Implement production vertical slice foundation

game/domain/rules/dive_difficulty_profile.gd

@@ -0,0 +1,52 @@
+class_name DiveDifficultyProfile
+extends RefCounted
+
+var profile_id: StringName
+var oxygen_consumption_multiplier: float
+var battery_consumption_multiplier: float
+var collision_damage_multiplier: float
+var pressure_damage_multiplier: float
+var crush_grace_multiplier: float
+
+
+func _init(
+	p_profile_id: StringName,
+	p_oxygen_consumption_multiplier: float,
+	p_battery_consumption_multiplier: float,
+	p_collision_damage_multiplier: float,
+	p_pressure_damage_multiplier: float,
+	p_crush_grace_multiplier: float
+) -> void:
+	profile_id = p_profile_id
+	oxygen_consumption_multiplier = p_oxygen_consumption_multiplier
+	battery_consumption_multiplier = p_battery_consumption_multiplier
+	collision_damage_multiplier = p_collision_damage_multiplier
+	pressure_damage_multiplier = p_pressure_damage_multiplier
+	crush_grace_multiplier = p_crush_grace_multiplier
+
+
+static func exploration():
+	return new(&"exploration", 0.75, 0.80, 0.65, 0.50, 1.50)
+
+
+static func standard():
+	return new(&"standard", 1.0, 1.0, 1.0, 1.0, 1.0)
+
+
+static func expert():
+	return new(&"expert", 1.20, 1.15, 1.25, 1.35, 0.75)
+
+
+func validation_error() -> String:
+	if profile_id.is_empty():
+		return "difficulty profile_id is empty"
+	for value: float in [
+		oxygen_consumption_multiplier,
+		battery_consumption_multiplier,
+		collision_damage_multiplier,
+		pressure_damage_multiplier,
+		crush_grace_multiplier,
+	]:
+		if not is_finite(value) or value <= 0.0:
+			return "difficulty multipliers must be finite and positive"
+	return ""