add commands to control the radio terminal

com/com.go

@@ -211,6 +211,10 @@ func (c *COM) ClearSyntaxErrors(ctx context.Context) error {
 	return nil
 }
 
+func (c *COM) Request(ctx context.Context, request string) ([]string, error) {
+	return c.AT(ctx, request)
+}
+
 func (c *COM) AT(ctx context.Context, request string) ([]string, error) {
 	cmd := command{
 		request:   request,

ctrl/command.go

@@ -0,0 +1,68 @@
+package ctrl
+
+import (
+	"context"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/ftl/tetra-pei/tetra"
+)
+
+// SetOperatingMode according to [PEI] 6.14.7.2
+func SetOperatingMode(mode AIMode) string {
+	return fmt.Sprintf("AT+CTOM=%d", mode)
+}
+
+var requestOperatingModeResponse = regexp.MustCompile(`^\+CTOM: (\d+)$`)
+
+// RequestOperatingMode reads the current operating mode according to [PEI] 6.14.7.4
+func RequestOperatingMode(ctx context.Context, requester tetra.Requester) (AIMode, error) {
+	responses, err := requester.Request(ctx, "AT+CTOM?")
+	if err != nil {
+		return 0, err
+	}
+	if len(responses) < 1 {
+		return 0, fmt.Errorf("no response received")
+	}
+	response := strings.ToUpper(strings.TrimSpace(responses[0]))
+	parts := requestOperatingModeResponse.FindStringSubmatch(response)
+
+	if len(parts) != 2 {
+		return 0, fmt.Errorf("unexpected response: %s", responses[0])
+	}
+
+	result, err := strconv.Atoi(parts[1])
+	if err != nil {
+		return 0, err
+	}
+
+	return AIMode(result), nil
+}
+
+// SetTalkgroup according to [PEI] 6.15.6.2
+func SetTalkgroup(gtsi string) string {
+	return fmt.Sprintf("AT+CTGS=1,%s", gtsi)
+}
+
+var requestTalkgroupResponse = regexp.MustCompile(`^\+CTGS: .*,(\d+)$`)
+
+// RequestTalkgroup reads the current talkgroup according to [PEI] 6.15.6.4
+func RequestTalkgroup(ctx context.Context, requester tetra.Requester) (string, error) {
+	responses, err := requester.Request(ctx, "AT+CTGS?")
+	if err != nil {
+		return "", err
+	}
+	if len(responses) < 1 {
+		return "", fmt.Errorf("no response received")
+	}
+	response := strings.ToUpper(strings.TrimSpace(responses[0]))
+	parts := requestTalkgroupResponse.FindStringSubmatch(response)
+
+	if len(parts) != 2 {
+		return "", fmt.Errorf("unexpected response: %s", responses[0])
+	}
+
+	return parts[1], nil
+}

ctrl/ctrl.go

@@ -0,0 +1,40 @@
+package ctrl
+
+import (
+	"fmt"
+	"strings"
+)
+
+// AIModeByName returns the AIMode with the given name
+func AIModeByName(name string) (AIMode, error) {
+	sanitized := strings.ToUpper(strings.TrimSpace(name))
+	result, ok := AIModesByName[sanitized]
+	if !ok {
+		return 0, fmt.Errorf("invalid operating mode %s", name)
+	}
+	return result, nil
+}
+
+// AIMode represents an operating mode according to [PEI] 6.17.4
+type AIMode byte
+
+func (m AIMode) String() string {
+	for k, v := range AIModesByName {
+		if v == m {
+			return k
+		}
+	}
+	return "UNKNOWN"
+}
+
+// All supported operating modes
+const (
+	TMO AIMode = iota
+	DMO
+)
+
+// AIModesByName maps all supported operating modes by their string representation
+var AIModesByName = map[string]AIMode{
+	"TMO": TMO,
+	"DMO": DMO,
+}

sds/command.go

@@ -20,16 +20,6 @@ func (f EncoderFunc) Encode() ([]byte, int) {
 	return f()
 }
 
-type Requester interface {
-	Request(context.Context, string) ([]string, error)
-}
-
-type RequesterFunc func(context.Context, string) ([]string, error)
-
-func (f RequesterFunc) Request(ctx context.Context, request string) ([]string, error) {
-	return f(ctx, request)
-}
-
 const (
 	// CRLF line ending for AT commands
 	CRLF = "\x0d\x0a"
@@ -53,7 +43,7 @@ func SendMessage(destination tetra.Identity, message Encoder) string {
 var sendMessageDescription = regexp.MustCompile(`^\+CMGS: .+\(\d*-(\d*)\)$`)
 
 // RequestMaxMessagePDUBits uses the given RequesterFunc to find out how many bits a message PDU may have (see [PEI] 6.13.2).
-func RequestMaxMessagePDUBits(ctx context.Context, requester Requester) (int, error) {
+func RequestMaxMessagePDUBits(ctx context.Context, requester tetra.Requester) (int, error) {
 	responses, err := requester.Request(ctx, "AT+CMGS=?")
 	if err != nil {
 		return 0, err

tetra/tetra.go

@@ -1,11 +1,25 @@
 package tetra
 
 import (
+	"context"
 	"encoding/hex"
 	"regexp"
 	"strings"
 )
 
+// Requester is used for commands that return more than an error code.
+type Requester interface {
+	Request(context.Context, string) ([]string, error)
+}
+
+// RequesterFunc wraps a match function into the Requester interface.
+type RequesterFunc func(context.Context, string) ([]string, error)
+
+// Request calls the wrapped RequesterFunc.
+func (f RequesterFunc) Request(ctx context.Context, request string) ([]string, error) {
+	return f(ctx, request)
+}
+
 // Identity represents an identity of a party in a TETRA communication
 type Identity string