package gpio

import "github.com/hybridgroup/gobot"

var _ gobot.Driver = (*RelayDriver)(nil)

// RelayDriver represents a digital relay
type RelayDriver struct {
	pin        string
	name       string
	connection DigitalWriter
	high       bool
	gobot.Commander
}

// NewRelayDriver return a new RelayDriver given a DigitalWriter, name and pin.
//
// Adds the following API Commands:
//	"Toggle" - See RelayDriver.Toggle
//	"On" - See RelayDriver.On
//	"Off" - See RelayDriver.Off
func NewRelayDriver(a DigitalWriter, name string, pin string) *RelayDriver {
	l := &RelayDriver{
		name:       name,
		pin:        pin,
		connection: a,
		high:       false,
		Commander:  gobot.NewCommander(),
	}

	l.AddCommand("Toggle", func(params map[string]interface{}) interface{} {
		return l.Toggle()
	})

	l.AddCommand("On", func(params map[string]interface{}) interface{} {
		return l.On()
	})

	l.AddCommand("Off", func(params map[string]interface{}) interface{} {
		return l.Off()
	})

	return l
}

// Start implements the Driver interface
func (l *RelayDriver) Start() (errs []error) { return }

// Halt implements the Driver interface
func (l *RelayDriver) Halt() (errs []error) { return }

// Name returns the RelayDrivers name
func (l *RelayDriver) Name() string { return l.name }

// Pin returns the RelayDrivers name
func (l *RelayDriver) Pin() string { return l.pin }

// Connection returns the RelayDrivers Connection
func (l *RelayDriver) Connection() gobot.Connection {
	return l.connection.(gobot.Connection)
}

// State return true if the relay is On and false if the relay is Off
func (l *RelayDriver) State() bool {
	return l.high
}

// On sets the relay to a high state.
func (l *RelayDriver) On() (err error) {
	if err = l.connection.DigitalWrite(l.Pin(), 1); err != nil {
		return
	}
	l.high = true
	return
}

// Off sets the relay to a low state.
func (l *RelayDriver) Off() (err error) {
	if err = l.connection.DigitalWrite(l.Pin(), 0); err != nil {
		return
	}
	l.high = false
	return
}

// Toggle sets the relay to the opposite of it's current state
func (l *RelayDriver) Toggle() (err error) {
	if l.State() {
		err = l.Off()
	} else {
		err = l.On()
	}
	return
}