#ifndef __CLASS_PGSQL_CONNECTION_H
#define __CLASS_PGSQL_CONNECTION_H
#include "libpq-fe.h"
#include "proxysql.h"
#include "cpp.h"
#include "PgSQL_Error_Helper.h"

#ifndef PROXYJSON
#define PROXYJSON
#include "../deps/json/json_fwd.hpp"
#endif // PROXYJSON

class PgSQL_SrvC;
class PgSQL_Query_Result;
//#define STATUS_MYSQL_CONNECTION_TRANSACTION          0x00000001 // DEPRECATED
#define STATUS_MYSQL_CONNECTION_COMPRESSION          0x00000002
#define STATUS_MYSQL_CONNECTION_USER_VARIABLE        0x00000004
#define STATUS_MYSQL_CONNECTION_PREPARED_STATEMENT   0x00000008
#define STATUS_MYSQL_CONNECTION_LOCK_TABLES          0x00000010
#define STATUS_MYSQL_CONNECTION_TEMPORARY_TABLE      0x00000020
#define STATUS_MYSQL_CONNECTION_GET_LOCK             0x00000040
#define STATUS_MYSQL_CONNECTION_NO_MULTIPLEX         0x00000080
#define STATUS_MYSQL_CONNECTION_SQL_LOG_BIN0         0x00000100
#define STATUS_MYSQL_CONNECTION_FOUND_ROWS           0x00000200
#define STATUS_MYSQL_CONNECTION_NO_MULTIPLEX_HG      0x00000400
#define STATUS_MYSQL_CONNECTION_HAS_SAVEPOINT        0x00000800
#define STATUS_MYSQL_CONNECTION_HAS_WARNINGS         0x00001000


enum PgSQL_Param_Name {
	PG_HOST = 0,  // Name of host to connect to
	PG_HOSTADDR,  // Numeric IP address of host to connect to
	PG_PORT,  // Port number to connect to at the server host
	PG_DATABASE,  // The database name
	PG_USER,  // PgSQL user name to connect as
	PG_PASSWORD,  // Password to be used if the server demands password authentication
	PG_PASSFILE,  // Specifies the name of the file used to store passwords
	PG_REQUIRE_AUTH,  // Specifies the authentication method that the client requires from the server
	PG_CHANNEL_BINDING,  // Controls the client's use of channel binding
	PG_CONNECT_TIMEOUT,  // Maximum time to wait while connecting, in seconds
	PG_OPTIONS,  // Specifies command-line options to send to the server at connection start
	PG_APPLICATION_NAME,  // Specifies a value for the application_name configuration parameter
	PG_FALLBACK_APPLICATION_NAME,  // Specifies a fallback value for the application_name configuration parameter
	PG_KEEPALIVES,  // Controls whether client-side TCP keepalives are used
	PG_KEEPALIVES_IDLE,  // Controls the number of seconds of inactivity after which TCP should send a keepalive message to the server
	PG_KEEPALIVES_INTERVAL,  // Controls the number of seconds after which a TCP keepalive message that is not acknowledged by the server should be retransmitted
	PG_KEEPALIVES_COUNT,  // Controls the number of TCP keepalives that can be lost before the client's connection to the server is considered dead
	PG_TCP_USER_TIMEOUT,  // Controls the number of milliseconds that transmitted data may remain unacknowledged before a connection is forcibly closed
	PG_REPLICATION,  // Determines whether the connection should use the replication protocol instead of the normal protocol
	PG_GSSENCMODE,  // Determines whether a secure GSS TCP/IP connection will be negotiated with the server
	PG_SSLMODE,  // Determines whether a secure SSL TCP/IP connection will be negotiated with the server
	PG_REQUIRESSL,  // Requires an SSL connection to the server
	PG_SSLCOMPRESSION,  // If set, data sent over SSL connections will be compressed
	PG_SSLCERT,  // Specifies the file name of the client SSL certificate
	PG_SSLKEY,  // Specifies the location for the secret key used for the client certificate
	PG_SSLPASSWORD,  // Specifies the password for the secret key specified in sslkey
	PG_SSLCERTMODE,  // Determines whether a client certificate may be sent to the server
	PG_SSLROOTCERT,  // Specifies the name of a file containing SSL certificate authority (CA) certificate(s)
	PG_SSLCRL,  // Specifies the file name of the SSL server certificate revocation list (CRL)
	PG_SSLCRLDIR,  // Specifies the directory name of the SSL server certificate revocation list (CRL)
	PG_SSLSNI,  // Sets the TLS extension “Server Name Indication” (SNI) on SSL-enabled connections
	PG_REQUIREPEER,  // Specifies the operating-system user name of the server
	PG_SSL_MIN_PROTOCOL_VERSION,  // Specifies the minimum SSL/TLS protocol version to allow for the connection
	PG_SSL_MAX_PROTOCOL_VERSION,  // Specifies the maximum SSL/TLS protocol version to allow for the connection
	PG_KRBSRVNAME,  // Kerberos service name to use when authenticating with GSSAPI
	PG_GSSLIB,  // GSS library to use for GSSAPI authentication
	PG_GSSDELEGATION,  // Forward (delegate) GSS credentials to the server
	PG_SERVICE,  // Service name to use for additional parameters
	PG_TARGET_SESSION_ATTRS,  // Determines whether the session must have certain properties to be acceptable
	PG_LOAD_BALANCE_HOSTS,  // Controls the order in which the client tries to connect to the available hosts and addresses
	// Environment Options
	//PG_DATESTYLE,  // Sets the value of the DateStyle parameter
	//PG_TIMEZONE,  // Sets the value of the TimeZone parameter
	//PG_GEQO,  // Enables or disables the use of the GEQO query optimizer

