package hardware

import (
	"bufio"
	"context"
	_ "embed"
	"fmt"
	"io"

	"github.com/rs/zerolog/log"

	"os"
	"os/exec"
)

const (
	activateCommandString   = 0x01
	deactivateCommandString = 0x02
	setCommandString        = 0x03
)

// FTDIPeripheral contains the data of an FTDI peripheral
type FTDIPeripheral struct {
	name            string         // The name of the peripheral
	serialNumber    string         // The S/N of the FTDI peripheral
	location        int            // The location of the peripheral
	universesNumber int            // The number of DMX universes handled by this peripheral
	programName     string         // The temp file name of the executable
	dmxSender       *exec.Cmd      // The command to pilot the DMX sender program
	stdin           io.WriteCloser // For writing in the DMX sender
	stdout          io.ReadCloser  // For reading from the DMX sender
	stderr          io.ReadCloser  // For reading the errors
	disconnectChan  chan struct{}  // Channel to cancel the connection
	errorsChan      chan error     // Channel to get the errors
}

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

// NewFTDIPeripheral creates a new FTDI peripheral
func NewFTDIPeripheral(name string, serialNumber string, location int) (*FTDIPeripheral, error) {
	log.Info().Str("file", "FTDIPeripheral").Str("name", name).Str("s/n", serialNumber).Int("location", location).Msg("FTDI peripheral created")
	// Create a temporary file
	tempFile, err := os.Create(fmt.Sprintf("dmxSender-%s.exe", serialNumber))
	if err != nil {
		return nil, err
	}
	log.Trace().Str("file", "FTDIPeripheral").Str("s/n", serialNumber).Msg("FTDI sender temp created")

	// Write the embedded executable to the temp file
	if _, err := tempFile.Write(dmxSender); err != nil {
		return nil, err
	}
	log.Trace().Str("file", "FTDIPeripheral").Str("s/n", serialNumber).Msg("FTDI sender written")

	tempFile.Close()

	return &FTDIPeripheral{
		name:            name,
		dmxSender:       nil,
		programName:     tempFile.Name(),
		serialNumber:    serialNumber,
		location:        location,
		universesNumber: 1,
		disconnectChan:  make(chan struct{}),
		errorsChan:      make(chan error, 1),
	}, nil
}

// Connect connects the FTDI peripheral
func (p *FTDIPeripheral) Connect(ctx context.Context) error {
	// Connect if no connection is already running
	log.Trace().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("connecting FTDI peripheral...")

	// Check if the connection has already been established
	if p.dmxSender != nil {
		log.Warn().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxSender already initialized")
		return nil
	}

	// Initialize the exec.Command for running the process
	p.dmxSender = exec.Command(p.programName, fmt.Sprintf("%d", p.location))
	log.Trace().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxSender instance created")

	// Create the pipes for stdin, stdout, and stderr asynchronously without blocking
	var err error
	if p.stdout, err = p.dmxSender.StdoutPipe(); err != nil {
		log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("unable to create stdout pipe")
		return fmt.Errorf("unable to create stdout pipe: %v", err)
	}
	if p.stdin, err = p.dmxSender.StdinPipe(); err != nil {
		log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("unable to create stdin pipe")
		return fmt.Errorf("unable to create stdin pipe: %v", err)
	}
	if p.stderr, err = p.dmxSender.StderrPipe(); err != nil {
		log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("unable to create stderr pipe")
		return fmt.Errorf("unable to create stderr pipe: %v", err)
	}

	// Launch a goroutine to read stderr asynchronously
	go func() {
		scanner := bufio.NewScanner(p.stderr)
		for scanner.Scan() {
			// Process each line read from stderr
			log.Err(fmt.Errorf(scanner.Text())).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("error detected in dmx sender")
		}
		if err := scanner.Err(); err != nil {
			log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("error reading from stderr")
		}
	}()

