Merge pull request #2297 from ChanceNCounter/prevent-repeating-dialog-lines

Cycle through dialog files to avoid repeating the same line

mycroft/dialog/__init__.py

@@ -35,6 +35,19 @@ class MustacheDialogRenderer:
 
     def __init__(self):
         self.templates = {}
+        self.recent_phrases = []
+
+        # TODO magic numbers are bad!
+        self.max_recent_phrases = 3
+        # We cycle through lines in .dialog files to keep Mycroft from
+        # repeating the same phrase over and over. However, if a .dialog
+        # file only contains a few entries, this can cause it to loop.
+        #
+        # This offset will override max_recent_phrases on very short .dialog
+        # files. With the offset at 2, .dialog files with 3 or more lines will
+        # be managed to avoid repetition, but .dialog files with only 1 or 2
+        # lines will be unaffected. Dialog should never get stuck in a loop.
+        self.loop_prevention_offset = 2
 
     def load_template_file(self, template_name, filename):
         """
@@ -67,6 +80,8 @@ class MustacheDialogRenderer:
         Given a template name, pick a template and render it using the context.
         If no matching template exists use template_name as template.
 
+        Tries not to let Mycroft say exactly the same thing twice in a row.
+
         Args:
             template_name (str): the name of a template group.
             context (dict): dictionary representing values to be rendered
@@ -84,14 +99,28 @@ class MustacheDialogRenderer:
             # "record not found" literal.
             return template_name.replace(".", " ")
 
+        # Get the .dialog file's contents, minus any which have been spoken
+        # recently.
         template_functions = self.templates.get(template_name)
+
         if index is None:
+            template_functions = ([t for t in template_functions
+                                   if t not in self.recent_phrases] or
+                                  template_functions)
             line = random.choice(template_functions)
         else:
             line = template_functions[index % len(template_functions)]
         # Replace {key} in line with matching values from context
         line = line.format(**context)
         line = random.choice(expand_options(line))
+
+        # Here's where we keep track of what we've said recently. Remember,
+        # this is by line in the .dialog file, not by exact phrase
+        self.recent_phrases.append(line)
+        if (len(self.recent_phrases) >
+                min(self.max_recent_phrases, len(self.templates.get(
+                    template_name)) - self.loop_prevention_offset)):
+            self.recent_phrases.pop(0)
         return line