Minimum gas calculation - Calculations and UI parameters

Add minimum gas calculation to planner output.
Add the two UI parameters prefs.sacfactor and prefs.problemsolvingtime.
Connect UI signals and slots for recalculation of diveplan.

Disable minimum gas calculation if there was already a warning before.
If minimum gas result is larger then cylinder start pressure give warning message instead of result.

Add line break before pO2 warnings but only if warnings exist.

Signed-off-by: Joachim Ritter <jritter@bitsenke.de>
Signed-off-by: Stefan Fuchs <sfuchs@gmx.de>

5 files changed, 112 insertions, 7 deletions

diff --git a/core/planner.c b/core/planner.c
index ad7678188..ab4ba2dd2 100644
--- a/core/planner.c
+++ b/core/planner.c
@@ -546,6 +546,7 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
 	bool gaschange_before;
 	bool lastentered = true;
 	struct divedatapoint *nextdp = NULL;
+	struct divedatapoint *lastbottomdp = NULL;
 
 	plan_verbatim = prefs.verbatim_plan;
 	plan_display_runtime = prefs.display_runtime;
@@ -639,6 +640,17 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
 		if (dp->time - lasttime < 10 && !(gaschange_after && dp->next && dp->depth != dp->next->depth))
 			continue;
 
+		/* Store pointer to last entered datapoint for minimum gas calculation */
+		/* Do this only if depth is larger than last/2nd last deco stop at ~6m */
+		int secondlastdecostop = 0;
+		if (prefs.units.length == METERS ) {
+			secondlastdecostop = decostoplevels_metric[2];
+		} else {
+			secondlastdecostop = decostoplevels_imperial[2];
+		}
+		if (dp->entered && !nextdp->entered && dp->depth > secondlastdecostop)
+			lastbottomdp = dp;
+
 		len = strlen(buffer);
 		if (plan_verbatim) {
 			/* When displaying a verbatim plan, we output a waypoint for every gas change.
@@ -847,10 +859,13 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
 		snprintf(temp, sz_temp, "%s %.*f|%.*f%s/min):", translate("gettextFromC", "Gas consumption (based on SAC"),
 			sacdecimals, bottomsacvalue, sacdecimals, decosacvalue, sacunit);
 	len += snprintf(buffer + len, sz_buffer - len, "<div>%s<br>", temp);
+
+	/* Print gas consumption: This loop covers all cylinders */
 	for (int gasidx = 0; gasidx < MAX_CYLINDERS; gasidx++) {
-		double volume, pressure, deco_volume, deco_pressure;
-		const char *unit, *pressure_unit;
+		double volume, pressure, deco_volume, deco_pressure, mingas_volume, mingas_pressure, mingas_depth;
+		const char *unit, *pressure_unit, *depth_unit;
 		char warning[1000] = "";
+		char mingas[1000] = "";
 		cylinder_t *cyl = &dive->cylinder[gasidx];
 		if (cylinder_none(cyl))
 			break;
@@ -867,23 +882,59 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
 			 * This only works if we have working pressure for the cylinder
 			 * 10bar is a made up number - but it seemed silly to pretend you could breathe cylinder down to 0 */
 			if (cyl->end.mbar < 10000)
-				snprintf(warning, sizeof(warning), " &mdash; <span style='color: red;'>%s </span> %s",
+				snprintf(warning, sizeof(warning), "<br>&nbsp;&mdash; <span style='color: red;'>%s </span> %s",
 					translate("gettextFromC", "Warning:"),
 					translate("gettextFromC", "this is more gas than available in the specified cylinder!"));
 			else
 				if ((float) cyl->end.mbar * cyl->type.size.mliter / 1000.0 / gas_compressibility_factor(&cyl->gasmix, cyl->end.mbar / 1000.0)
 				    < (float) cyl->deco_gas_used.mliter)
-					snprintf(warning, sizeof(warning), " &mdash; <span style='color: red;'>%s </span> %s",
+					snprintf(warning, sizeof(warning), "<br>&nbsp;&mdash; <span style='color: red;'>%s </span> %s",
 						translate("gettextFromC", "Warning:"),
 						translate("gettextFromC", "not enough reserve for gas sharing on ascent!"));
 
