Added draft GPS checks though NMEA reports.

api/modem/gps/check.go

@@ -0,0 +1,51 @@
+package gps
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+func (g *gps) CheckStatus() error {
+	// Provides more information about signal and possible problems using NMEA reports
+
+	// Collect reports
+	reports, err := g.collectNmeaReports(gpgsv | gpgsa) // Now minimum
+	if err != nil {
+		return fmt.Errorf("collect nmea reports: %w", err)
+	}
+
+	// Annalise
+	// Now simpliest variant
+	// Checks if there is any satelites
+	sc := 0 // Satelites' counter
+	// asc := 0 // Active satelites' counter
+checkLoop:
+	for _, s := range reports {
+		g.logger.Println("NMEA check:", s)
+		values := strings.Split(s, ",")
+		if len(values) < 1 || len(values[0]) != 6 || values[0][0] != '$' {
+			return fmt.Errorf("nmea invalid sentence: %s", s)
+		}
+		switch values[0][3:] { // Switch by content
+		case "gsv":
+			if len(values) < 17 {
+				g.logger.Println("GSV too small values")
+				continue checkLoop
+			}
+			c, err := strconv.Atoi(values[4])
+			if err != nil {
+				g.logger.Println("GSV too small values")
+				continue checkLoop
+			}
+			sc += c
+		}
+	}
+
+	g.logger.Println("FOUND:", sc, "SATELITES")
+	if sc == 0 {
+		return fmt.Errorf("no satelites found")
+	}
+
+	return nil
+}

api/modem/gps/gps.go

@@ -63,11 +63,11 @@ func (g *gps) switchGpsMode(on bool) error {
 	}
 
 	// Reset input
-	if err := g.port.GetSerialPort().ResetInputBuffer(); err != nil {
+	if err := g.port.SerialPort().ResetInputBuffer(); err != nil {
 		return fmt.Errorf("reset input buffer: %w", err)
 	}
 	// Reset output
-	if err := g.port.GetSerialPort().ResetOutputBuffer(); err != nil {
+	if err := g.port.SerialPort().ResetOutputBuffer(); err != nil {
 		return fmt.Errorf("reset output buffer: %w", err)
 	}
 
@@ -99,10 +99,6 @@ func (g *gps) GetData() Data {
 	return g.data
 }
 
-func (g *gps) CheckStatus() error {
-	return fmt.Errorf("not impemented yet")
-}
-
 func (g *gps) Close() error {
 	return nil
 }

api/modem/gps/nmea.go

@@ -0,0 +1,115 @@
+package gps
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+type nmeaFlags int
+
+const (
+	gga     nmeaFlags = 1 << iota // global positioning systemfix data
+	rmc                           // recommended minimumspecific	GPS/TRANSIT data
+	gpgsv                         // GPS satellites in view
+	gpgsa                         // GPS DOP and active satellites
+	vtg                           // track made good and ground speed
+	xfi                           // Global Positioning SystemExtended FixData.)Bit 6 – GLGSV (GLONASS satellites in view GLONASSfixesonly
+	glgsa                         // 1. GPS/2. Glonass/3. GALILE DOPandActiveSatellites.
+	gns                           // fix data for GNSS receivers; output for GPS, GLONASS, GALILEO
+	_                             // Reserved
+	gagsv                         // GALILEO satellites in view
+	_                             // Reserved
+	_                             // Reserved
+	_                             // Reserved
+	_                             // Reserved
+	_                             // Reserved
+	bdpqgsa                       // BEIDOU/QZSS DOP and activesatellites
+	bdpqgsv                       // BEIDOUQZSS satellites in view
+
+	nmeaFlagsMask = (1 << 18) - 1
+
+	collectTimeout = 2 * time.Second
+)
+
+// Go... otherwise will throw warning
+var _ = gga | rmc | gpgsv | gpgsa | vtg | xfi | glgsa | gns | gagsv | bdpqgsa | bdpqgsv
+
+func (g *gps) rawCollect(flags nmeaFlags) (string, error) {
+	// Need to omplement low level write/read here because collect must be atomic operation
+	// If other command is executed(write/read) it will read a part of nmea report and cause an error
+	g.port.Mutex().Lock()
+	s := g.port.SerialPort()
+	defer func() {
+		s.ResetInputBuffer()
+		s.ResetOutputBuffer()
+		g.port.Mutex().Unlock()
+	}()
+
+	// Send AT+CGPSINFOCFG=255, flags
+	flags &= nmeaFlagsMask
+	if _, err := s.Write([]byte("AT+CGPSINFOCFG=255," + string(flags) + "\r\n")); err != nil {
+		return "", fmt.Errorf("serial port write 1: %w", err)
+	}
+	// Do I need to read answer
+
+	// Wait
+	time.Sleep(collectTimeout)
+
+	// Send AT+CGPSINFOCFG=0, flags
+	if _, err := s.Write([]byte("AT+CGPSINFOCFG=255," + string(flags) + "\r\n")); err != nil {
+		return "", fmt.Errorf("serial port write 2: %w", err)
+	}
+
+	// Read
+	outBuf := make([]byte, 0)
+	buf := make([]byte, 128)
+
+readLoop:
+	for {
+		n, err := s.Read(buf)
+		if err != nil {
+			return string(outBuf), fmt.Errorf("serial port read: %w", err)
+		}
+		if n == 0 {
+			break readLoop
+		}
+		outBuf = append(outBuf, buf[:n]...)
+	}
+
+	return string(outBuf), nil
+}
+
+func (g *gps) collectNmeaReports(flags nmeaFlags) ([]string, error) {
+	// Raw collect
+	resp, err := g.rawCollect(flags)
+	if err != nil {
+		return nil, fmt.Errorf("raw collect: %w", err)
+	}
+
+	// DEBUG
+	g.logger.Println("NMEA raw collect:", resp)
+
+	// Right responce struct:
+	// \r\n
+	// OK
+	// \r\n
+	// (NMEA sentence)...
+	// \r\n
+	// OK
+	// \r\n
+	strs := strings.Split(strings.Replace(resp, "\r", "", -1), "\n")
+
+	// Check
+	// Now wait for:
+	// OK
+	// (NMEA sentence)...
+	// OK
+	if len(strs) < 2 {
+		return nil, fmt.Errorf("responce too few rows: %d", len(strs))
+	}
+	if !(strs[0] == "OK" && strs[len(strs)-1] == "OK") {
+		return nil, fmt.Errorf("not OK responce: [%  s]", strs)
+	}
+	return strs[1 : len(strs)-1], nil
+}