const (
	DsnTypeURL  = 1
	DsnTypeOdbc = 2
	DsnTypeAdo  = 3
)

const (
	EncryptionOff      = 0
	EncryptionRequired = 1
	EncryptionDisabled = 3
	EncryptionStrict   = 4
)

const (
	Database               = "database"
	Encrypt                = "encrypt"
	Password               = "password"
	ChangePassword         = "change password"
	UserID                 = "user id"
	Port                   = "port"
	TrustServerCertificate = "trustservercertificate"
	Certificate            = "certificate"
	TLSMin                 = "tlsmin"
	PacketSize             = "packet size"
	LogParam               = "log"
	ConnectionTimeout      = "connection timeout"
	HostNameInCertificate  = "hostnameincertificate"
	KeepAlive              = "keepalive"
	ServerSpn              = "serverspn"
	WorkstationID          = "workstation id"
	AppName                = "app name"
	ApplicationIntent      = "applicationintent"
	FailoverPartner        = "failoverpartner"
	FailOverPort           = "failoverport"
	DisableRetry           = "disableretry"
	Server                 = "server"
	Protocol               = "protocol"
	DialTimeout            = "dial timeout"
	Pipe                   = "pipe"
	MultiSubnetFailover    = "multisubnetfailover"
)

var ProtocolDialers map[string]ProtocolDialer = map[string]ProtocolDialer{}

var ProtocolParsers []ProtocolParser = []ProtocolParser{
	tcpParser{Prefix: "tcp"},
	tcpParser{Prefix: "admin"},
}

type BrowserData map[string]map[string]string

type BrowserMsg byte

const (
	BrowserDefault      BrowserMsg = 0
	BrowserAllInstances BrowserMsg = 0x03
	BrowserDAC          BrowserMsg = 0x0f
)

type Config struct {
	Port       uint64
	Host       string
	Instance   string
	Database   string
	User       string
	Password   string
	Encryption Encryption
	TLSConfig  *tls.Config

	FailOverPartner string
	FailOverPort    uint64

	// If true the TLSConfig servername should use the routed server.
	HostInCertificateProvided bool

	// Read Only intent for application database.
	// NOTE: This does not make queries to most databases read-only.
	ReadOnlyIntent bool

	LogFlags Log

	ServerSPN   string
	Workstation string
	AppName     string

	// If true disables database/sql's automatic retry of queries
	// that start on bad connections.
	DisableRetry bool

	DialTimeout time.Duration // DialTimeout defaults to 15s per protocol. Set negative to disable.
	ConnTimeout time.Duration // Use context for timeouts.
	KeepAlive   time.Duration // Leave at default.
	PacketSize  uint16

	Parameters map[string]string
	// Protocols is an ordered list of protocols to dial
	Protocols []string
	// ProtocolParameters are written by non-tcp ProtocolParser implementations
	ProtocolParameters map[string]interface{}
	// BrowserMsg is the message identifier to fetch instance data from SQL browser
	BrowserMessage BrowserMsg
	// ChangePassword is used to set the login's password during login. Ignored for non-SQL authentication.
	ChangePassword string
	//ColumnEncryption is true if the application needs to decrypt or encrypt Always Encrypted values
	ColumnEncryption bool
	// Attempt to connect to all IPs in parallel when MultiSubnetFailover is true
	MultiSubnetFailover bool
}

type Encryption int

type Log uint64

const (
	LogErrors      Log = 1
	LogMessages    Log = 2
	LogRows        Log = 4
	LogSQL         Log = 8
	LogParams      Log = 16
	LogTransaction Log = 32
	LogDebug       Log = 64
	LogRetries     Log = 128
)

type ProtocolDialer interface {
	// Translates data from SQL Browser to parameters in the config
	ParseBrowserData(data BrowserData, p *Config) error
	// DialConnection eturns a Dialer to make the connection. On success, also set Config.ServerSPN if it is unset.
	DialConnection(ctx context.Context, p *Config) (conn net.Conn, err error)
	// Returns true if information is needed from the SQL Browser service to make a connection
	CallBrowser(p *Config) bool
}

type ProtocolParser interface {
	// ParseServer updates the Config with protocol properties from the server. Returns an error if the server isn't compatible.
	ParseServer(server string, p *Config) error
	// Protocol returns the name of the protocol dialer
	Protocol() string
	// Hidden returns true if this protocol must be explicitly chosen by the application
	Hidden() bool
}