	// Launch the command asynchronously in another goroutine
	go func() {
		// Run the command, respecting the context cancellation
		err := p.dmxSender.Run()
		select {
		case <-ctx.Done():
			// If the context is canceled, handle it gracefully
			log.Warn().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxSender was canceled by context")
			return
		default:
			// Handle command exit normally
			if err != nil {
				log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("error while execution of dmx sender")
				if exitError, ok := err.(*exec.ExitError); ok {
					log.Warn().Str("file", "FTDIPeripheral").Int("exitCode", exitError.ExitCode()).Str("s/n", p.serialNumber).Msg("dmx sender exited with code")
				}
			} else {
				log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmx sender exited successfully")
			}
		}
	}()

	log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxSender process started successfully")
	return nil
}

// Disconnect disconnects the FTDI peripheral
func (p *FTDIPeripheral) Disconnect(ctx context.Context) error {
	log.Trace().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("disconnecting FTDI peripheral...")
	if p.dmxSender != nil {
		log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxsender is defined for this FTDI")
		_, err := io.WriteString(p.stdin, string([]byte{0x04, 0x00, 0x00, 0x00}))
		if err != nil {
			log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("unable to write command to sender")
			return fmt.Errorf("unable to disconnect: %v", err)
		}
		p.stdin.Close()
		p.stdout.Close()
		p.dmxSender = nil
		err = os.Remove(p.programName)
		if err != nil {
			log.Warn().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Str("senderPath", p.programName).Msg("unable to delete the dmx sender temporary file")
			return fmt.Errorf("unable to delete the temporary file: %v", err)
		}
		return nil
	}
	log.Warn().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("error while disconnecting: not connected")
	return fmt.Errorf("unable to disconnect: not connected")
}

// Activate activates the FTDI peripheral
func (p *FTDIPeripheral) Activate(ctx context.Context) error {
	if p.dmxSender != nil {
		log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxsender is defined for this FTDI")
		_, err := io.WriteString(p.stdin, string([]byte{0x01, 0x00, 0x00, 0x00}))
		if err != nil {
			log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("unable to write command to sender")
			return fmt.Errorf("unable to activate: %v", err)
		}
		return nil
	}
	log.Warn().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("error while activating: not connected")
	return fmt.Errorf("unable to activate: not connected")
}

// Deactivate deactivates the FTDI peripheral
func (p *FTDIPeripheral) Deactivate(ctx context.Context) error {
	if p.dmxSender != nil {
		log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxsender is defined for this FTDI")
		_, err := io.WriteString(p.stdin, string([]byte{0x02, 0x00, 0x00, 0x00}))
		if err != nil {
			log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("unable to write command to sender")
			return fmt.Errorf("unable to deactivate: %v", err)
		}
		return nil
	}
	log.Warn().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("error while deactivating: not connected")
	return fmt.Errorf("unable to deactivate: not connected")
}

// SetDeviceProperty sends a command to the specified device
func (p *FTDIPeripheral) SetDeviceProperty(ctx context.Context, uint32, channelNumber uint32, channelValue byte) error {
	if p.dmxSender != nil {
		log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("dmxsender is defined for this FTDI")
		commandString := []byte{0x03, 0x01, 0x00, 0xff, 0x03, 0x02, 0x00, channelValue}
		_, err := io.WriteString(p.stdin, string(commandString))
		if err != nil {
			log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("unable to write command to sender")
			return fmt.Errorf("unable to set device property: %v", err)
		}
		return nil
	}
	log.Warn().Str("file", "FTDIPeripheral").Str("s/n", p.serialNumber).Msg("error while setting device property: not connected")
	return fmt.Errorf("unable to set device property: not connected")
}

// GetInfo gets all the peripheral information
func (p *FTDIPeripheral) GetInfo() PeripheralInfo {
	return PeripheralInfo{
		Name:         p.name,
		SerialNumber: p.serialNumber,
		ProtocolName: "FTDI",
	}
}