Adds fire/air alarms (#5018)

Co-authored-by: Vera Aguilera Puerto <6766154+Zumorica@users.noreply.github.com>
Co-authored-by: E F R <602406+Efruit@users.noreply.github.com>
Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Server/Atmos/Monitor/Components/AtmosMonitorComponent.cs

@@ -0,0 +1,114 @@
+using System.Collections.Generic;
+using Content.Server.Atmos.Piping.Components;
+using Content.Server.Power.Components;
+using Content.Shared.Atmos;
+using Content.Shared.Atmos.Monitor;
+using Content.Shared.Sound;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Server.Atmos.Monitor.Components
+{
+    [RegisterComponent]
+    public class AtmosMonitorComponent : Component
+    {
+        public override string Name => "AtmosMonitor";
+
+        // Requires power. No logic related to this will be performed here, however,
+        // save for ensuring that the data is valid upon set.
+        // This is how the system discovers entities that are alarmable.
+        [ComponentDependency] public readonly ApcPowerReceiverComponent? PowerRecvComponent = default!;
+        [ComponentDependency] public readonly AtmosDeviceComponent? AtmosDeviceComponent = default!;
+
+        // Whether this monitor can send alarms,
+        // or recieve atmos command events.
+        //
+        // Useful for wires; i.e., pulsing a monitor wire
+        // will make it send an alert, and cutting
+        // it will make it so that alerts are no longer
+        // sent/receieved.
+        //
+        // Note that this cancels every single network
+        // event, including ones that may not be
+        // related to atmos monitor events.
+        [ViewVariables]
+        public bool NetEnabled = true;
+
+        // Entities that the monitor will alarm. Stores only EntityUids, is populated
+        // when this component starts up.
+        [ViewVariables]
+        public List<EntityUid> LinkedEntities = new();
+
+        [DataField("temperatureThreshold", customTypeSerializer: (typeof(PrototypeIdSerializer<AtmosAlarmThreshold>)))]
+        public readonly string? TemperatureThresholdId;
+
+        [ViewVariables]
+        public AtmosAlarmThreshold? TemperatureThreshold;
+
+        [DataField("pressureThreshold", customTypeSerializer: (typeof(PrototypeIdSerializer<AtmosAlarmThreshold>)))]
+        public readonly string? PressureThresholdId;
+
+        [ViewVariables]
+        public AtmosAlarmThreshold? PressureThreshold;
+
+        // monitor fire - much different from temperature
+        // since there's events for fire, setting this to true
+        // will make the atmos monitor act like a smoke detector,
+        // immediately signalling danger if there's a fire
+        [DataField("monitorFire")]
+        public bool MonitorFire = false;
+
+        [DataField("displayMaxAlarmInNet")]
+        public bool DisplayMaxAlarmInNet = false;
+
+        [DataField("alarmSound")]
+        public SoundSpecifier AlarmSound { get; set; } = new SoundPathSpecifier("/Audio/Machines/alarm.ogg");
+
+        [DataField("alarmVolume")]
+        public float AlarmVolume { get; set; } = -10;
+
+        // really messy but this is parsed at runtime after
+        // prototypes are initialized, there's no
+        // way without implementing a new
+        // type serializer
+        [DataField("gasThresholds")]
+        public Dictionary<Gas, string>? GasThresholdIds;
+
+        [ViewVariables]
+        public Dictionary<Gas, AtmosAlarmThreshold>? GasThresholds;
+
+        // Stores a reference to the gas on the tile this is on.
+        [ViewVariables]
+        public GasMixture? TileGas;
+
+        // Stores the last alarm state of this alarm.
+        [ViewVariables]
+        public AtmosMonitorAlarmType LastAlarmState = AtmosMonitorAlarmType.Normal;
+
+        // feeling real dirty about this one
+        // Caches the alarm states it recieves from the rest of the network.
+        // This is so that the highest alarm in the network can be calculated
+        // from any monitor without having to reping every alarm.
+        [ViewVariables]
+        public Dictionary<string, AtmosMonitorAlarmType> NetworkAlarmStates = new();
+
+        // Calculates the highest alarm in the network, including itself.
+        [ViewVariables]
+        public AtmosMonitorAlarmType HighestAlarmInNetwork
+        {
+            get
+            {
+                var state = AtmosMonitorAlarmType.Normal;
+                foreach (var (_, netState) in NetworkAlarmStates)
+                    if (state < netState)
+                        state = netState;
+
+                if (LastAlarmState > state) state = LastAlarmState;
+
+                return state;
+            }
+        }
+    }
+}