package hardware

import (
	"bufio"
	"context"
	_ "embed"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	goRuntime "runtime"
	"strconv"
	"strings"
	"sync"
	"time"

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

const (
	ftdiFinderExecutableName = "FTDI_finder.exe"
	ftdiSenderExecutableName = "FTDI_sender.exe"
)

// FTDIFinder represents how the protocol is defined
type FTDIFinder struct {
	findTicker  time.Ticker           // Peripherals find ticker
	peripherals map[string]Peripheral // The list of peripherals handled by this finder
	scanChannel chan struct{}         // The channel to trigger a scan event
	goWait      sync.WaitGroup        // Check goroutines execution
}

// 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),
		peripherals: make(map[string]Peripheral),
		scanChannel: make(chan struct{}),
	}
}

//go:embed third-party/ftdi/detectFTDI.exe
var finderExe []byte

//go:embed third-party/ftdi/dmxSender.exe
var senderExe []byte

// 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)
	}
	// Create the FTDI executables
	err := createExecutable(ftdiFinderExecutableName, finderExe)
	if err != nil {
		return err
	}
	createExecutable(ftdiSenderExecutableName, senderExe)
	if err != nil {
		return err
	}
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder initialized")
	return nil
}

// createExecutable creates and writes an executable to the temporary directory of the system
func createExecutable(fileName string, storedFile []byte) error {
	tempFile, err := os.Create(filepath.Join(os.TempDir(), fileName))
	if err != nil {
		log.Err(err).Str("file", "FTDIFinder").Str("fileName", fileName).Msg("unable to create an FTDI executable")
		return err
	}
	log.Trace().Str("file", "FTDIFinder").Str("filePath", tempFile.Name()).Msg("FTDI executable created")

	// Write the embedded executable to the temp file
	if _, err := tempFile.Write(storedFile); err != nil {
		log.Err(err).Str("file", "FTDIFinder").Str("fileName", fileName).Msg("unable to write the content to an FTDI executable")
		return err
	}
	tempFile.Close()
	log.Trace().Str("file", "FTDIPeripheral").Str("fileName", fileName).Msg("FTDI executable written")
	return nil
}

// Start starts the finder and search for peripherals
func (f *FTDIFinder) Start(ctx context.Context) error {
	f.goWait.Add(1)
	go func() {
		defer f.goWait.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() {
	f.scanChannel <- struct{}{}
}

// Stop stops the finder
func (f *FTDIFinder) Stop() error {
	log.Trace().Str("file", "FTDIFinder").Msg("stopping the FTDI finder...")
	// Wait for goroutines to stop
	f.goWait.Wait()
	// Stop the ticker
	f.findTicker.Stop()
	// Delete the FTDI executable files
	fileToDelete := filepath.Join(os.TempDir(), ftdiFinderExecutableName)
	err := os.Remove(fileToDelete)
	if err != nil {
		log.Warn().Str("file", "FTDIFinder").Str("fileName", fileToDelete).AnErr("error", err).Msg("unable to remove the executable file")
	}
	fileToDelete = filepath.Join(os.TempDir(), ftdiSenderExecutableName)
	err = os.Remove(fileToDelete)
	if err != nil {
		log.Warn().Str("file", "FTDIFinder").Str("fileName", fileToDelete).AnErr("error", err).Msg("unable to remove the executable file")
	}
	log.Trace().Str("file", "FTDIFinder").Msg("FTDI finder stopped")
	return nil
}

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

// GetPeripheral gets the peripheral that correspond to the specified ID
func (f *FTDIFinder) GetPeripheral(peripheralID string) (Peripheral, bool) {
	// Return the specified peripheral
	peripheral := f.peripherals[peripheralID]
	if peripheral == nil {
		log.Error().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("unable to get this peripheral from the FTDI finder")
		return nil, false
	}
	log.Debug().Str("file", "FTDIFinder").Str("peripheralID", peripheralID).Msg("peripheral found by the FTDI finder")
	return peripheral, true
}

// scanPeripherals scans the FTDI peripherals
func (f *FTDIFinder) scanPeripherals(ctx context.Context) error {
	detectionCtx, cancel := context.WithCancel(ctx)
	defer cancel()

	log.Trace().Str("file", "FTDIFinder").Msg("FTDI scan triggered")

	ftdiPeripherals := make(map[string]Peripheral)

	finder := exec.CommandContext(detectionCtx, filepath.Join(os.TempDir(), ftdiFinderExecutableName))
	log.Trace().Str("file", "FTDIFinder").Msg("has executed the FIND executable")

	stdout, err := finder.StdoutPipe()
	if err != nil {
		return fmt.Errorf("unable to create the stdout pipe: %s", err)
	}
	defer stdout.Close()

	stderr, err := finder.StderrPipe()
	if err != nil {
		return fmt.Errorf("unable to create the stderr pipe: %s", err)
	}
	defer stderr.Close()

	err = finder.Start()
	if err != nil {
		return fmt.Errorf("unable to find FTDI peripherals: %s", err)
	}

	scannerErr := bufio.NewScanner(stderr)
	for scannerErr.Scan() {
		return fmt.Errorf("unable to find FTDI peripherals: %s", scannerErr.Text())
	}

	scanner := bufio.NewScanner(stdout)
	for scanner.Scan() {
		peripheralString := scanner.Text()
		// The program output is like '0:1:2' where 0 is the location, 1 is the S/N and 2 is the name
		peripheralInfo := strings.Split(peripheralString, ":")

		log.Debug().Str("file", "FTDIFinder").Str("peripheralName", peripheralInfo[2]).Str("peripheralSN", peripheralInfo[1]).Msg("new FTDI peripheral detected")
		// Convert the location to an integer
		location, err := strconv.Atoi(peripheralInfo[0])
		if err != nil {
			log.Warn().Str("file", "FTDIFinder").Str("peripheralName", peripheralInfo[2]).Msg("no location provided for this FTDI peripheral")
			location = -1
		}
		// Add the peripheral to the temporary list
		peripheral, err := NewFTDIPeripheral(peripheralInfo[2], peripheralInfo[1], location)
		if err != nil {
			return fmt.Errorf("unable to create the FTDI peripheral: %v", err)
		}
		ftdiPeripherals[peripheralInfo[1]] = peripheral
		log.Trace().Str("file", "FTDIFinder").Str("peripheralName", peripheralInfo[2]).Msg("successfully added the FTDI peripheral to the finder")
	}
	// Compare with the current peripherals to detect arrivals/removals
	removedList, addedList := comparePeripherals(f.peripherals, ftdiPeripherals)
	// Emit the events
	emitPeripheralsEvents(ctx, removedList, PeripheralRemoval)
	log.Info().Str("file", "FTDIFinder").Msg("FTDI remove list emitted to the front")
	emitPeripheralsEvents(ctx, addedList, PeripheralArrival)
	log.Info().Str("file", "FTDIFinder").Msg("FTDI add list emitted to the front")
	// Store the new peripherals list
	f.peripherals = ftdiPeripherals
	return nil
}

// CreatePeripheral is not implemented here
func (f *FTDIFinder) CreatePeripheral(context.Context) (Peripheral, error) {
	return nil, nil
}

// DeletePeripheral is not implemented here
func (f *FTDIFinder) DeletePeripheral(serialNumber string) error {
	return nil
}