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 {
	info           PeripheralInfo         // The peripheral basic data
	programName    string                 // The temp file name of the executable
	settings       map[string]interface{} // The settings of the peripheral
	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
}

// NewFTDIPeripheral creates a new FTDI peripheral
func NewFTDIPeripheral(info PeripheralInfo) (*FTDIPeripheral, error) {
	log.Info().Str("file", "FTDIPeripheral").Str("name", info.Name).Str("s/n", info.SerialNumber).Msg("FTDI peripheral created")
	settings := make(map[string]interface{})
	return &FTDIPeripheral{
		info:           info,
		dmxSender:      nil,
		settings:       settings,
		disconnectChan: make(chan struct{}),
		errorsChan:     make(chan error, 1),
	}, nil
}

// Connect connects the FTDI peripheral
func (p *FTDIPeripheral) Connect(ctx context.Context, location int) error {
	// Connect if no connection is already running
	log.Trace().Str("file", "FTDIPeripheral").Str("s/n", p.info.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.info.SerialNumber).Msg("dmxSender already initialized")
		return nil
	}

	// Initialize the exec.Command for running the process
	p.dmxSender = exec.Command(p.programName, fmt.Sprintf("%d", location))
	log.Trace().Str("file", "FTDIPeripheral").Str("s/n", p.info.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.info.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.info.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.info.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.info.SerialNumber).Msg("error detected in dmx sender")
		}
		if err := scanner.Err(); err != nil {
			log.Err(err).Str("file", "FTDIPeripheral").Str("s/n", p.info.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.info.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.info.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.info.SerialNumber).Msg("dmx sender exited with code")
				}
			} else {
				log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.info.SerialNumber).Msg("dmx sender exited successfully")
			}
		}
	}()

	log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.info.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.info.SerialNumber).Msg("disconnecting FTDI peripheral...")
	if p.dmxSender != nil {
		log.Debug().Str("file", "FTDIPeripheral").Str("s/n", p.info.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.info.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.info.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.info.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.info.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.info.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.info.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.info.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.info.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.info.SerialNumber).Msg("error while deactivating: not connected")
	return fmt.Errorf("unable to deactivate: not connected")
}

// SetSettings sets a specific setting for this peripheral
func (p *FTDIPeripheral) SetSettings(settings map[string]interface{}) error {
	p.settings = settings
	return nil
}

// 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.info.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.info.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.info.SerialNumber).Msg("error while setting device property: not connected")
	return fmt.Errorf("unable to set device property: not connected")
}

// GetSettings gets the peripheral settings
func (p *FTDIPeripheral) GetSettings() map[string]interface{} {
	return p.settings
}

// GetInfo gets all the peripheral information
func (p *FTDIPeripheral) GetInfo() PeripheralInfo {
	return p.info
}