	PG_PARAM_SIZE
};

struct Param_Name_Validation {
	const char** accepted_values;
	int default_value_idx;
};

static const Param_Name_Validation require_auth{ (const char* []) { "password","md5","gss","sspi","scram-sha-256","none",nullptr },-1 };
static const Param_Name_Validation replication{ (const char* []) { "true","on","yes","1","database","false","off","no","0",nullptr },-1 };
static const Param_Name_Validation gsseencmode{ (const char* []) { "disable","prefer","require",nullptr },1 };
static const Param_Name_Validation sslmode{ (const char* []) { "disable","allow","prefer","require","verify-ca","verify-full",nullptr },2 };
static const Param_Name_Validation sslcertmode{ (const char* []) { "disable","allow","require",nullptr },1 };
static const Param_Name_Validation target_session_attrs{ (const char* []) { "any","read-write","read-only","primary","standby","prefer-standby",nullptr },0 };
static const Param_Name_Validation load_balance_hosts{ (const char* []) { "disable","random",nullptr },-1 };

// Excluding client_encoding since it is managed as part of the session variables
#define PARAMETER_LIST \
    PARAM("host", nullptr) \
    PARAM("hostaddr", nullptr) \
    PARAM("port", nullptr) \
    PARAM("database", nullptr) \
    PARAM("user", nullptr) \
    PARAM("password", nullptr) \
    PARAM("passfile", nullptr) \
    PARAM("require_auth", &require_auth) \
    PARAM("channel_binding", nullptr) \
    PARAM("connect_timeout", nullptr) \
    PARAM("options", nullptr) \
    PARAM("application_name", nullptr) \
    PARAM("fallback_application_name", nullptr) \
    PARAM("keepalives", nullptr) \
    PARAM("keepalives_idle", nullptr) \
    PARAM("keepalives_interval", nullptr) \
    PARAM("keepalives_count", nullptr) \
    PARAM("tcp_user_timeout", nullptr) \
    PARAM("replication", &replication) \
    PARAM("gsseencmode", &gsseencmode) \
    PARAM("sslmode", &sslmode) \
    PARAM("requiressl", nullptr) \
    PARAM("sslcompression", nullptr) \
    PARAM("sslcert", nullptr) \
    PARAM("sslkey", nullptr) \
    PARAM("sslpassword", nullptr) \
    PARAM("sslcertmode", &sslcertmode) \
    PARAM("sslrootcert", nullptr) \
    PARAM("sslcrl", nullptr) \
    PARAM("sslcrldir", nullptr) \
    PARAM("sslsni", nullptr) \
    PARAM("requirepeer", nullptr) \
    PARAM("ssl_min_protocol_version", nullptr) \
    PARAM("ssl_max_protocol_version", nullptr) \
    PARAM("krbsrvname", nullptr) \
    PARAM("gsslib", nullptr) \
    PARAM("gssdelegation", nullptr) \
    PARAM("service", nullptr) \
    PARAM("target_session_attrs", &target_session_attrs) \
    PARAM("load_balance_hosts", &load_balance_hosts)