-			snprintf(temp, sz_temp, translate("gettextFromC", "%.0f%s/%.0f%s of %s (%.0f%s/%.0f%s in planned ascent)"), volume, unit, pressure, pressure_unit, gasname(&cyl->gasmix), deco_volume, unit, deco_pressure, pressure_unit);
+			/* Do and print minimum gas calculation for last bottom gas, but only for OC mode */
+			/* and if no other warning was set before. */
+			else
+				if (lastbottomdp && gasidx == lastbottomdp->cylinderid
+					&& dive->dc.divemode == OC) {
+					/* Calculate minimum gas volume. */
+					volume_t mingasv;
+					mingasv.mliter = prefs.problemsolvingtime * prefs.bottomsac * prefs.sacfactor / 100.0
+						* depth_to_bar(lastbottomdp->depth, dive)
+						+ cyl->deco_gas_used.mliter * prefs.sacfactor / 100.0;
+					/* Calculate minimum gas pressure for cyclinder. */
+					pressure_t mingasp;
+					mingasp.mbar = isothermal_pressure(&cyl->gasmix, 1.0,
+						mingasv.mliter, cyl->type.size.mliter) * 1000;
+					/* Translate all results into correct units */
+					mingas_volume = get_volume_units(mingasv.mliter, NULL, &unit);
+					mingas_pressure = get_pressure_units(mingasp.mbar, &pressure_unit);
+					mingas_depth = get_depth_units(lastbottomdp->depth, NULL, &depth_unit);
+					/* Print it to results */
+					if (cyl->start.mbar > mingasp.mbar) snprintf(mingas, sizeof(mingas),
+						translate("gettextFromC", "<br>&nbsp;&mdash; <span style='color: green;'>Minimum gas</span> (based on %.1fxSAC/+%dmin@%.0f%s): %.0f%s/%.0f%s"),
+						prefs.sacfactor / 100.0, prefs.problemsolvingtime,
+						mingas_depth, depth_unit,
+						mingas_volume, unit,
+						mingas_pressure, pressure_unit);
+					else snprintf(warning, sizeof(warning), "<br>&nbsp;&mdash; <span style='color: red;'>%s </span> %s",
+						translate("gettextFromC", "Warning:"),
+						translate("gettextFromC", "required minimum gas for ascent already exceeding start pressure of cylinder!"));
+				}
+			/* Print the gas consumption for every cylinder here to temp buffer. */
+			snprintf(temp, sz_temp, translate("gettextFromC", "%.0f%s/%.0f%s of <span style='color: red;'><b>%s</b></span> (%.0f%s/%.0f%s in planned ascent)"), volume, unit, pressure, pressure_unit, gasname(&cyl->gasmix), deco_volume, unit, deco_pressure, pressure_unit);
+			
 		} else {
-			snprintf(temp, sz_temp, translate("gettextFromC", "%.0f%s (%.0f%s during planned ascent) of %s"), volume, unit, deco_volume, unit, gasname(&cyl->gasmix));
