Implemented custom expression evaluation options

This option allows customization of the boolean logic used to
determine how conditional values are used to filter notifications for
channel messages.  It evaluates as a full boolean logic expression,
including the use of sub-expressions.  The default value of "all" will
bypass this evaluation and simply require all conditions to be true.

The expression consists of space-separated tokens in the following grammar:

* expression = expression operator expression | "(" expression ")" | value
* operator = "and" | "or"
* value = "true" | "false" | condition
* condition = <any condition option>

Also implemented EVAL command for testing purposes.

README.md

@@ -97,6 +97,11 @@ Commands
     Manually trigger a notification with the given message.  Useful for testing to validate
     credentials, etc.
 
+*   `eval <expression>`
+
+    Evaluate the given expression in an empty context.  Useful for testing to validate that
+    a given expression is properly formatted and does not contain invalid tokens.
+
 
 Configuration
 -------------
@@ -196,6 +201,39 @@ Configuration
     URI that will be sent with the notification to Notifo.  This could be a web address or a
     local scheme to access a mobile application.
 
+### Advanced
+
+*   `channel_conditions = "all"`
+
+    This option allows customization of the boolean logic used to determine how conditional
+    values are used to filter notifications for channel messages.  It evaluates as a full
+    boolean logic expression,  including the use of sub-expressions.  The default value of
+    "all" will bypass this evaluation and simply require all conditions to be true.
+
+    The expression consists of space-separated tokens in the following grammar:
+
+    *   `expression = expression operator expression | "(" expression ")" | value`
+    *   `operator = "and" | "or"`
+    *   `value = "true" | "false" | condition`
+    *   `condition = <any condition option>`
+
+    As a simple example, to replicate the default "all" value, would be the value of
+    `away_only and client_count_less_than and highlight and idle and last_active and
+    last_notification and nick_blacklist and replied`.
+
+    Alternately, setting a value of `true` would send a notification for *every* message,
+    while a value of `false` would *never* send a notification.
+
+    For a more complicated example, the value of `client_count_less_than and highlight and
+    (last_active or last_notification or replied) and nick_blacklist` would send a
+    notification if any of the three conditions in the sub-expression are met, while still
+    requiring all of the conditions outside of the parentheses to also be met.
+
+*   `query_conditions = "all"`
+
+    This option is more or less identical to `channel_conditions`, except that it is used
+    to filter notifications for private messages.
+
 
 Roadmap
 -------

notifo.cpp

@@ -83,6 +83,10 @@ class CNotifoMod : public CModule
 			defaults["username"] = "";
 			defaults["secret"] = "";
 
+			// Condition strings
+			defaults["channel_conditions"] = "all";
+			defaults["query_conditions"] = "all";
+
 			// Notification conditions
 #ifdef NOTIFO_AWAY
 			defaults["away_only"] = "no";
@@ -171,6 +175,91 @@ class CNotifoMod : public CModule
 			AddSocket(sock);
 		}
 
