Add code documentation

src/modules/Nightlighter.js

@@ -26,6 +26,11 @@ const Gettext = imports.gettext.domain(config.EXT_UUID);
 const _ = Gettext.gettext;
 
 
+/*
+The Nightlighter establishes a connection with the session bus to get the
+current Night Light status. It can also be asked to listen to status changes.
+*/
+
 var Nightlighter = class {
 
 	constructor() {
@@ -33,7 +38,7 @@ var Nightlighter = class {
 			this._connect_to_dbus();
 		}
 		catch(e) {
-			throw e;
+			throw e; // Let's pass the error up.
 		}
 	}
 
@@ -42,7 +47,7 @@ var Nightlighter = class {
 			return this.proxy.get_cached_property('NightLightActive').get_boolean();
 		}
 		catch(e) {
-			return false;
+			return false; // If Night Light is disabled, we consider it is inactive.
 		}
 	}
 

src/modules/Switcher.js

@@ -27,6 +27,20 @@ const { Themer } = Me.imports.modules.Themer;
 const { Variants } = Me.imports.modules.Variants;
 
 
+/*
+The Switcher is the brain of the extension.
+
+When the extension is enabled, it listens to theme changes from the user and
+changes in the Night Light status:
+	- On theme changes, it asks for the new day and night variants for that
+	theme.
+	- On Night Light activation or deactivation, it asks for the relevant
+	variant to be applied.
+
+When the extension is disabled, it resets the theme to the last one the user
+explicitely selected, stops listening to changes and cleans itself.
+*/
+
 var Switcher = class {
 
 	constructor() {
@@ -55,7 +69,7 @@ var Switcher = class {
 			this.theme.stop_listening();
 			this.nightlight.stop_listening();
 		}
-		catch(e) {}
+		catch(e) {} // Since we're disabling, we'll just ignore errors.
 		finally {
 			this.theme = null;
 			this.variants = null;

src/modules/Themer.js

@@ -23,6 +23,11 @@ const Me = extensionUtils.getCurrentExtension();
 const config = Me.imports.config;
 
 
+/*
+The Theme communicates with the system to get the current theme or set a new
+one. It can also be asked to listen to theme changes.
+*/
+
 var Themer = class {
 
 	constructor() {

src/modules/Variants.js

@@ -17,6 +17,31 @@ You should have received a copy of the GNU General Public License along with
 this program. If not, see <http s ://www.gnu.org/licenses/>.
 */
 
+
+/*
+The magic of guessing theme variants happens here.
+
+If the theme doesn't fit a particular case, we'll do the following:
+	- Remove any signs of a dark variant to the theme name to get the day
+	variant
+	- Remove any signs of a light variant to the day variant and add '-dark' to
+	get the night variant
+
+For themes that don't work with the general rule, a particular case must be
+written. Day and night variants should be guessed with the most generic light
+and dark variants the theme offer, except if the user explicitly chose a
+specific variant.
+
+Light variants, from the most to the least generic:
+	- ''
+	- '-light'
+	- '-darker'
+
+Dark variants, from the most the least generic:
+	- '-dark'
+	- '-darkest'
+*/
+
 var Variants = class {
 
 	static guess_from(name) {