// Copyright (c) 2017 Anatoly Ikorsky
//
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. All files in the project carrying such notice may not be copied,
// modified, or distributed except according to those terms.

pub static MAX_PAYLOAD_LEN: usize = 16_777_215;
pub static DEFAULT_MAX_ALLOWED_PACKET: usize = 4 * 1024 * 1024;
pub static MIN_COMPRESS_LENGTH: usize = 50;

pub static UTF8_GENERAL_CI: u16 = 33;
pub static UTF8MB4_GENERAL_CI: u16 = 45;

bitflags! {
    /// MySql server status flags
    pub struct StatusFlags: u16 {
        /// Is raised when a multi-statement transaction has been started, either explicitly,
        /// by means of BEGIN or COMMIT AND CHAIN, or implicitly, by the first transactional
        /// statement, when autocommit=off.
        const SERVER_STATUS_IN_TRANS             = 0x0001;

        /// Server in auto_commit mode.
        const SERVER_STATUS_AUTOCOMMIT           = 0x0002;

        /// Multi query - next query exists.
        const SERVER_MORE_RESULTS_EXISTS         = 0x0008;

        const SERVER_STATUS_NO_GOOD_INDEX_USED   = 0x0010;

        const SERVER_STATUS_NO_INDEX_USED        = 0x0020;

        /// The server was able to fulfill the clients request and opened a read-only
        /// non-scrollable cursor for a query. This flag comes in reply to COM_STMT_EXECUTE
        /// and COM_STMT_FETCH commands. Used by Binary Protocol Resultset to signal that
        /// COM_STMT_FETCH must be used to fetch the row-data.
        const SERVER_STATUS_CURSOR_EXISTS        = 0x0040;

        /// This flag is sent when a read-only cursor is exhausted, in reply to
        /// COM_STMT_FETCH command.
        const SERVER_STATUS_LAST_ROW_SENT        = 0x0080;

        /// A database was dropped.
        const SERVER_STATUS_DB_DROPPED           = 0x0100;

        const SERVER_STATUS_NO_BACKSLASH_ESCAPES = 0x0200;

        /// Sent to the client if after a prepared statement reprepare we discovered
        /// that the new statement returns a different number of result set columns.
        const SERVER_STATUS_METADATA_CHANGED     = 0x0400;

        const SERVER_QUERY_WAS_SLOW              = 0x0800;

        /// To mark ResultSet containing output parameter values.
        const SERVER_PS_OUT_PARAMS               = 0x1000;

        /// Set at the same time as SERVER_STATUS_IN_TRANS if the started multi-statement
        /// transaction is a read-only transaction. Cleared when the transaction commits
        /// or aborts. Since this flag is sent to clients in OK and EOF packets, the flag
        /// indicates the transaction status at the end of command execution.
        const SERVER_STATUS_IN_TRANS_READONLY    = 0x2000;

        /// This status flag, when on, implies that one of the state information has
        /// changed on the server because of the execution of the last statement.
        const SERVER_SESSION_STATE_CHANGED       = 0x4000;
    }
}

bitflags! {
    /// Client capability flags
    pub struct CapabilityFlags: u32 {
        /// Use the improved version of Old Password Authentication. Assumed to be set since 4.1.1.
        const CLIENT_LONG_PASSWORD                  = 0x0000_0001;

        /// Send found rows instead of affected rows in EOF_Packet.
        const CLIENT_FOUND_ROWS                     = 0x0000_0002;

        /// Get all column flags.
        /// Longer flags in Protocol::ColumnDefinition320.
        ///
        /// ### Server
        /// Supports longer flags.
        ///
        /// ### Client
        /// Expects longer flags.
        const CLIENT_LONG_FLAG                      = 0x0000_0004;

        /// Database (schema) name can be specified on connect in Handshake Response Packet.
        /// ### Server
        /// Supports schema-name in Handshake Response Packet.
        ///
        /// ### Client
        /// Handshake Response Packet contains a schema-name.
        const CLIENT_CONNECT_WITH_DB                = 0x0000_0008;

