dmxconnect/hardware/FTDIFinder.go

package hardware

import (
	"context"
	"fmt"
	goRuntime "runtime"
	"sync"
	"time"
	"unsafe"

	"github.com/rs/zerolog/log"
)

/*
#include <stdlib.h>
#cgo LDFLAGS: -L${SRCDIR}/../build/bin -ldetectFTDI
#include "cpp/include/detectFTDIBridge.h"
*/
import "C"

// FTDIFinder manages all the FTDI peripherals
type FTDIFinder struct {
	wg sync.WaitGroup
	mu sync.Mutex

	detected map[string]*FTDIPeripheral // Detected peripherals

	scanEvery time.Duration // Scans peripherals periodically

	onArrival func(context.Context, Peripheral) // When a peripheral arrives
	onRemoval func(context.Context, Peripheral) // When a peripheral goes away
}

// NewFTDIFinder creates a new FTDI finder
func NewFTDIFinder(scanEvery time.Duration) *FTDIFinder {
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder created")
	return &FTDIFinder{
		scanEvery: scanEvery,
		detected:  make(map[string]*FTDIPeripheral),
	}
}

// OnArrival is the callback function when a new peripheral arrives
func (f *FTDIFinder) OnArrival(cb func(context.Context, Peripheral)) {
	f.onArrival = cb
}

// OnRemoval i the callback when a peripheral goes away
func (f *FTDIFinder) OnRemoval(cb func(context.Context, Peripheral)) {
	f.onRemoval = cb
}

// Initialize initializes the FTDI finder
func (f *FTDIFinder) Initialize() error {
	// Check platform
	if goRuntime.GOOS != "windows" {
		log.Error().Str("file", "FTDIFinder").Str("platform", goRuntime.GOOS).Msg("FTDI finder not compatible with your platform")
		return fmt.Errorf("the FTDI finder is not compatible with your platform yet (%s)", goRuntime.GOOS)
	}
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder initialized")
	return nil
}

// Create creates a new peripheral, based on the peripheral information (manually created)
func (f *FTDIFinder) Create(ctx context.Context, peripheralInfo PeripheralInfo) (string, error) {
	return "", nil
}

// Remove removes an existing peripheral (manually created)
func (f *FTDIFinder) Remove(ctx context.Context, peripheral Peripheral) error {
	return nil
}

// Start starts the finder and search for peripherals
func (f *FTDIFinder) Start(ctx context.Context) error {
	f.wg.Add(1)
	go func() {
		ticker := time.NewTicker(f.scanEvery)
		defer ticker.Stop()
		defer f.wg.Done()

		for {
			select {
			case <-ctx.Done():
				return
			case <-ticker.C:
				// Scan the peripherals
				err := f.scanPeripherals(ctx)
				if err != nil {
					log.Err(err).Str("file", "FTDIFinder").Msg("unable to scan FTDI peripherals")
				}
			}
		}
	}()
	return nil
}

// GetName returns the name of the driver
func (f *FTDIFinder) GetName() string {
	return "FTDI"
}

// scanPeripherals scans the FTDI peripherals
func (f *FTDIFinder) scanPeripherals(ctx context.Context) error {
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI scan triggered")

	count := int(C.get_peripherals_number())

	log.Info().Int("number", count).Msg("number of FTDI devices connected")

	// Allocating C array
	size := C.size_t(count) * C.size_t(unsafe.Sizeof(C.FTDIPeripheralC{}))
	devicesPtr := C.malloc(size)
	defer C.free(devicesPtr)

	devices := (*[1 << 20]C.FTDIPeripheralC)(devicesPtr)[:count:count]

	C.get_ftdi_devices((*C.FTDIPeripheralC)(devicesPtr), C.int(count))

	currentMap := make(map[string]PeripheralInfo)

	for i := 0; i < count; i++ {
		d := devices[i]

		sn := C.GoString(d.serialNumber)
		desc := C.GoString(d.description)
		// isOpen := d.isOpen != 0

		currentMap[sn] = PeripheralInfo{
			SerialNumber: sn,
			Name:         desc,
			// IsOpen:       isOpen,
			ProtocolName: "FTDI",
		}

		// Free C memory
		C.free_ftdi_device(&d)
	}

	log.Info().Any("peripherals", currentMap).Msg("available FTDI peripherals")

	// Detect arrivals
	for sn, peripheralData := range currentMap {
		// If the scanned peripheral isn't in the detected list, create it
		if _, known := f.detected[sn]; !known {

			peripheral := NewFTDIPeripheral(peripheralData)

			if f.onArrival != nil {
				f.onArrival(ctx, peripheral)
			}
		}
	}

	// Detect removals
	for detectedSN, detectedPeripheral := range f.detected {
		if _, still := currentMap[detectedSN]; !still {

			// Delete it from the detected list
			delete(f.detected, detectedSN)

			// Execute the removal callback
			if f.onRemoval != nil {
				f.onRemoval(ctx, detectedPeripheral)
			}
		}
	}
	return nil
}

// WaitStop stops the finder
func (f *FTDIFinder) WaitStop() error {
	log.Trace().Str("file", "FTDIFinder").Msg("stopping the FTDI finder...")

	// Wait for goroutines to stop
	f.wg.Wait()

	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder stopped")
	return nil
}