Calculate the gas used during the planned dive

This works on the assumption that the diver uses the deco SAC rate while
on a calculated deco stop and the bottom SAC rate during the rest of the
dive (including the time they move from deco stop to deco stop).

This is making the planning function mostly useful for open circuit
diving.

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

1 files changed, 24 insertions, 1 deletions

diff --git a/planner.c b/planner.c
index 8ad771064..65d86f7e3 100644
--- a/planner.c
+++ b/planner.c
@@ -431,7 +431,8 @@ static int *sort_stops(int *dstops, int dnr, struct gaschanges *gstops, int gnr)
 static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive)
 {
 	char buffer[2000];
-	int len, lastdepth = 0, lasttime = 0;
+	int consumption[MAX_CYLINDERS] = { 0, };
+	int len, gasidx, lastdepth = 0, lasttime = 0;
 	struct divedatapoint *dp = diveplan->dp;
 	int o2, he;
 
@@ -448,6 +449,7 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive)
 		char gas[12];
 		double depthvalue;
 		int decimals;
+		double used;
 		int newo2 = o2, newhe = he;
 		struct divedatapoint *nextdp;
 
@@ -473,20 +475,27 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive)
 		if (!dp->entered && o2 == newo2 && he == newhe && nextdp && dp->depth != lastdepth && nextdp->depth != dp->depth)
 			continue;
 		get_gas_string(o2, he, gas, 12);
+		gasidx = get_gasidx(dive, o2, he);
 		len = strlen(buffer);
 		if (dp->depth != lastdepth) {
+			used = diveplan->bottomsac / 1000.0 * depth_to_mbar((dp->depth + lastdepth) / 2, dive) *
+						(dp->time - lasttime) / 60;
 			snprintf(buffer + len, sizeof(buffer) - len, "Transition to %.*f %s in %d:%02d min - runtime %d:%02u on %s\n",
 							decimals, depthvalue, depth_unit,
 							FRACTION(dp->time - lasttime, 60),
 							FRACTION(dp->time, 60),
 							gas);
 		} else {
+			/* we use deco SAC rate during the calculated deco stops, bottom SAC rate everywhere else */
+			int sac = dp->entered ? diveplan->bottomsac : diveplan->decosac;
+			used = sac / 1000.0 * depth_to_mbar(dp->depth, dive) * (dp->time - lasttime) / 60;
 			snprintf(buffer + len, sizeof(buffer) - len, "Stay at %.*f %s for %d:%02d min - runtime %d:%02u on %s\n",
 							decimals, depthvalue, depth_unit,
 							FRACTION(dp->time - lasttime, 60),
 							FRACTION(dp->time, 60),
 							gas);
 		}
+		consumption[gasidx] += used;
 		get_gas_string(newo2, newhe, gas, 12);
 		if (o2 != newo2 || he != newhe) {
 			len = strlen(buffer);
@@ -497,6 +506,20 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive)
 		lasttime = dp->time;
 		lastdepth = dp->depth;
 	} while((dp = dp->next) != NULL);
+	len = strlen(buffer);
+	snprintf(buffer + len, sizeof(buffer) - len, "Gas consumption:\n");
+	for (gasidx = 0; gasidx < MAX_CYLINDERS; gasidx++) {
+		double volume;
+		const char *unit;
+		char gas[12];
+		if (consumption[gasidx] == 0)
+			continue;
+		len = strlen(buffer);
+		volume = get_volume_units(consumption[gasidx], NULL, &unit);
+		get_gas_string(dive->cylinder[gasidx].gasmix.o2.permille,
+				dive->cylinder[gasidx].gasmix.he.permille, gas, 12);
+		snprintf(buffer + len, sizeof(buffer) - len, "%.0f%s of %s\n", volume, unit, gas);
+	}
 	dive->notes = strdup(buffer);
 }