document, impl, and patch up FlaggableObject tags

src/main/java/com/denizenscript/denizencore/flags/AbstractFlagTracker.java

@@ -1,10 +1,12 @@
 package com.denizenscript.denizencore.flags;
 
 import com.denizenscript.denizencore.objects.ObjectTag;
+import com.denizenscript.denizencore.objects.core.DurationTag;
 import com.denizenscript.denizencore.objects.core.ElementTag;
 import com.denizenscript.denizencore.objects.core.ListTag;
 import com.denizenscript.denizencore.objects.core.TimeTag;
 import com.denizenscript.denizencore.tags.Attribute;
+import com.denizenscript.denizencore.tags.ObjectTagProcessor;
 import com.denizenscript.denizencore.utilities.Deprecations;
 import com.denizenscript.denizencore.utilities.debugging.SlowWarning;
 import com.denizenscript.denizencore.utilities.debugging.Warning;
@@ -25,6 +27,56 @@ public boolean hasFlag(String key) {
         return getFlagValue(key) != null;
     }
 
+    public <T extends FlaggableObject> void registerFlagHandlers(ObjectTagProcessor<T> processor) {
+
+        // <--[tag]
+        // @attribute <FlaggableObject.flag[<name>]>
+        // @returns ObjectTag
+        // @description
+        // Returns the specified flag from the flaggable object.
+        // If the flag is expired, will return null.
+        // Consider also using <@link tag FlaggableObject.has_flag>.
+        // See <@link language Flag System>.
+        // -->
+        processor.registerTag("flag", (attribute, object) -> {
+            return object.getFlagTracker().doFlagTag(attribute);
+        });
+
+        // <--[tag]
+        // @attribute <FlaggableObject.has_flag[<flag_name>]>
+        // @returns ElementTag(Boolean)
+        // @description
+        // Returns true if the flaggable object has the specified flag, otherwise returns false.
+        // See <@link language Flag System>.
+        // -->
+        processor.registerTag("has_flag", (attribute, object) -> {
+            return object.getFlagTracker().doHasFlagTag(attribute);
+        });
+
+        // <--[tag]
+        // @attribute <FlaggableObject.flag_expiration[<flag_name>]>
+        // @returns TimeTag
+        // @description
+        // Returns a TimeTag indicating when the specified flag will expire.
+        // See <@link language Flag System>.
+        // -->
+        processor.registerTag("flag_expiration", (attribute, object) -> {
+            return object.getFlagTracker().doFlagExpirationTag(attribute);
+        });
+
+        // <--[tag]
+        // @attribute <FlaggableObject.list_flags>
+        // @returns ListTag
+        // @description
+        // Returns a list of the flaggable object's flags.
+        // Note that this is exclusively for debug/testing reasons, and should never be used in a real script.
+        // See <@link language Flag System>.
+        // -->
+        processor.registerTag("list_flags", (attribute, object) -> {
+            return object.getFlagTracker().doListFlagsTag(attribute);
+        });
+    }
+
     public ElementTag doHasFlagTag(Attribute attribute) {
         if (!attribute.hasContext(1)) {
             attribute.echoError("The has_flag[...] tag must have an input!");
@@ -44,7 +96,11 @@ public ObjectTag doFlagTag(Attribute attribute) {
         }
         else if (attribute.getAttributeWithoutContext(2).equals("expiration")) {
             Deprecations.flagExpirationTag.warn(attribute.context);
-            return getFlagExpirationTime(attribute.getContext(1));
+            TimeTag time = getFlagExpirationTime(attribute.getContext(1));
+            if (time == null) {
+                return null;
+            }
+            return new DurationTag((TimeTag.now().millis() - time.millis()) / 1000.0);
         }
         return getFlagValue(attribute.getContext(1));
     }