        /// Don't allow database.table.column.
        const CLIENT_NO_SCHEMA                      = 0x0000_0010;

        /// Compression protocol supported.
        ///
        /// ### Server
        /// Supports compression.
        ///
        /// ### Client
        /// Switches to Compression compressed protocol after successful authentication.
        const CLIENT_COMPRESS                       = 0x0000_0020;

        /// Special handling of ODBC behavior.
        const CLIENT_ODBC                           = 0x0000_0040;

        /// Can use LOAD DATA LOCAL.
        ///
        /// ### Server
        /// Enables the LOCAL INFILE request of LOAD DATA|XML.
        ///
        /// ### Client
        /// Will handle LOCAL INFILE request.
        const CLIENT_LOCAL_FILES                    = 0x0000_0080;

        /// Ignore spaces before '('.
        ///
        /// ### Server
        /// Parser can ignore spaces before '('.
        ///
        /// ### Client
        /// Let the parser ignore spaces before '('.
        const CLIENT_IGNORE_SPACE                   = 0x0000_0100;

        const CLIENT_PROTOCOL_41                    = 0x0000_0200;

        /// This is an interactive client.
        /// Use System_variables::net_wait_timeout versus System_variables::net_interactive_timeout.
        ///
        /// ### Server
        /// Supports interactive and noninteractive clients.
        ///
        /// ### Client
        /// Client is interactive.
        const CLIENT_INTERACTIVE                    = 0x0000_0400;

        /// Use SSL encryption for the session.
        ///
        /// ### Server
        /// Supports SSL
        ///
        /// ### Client
        /// Switch to SSL after sending the capability-flags.
        const CLIENT_SSL                            = 0x0000_0800;

        /// Client only flag. Not used.
        ///
        /// ### Client
        /// Do not issue SIGPIPE if network failures occur (libmysqlclient only).
        const CLIENT_IGNORE_SIGPIPE                 = 0x0000_1000;

        /// Client knows about transactions.
        ///
        /// ### Server
        /// Can send status flags in OK_Packet / EOF_Packet.
        ///
        /// ### Client
        /// Expects status flags in OK_Packet / EOF_Packet.
        ///
        /// ### Note
        /// This flag is optional in 3.23, but always set by the server since 4.0.
        const CLIENT_TRANSACTIONS                   = 0x0000_2000;

        const CLIENT_RESERVED                       = 0x0000_4000;

        const CLIENT_SECURE_CONNECTION              = 0x0000_8000;

        /// Enable/disable multi-stmt support.
        /// Also sets CLIENT_MULTI_RESULTS. Currently not checked anywhere.
        ///
        /// ### Server
        /// Can handle multiple statements per COM_QUERY and COM_STMT_PREPARE.
        ///
        /// ### Client
        /// May send multiple statements per COM_QUERY and COM_STMT_PREPARE.
        const CLIENT_MULTI_STATEMENTS               = 0x0001_0000;

        /// Enable/disable multi-results.
        ///
        /// ### Server
        /// Can send multiple resultsets for COM_QUERY. Error if the server needs to send
        /// them and client does not support them.
        ///
        /// ### Client
        /// Can handle multiple resultsets for COM_QUERY.
        ///
        /// ### Requires
        /// `CLIENT_PROTOCOL_41`
        const CLIENT_MULTI_RESULTS                  = 0x0002_0000;

        /// Multi-results and OUT parameters in PS-protocol.
        ///
        /// ### Server
        /// Can send multiple resultsets for COM_STMT_EXECUTE.
        ///
        /// ### Client
        /// Can handle multiple resultsets for COM_STMT_EXECUTE.
        ///
        /// ### Requires
        /// `CLIENT_PROTOCOL_41`
        const CLIENT_PS_MULTI_RESULTS               = 0x0004_0000;

        /// Client supports plugin authentication.
        ///
        /// ### Server
        /// Sends extra data in Initial Handshake Packet and supports the pluggable
        /// authentication protocol.
        ///
        /// ### Client
        /// Supports authentication plugins.
        ///
        /// ### Requires
        /// `CLIENT_PROTOCOL_41`
        const CLIENT_PLUGIN_AUTH                    = 0x0008_0000;

