        std::vector<field> m_fields;
        std::vector<data> m_values;
        std::unordered_map<std::string, uint32> m_name_index; // value: 0-based
    };

    struct mysql_conn_info
    {
        mysql_conn_info() {
            port = 0;
        }
        std::string ipaddress;
        std::string username;
        std::string password;
        std::string database;
        std::string charset;
        uint32 port;
    };
    class result :public ylib::error_base
    {
    public:
        result(void* handle);
        ~result();
        // 列名
        std::string field_name(uint32 index);
        // 列数量 
        uint32 field_count();
        // 行数量
        size_t row_count();
        // 下一行
        bool next();

        // 按列下标(从1开始) / 列名取值
        ylib::mysql::data get(uint32 index);
        ylib::mysql::data get(const std::string& name);
        // 获取当前整行
        ylib::mysql::row get_row();
        // 当前行转 json 对象
        ylib::json row_to_json();

        ylib::json table();
    private:
        uint32 field_index(const std::string& name) const;
        ylib::mysql::data read_data(uint32 index) const;

        void* m_handle = nullptr;
        std::vector<ylib::mysql::field> m_fields;
        std::unordered_map<std::string, uint32> m_field_index;
    };

    class prepare_statement :public ylib::error_base {
    public:
        prepare_statement();
        ~prepare_statement();
        void set_bigint(uint32 index, const std::string& value);
        void set_boolean(uint32 index, bool value);
        void set_datetime(uint32 index, const std::string& value);
        void set_double(uint32 index, double value);
        void set_int32(uint32 index, int32 value);
        void set_uint32(uint32 index, uint32 value);
        void set_int64(uint32 index, int64 value);
        void set_uint64(uint32 index, uint64 value);
        void set_null(uint32 index);
        void set_string(uint32 index, const std::string& value);
        void set_string(uint32 index,const char* data,int size);
        void set_blob(uint32 index, const char* data, int size);
        void clear();
        uint64 update();
        ylib::mysql::result* query();

        friend class ylib::mysql::conn;
    private:
        ylib::mysql::result* m_result = nullptr;
        void* m_handle = nullptr;

        // 持有 blob 流，保证 execute 前有效（仅一次拷贝进 stringstream）
        std::queue<std::shared_ptr<std::stringstream>> m_blobs;
    };
    class conn :public ylib::example<ylib::mysql::mysql_conn_info>, public ylib::error_base
    {
    public:
        conn();
        ~conn();
        virtual EXAMPLE_START_RESULT start(const ylib::mysql::mysql_conn_info& info) override;
        virtual void close() override;


        virtual void recover() override;
        virtual void task_out() override;


        void clear();
        ylib::mysql::prepare_statement* setsql(const std::string& sql);
        uint64 insert_id();

        void begin(bool autocommit = false);
        void commit();
        void rollback();

        void setDatabase(const std::string& name);

        friend class ylib::mysql::pool;
    private:
        void* m_handle = nullptr;
        ylib::mysql::mysql_conn_info m_info;
        class prepare_statement* m_ppst = nullptr;
        // 事务状态 0=未开启 1=已开启
        int m_sw = 0;
    };


    // 连接池：增量配置，未填字段用默认值
    //   ylib::pool_options opt;
    //   opt.max_size = 50;   // 只改需要的项
    //   pool.start(info, opt);
    class pool : public ylib::pool<ylib::mysql::conn, ylib::mysql::mysql_conn_info>
    {
    public:
        pool() = default;
        ~pool() = default;
    };
}