package shared

import (
	"fmt"
	"io"
	"time"

	log "github.com/sirupsen/logrus"
)

// receive at maximum the requested number of bytes from serial port and stop after the given timeout
func ReceiveBytes(port io.Reader, count int, timeout time.Duration) ([]byte, error) {
	readCh := make(chan []byte, 1)
	errCh := make(chan error, 1)
	go func() {
		sumRead := 0
		for {
			data := make([]byte, count)
			if readBytes, err := port.Read(data); err != nil {
				errCh <- err
			} else if readBytes > 0 {
				log.Tracef("%d bytes read", readBytes)
				sumRead += readBytes
				readCh <- data[0:readBytes]
			} else {
				readCh <- make([]byte, 0)
			}
			if sumRead >= count {
				break
			}
		}
	}()
	select {
	case <-time.After(timeout):
		return nil, fmt.Errorf("timeout passed %v", timeout)
	case err := <-errCh:
		return nil, err
	case data := <-readCh:
		return data, nil
	}
}

func SendBytes(port io.Writer, data []byte) error {
	if bytesWritten, err := port.Write(data); err != nil {
		return err
	} else {
		log.Tracef("wrote %d bytes", bytesWritten)
	}
	return nil
}