//
// Copyright 2014-2016 Cristian Maglie. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//

package serial // import "go.bug.st/serial"

// Mode describes a serial port configuration.
type Mode struct {
	BaudRate int      // The serial port bitrate (aka Baudrate)
	DataBits int      // Size of the character (must be 5, 6, 7 or 8)
	Parity   Parity   // Parity (see Parity type for more info)
	StopBits StopBits // Stop bits (see StopBits type for more info)
}

// Parity describes a serial port parity setting
type Parity int

const (
	// NoParity disable parity control (default)
	NoParity Parity = iota
	// OddParity enable odd-parity check
	OddParity
	// EvenParity enable even-parity check
	EvenParity
	// MarkParity enable mark-parity (always 1) check
	MarkParity
	// SpaceParity enable space-parity (always 0) check
	SpaceParity
)

// StopBits describe a serial port stop bits setting
type StopBits int

const (
	// OneStopBit sets 1 stop bit (default)
	OneStopBit StopBits = iota
	// OnePointFiveStopBits sets 1.5 stop bits
	OnePointFiveStopBits
	// TwoStopBits sets 2 stop bits
	TwoStopBits
)

// PortError is a platform independent error type for serial ports
type PortError struct {
	err  string
	code PortErrorCode
}

// PortErrorCode is a code to easily identify the type of error
type PortErrorCode int

const (
	// PortBusy the serial port is already in used by another process
	PortBusy PortErrorCode = iota
	// PortNotFound the requested port doesn't exist
	PortNotFound
	// InvalidSerialPort the requested port is not a serial port
	InvalidSerialPort
	// PermissionDenied the user doesn't have enough priviledges
	PermissionDenied
	// InvalidSpeed the requested speed is not valid or not supported
	InvalidSpeed
	// InvalidDataBits the number of data bits is not valid or not supported
	InvalidDataBits
	// ErrorEnumeratingPorts an error occurred while listing serial port
	ErrorEnumeratingPorts
)

// Error returns a string explaining the error occurred
func (e PortError) Error() string {
	switch e.code {
	case PortBusy:
		return "Serial port busy"
	case PortNotFound:
		return "Serial port not found"
	case InvalidSerialPort:
		return "Invalid serial port"
	case PermissionDenied:
		return "Permission denied"
	case InvalidSpeed:
		return "Invalid port speed"
	case InvalidDataBits:
		return "Invalid port data bits"
	case ErrorEnumeratingPorts:
		return "Could not enumerate serial ports"
	}
	return e.err
}

// Code returns an identifier for the kind of error occurred
func (e PortError) Code() PortErrorCode {
	return e.code
}