+			snprintf(temp, sz_temp, translate("gettextFromC", "%.0f%s (%.0f%s during planned ascent) of <span style='color: red;'><b>%s</b></span>"),
+				volume, unit, deco_volume, unit, gasname(&cyl->gasmix));
 		}
-		len += snprintf(buffer + len, sz_buffer - len, "%s%s<br>", temp, warning);
+		/* Gas consumption: Now finally print all strings to output */
+		len += snprintf(buffer + len, sz_buffer - len, "%s%s%s<br>", temp, warning, mingas);
 	}
+	
+	/* Print warnings for pO2 */
 	dp = diveplan->dp;
+	bool o2warning_exist = false;
 	if (dive->dc.divemode != CCR) {
 		while (dp) {
 			if (dp->time != 0) {
@@ -896,6 +947,8 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
 					int decimals;
 					double depth_value = get_depth_units(dp->depth, &decimals, &depth_unit);
 					len = strlen(buffer);
+					if (!o2warning_exist) len += snprintf(buffer + len, sz_buffer - len, "<br>");
+					o2warning_exist = true;
 					snprintf(temp, sz_temp,
 						 translate("gettextFromC", "high pO₂ value %.2f at %d:%02u with gas %s at depth %.*f %s"),
 						 pressures.o2, FRACTION(dp->time, 60), gasname(gasmix), decimals, depth_value, depth_unit);
@@ -906,6 +959,8 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
 					int decimals;
 					double depth_value = get_depth_units(dp->depth, &decimals, &depth_unit);
 					len = strlen(buffer);
+					if (!o2warning_exist) len += snprintf(buffer + len, sz_buffer - len, "<br>");
+					o2warning_exist = true;
 					snprintf(temp, sz_temp,
 						 translate("gettextFromC", "low pO₂ value %.2f at %d:%02u with gas %s at depth %.*f %s"),
 						 pressures.o2, FRACTION(dp->time, 60), gasname(gasmix), decimals, depth_value, depth_unit);
diff --git a/core/pref.h b/core/pref.h
index 1360fba14..9122800bb 100644
--- a/core/pref.h
+++ b/core/pref.h
@@ -105,6 +105,8 @@ struct preferences {
 	int ascratestops;
 	int ascratelast6m;
 	int descrate;
+	int sacfactor;
+	int problemsolvingtime;
 	int bottompo2;
 	int decopo2;
 	enum deco_mode display_deco_mode;
diff --git a/core/subsurface-qt/SettingsObjectWrapper.cpp b/core/subsurface-qt/SettingsObjectWrapper.cpp
index dfb486065..f5d2e0f9a 100644
--- a/core/subsurface-qt/SettingsObjectWrapper.cpp
+++ b/core/subsurface-qt/SettingsObjectWrapper.cpp
@@ -1240,6 +1240,16 @@ int DivePlannerSettings::descrate() const
 	return prefs.descrate;
 }
 