// Generate parameter array
constexpr const char* param_name[] = {
#define PARAM(name, val) name,
	PARAMETER_LIST
#undef PARAM
};

// make sure all the keys are in lower case
static const std::unordered_map<std::string_view, const Param_Name_Validation*> param_name_map = {
#define PARAM(name, val) {name, val},
	PARAMETER_LIST
#undef PARAM
};

#define PG_EVENT_NONE	 0x00
#define PG_EVENT_READ	 0x01
#define PG_EVENT_WRITE	 0x02
#define PG_EVENT_EXCEPT  0x04
#define PG_EVENT_TIMEOUT 0x08


/**
 * @class PgSQL_Conn_Param
 * @brief Stores PostgreSQL connection parameters sent by client.
 *
 * This class stores key-value pairs representing connection parameters 
 * for PostgreSQL connection. 
 *
 */
class PgSQL_Conn_Param {
public:
    PgSQL_Conn_Param() {}
    ~PgSQL_Conn_Param() {}

    bool set_value(const char* key, const char* val) {
        if (key == nullptr || val == nullptr) return false;
        connection_parameters[key] = val;
        return true;
    }

    inline
    const char* get_value(PgSQL_Param_Name key) const {
        return get_value(param_name[key]);
    }

    const char* get_value(const char* key) const {
        auto it = connection_parameters.find(key);
        if (it != connection_parameters.end()) {
            return it->second.c_str();
        }
        return nullptr;
    }

    bool remove_value(const char* key) {
        auto it = connection_parameters.find(key);
        if (it != connection_parameters.end()) {
            connection_parameters.erase(it);
            return true;
        }
        return false;
    }

    inline
    bool is_empty() const {
        return connection_parameters.empty();
    }

    inline
    void clear() {
        connection_parameters.clear();
    }

private:
    /**
     * @brief Stores the connection parameters as key-value pairs.
     */
    std::map<std::string, std::string> connection_parameters;

    friend class PgSQL_Session; 
    friend class PgSQL_Protocol;
};

class PgSQL_Variable {
public:
	char *value = (char*)"";
	void fill_server_internal_session(nlohmann::json &j, int conn_num, int idx);
	void fill_client_internal_session(nlohmann::json &j, int idx);
};

class PgSQL_Connection_userinfo {
	private:
	uint64_t compute_hash();
  public:
	uint64_t hash;
	char *username;
	char *password;
	union {
		char* dbname;
		char* schemaname; // temporary fix. To avoid changes in Base_Session and Query_Processor
	};
	char *sha1_pass;
	char *fe_username;
	// TODO POSGRESQL: add client and server scram keys
	PgSQL_Connection_userinfo();
	~PgSQL_Connection_userinfo();
	void set(char *, char *, char *, char *);
	void set(PgSQL_Connection_userinfo *);
	bool set_dbname(const char *);
};

class PgSQL_Connection {
public:
	PgSQL_Connection();
	~PgSQL_Connection();

	PG_ASYNC_ST handler(short event);
	void connect_start();
	void connect_cont(short event);
	void query_start();
	void query_cont(short event);
	void fetch_result_start();
	void fetch_result_cont(short event);
	void reset_session_start();
	void reset_session_cont(short event);
	
	int  async_connect(short event);

	int  async_query(short event, char* stmt, unsigned long length);
	int  async_ping(short event);
	int  async_reset_session(short event);
	int	 async_send_simple_command(short event, char* stmt, unsigned long length); // no result set expected

	void next_event(PG_ASYNC_ST new_st);
	bool IsAutoCommit();
	bool is_connected() const;
	void compute_unknown_transaction_status();
	void async_free_result();
	void flush();
	bool IsActiveTransaction();
	bool IsKnownActiveTransaction();
	bool IsServerOffline();
	
	bool is_connection_in_reusable_state() const;

	bool requires_RESETTING_CONNECTION(const PgSQL_Connection* client_conn);
	
	bool has_same_connection_options(const PgSQL_Connection* c);

	int get_server_version() {
		return PQserverVersion(pgsql_conn);
	}

	int get_protocol_version() {
		return PQprotocolVersion(pgsql_conn);
	}

	inline
	bool is_error_present() const {
		if (error_info.severity == PGSQL_ERROR_SEVERITY::ERRSEVERITY_FATAL ||
			error_info.severity == PGSQL_ERROR_SEVERITY::ERRSEVERITY_ERROR ||
			error_info.severity == PGSQL_ERROR_SEVERITY::ERRSEVERITY_PANIC) {
				return true;
		}
		return false;
	}

