From 77064852c46786f23433e2c5ac8c3ec0127d267d Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Thu, 13 Oct 2016 21:44:30 +1100
Subject: [PATCH] AP_Stats: AP_Stats flighttime

---
 libraries/AP_Stats/AP_Stats.cpp | 33 +++++++++++++++++++++++++++++++++
 libraries/AP_Stats/AP_Stats.h   | 13 +++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/libraries/AP_Stats/AP_Stats.cpp b/libraries/AP_Stats/AP_Stats.cpp
index ed22f693e7..cf0b298dc5 100644
--- a/libraries/AP_Stats/AP_Stats.cpp
+++ b/libraries/AP_Stats/AP_Stats.cpp
@@ -9,23 +9,56 @@ const AP_Param::GroupInfo AP_Stats::var_info[] = {
     // @User: Standard
     AP_GROUPINFO("_BOOTCNT",    0, AP_Stats, params.bootcount, 0),
 
+    // @Param: _FLTTIME
+    // @DisplayName: Total FlightTime
+    // @Description: Total FlightTime (seconds)
+    // @User: Standard
+    AP_GROUPINFO("_FLTTIME",    1, AP_Stats, params.flttime, 0),
+
     AP_GROUPEND
 };
 
 void AP_Stats::init()
 {
     params.bootcount.set_and_save(params.bootcount+1);
+
+    // initialise our variables from parameters:
+    flttime = params.flttime;
 }
 
 void AP_Stats::flush()
 {
+    params.flttime.set_and_save(flttime);
+}
+
+void AP_Stats::update_flighttime()
+{
+    if (_flying_ms) {
+        const uint32_t now = AP_HAL::millis();
+        const uint32_t delta = (now - _flying_ms)/1000;
+        flttime += delta;
+        _flying_ms += delta*1000;
+    }
 }
 
 void AP_Stats::update()
 {
     const uint32_t now_ms = AP_HAL::millis();
     if (now_ms -  last_flush_ms > flush_interval_ms) {
+        update_flighttime();
         flush();
         last_flush_ms = now_ms;
     }
 }
+
+void AP_Stats::set_flying(const bool is_flying)
+{
+    if (is_flying) {
+        if (!_flying_ms) {
+            _flying_ms = AP_HAL::millis();
+        }
+    } else {
+        update_flighttime();
+        _flying_ms = 0;
+    }
+}
diff --git a/libraries/AP_Stats/AP_Stats.h b/libraries/AP_Stats/AP_Stats.h
index d9459e6ddb..72f39f8de1 100644
--- a/libraries/AP_Stats/AP_Stats.h
+++ b/libraries/AP_Stats/AP_Stats.h
@@ -10,6 +10,11 @@ class AP_Stats
 {
 public:
 
+    // these variables are periodically written into the actual
+    // parameters.  If you add a variable here, make sure to update
+    // init() to set initial values from the parameters!
+    uint32_t flttime; // seconds in flight (or driving)
+
     void init();
 
     // copy state into underlying parameters:
@@ -19,14 +24,22 @@ public:
     // call at least 1Hz
     void update();
 
+    void set_flying(bool b);
+
     static const struct AP_Param::GroupInfo var_info[];
 
 private:
 
     struct {
         AP_Int16 bootcount;
+        AP_Int32 flttime;
     } params;
 
     uint64_t last_flush_ms; // in terms of system uptime
     const uint16_t flush_interval_ms = 30000;
+
+    uint64_t _flying_ms;
+
+    void update_flighttime();
+
 };