        /// Client supports connection attributes.
        ///
        /// ### Server
        /// Permits connection attributes in Protocol::HandshakeResponse41.
        ///
        /// ### Client
        /// Sends connection attributes in Protocol::HandshakeResponse41.
        const CLIENT_CONNECT_ATTRS                  = 0x0010_0000;

        /// Enable authentication response packet to be larger than 255 bytes.
        /// When the ability to change default plugin require that the initial password
        /// field in the Protocol::HandshakeResponse41 paclet can be of arbitrary size.
        /// However, the 4.1 client-server protocol limits the length of the auth-data-field
        /// sent from client to server to 255 bytes. The solution is to change the type of
        /// the field to a true length encoded string and indicate the protocol change with
        /// this client capability flag.
        ///
        /// ### Server
        /// Understands length-encoded integer for auth response data in
        /// Protocol::HandshakeResponse41.
        ///
        /// ### Client
        /// Length of auth response data in Protocol::HandshakeResponse41 is a
        /// length-encoded integer.
        ///
        /// ### Note
        /// The flag was introduced in 5.6.6, but had the wrong value.
        const CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA = 0x0020_0000;

        /// Don't close the connection for a user account with expired password.
        ///
        /// ### Server
        /// Announces support for expired password extension.
        ///
        /// ### Client
        /// Can handle expired passwords.
        const CLIENT_CAN_HANDLE_EXPIRED_PASSWORDS   = 0x0040_0000;

        /// Capable of handling server state change information.
        /// Its a hint to the server to include the state change information in OK_Packet.
        ///
        /// ### Server
        /// Can set SERVER_SESSION_STATE_CHANGED in the SERVER_STATUS_flags_enum and send
        /// Session State Information in a OK_Packet.
        ///
        /// ### Client
        /// Expects the server to send Session State Information in a OK_Packet.
        const CLIENT_SESSION_TRACK                  = 0x0080_0000;

        /// Client no longer needs EOF_Packet and will use OK_Packet instead.
        ///
        /// ### Server
        /// Can send OK after a Text Resultset.
        ///
        /// ### Client
        /// Expects an OK_Packet (instead of EOF_Packet) after the resultset
        /// rows of a Text Resultset.
        ///
        /// ### Background
        /// To support CLIENT_SESSION_TRACK, additional information must be sent after all
        /// successful commands. Although the OK_Packet is extensible, the EOF_Packet is
        /// not due to the overlap of its bytes with the content of the Text Resultset Row.
        ///
        /// Therefore, the EOF_Packet in the Text Resultset is replaced with an OK_Packet.
        /// EOF_Packet is deprecated as of MySQL 5.7.5.
        const CLIENT_DEPRECATE_EOF                  = 0x0100_0000;

        /// Client or server supports progress reports within error packet.
        const CLIENT_PROGRESS_OBSOLETE              = 0x2000_0000;

        /// Verify server certificate. Client only flag.
        ///
        /// Deprecated in favor of –ssl-mode.
        const CLIENT_SSL_VERIFY_SERVER_CERT         = 0x4000_0000;

        /// Don't reset the options after an unsuccessful connect. Client only flag.
        const CLIENT_REMEMBER_OPTIONS               = 0x8000_0000;
    }
}

bitflags! {
    /// MySql column flags
    pub struct ColumnFlags: u16 {
        /// Field can't be NULL.
        const NOT_NULL_FLAG         = 1u16;

        /// Field is part of a primary key.
        const PRI_KEY_FLAG          = 2u16;

        /// Field is part of a unique key.
        const UNIQUE_KEY_FLAG       = 4u16;

        /// Field is part of a key.
        const MULTIPLE_KEY_FLAG     = 8u16;

        /// Field is a blob.
        const BLOB_FLAG             = 16u16;

        /// Field is unsigned.
        const UNSIGNED_FLAG         = 32u16;

        /// Field is zerofill.
        const ZEROFILL_FLAG         = 64u16;