	inline
	PGSQL_ERROR_SEVERITY get_error_severity() const {
		return error_info.severity;
	}

	inline
	PGSQL_ERROR_CATEGORY get_error_category() const {
		return error_info.category;
	}

	inline
	const std::string& get_error_message() const {
		return error_info.message;
	}

	inline
	const char* get_error_code_str() const {
		return error_info.sqlstate;
	}

	inline
	PGSQL_ERROR_CODES get_error_code() const {
		return error_info.code;
	}

	inline
	std::string get_error_code_with_message() const {
		return ("[" + std::string(error_info.sqlstate) + "] " + error_info.message);
	}

	void set_error(const char* code, const char* message, bool is_fatal) {
		PgSQL_Error_Helper::fill_error_info(error_info, code, message, is_fatal ? "FATAL" : "ERROR");
	}

	void set_error(PGSQL_ERROR_CODES code, const char* message, bool is_fatal) {
		PgSQL_Error_Helper::fill_error_info(error_info, code, message, is_fatal ? 
			PGSQL_ERROR_SEVERITY::ERRSEVERITY_FATAL : PGSQL_ERROR_SEVERITY::ERRSEVERITY_ERROR);
	}

	// safety check. Sometimes libpq return garbage result when connection is lost with the backend
	bool is_error_result_valid(const PGresult* result) const {
		if (result == nullptr)
			return false;
		return (PQresultErrorField(result, PG_DIAG_SQLSTATE) != nullptr);
	}

	void set_error_from_result(const PGresult* result, uint16_t ext_fields = 0) {
		if (is_error_result_valid(result)) { 
			PgSQL_Error_Helper::fill_error_info(error_info, result, ext_fields);
		} else {
			const char* errmsg = PQerrorMessage(pgsql_conn);
			set_error(PGSQL_ERROR_CODES::ERRCODE_RAISE_EXCEPTION, errmsg ? errmsg : "Unknown error", true);
			//PgSQL_Error_Helper::fill_error_info_from_error_message(error_info, errmsg);
		}
	}

	void reset_error() { reset_error_info(error_info, false); }

	bool reset_session_in_txn = false;

	PGresult* get_result();
	void next_multi_statement_result(PGresult* result);
	bool set_single_row_mode();
	void update_bytes_recv(uint64_t bytes_recv);
	void update_bytes_sent(uint64_t bytes_sent);
	void ProcessQueryAndSetStatusFlags(char* query_digest_text);

	inline const PGconn* get_pg_connection() const { return pgsql_conn; }
	inline int get_pg_server_version() { return PQserverVersion(pgsql_conn); }
	inline int get_pg_protocol_version() { return PQprotocolVersion(pgsql_conn); }
	inline const char* get_pg_host() { return PQhost(pgsql_conn); }
	inline const char* get_pg_hostaddr() { return PQhostaddr(pgsql_conn); }
	inline const char* get_pg_port() { return PQport(pgsql_conn); }
	inline const char* get_pg_dbname() { return PQdb(pgsql_conn); }
	inline const char* get_pg_user() { return PQuser(pgsql_conn); }
	inline const char* get_pg_password() { return PQpass(pgsql_conn); }
	inline const char* get_pg_options() { return PQoptions(pgsql_conn); }
	inline int get_pg_socket_fd() { return PQsocket(pgsql_conn); }
	inline int get_pg_backend_pid() { return PQbackendPID(pgsql_conn); }
	inline int get_pg_connection_needs_password() { return PQconnectionNeedsPassword(pgsql_conn); }
	inline int get_pg_connection_used_password() { return PQconnectionUsedPassword(pgsql_conn); }
	inline int get_pg_connection_used_gssapi() { return PQconnectionUsedGSSAPI(pgsql_conn); }
	inline int get_pg_client_encoding() { return PQclientEncoding(pgsql_conn); }
	inline int get_pg_ssl_in_use() { return PQsslInUse(pgsql_conn); }
	inline ConnStatusType get_pg_connection_status() { return PQstatus(pgsql_conn); }
	inline PGTransactionStatusType get_pg_transaction_status() { return PQtransactionStatus(pgsql_conn); }
	inline int get_pg_is_nonblocking() { return PQisnonblocking(pgsql_conn); }
	inline int get_pg_is_threadsafe() { return PQisthreadsafe(); }
	inline const char* get_pg_error_message() { return PQerrorMessage(pgsql_conn); }
	inline SSL* get_pg_ssl_object() { return (SSL*)PQsslStruct(pgsql_conn, "OpenSSL"); }
	const char* get_pg_server_version_str(char* buff, int buff_size);
	const char* get_pg_connection_status_str();
	const char* get_pg_transaction_status_str();
	unsigned int get_memory_usage() const;

