package i2c

import "github.com/hybridgroup/gobot"

var _ gobot.Driver = (*HMC6352Driver)(nil)

type HMC6352Driver struct {
	name       string
	connection I2c
}

// NewHMC6352Driver creates a new driver with specified name and i2c interface
func NewHMC6352Driver(a I2c, name string) *HMC6352Driver {
	return &HMC6352Driver{
		name:       name,
		connection: a,
	}
}

func (h *HMC6352Driver) Name() string                 { return h.name }
func (h *HMC6352Driver) Connection() gobot.Connection { return h.connection.(gobot.Connection) }

// Start initialized the hmc6352
func (h *HMC6352Driver) Start() (errs []error) {
	if err := h.connection.I2cStart(0x21); err != nil {
		return []error{err}
	}
	if err := h.connection.I2cWrite([]byte("A")); err != nil {
		return []error{err}
	}
	return
}

// Halt returns true if devices is halted successfully
func (h *HMC6352Driver) Halt() (errs []error) { return }

// Heading returns the current heading
func (h *HMC6352Driver) Heading() (heading uint16, err error) {
	if err = h.connection.I2cWrite([]byte("A")); err != nil {
		return
	}
	ret, err := h.connection.I2cRead(2)
	if err != nil {
		return
	}
	if len(ret) == 2 {
		heading = (uint16(ret[1]) + uint16(ret[0])*256) / 10
		return
	} else {
		err = ErrNotEnoughBytes
	}
	return
}