Add --debug for verbose output

This currently prints differences between detected/to-be-loaded and
current configurations.

See bug wertarbyte#27

autorandr.py

@@ -62,6 +62,7 @@
 --fingerprint           fingerprint your current hardware setup
 --config                dump your current xrandr setup
 --dry-run               don't change anything, only print the xrandr commands
+--debug                 enable verbose output
 
  To prevent a profile from being loaded, place a script call "block" in its
  directory. The script is evaluated before the screen setup is inspected, and
@@ -171,7 +172,11 @@ class XrandrOutput(object):
     EDID_UNAVAILABLE = "--CONNECTED-BUT-EDID-UNAVAILABLE-"
 
     def __repr__(self):
-        return "<%s%s %s>" % (self.output, (" %s..%s" % (self.edid[:5], self.edid[-5:])) if self.edid else "", " ".join(self.option_vector))
+        return "<%s%s %s>" % (self.output, self.short_edid, " ".join(self.option_vector))
+
+    @property
+    def short_edid(self):
+        return ("%s..%s" % (self.edid[:5], self.edid[-5:])) if self.edid else ""
 
     @property
     def options_with_defaults(self):
@@ -358,6 +363,27 @@ def __ne__(self, other):
     def __eq__(self, other):
         return self.edid_equals(other) and self.output == other.output and self.filtered_options == other.filtered_options
 
+    def verbose_diff(self, other):
+        "Compare to another XrandrOutput and return a list of human readable differences"
+        diffs = []
+        if not self.edid_equals(other):
+            diffs.append("EDID `%s' differs from `%s'" % (self.short_edid, other.short_edid))
+        if self.output != other.output:
+            diffs.append("Output name `%s' differs from `%s'" % (self.output, other.output))
+        if "off" in self.options and "off" not in other.options:
+            diffs.append("The output is disabled currently, but active in the new configuration")
+        elif "off" in other.options and "off" not in self.options:
+            diffs.append("The output is currently enabled, but inactive in the new configuration")
+        else:
+            for name in set(chain.from_iterable((self.options.keys(), other.options.keys()))):
+                if name not in other.options:
+                    diffs.append("Option --%s %sis not present in the new configuration" % (name, "(= `%s') " % self.options[name] if self.options[name] else ""))
+                elif name not in self.options:
+                    diffs.append("Option --%s (`%s' in the new configuration) is not present currently" % (name, other.options[name]))
+                elif self.options[name] != other.options[name]:
+                    diffs.append("Option --%s %sis `%s' in the new configuration" % (name, "(= `%s') " % self.options[name] if self.options[name] else "", other.options[name]))
+        return diffs
+
 def xrandr_version():
     "Return the version of XRandR that this system uses"
     if getattr(xrandr_version, "version", False) is False:
@@ -619,6 +645,23 @@ def generate_virtual_profile(configuration, modes, profile_name):
                 configuration[output].options["off"] = None
     return configuration
 
+def print_profile_differences(one, another):
+    "Print the differences between two profiles for debugging"
+    if one == another:
+        return
+    print("| Differences between the two profiles:", file=sys.stderr)
+    for output in set(chain.from_iterable((one.keys(), another.keys()))):
+        if output not in one:
+            if "off" not in another[output].options:
+                print("| Output `%s' is missing from the active configuration" % output, file=sys.stderr)
+        elif output not in another:
+            if "off" not in one[output].options:
+                print("| Output `%s' is missing from the new configuration" % output, file=sys.stderr)
+        else:
+            for line in one[output].verbose_diff(another[output]):
+                print("| [Output %s] %s" % (output, line), file=sys.stderr)
+    print ("\\-", file=sys.stderr)
+
 def exit_help():
     "Print help and exit"
     print(help_text)
@@ -634,7 +677,7 @@ def exec_scripts(profile_path, script_name):
 
 def main(argv):
     try:
-       options = dict(getopt.getopt(argv[1:], "s:l:d:cfh", [ "dry-run", "change", "default=", "save=", "load=", "force", "fingerprint", "config", "skip-options=", "help" ])[0])
+       options = dict(getopt.getopt(argv[1:], "s:l:d:cfh", [ "dry-run", "change", "default=", "save=", "load=", "force", "fingerprint", "config", "debug", "skip-options=", "help" ])[0])
     except getopt.GetoptError as e:
         print("Failed to parse options: {0}.\n"
               "Use --help to get usage information.".format(str(e)),
@@ -711,9 +754,12 @@ def main(argv):
                 props.append("(detected)")
                 if ("-c" in options or "--change" in options) and not load_profile:
                     load_profile = profile_name
-            if is_equal_configuration(config, profiles[profile_name]["config"]):
+            configs_are_equal = is_equal_configuration(config, profiles[profile_name]["config"])
+            if configs_are_equal:
                 props.append("(current)")
             print("%s%s%s" % (profile_name, " " if props else "", " ".join(props)), file=sys.stderr)
+            if not configs_are_equal and "--debug" in options and profile_name in detected_profiles:
+                print_profile_differences(config, profiles[profile_name]["config"])
 
     if "-d" in options:
         options["--default"] = options["-d"]
@@ -737,6 +783,10 @@ def main(argv):
         if load_config == dict(config) and not "-f" in options and not "--force" in options:
             print("Config already loaded", file=sys.stderr)
             sys.exit(0)
+        if "--debug" in options and load_config != dict(config):
+            print("Loading profile '%s'" % load_profile)
+            print_profile_differences(config, load_config)
+
         remove_irrelevant_outputs(config, load_config)
 
         try: