Add gas consumption statistic for selected dives

We already did a list of gases and volume consumed for the selected dive
on the Dive Info tab, but did not provide that same data on the Stats tab
for all the selected dives.

I arbitrary limited this to eight gases (as the list can get quite long
when you select a lot of dives). The gases are sorted by volume consumed.

Fixes #535

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

4 files changed, 81 insertions, 14 deletions

diff --git a/helpers.h b/helpers.h
index 445e9135c..392dcb5ac 100644
--- a/helpers.h
+++ b/helpers.h
@@ -33,6 +33,7 @@ QString get_dive_date_string(timestamp_t when);
 QString get_short_dive_date_string(timestamp_t when);
 QString get_trip_date_string(timestamp_t when, int nr);
 QString uiLanguage(QLocale *callerLoc);
+void selectedDivesGasUsed(QVector<QPair<QString, int> > &gasUsed);
 
 #define M_OR_FT(_m, _f) ((prefs.units.length == units::METERS) ? ((_m) * 1000) : (feet_to_mm(_f)))
 
diff --git a/qt-ui/maintab.cpp b/qt-ui/maintab.cpp
index 19b47c872..5b8985b3e 100644
--- a/qt-ui/maintab.cpp
+++ b/qt-ui/maintab.cpp
@@ -530,6 +530,23 @@ void MainTab::updateDiveInfo(int dive)
 		ui.timeLimits->setAverage(get_time_string(seconds, 0));
 		ui.timeLimits->setMaximum(get_time_string(stats_selection.longest_time.seconds, 0));
 		ui.timeLimits->setMinimum(get_time_string(stats_selection.shortest_time.seconds, 0));
+		// now let's get some gas use statistics
+		QVector<QPair<QString, int> > gasUsed;
+		QString gasUsedString;
+		QPair<QString, int> topGases[8] = { };
+		volume_t vol;
+		selectedDivesGasUsed(gasUsed);
+		for (int j = 0; j < 8; j++) {
+			if (gasUsed.isEmpty())
+				break;
+			QPair<QString, int> gasPair = gasUsed.last();
+			gasUsed.pop_back();
+			vol.mliter = gasPair.second;
+			gasUsedString.append(gasPair.first).append(": ").append(get_volume_string(vol, true)).append("\n");
+		}
+		if (!gasUsed.isEmpty())
+			gasUsedString.append("...");
+		ui.gasConsumption->setText(gasUsedString);
 	} else {
 		/* clear the fields */
 		clearInfo();
diff --git a/qt-ui/maintab.ui b/qt-ui/maintab.ui
index 904a49304..2a0d3353e 100644
--- a/qt-ui/maintab.ui
+++ b/qt-ui/maintab.ui
@@ -37,8 +37,8 @@
         <rect>
          <x>0</x>
          <y>0</y>
-         <width>662</width>
-         <height>649</height>
+         <width>668</width>
+         <height>658</height>
         </rect>
        </property>
        <layout class="QGridLayout" name="gridLayout_2">
@@ -289,8 +289,8 @@
         <rect>
          <x>0</x>
          <y>0</y>
-         <width>662</width>
-         <height>649</height>
+         <width>100</width>
+         <height>30</height>
         </rect>
        </property>
        <layout class="QGridLayout" name="gridLayout_5">
@@ -369,8 +369,8 @@
         <rect>
          <x>0</x>
          <y>0</y>
-         <width>662</width>
-         <height>649</height>
+         <width>387</width>
+         <height>285</height>
         </rect>
        </property>
        <layout class="QGridLayout" name="gridLayout_6">
@@ -679,8 +679,8 @@
         <rect>
          <x>0</x>
          <y>0</y>
-         <width>662</width>
-         <height>649</height>
+         <width>337</width>
+         <height>157</height>
         </rect>
        </property>
        <layout class="QGridLayout" name="gridLayout_7">
@@ -766,7 +766,7 @@
           </layout>
          </widget>
         </item>
-        <item row="1" column="2">
+        <item row="2" column="1">
          <widget class="QGroupBox" name="groupBox_7b">
           <property name="title">
            <string>Dives</string>
@@ -785,8 +785,27 @@
           </layout>
          </widget>
         </item>
-        <item row="2" column="0">
-         <spacer>
+        <item row="1" column="2">
+         <widget class="QGroupBox" name="groupBox_13">
+          <property name="title">
+           <string>Gas Consumption</string>
+          </property>
+          <layout class="QHBoxLayout" name="horizontalLayout_15b">
+           <item>
+            <widget class="QLabel" name="gasConsumption">
+             <property name="text">
+              <string/>
+             </property>
+             <property name="alignment">
+              <set>Qt::AlignCenter</set>
+             </property>
+            </widget>
+           </item>
+          </layout>
+         </widget>
+        </item>
+        <item row="3" column="0">
+         <spacer name="verticalSpacer">
           <property name="orientation">
            <enum>Qt::Vertical</enum>
           </property>
@@ -795,8 +814,8 @@
           </property>
           <property name="sizeHint" stdset="0">
            <size>
-            <width>20</width>
-            <height>20</height>
+            <width>0</width>
+            <height>0</height>
            </size>
           </property>
          </spacer>
@@ -808,6 +827,7 @@
        <zorder>groupBox_14</zorder>
        <zorder>groupBoxb</zorder>
        <zorder>groupBox_7b</zorder>
+       <zorder>groupBox_13</zorder>
       </widget>
      </widget>
     </item>
diff --git a/qthelper.cpp b/qthelper.cpp
index 7eba936a6..8b7b3960f 100644
--- a/qthelper.cpp
+++ b/qthelper.cpp
@@ -1,11 +1,12 @@
 #include "qthelper.h"
 #include "qt-gui.h"
 #include "dive.h"
+#include "statistics.h"
 #include <exif.h>
 #include "file.h"
 #include <QRegExp>
 #include <QDir>
-
+#include <QMap>
 #include <QDebug>
 #include <QSettings>
 #include <libxslt/documents.h>
@@ -280,3 +281,31 @@ extern "C" void picture_load_exif_data(struct picture *p, timestamp_t *timestamp
 		free(mem.buffer);
 		return;
 }
+
+static bool lessThan(const QPair<QString, int> &a, const QPair<QString, int> &b)
+{
+	return a.second < b.second;
+}
+
+void selectedDivesGasUsed(QVector<QPair<QString, int> > &gasUsedOrdered)
+{
+	int i, j;
+	struct dive *d;
+	QString gas;
+	QMap<QString, int> gasUsed;
+	for_each_dive (i, d) {
+		if (!d->selected)
+			continue;
+		volume_t diveGases[MAX_CYLINDERS] = {};
+		get_gas_used(d, diveGases);
+		for (j = 0; j < MAX_CYLINDERS; j++)
+			if (diveGases[j].mliter) {
+				QString gasName = gasname(&d->cylinder[j].gasmix);
+				gasUsed[gasName] += diveGases[j].mliter;
+			}
+	}
+	Q_FOREACH(gas, gasUsed.keys()) {
+		gasUsedOrdered.append(QPair<QString, int>(gas, gasUsed[gas]));
+	}
+	qSort(gasUsedOrdered.begin(), gasUsedOrdered.end(), lessThan);
+}