#334: Don't wait for all rules before showing result

thefuck/types.py

@@ -1,5 +1,6 @@
 from collections import namedtuple
-
+from traceback import format_stack
+from .logs import debug
 
 Command = namedtuple('Command', ('script', 'stdout', 'stderr'))
 
@@ -18,7 +19,6 @@ class RulesNamesList(list):
 
 
 class Settings(dict):
-
     def __getattr__(self, item):
         return self.get(item)
 
@@ -29,3 +29,73 @@ class Settings(dict):
         conf = dict(kwargs)
         conf.update(self)
         return Settings(conf)
+
+
+class SortedCorrectedCommandsSequence(object):
+    """List-like collection/wrapper around generator, that:
+
+    - immediately gives access to the first commands through [];
+    - realises generator and sorts commands on first access to other
+      commands through [], or when len called.
+
+    """
+
+    def __init__(self, commands, settings):
+        self._settings = settings
+        self._commands = commands
+        self._cached = self._get_first_two_unique()
+        self._realised = False
+
+    def _get_first_two_unique(self):
+        """Returns first two unique commands."""
+        try:
+            first = next(self._commands)
+        except StopIteration:
+            return []
+
+        for command in self._commands:
+            if command.script != first.script or \
+                            command.side_effect != first.side_effect:
+                return [first, command]
+        return [first]
+
+    def _remove_duplicates(self, corrected_commands):
+        """Removes low-priority duplicates."""
+        commands = {(command.script, command.side_effect): command
+                    for command in sorted(corrected_commands,
+                                          key=lambda command: -command.priority)
+                    if command.script != self._cached[0].script
+                    or command.side_effect != self._cached[0].side_effect}
+        return commands.values()
+
+    def _realise(self):
+        """Realises generator, removes duplicates and sorts commands."""
+        commands = self._cached[1:] + list(self._commands)
+        commands = self._remove_duplicates(commands)
+        self._cached = [self._cached[0]] + sorted(
+            commands, key=lambda corrected_command: corrected_command.priority)
+        self._realised = True
+        debug('SortedCommandsSequence was realised with: {}, after: {}'.format(
+            self._cached, '\n'.join(format_stack())), self._settings)
+
+    def __getitem__(self, item):
+        if item != 0 and not self._realised:
+            self._realise()
+        return self._cached[item]
+
+    def __bool__(self):
+        return bool(self._cached)
+
+    def __len__(self):
+        if not self._realised:
+            self._realise()
+        return len(self._cached)
+
+    def __iter__(self):
+        if not self._realised:
+            self._realise()
+        return iter(self._cached)
+
+    @property
+    def is_multiple(self):
+        return len(self._cached) > 1