From 684881d13a6faf7b806534112b7bcc288066fea0 Mon Sep 17 00:00:00 2001
From: Iampete1 <iampete@hotmail.co.uk>
Date: Sat, 9 Nov 2024 12:08:01 +0000
Subject: [PATCH] Plane: add support `AVAILABLE_MODES` msg

---
 ArduPlane/GCS_Mavlink.cpp | 99 ++++++++++++++++++++++++++++++++++++++-
 ArduPlane/GCS_Mavlink.h   |  4 ++
 2 files changed, 102 insertions(+), 1 deletion(-)

diff --git a/ArduPlane/GCS_Mavlink.cpp b/ArduPlane/GCS_Mavlink.cpp
index b733f7b7bf..298b4e47a5 100644
--- a/ArduPlane/GCS_Mavlink.cpp
+++ b/ArduPlane/GCS_Mavlink.cpp
@@ -716,7 +716,8 @@ static const ap_message STREAM_EXTRA3_msgs[] = {
     MSG_VIBRATION,
 };
 static const ap_message STREAM_PARAMS_msgs[] = {
-    MSG_NEXT_PARAM
+    MSG_NEXT_PARAM,
+    MSG_AVAILABLE_MODES
 };
 static const ap_message STREAM_ADSB_msgs[] = {
     MSG_ADSB_VEHICLE,
@@ -1545,3 +1546,99 @@ MAV_LANDED_STATE GCS_MAVLINK_Plane::landed_state() const
     return MAV_LANDED_STATE_ON_GROUND;
 }
 
+// Send the mode with the given index (not mode number!) return the total number of modes
+// Index starts at 1
+uint8_t GCS_MAVLINK_Plane::send_available_mode(uint8_t index) const
+{
+    // Fixed wing modes
+    const Mode* fw_modes[] {
+        &plane.mode_manual,
+        &plane.mode_circle,
+        &plane.mode_stabilize,
+        &plane.mode_training,
+        &plane.mode_acro,
+        &plane.mode_fbwa,
+        &plane.mode_fbwb,
+        &plane.mode_cruise,
+        &plane.mode_autotune,
+        &plane.mode_auto,
+        &plane.mode_rtl,
+        &plane.mode_loiter,
+#if HAL_ADSB_ENABLED
+        &plane.mode_avoidADSB,
+#endif
+        &plane.mode_guided,
+        &plane.mode_initializing,
+        &plane.mode_takeoff,
+#if HAL_SOARING_ENABLED
+        &plane.mode_thermal,
+#endif
+    };
+
+    const uint8_t fw_mode_count = ARRAY_SIZE(fw_modes);
+
+    // Fixedwing modes are always present
+    uint8_t mode_count = fw_mode_count;
+
+#if HAL_QUADPLANE_ENABLED
+    // Quadplane modes
+    const Mode* q_modes[] {
+        &plane.mode_qstabilize,
+        &plane.mode_qhover,
+        &plane.mode_qloiter,
+        &plane.mode_qland,
+        &plane.mode_qrtl,
+        &plane.mode_qacro,
+        &plane.mode_loiter_qland,
+#if QAUTOTUNE_ENABLED
+        &plane.mode_qautotune,
+#endif
+    };
+
+    // Quadplane modes must be enabled
+    if (plane.quadplane.available()) {
+        mode_count += ARRAY_SIZE(q_modes);
+    }
+#endif // HAL_QUADPLANE_ENABLED
+
+
+    // Convert to zero indexed
+    const uint8_t index_zero = index - 1;
+    if (index_zero >= mode_count) {
+        // Mode does not exist!?
+        return mode_count;
+    }
+
+    // Ask the mode for its name and number
+    const char* name;
+    uint8_t mode_number;
+
+    if (index_zero < fw_mode_count) {
+        // A fixedwing mode
+        name = fw_modes[index_zero]->name();
+        mode_number = (uint8_t)fw_modes[index_zero]->mode_number();
+
+    } else {
+#if HAL_QUADPLANE_ENABLED
+        // A Quadplane mode
+        const uint8_t q_index = index_zero - fw_mode_count;
+        name = q_modes[q_index]->name();
+        mode_number = (uint8_t)q_modes[q_index]->mode_number();
+#else
+        // Should not endup here
+        return mode_count;
+#endif
+    }
+
+    mavlink_msg_available_modes_send(
+        chan,
+        mode_count,
+        index,
+        MAV_STANDARD_MODE::MAV_STANDARD_MODE_NON_STANDARD,
+        mode_number,
+        0, // MAV_MODE_PROPERTY bitmask
+        name
+    );
+
+    return mode_count;
+}
diff --git a/ArduPlane/GCS_Mavlink.h b/ArduPlane/GCS_Mavlink.h
index 9e03940882..2fa88274e1 100644
--- a/ArduPlane/GCS_Mavlink.h
+++ b/ArduPlane/GCS_Mavlink.h
@@ -50,6 +50,10 @@ protected:
     void handle_manual_control_axes(const mavlink_manual_control_t &packet, const uint32_t tnow) override;
     void handle_landing_target(const mavlink_landing_target_t &packet, uint32_t timestamp_ms) override;
 
+    // Send the mode with the given index (not mode number!) return the total number of modes
+    // Index starts at 1
+    uint8_t send_available_mode(uint8_t index) const override;
+
 private:
 
     void send_pid_info(const struct AP_PIDInfo *pid_info, const uint8_t axis, const float achieved);