        /// Field is binary.
        const BINARY_FLAG           = 128u16;

        /// Field is an enum.
        const ENUM_FLAG             = 256u16;

        /// Field is a autoincrement field.
        const AUTO_INCREMENT_FLAG   = 512u16;

        /// Field is a timestamp.
        const TIMESTAMP_FLAG        = 1024u16;

        /// Field is a set.
        const SET_FLAG              = 2048u16;

        /// Field doesn't have default value.
        const NO_DEFAULT_VALUE_FLAG = 4096u16;

        /// Field is set to NOW on UPDATE.
        const ON_UPDATE_NOW_FLAG    = 8192u16;

        /// Intern; Part of some key.
        const PART_KEY_FLAG         = 16384u16;

        /// Field is num (for clients).
        const NUM_FLAG              = 32768u16;
    }
}

/// MySql server commands
#[allow(non_camel_case_types)]
#[derive(Clone, Copy, Eq, PartialEq, Debug)]
#[repr(u8)]
pub enum Command {
    COM_SLEEP = 0,
    COM_QUIT,
    COM_INIT_DB,
    COM_QUERY,
    COM_FIELD_LIST,
    COM_CREATE_DB,
    COM_DROP_DB,
    COM_REFRESH,
    COM_DEPRECATED_1,
    COM_STATISTICS,
    COM_PROCESS_INFO,
    COM_CONNECT,
    COM_PROCESS_KILL,
    COM_DEBUG,
    COM_PING,
    COM_TIME,
    COM_DELAYED_INSERT,
    COM_CHANGE_USER,
    COM_BINLOG_DUMP,
    COM_TABLE_DUMP,
    COM_CONNECT_OUT,
    COM_REGISTER_SLAVE,
    COM_STMT_PREPARE,
    COM_STMT_EXECUTE,
    COM_STMT_SEND_LONG_DATA,
    COM_STMT_CLOSE,
    COM_STMT_RESET,
    COM_SET_OPTION,
    COM_STMT_FETCH,
    COM_DAEMON,
    COM_BINLOG_DUMP_GTID,
    COM_RESET_CONNECTION,
    COM_END,
}

/// Type of state change information (part of MySql's Ok packet).
#[allow(non_camel_case_types)]
#[derive(Clone, Copy, Eq, PartialEq, Debug)]
#[repr(u8)]
pub enum SessionStateType {
    /// Session system variables.
    SESSION_TRACK_SYSTEM_VARIABLES,
    /// Current schema.
    SESSION_TRACK_SCHEMA,
    /// track session state changes
    SESSION_TRACK_STATE_CHANGE,
    /// See also: session_track_gtids.
    SESSION_TRACK_GTIDS,
    /// Transaction characteristics.
    SESSION_TRACK_TRANSACTION_CHARACTERISTICS,
    /// Transaction state.
    SESSION_TRACK_TRANSACTION_STATE,
}

impl From<u8> for SessionStateType {
    fn from(x: u8) -> Self {
        match x {
            0x00 => SessionStateType::SESSION_TRACK_SYSTEM_VARIABLES,
            0x01 => SessionStateType::SESSION_TRACK_SCHEMA,
            0x02 => SessionStateType::SESSION_TRACK_STATE_CHANGE,
            0x03 => SessionStateType::SESSION_TRACK_GTIDS,
            0x04 => SessionStateType::SESSION_TRACK_TRANSACTION_CHARACTERISTICS,
            0x05 => SessionStateType::SESSION_TRACK_TRANSACTION_STATE,
            x => panic!("Unknown session state type {}", x),
        }
    }
}

