From 4d6bd13e03991d97033db4f7153cce966a67f1e7 Mon Sep 17 00:00:00 2001
From: Noikoio <noikoio1@gmail.com>
Date: Tue, 23 Jan 2018 14:06:31 -0800
Subject: [PATCH] Added RandomChance parameter to AutoRespond

---
 Module/AutoRespond/ConfigItem.cs | 30 ++++++++++++++++++++++++++++++
 docs/autorespond.md              | 10 ++++++----
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/Module/AutoRespond/ConfigItem.cs b/Module/AutoRespond/ConfigItem.cs
index 7ed89a1..60fc7f8 100644
--- a/Module/AutoRespond/ConfigItem.cs
+++ b/Module/AutoRespond/ConfigItem.cs
@@ -13,6 +13,7 @@ namespace Noikoio.RegexBot.Module.AutoRespond
     class ConfigItem
     {
         public enum ResponseType { None, Exec, Reply }
+        private static Random ChangeRng = new Random();
 
         string _label;
         IEnumerable<Regex> _regex;
@@ -20,12 +21,14 @@ namespace Noikoio.RegexBot.Module.AutoRespond
         string _rbody;
         private FilterList _filter;
         private RateLimitCache _limit;
+        private double _random;
 
         public string Label => _label;
         public IEnumerable<Regex> Regex => _regex;
         public (ResponseType, string) Response => (_rtype, _rbody);
         public FilterList Filter => _filter;
         public RateLimitCache RateLimit => _limit;
+        public double RandomChance => _random;
 
         public ConfigItem(JProperty definition)
         {
@@ -119,6 +122,24 @@ namespace Noikoio.RegexBot.Module.AutoRespond
                     throw new RuleImportException("Rate limit value is invalid" + errorpfx);
                 }
             }
+
+            // random chance
+            string randstr = data["RandomChance"]?.Value<string>();
+            if (string.IsNullOrWhiteSpace(randstr))
+            {
+                _random = double.NaN;
+            }
+            else
+            {
+                if (!double.TryParse(randstr, out _random))
+                {
+                    throw new RuleImportException("Random value is invalid (unable to parse)" + errorpfx);
+                }
+                if (_random > 1 || _random < 0)
+                {
+                    throw new RuleImportException("Random value is invalid (not between 0 and 1)" + errorpfx);
+                }
+            }
         }
 
         /// <summary>
@@ -145,6 +166,15 @@ namespace Noikoio.RegexBot.Module.AutoRespond
             // Rate limit check - currently per channel
             if (!RateLimit.AllowUsage(m.Channel.Id)) return false;
 
+            // Random chance check
+            if (!double.IsNaN(RandomChance))
+            {
+                // Fail if randomly generated value is higher than the parameter
+                // Example: To fail a 75% chance, the check value must be between 0.75000...001 and 1.0.
+                var chk = ChangeRng.NextDouble();
+                if (chk > RandomChance) return false;
+            }
+
             return true;
         }
 
diff --git a/docs/autorespond.md b/docs/autorespond.md
index b3b6838..ba2db8b 100644
--- a/docs/autorespond.md
+++ b/docs/autorespond.md
@@ -18,7 +18,8 @@ Sample within a [server definition](serverdef.html):
             "dumb",
             "productive conversation"
         ],
-        "exec": "python /home/bot/did-someone-say-botspam.py"
+        "exec": "python /home/bot/did-someone-say-botspam.py",
+		"RandomChance": 0.5
     }
 }
 ```
@@ -26,8 +27,9 @@ Sample within a [server definition](serverdef.html):
 ### Definition structure
 The following is a list of accepted members within an AutoRespond definition:
 * regex (*string* or *string array*) - **Required.** Regular expression pattern(s) that will invoke the response.
-* reply *(string)* - The message to send out to the channel in which the response was invoked.<sup>1</sup>
-* exec *(string)* - Command line path and optional parameters to an external program. The program's output will be sent to the channel in which the response was invoked.<sup>1</sup>
-* ratelimit *(integer)* - The amount of time in seconds in which the response may not be triggered again within the same channel. Defaults to 20.
+* reply (*string*) - The message to send out to the channel in which the response was invoked.<sup>1</sup>
+* exec (*string*) - Command line path and optional parameters to an external program. The program's output will be sent to the channel in which the response was invoked.<sup>1</sup>
+* ratelimit (*integer*) - The amount of time in seconds in which the response may not be triggered again within the same channel. Defaults to 20.
+* RandomChance (*number*) - A value between 0 and 1 representing the percent chance for the bot to respond to the corresponding trigger. Defaults to 1.0 (100%).
 
 <sup>1</sup> It is **required** to have either *reply* or *exec* specified in a definition.
\ No newline at end of file