package hardware

import (
	"context"
	_ "embed"
	"errors"
	"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

	findTicker            *time.Ticker               // Peripherals find ticker
	foundPeripherals      map[string]PeripheralInfo  // The list of peripherals handled by this finder
	registeredPeripherals map[string]*FTDIPeripheral // The list of found peripherals
	scanChannel           chan struct{}              // The channel to trigger a scan event
}

// NewFTDIFinder creates a new FTDI finder
func NewFTDIFinder(findPeriod time.Duration) *FTDIFinder {
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder created")
	return &FTDIFinder{
		findTicker:            time.NewTicker(findPeriod),
		foundPeripherals:      make(map[string]PeripheralInfo),
		registeredPeripherals: make(map[string]*FTDIPeripheral),
		scanChannel:           make(chan struct{}),
	}
}

// RegisterPeripheral registers a new peripheral
func (f *FTDIFinder) RegisterPeripheral(ctx context.Context, peripheralData PeripheralInfo) (string, error) {
	// Create a new FTDI peripheral
	ftdiPeripheral, err := NewFTDIPeripheral(peripheralData)
	if err != nil {
		return "", fmt.Errorf("unable to create the FTDI peripheral: %v", err)
	}
	// Register it in the finder
	f.registeredPeripherals[peripheralData.SerialNumber] = ftdiPeripheral
	log.Trace().Any("periph", &ftdiPeripheral).Str("file", "FTDIFinder").Str("peripheralName", peripheralData.Name).Msg("FTDI peripheral has been created")

	// Peripheral created, connect it
	err = ftdiPeripheral.Connect(ctx)
	if err != nil {
		log.Err(err).Str("file", "FTDIFinder").Str("peripheralSN", peripheralData.SerialNumber).Msg("unable to connect the peripheral")
	}
	// Peripheral connected, activate it
	err = ftdiPeripheral.Activate(ctx)
	if err != nil {
		log.Err(err).Str("file", "FTDIFinder").Str("peripheralSN", peripheralData.SerialNumber).Msg("unable to activate the peripheral")
	}
	// Peripheral activated
	return peripheralData.SerialNumber, nil
}

// UnregisterPeripheral unregisters an existing peripheral
func (f *FTDIFinder) UnregisterPeripheral(ctx context.Context, peripheralID string) error {
	peripheral, registered := f.registeredPeripherals[peripheralID]
	if registered {
		// Deactivating peripheral
		err := peripheral.Deactivate(ctx)
		if err != nil {
			return err
		}
		// Disconnecting peripheral
		err = peripheral.Disconnect()
		if err != nil {
			return err
		}
	}
	delete(f.registeredPeripherals, peripheralID)
	return nil
}

// 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
}

// Start starts the finder and search for peripherals
func (f *FTDIFinder) Start(ctx context.Context) error {
	f.wg.Add(1)
	go func() {
		defer f.wg.Done()
		for {
			select {
			case <-ctx.Done():
				return
			case <-f.findTicker.C:
				// Scan the peripherals
				err := f.scanPeripherals(ctx)
				if err != nil {
					log.Err(err).Str("file", "FTDIFinder").Msg("unable to scan FTDI peripherals")
				}
			case <-f.scanChannel:
				// Scan the peripherals
				err := f.scanPeripherals(ctx)
				if err != nil {
					log.Err(err).Str("file", "FTDIFinder").Msg("unable to scan FTDI peripherals")
				}
			}
		}
	}()
	return nil
}

// ForceScan explicily asks for scanning peripherals
func (f *FTDIFinder) ForceScan() {
	select {
	case f.scanChannel <- struct{}{}:
	default:
		// Ignore if the channel is full or if it is closed
	}
}

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

// GetPeripheralSettings gets the peripheral settings
func (f *FTDIFinder) GetPeripheralSettings(peripheralID string) (map[string]interface{}, error) {
	// Return the specified peripheral
	peripheral, found := f.registeredPeripherals[peripheralID]
	if !found {
		log.Error().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("unable to get this peripheral from the FTDI finder")
		return nil, fmt.Errorf("unable to found the peripheral")
	}
	log.Debug().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("peripheral found by the FTDI finder")
	return peripheral.GetSettings(), nil
}

// SetPeripheralSettings sets the peripheral settings
func (f *FTDIFinder) SetPeripheralSettings(peripheralID string, settings map[string]interface{}) error {
	// Return the specified peripheral
	peripheral, found := f.registeredPeripherals[peripheralID]
	if !found {
		log.Error().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("unable to get this peripheral from the FTDI finder")
		return fmt.Errorf("unable to found the peripheral")
	}
	log.Debug().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("peripheral found by the FTDI finder")
	return peripheral.SetSettings(settings)
}

// 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))

	temporaryPeripherals := 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

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

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

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

	// Emit the peripherals changes to the front
	emitPeripheralsChanges(ctx, f.foundPeripherals, temporaryPeripherals)
	// Store the new peripherals list
	f.foundPeripherals = temporaryPeripherals
	return nil
}

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

	// Stop the ticker
	f.findTicker.Stop()

	// Close the channel
	close(f.scanChannel)

	// Wait for all the peripherals to close
	log.Trace().Str("file", "FTDIFinder").Msg("closing all FTDI peripherals")
	var errs []error
	for registeredPeripheralSN, registeredPeripheral := range f.registeredPeripherals {
		err := registeredPeripheral.WaitStop()
		if err != nil {
			errs = append(errs, fmt.Errorf("%s: %w", registeredPeripheralSN, err))
		}
	}

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

	// Returning errors
	if len(errs) > 0 {
		return errors.Join(errs...)
	}
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder stopped")
	return nil
}