Implement auto color-scheme in order to respect browser's selected prefers-color-scheme

api/js/framework/fw_base.js

@@ -64,8 +64,17 @@ var fw_base = (function(){ "use strict"; return Class.extend(
 		// keep track of opened popups
 		this.popups = [];
 
+
 		// initiate dark mode
-		this._setDarkMode(egw.preference('darkmode', 'common'));
+		let darkmode = egw.getSessionItem('api', 'darkmode');
+		if (darkmode == '0' || darkmode == '1')
+		{
+			this._setDarkMode(darkmode);
+		}
+		else if (egw.preference('darkmode', 'common') !='2')
+		{
+			this._setDarkMode( egw.preference('darkmode', 'common'));
+		}
 	},
 
 	/**
@@ -1304,8 +1313,14 @@ var fw_base = (function(){ "use strict"; return Class.extend(
 		return _app && _app.appName != _app.internalName;
 	},
 
+	/**
+	 * set darkmode attribute into html tag
+	 * @param string _state '0' means off and '1' means on
+	 * @private
+	 */
 	_setDarkMode: function(_state)
 	{
 		jQuery('html').attr('data-darkmode', _state);
+		egw.setSessionItem('api', 'darkmode',_state == '0' ?'0':'1');
 	}
 });}).call(this);

api/js/framework/fw_desktop.js

@@ -220,6 +220,31 @@
 					egw.message(egw.lang('Browser %1 %2 is not recommended. You may experience issues and not working features. Please use the latest version of Chrome, Firefox or Edge. Thank You!', 'IE',''), 'info', 'browser:ie:warning');
 				}
 			});
+
+			// initiate darkmode
+			let darkmode = egw.preference('darkmode', 'common');
+			if (darkmode == '2')
+			{
+				let prefes_color_scheme = this._get_prefers_color_scheme();
+				if (prefes_color_scheme)
+				{
+
+					window.matchMedia('(prefers-color-scheme: dark)')
+						.addEventListener('change', event => {
+							this.toggle_darkmode(document.getElementById('topmenu_info_darkmode'), event.matches?false:true);
+						});
+					this.toggle_darkmode(document.getElementById('topmenu_info_darkmode'), prefes_color_scheme == 'light');
+				}
+			}
+			else if (egw.getSessionItem('api', 'darkmode') == '1')
+			{
+				this.toggle_darkmode(document.getElementById('topmenu_info_darkmode'), false);
+			}
+			else if(egw.getSessionItem('api', 'darkmode') == '0')
+			{
+				this.toggle_darkmode(document.getElementById('topmenu_info_darkmode'), true);
+			}
+
 		},
 
 		/**
@@ -537,14 +562,31 @@
 			if (app.status) app.status.mergeContent(_data, true);
 		},
 
+		/**
+		 * Get color scheme
+		 * @return {string|null} returns active color scheme mode or null in case browser not supporting it
+		 * @private
+		 */
+		_get_prefers_color_scheme: function ()
+		{
+			if (window.matchMedia('(prefers-color-scheme: light)').matches)
+			{
+				return 'light';
+			}
+			if (window.matchMedia('(prefers-color-scheme: dark)').matches)
+			{
+				return 'dark'
+			}
+			return null;
+		},
+
 		/**
 		 *
 		 * @param node
 		 */
-		toggle_darkmode: function(node)
+		toggle_darkmode: function(node, _state)
 		{
-			let state = node.firstElementChild.classList.contains('darkmode_on');
-			egw.set_preference('common', 'darkmode',state?'0':'1');
+			let state = (typeof _state != 'undefined') ? _state : node.firstElementChild.classList.contains('darkmode_on');
 			this._setDarkMode(state?'0':'1');
 			if (state == 1)
 			{

api/js/jsapi/egw_app.js

@@ -118,7 +118,7 @@ var EgwApp = /** @class */ (function () {
         // Highlights the favorite based on initial list state
         this.highlight_favorite();
         // apply theme mode
-        jQuery('html').attr('data-darkmode', egw.preference('darkmode', 'common'));
+        window.framework._setDarkMode(egw.getSessionItem('api', 'darkmode'));
     };
     /**
      * Observer method receives update notifications from all applications

api/js/jsapi/egw_app.ts

@@ -208,7 +208,7 @@ export abstract class EgwApp
 		// Highlights the favorite based on initial list state
 		this.highlight_favorite();
 		// apply theme mode
-		jQuery('html').attr('data-darkmode', <string> egw.preference('darkmode', 'common'));
+		window.framework._setDarkMode(egw.getSessionItem('api', 'darkmode'));
 	}
 
 	/**

api/js/login.js

@@ -72,6 +72,8 @@ egw_LAB.wait(function()
 			this.form.method = 'get';
 			jQuery(this.form).append('<input type="hidden" name="auth" value="saml"/>');
 		});
+		//cleanup darkmode session value
+		egw.setSessionItem('api', 'darkmode','');
 	});
 });
 

pixelegg/less/darkmode.less

@@ -25,7 +25,7 @@
       filter: invert(1) hue-rotate(180deg) !important;
     }
     div.dhtmlxMenu_egw_SubLevelArea_Polygon,.egw_tooltip,
-    body .egw_message_wrapper,#egw_fw_header #egw_fw_topmenu,.ui-dialog, .box_shadow,
+    body .egw_message_wrapper,#egw_fw_header #egw_fw_topmenu,.ui-dialog, .box_shadow
     {
       box-shadow: 0px 0px 2px 2px #666666;
       -moz-box-shadow: 0px 0px 2px 2px #666666;

preferences/inc/class.preferences_hooks.inc.php

@@ -182,7 +182,7 @@ class preferences_hooks
 				'type'   => 'select',
 				'label'  => 'Dark mode theme',
 				'name'   => 'darkmode',
-				'values' => array('0' => 'off', '1' => 'on'),
+				'values' => array('0' => 'off', '1' => 'on', '2'=> 'auto'),
 				'help'   => 'Dark mode theme',
 				'admin'  => False,
 				'default' => '0'