+int DivePlannerSettings::sacfactor() const
+{
+	return prefs.sacfactor;
+}
+
+int DivePlannerSettings::problemsolvingtime() const
+{
+	return prefs.problemsolvingtime;
+}
+
 int DivePlannerSettings::bottompo2() const
 {
 	return prefs.bottompo2;
@@ -1441,6 +1451,30 @@ void DivePlannerSettings::setDescrate(int value)
 	emit descrateChanged(value);
 }
 
+void DivePlannerSettings::setSacFactor(int value)
+{
+	if (value == prefs.sacfactor)
+		return;
+
+	QSettings s;
+	s.beginGroup(group);
+	s.setValue("sacfactor", value);
+	prefs.sacfactor = value;
+	emit sacFactorChanged(value);
+}
+
+void DivePlannerSettings::setProblemSolvingTime(int value)
+{
+	if (value == prefs.problemsolvingtime)
+		return;
+
+	QSettings s;
+	s.beginGroup(group);
+	s.setValue("problemsolvingtime", value);
+	prefs.problemsolvingtime = value;
+	emit problemSolvingTimeChanged(value);
+}
+
 void DivePlannerSettings::setBottompo2(int value)
 {
 	if (value == prefs.bottompo2)
@@ -2279,6 +2313,8 @@ void SettingsObjectWrapper::load()
 	GET_INT("ascratestops", ascratestops);
 	GET_INT("ascratelast6m", ascratelast6m);
 	GET_INT("descrate", descrate);
+	GET_INT("sacfactor", sacfactor);
+	GET_INT("problemsolvingtime", problemsolvingtime);
 	GET_INT("bottompo2", bottompo2);
 	GET_INT("decopo2", decopo2);
 	GET_INT("bestmixend", bestmixend.mm);
@@ -2331,6 +2367,8 @@ void SettingsObjectWrapper::sync()
 	s.setValue("ascratestops", prefs.ascratestops);
 	s.setValue("ascratelast6m", prefs.ascratelast6m);
 	s.setValue("descrate", prefs.descrate);
+	s.setValue("sacfactor", prefs.sacfactor);
+	s.setValue("problemsolvingtime", prefs.problemsolvingtime);
 	s.setValue("bottompo2", prefs.bottompo2);
 	s.setValue("decopo2", prefs.decopo2);
 	s.setValue("bestmixend", prefs.bestmixend.mm);
diff --git a/core/subsurface-qt/SettingsObjectWrapper.h b/core/subsurface-qt/SettingsObjectWrapper.h
index 7fdd10498..1d35dd5d5 100644
--- a/core/subsurface-qt/SettingsObjectWrapper.h
+++ b/core/subsurface-qt/SettingsObjectWrapper.h
@@ -402,6 +402,8 @@ class DivePlannerSettings : public QObject {
 	Q_PROPERTY(int ascratestops         READ ascratestops         WRITE setAscratestops         NOTIFY ascratestopsChanged)
 	Q_PROPERTY(int ascratelast6m        READ ascratelast6m        WRITE setAscratelast6m        NOTIFY ascratelast6mChanged)
 	Q_PROPERTY(int descrate             READ descrate             WRITE setDescrate             NOTIFY descrateChanged)
+	Q_PROPERTY(int sacfactor            READ sacfactor            WRITE setSacFactor            NOTIFY sacFactorChanged)
+	Q_PROPERTY(int problemsolvingtime   READ problemsolvingtime   WRITE setProblemSolvingTime   NOTIFY problemSolvingTimeChanged)
 	Q_PROPERTY(int bottompo2            READ bottompo2            WRITE setBottompo2            NOTIFY bottompo2Changed)
 	Q_PROPERTY(int decopo2              READ decopo2              WRITE setDecopo2              NOTIFY decopo2Changed)
 	Q_PROPERTY(int bestmixend           READ bestmixend           WRITE setBestmixend           NOTIFY bestmixendChanged)
@@ -427,6 +429,8 @@ public:
 	int ascratestops() const;
 	int ascratelast6m() const;
 	int descrate() const;
+	int sacfactor() const;
+	int problemsolvingtime() const;
 	int bottompo2() const;
 	int decopo2() const;
 	int bestmixend() const;
@@ -451,6 +455,8 @@ public slots:
 	void setAscratestops(int value);
 	void setAscratelast6m(int value);
 	void setDescrate(int value);
+	void setSacFactor(int value);
+	void setProblemSolvingTime(int value);
 	void setBottompo2(int value);
 	void setDecopo2(int value);
 	void setBestmixend(int value);
@@ -475,6 +481,8 @@ signals:
 	void ascratestopsChanged(int value);
 	void ascratelast6mChanged(int value);
 	void descrateChanged(int value);
+	void sacFactorChanged(int value);
+	void problemSolvingTimeChanged(int value);
 	void bottompo2Changed(int value);
 	void decopo2Changed(int value);
 	void bestmixendChanged(int value);
diff --git a/core/subsurfacestartup.c b/core/subsurfacestartup.c
index 1f9518136..89ecbd2fb 100644
--- a/core/subsurfacestartup.c
+++ b/core/subsurfacestartup.c
@@ -50,6 +50,8 @@ struct preferences default_prefs = {
 	.ascratestops = 6000 / 60,
 	.ascratelast6m = 1000 / 60,
 	.descrate = 18000 / 60,
+	.sacfactor = 400,
+	.problemsolvingtime = 4,
 	.bottompo2 = 1400,
 	.decopo2 = 1600,
 	.bestmixend.mm = 30000,