	inline
	int get_backend_pid() { return (pgsql_conn) ? get_pg_backend_pid() : -1; }

	static int char_to_encoding(const char* name) {
		return pg_char_to_encoding(name);
	}

	static const char* encoding_to_char(int encoding) {
		return pg_encoding_to_char(encoding);
	}

	static int valid_server_encoding_id(int encoding) {
		return pg_valid_server_encoding_id(encoding);
	}

	inline
	void reduce_auto_increment_delay_token() { if (auto_increment_delay_token) auto_increment_delay_token--; };

	void set_status(bool set, uint32_t status_flag);
	bool get_status(uint32_t status_flag);
	bool MultiplexDisabled(bool check_delay_token = true);

	bool AutocommitFalse_AndSavepoint();

	unsigned int reorder_dynamic_variables_idx();
	unsigned int number_of_matching_session_variables(const PgSQL_Connection* client_conn, unsigned int& not_matching);
	void set_query(char* stmt, unsigned long length);
	void reset();

	bool IsKeepMultiplexEnabledVariables(char* query_digest_text);

	struct {
		unsigned long length;
		char* ptr;
	} query;

	struct {
		char* init_connect;
		bool init_connect_sent;
	} options;

	struct {
		char* hostname;
		char* ip;
	} connected_host_details;

	bytes_stats_t bytes_info; // bytes statistics
	struct {
		unsigned long long questions;
		unsigned long long pgconnpoll_get;
		unsigned long long pgconnpoll_put;
	} statuses;

	PgSQL_Variable variables[PGSQL_NAME_LAST_HIGH_WM];
	uint32_t var_hash[PGSQL_NAME_LAST_HIGH_WM];
	// for now we store possibly missing variables in the lower range
	// we may need to fix that, but this will cost performance
	bool var_absent[PGSQL_NAME_LAST_HIGH_WM] = { false };
	std::vector<uint32_t> dynamic_variables_idx;

	/**
	 * @brief Keeps tracks of the 'server_status'. Do not confuse with the 'server_status' from the
	 *  'MYSQL' connection itself. This flag keeps track of the configured server status from the
	 *  parent 'MySrvC'.
	 */
	enum MySerStatus server_status; // this to solve a side effect of #774

	PgSQL_Conn_Param conn_params;
	PgSQL_ErrorInfo error_info;
	PGconn* pgsql_conn;
	uint8_t result_type;
	PGresult* pgsql_result;
	PSresult  ps_result;
	PgSQL_Query_Result* query_result;
	PgSQL_Query_Result* query_result_reuse;
	unsigned long long creation_time;
	unsigned long long last_time_used;
	unsigned long long timeout;
	int auto_increment_delay_token;
	PG_ASYNC_ST async_state_machine;	// Async state machine
	short wait_events;
	bool new_result;
	bool is_copy_out;

	bool send_quit;
	bool reusable;
	bool processing_multi_statement;
	bool multiplex_delayed;


	PgSQL_SrvC *parent;
	PgSQL_Connection_userinfo* userinfo;
	PgSQL_Data_Stream* myds;
	//unsigned int warning_count;
	int fd;
	/**
	 * @brief This represents the internal knowledge of ProxySQL about the connection. It keeps track of those
	 *  states which *are not reflected* into 'server_status', but are relevant for connection handling.
	 */
	uint32_t status_flags;
	unsigned long largest_query_length;
	int async_exit_status; // exit status of Non blocking API
	bool unknown_transaction_status;




private:
	// Handles the COPY OUT response from the server.
	// Returns true if it consumes all buffer data, or false if the threshold for result size is reached
	bool handle_copy_out(const PGresult* result, uint64_t* processed_bytes);
	static void notice_handler_cb(void* arg, const PGresult* result);
	static void unhandled_notice_cb(void* arg, const PGresult* result);
	//void update_warning_count_from_connection();
	//void update_warning_count_from_statement();
};

#endif /* __CLASS_PGSQL_CONNECTION_H */