/// Type of MySql column field
#[allow(non_camel_case_types)]
#[derive(Clone, Copy, Eq, PartialEq, Debug)]
#[repr(u8)]
pub enum ColumnType {
    MYSQL_TYPE_DECIMAL = 0,
    MYSQL_TYPE_TINY,
    MYSQL_TYPE_SHORT,
    MYSQL_TYPE_LONG,
    MYSQL_TYPE_FLOAT,
    MYSQL_TYPE_DOUBLE,
    MYSQL_TYPE_NULL,
    MYSQL_TYPE_TIMESTAMP,
    MYSQL_TYPE_LONGLONG,
    MYSQL_TYPE_INT24,
    MYSQL_TYPE_DATE,
    MYSQL_TYPE_TIME,
    MYSQL_TYPE_DATETIME,
    MYSQL_TYPE_YEAR,
    MYSQL_TYPE_NEWDATE, // Internal to MySql
    MYSQL_TYPE_VARCHAR,
    MYSQL_TYPE_BIT,
    MYSQL_TYPE_TIMESTAMP2,
    MYSQL_TYPE_DATETIME2,
    MYSQL_TYPE_TIME2,
    MYSQL_TYPE_JSON = 245,
    MYSQL_TYPE_NEWDECIMAL = 246,
    MYSQL_TYPE_ENUM = 247,
    MYSQL_TYPE_SET = 248,
    MYSQL_TYPE_TINY_BLOB = 249,
    MYSQL_TYPE_MEDIUM_BLOB = 250,
    MYSQL_TYPE_LONG_BLOB = 251,
    MYSQL_TYPE_BLOB = 252,
    MYSQL_TYPE_VAR_STRING = 253,
    MYSQL_TYPE_STRING = 254,
    MYSQL_TYPE_GEOMETRY = 255,
}

impl From<u8> for ColumnType {
    fn from(x: u8) -> ColumnType {
        match x {
            0x00_u8 => ColumnType::MYSQL_TYPE_DECIMAL,
            0x01_u8 => ColumnType::MYSQL_TYPE_TINY,
            0x02_u8 => ColumnType::MYSQL_TYPE_SHORT,
            0x03_u8 => ColumnType::MYSQL_TYPE_LONG,
            0x04_u8 => ColumnType::MYSQL_TYPE_FLOAT,
            0x05_u8 => ColumnType::MYSQL_TYPE_DOUBLE,
            0x06_u8 => ColumnType::MYSQL_TYPE_NULL,
            0x07_u8 => ColumnType::MYSQL_TYPE_TIMESTAMP,
            0x08_u8 => ColumnType::MYSQL_TYPE_LONGLONG,
            0x09_u8 => ColumnType::MYSQL_TYPE_INT24,
            0x0a_u8 => ColumnType::MYSQL_TYPE_DATE,
            0x0b_u8 => ColumnType::MYSQL_TYPE_TIME,
            0x0c_u8 => ColumnType::MYSQL_TYPE_DATETIME,
            0x0d_u8 => ColumnType::MYSQL_TYPE_YEAR,
            0x0f_u8 => ColumnType::MYSQL_TYPE_VARCHAR,
            0x10_u8 => ColumnType::MYSQL_TYPE_BIT,
            0x11_u8 => ColumnType::MYSQL_TYPE_TIMESTAMP2,
            0x12_u8 => ColumnType::MYSQL_TYPE_DATETIME2,
            0x13_u8 => ColumnType::MYSQL_TYPE_TIME2,
            0xf5_u8 => ColumnType::MYSQL_TYPE_JSON,
            0xf6_u8 => ColumnType::MYSQL_TYPE_NEWDECIMAL,
            0xf7_u8 => ColumnType::MYSQL_TYPE_ENUM,
            0xf8_u8 => ColumnType::MYSQL_TYPE_SET,
            0xf9_u8 => ColumnType::MYSQL_TYPE_TINY_BLOB,
            0xfa_u8 => ColumnType::MYSQL_TYPE_MEDIUM_BLOB,
            0xfb_u8 => ColumnType::MYSQL_TYPE_LONG_BLOB,
            0xfc_u8 => ColumnType::MYSQL_TYPE_BLOB,
            0xfd_u8 => ColumnType::MYSQL_TYPE_VAR_STRING,
            0xfe_u8 => ColumnType::MYSQL_TYPE_STRING,
            0xff_u8 => ColumnType::MYSQL_TYPE_GEOMETRY,
            _ => panic!("Unknown column type {}", x),
        }
    }
}