Planner: add warning if the plan consumes more gas than provided

If we have size information including working pressure for a cylinder, we
already track the expected pressure at each way point - this way we can
also alert the user if more gas is consumed than is available in the
cylinder.

This does not include sound planning strategies like "rule of thirds". It
simply assumes that you won't be able to breathe down the cylinder past
about 10bar (using 0 as cutoff seemed silly).

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

1 files changed, 8 insertions, 1 deletions

diff --git a/planner.c b/planner.c
index f062ee699..13480410f 100644
--- a/planner.c
+++ b/planner.c
@@ -601,14 +601,21 @@ static void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool
 		double volume;
 		const char *unit;
 		char gas[64];
+		const char *warning = "";
 		cylinder_t *cyl = &dive->cylinder[gasidx];
 		if (cylinder_none(cyl))
 			break;
 		int consumed = mbar_to_atm(cyl->start.mbar - cyl->end.mbar) * cyl->type.size.mliter;
+		/* Warn if the plan uses more gas than is available in a cylinder
+		 * 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->type.workingpressure.mbar && cyl->end.mbar < 10000)
+			warning = translate("gettextFromC", "WARNING: this is more gas than available in the specified cylinder!");
+
 		len = strlen(buffer);
 		volume = get_volume_units(consumed, NULL, &unit);
 		get_gas_string(get_o2(&cyl->gasmix), get_he(&cyl->gasmix), gas, sizeof(gas));
-		snprintf(buffer + len, sizeof(buffer) - len, translate("gettextFromC", "%.0f%s of %s\n"), volume, unit, gas);
+		snprintf(buffer + len, sizeof(buffer) - len, translate("gettextFromC", "%.0f%s of %s%s\n"), volume, unit, gas, warning);
 	}
 	dive->notes = strdup(buffer);
 }