sim-modem/api/modem/gps/check.go

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(nmeaFlagsAll) // 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 {
		// Check for NMEA format
		if len(s) < 1 || s[0] != '$' {
			continue checkLoop
		}

		g.logger.Println("NMEA check:", s)
		values := strings.Split(s, ",")
		if len(values[0]) != 6 {
			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
}