+		/**
+		 * Evaluate a boolean expression using condition values.
+		 * All tokens must be separated by spaces, using "and" and "or" for
+		 * boolean operators, "(" and ")" to enclose sub-expressions, and
+		 * condition option names to evaluate each condition.
+		 *
+		 * @param expression Boolean expression string
+		 * @param context Notification context
+		 * @param nick Sender nick
+		 * @param message Message contents
+		 * @return Result of boolean evaluation
+		 */
+		bool eval(const CString& expression, const CString& context=CString(""), const CNick& nick=CNick(""), const CString& message=" ")
+		{
+			CString padded = expression.Replace_n("(", " ( ");
+			padded.Replace(")", " ) ");
+
+			VCString tokens;
+			padded.Split(" ", tokens, false);
+
+			return eval_tokens(tokens.begin(), tokens.end(), context, nick, message);
+		}
+
+#define expr(x, y) else if (token == x) { value = oper ? value && y : value || y; }
+
+		/**
+		 * Evaluate a tokenized boolean expression, or sub-expression.
+		 *
+		 * @param pos Token vector iterator current position
+		 * @param end Token vector iterator end position
+		 * @param context Notification context
+		 * @param nick Sender nick
+		 * @param message Message contents
+		 * @return Result of boolean expression
+		 */
+		bool eval_tokens(VCString::iterator pos, VCString::iterator end, const CString& context, const CNick& nick, const CString& message)
+		{
+			bool oper = true;
+			bool value = true;
+
+			for(; pos != end; pos++)
+			{
+				CString token = pos->AsLower();
+
+				if (token == "(")
+				{
+					bool inner = eval_tokens(++pos, end, context, nick, message);
+					value = oper ? value && inner : value || inner;
+				}
+				else if (token == ")")
+				{
+					pos++;
+					return value;
+				}
+				else if (token == "and")
+				{
+					oper = true;
+				}
+				else if (token == "or")
+				{
+					oper = false;
+				}
+
+				expr("true", true)
+				expr("false", false)
+				expr("away_only", away_only())
+				expr("client_count_less_than", client_count_less_than())
+				expr("highlight", highlight(message))
+				expr("idle", idle())
+				expr("last_active", last_active(context))
+				expr("last_notification", last_notification(context))
+				expr("nick_blacklist", nick_blacklist(nick))
+				expr("replied", replied(context))
+
+				else
+				{
+					PutModule("Error: Unexpected token \"" + token + "\"");
+				}
+			}
+
+			return value;
+		}
+
+#undef expr
+
 	protected:
 
 		/**
@@ -348,6 +437,13 @@ class CNotifoMod : public CModule
 		bool notify_channel(const CNick& nick, const CChan& channel, const CString& message)
 		{
 			CString context = channel.GetName();
+
+			CString expression = options["channel_conditions"].AsLower();
+			if (expression != "all")
+			{
+				return eval(expression, context, nick, message);
+			}
+
 			return away_only()
 				&& client_count_less_than()
 				&& highlight(message)
@@ -365,9 +461,16 @@ class CNotifoMod : public CModule
 		 * @param nick Nick that sent the message
 		 * @return Notification should be sent
 		 */
-		bool notify_pm(const CNick& nick)
+		bool notify_pm(const CNick& nick, const CString& message)
 		{
 			CString context = nick.GetNick();
+
+			CString expression = options["query_conditions"].AsLower();
+			if (expression != "all")
+			{
+				return eval(expression, context, nick, message);
+			}
+
 			return away_only()
 				&& client_count_less_than()
 				&& idle()
@@ -458,7 +561,7 @@ class CNotifoMod : public CModule
 		 */
 		EModRet OnPrivMsg(CNick& nick, CString& message)
 		{
-			if (notify_pm(nick))
+			if (notify_pm(nick, message))
 			{
 				CString title = "Private Message";
 				CString msg = "From " + nick.GetNick();
@@ -478,7 +581,7 @@ class CNotifoMod : public CModule
 		 */
 		EModRet OnPrivAction(CNick& nick, CString& message)
 		{
-			if (notify_pm(nick))
+			if (notify_pm(nick, message))
 			{
 				CString title = "Private Message";
 				CString msg = "* " + nick.GetNick();
@@ -597,6 +700,14 @@ class CNotifoMod : public CModule
 				}
 				else
 				{
+					if (option == "channel_conditions" || option == "query_conditions")
+					{
+						if (value != "all")
+						{
+							eval(value);
+						}
+					}
+
 					options[option] = value;
 					options[option].Trim();
 					SetNV(option, options[option]);
@@ -792,6 +903,12 @@ class CNotifoMod : public CModule
 			{
 				PutModule("View the detailed documentation at https://github.com/jreese/znc-notifo/blob/master/README.md");
 			}
+			// EVAL command
+			else if (action == "eval")
+			{
+				CString value = command.Token(1, true, " ");
+				PutModule(eval(value) ? "true" : "false");
+			}
 			else
 			{
 				PutModule("Error: invalid command, try `help`");