fix style of MouseEvent interface

src/browser/events/mouse_event.zig

@@ -16,14 +16,29 @@
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+const std = @import("std");
+const log = std.log.scoped(.mouse_event);
+
 const parser = @import("../netsurf.zig");
 const Event = @import("event.zig").Event;
 const JsObject = @import("../env.zig").JsObject;
 
+// TODO: We currently don't have a UIEvent interface so we skip it in the prototype chain.
+// https://developer.mozilla.org/en-US/docs/Web/API/UIEvent
+const UIEvent = Event;
+
 // https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent
 pub const MouseEvent = struct {
     pub const Self = parser.MouseEvent;
-    pub const prototype = *Event;
+    pub const prototype = *UIEvent;
+
+    const MouseButton = enum(u16) {
+        main_button = 0,
+        auxillary_button = 1,
+        secondary_button = 2,
+        fourth_button = 3,
+        fifth_button = 4,
+    };
 
     const MouseEventInit = struct {
         screenX: i32 = 0,
@@ -34,13 +49,14 @@ pub const MouseEvent = struct {
         shiftKey: bool = false,
         altKey: bool = false,
         metaKey: bool = false,
-        button: u16 = 0,
+        button: MouseButton = .main_button,
     };
 
-    pub fn constructor(event_type: []const u8, opts_: ?MouseEventInit) !*Self {
+    pub fn constructor(event_type: []const u8, opts_: ?MouseEventInit) !*parser.MouseEvent {
         const opts = opts_ orelse MouseEventInit{};
 
-        const mouse_event = try parser.mouseEventCreate();
+        var mouse_event = try parser.mouseEventCreate();
+        try parser.eventSetInternalType(@ptrCast(&mouse_event), .mouse_event);
 
         try parser.mouseEventInit(mouse_event, event_type, .{
             .x = opts.clientX,
@@ -49,35 +65,43 @@ pub const MouseEvent = struct {
             .shift = opts.shiftKey,
             .alt = opts.altKey,
             .meta = opts.metaKey,
-            .button = opts.button,
+            .button = @intFromEnum(opts.button),
         });
 
+        if (!std.mem.eql(u8, event_type, "click")) {
+            log.warn("MouseEvent currently only supports listeners for 'click' events!", .{});
+        }
+
         return mouse_event;
     }
 
+    pub fn get_button(self: *parser.MouseEvent) u16 {
+        return self.button;
+    }
+
     // These is just an alias for clientX.
-    pub fn get_x(self: *Self) !i32 {
+    pub fn get_x(self: *parser.MouseEvent) i32 {
         return self.cx;
     }
 
     // These is just an alias for clientY.
-    pub fn get_y(self: *Self) !i32 {
+    pub fn get_y(self: *parser.MouseEvent) i32 {
         return self.cy;
     }
 
-    pub fn get_clientX(self: *Self) !i32 {
+    pub fn get_clientX(self: *parser.MouseEvent) i32 {
         return self.cx;
     }
 
-    pub fn get_clientY(self: *Self) !i32 {
+    pub fn get_clientY(self: *parser.MouseEvent) i32 {
         return self.cy;
     }
 
-    pub fn get_screenX(self: *Self) !i32 {
+    pub fn get_screenX(self: *parser.MouseEvent) i32 {
         return self.sx;
     }
 
-    pub fn get_screenY(self: *Self) !i32 {
+    pub fn get_screenY(self: *parser.MouseEvent) i32 {
         return self.sy;
     }
 };
@@ -88,6 +112,7 @@ test "Browser.MouseEvent" {
     defer runner.deinit();
 
     try runner.testCases(&.{
+        // Default MouseEvent
         .{ "let event = new MouseEvent('click')", "undefined" },
         .{ "event.type", "click" },
         .{ "event instanceof MouseEvent", "true" },
@@ -96,10 +121,20 @@ test "Browser.MouseEvent" {
         .{ "event.clientY", "0" },
         .{ "event.screenX", "0" },
         .{ "event.screenY", "0" },
-        .{ "let new_event = new MouseEvent('click2', { 'clientX': 10, 'clientY': 20 })", "undefined" },
+        // MouseEvent with parameters
+        .{ "let new_event = new MouseEvent('click', { 'button': 0, 'clientX': 10, 'clientY': 20 })", "undefined" },
+        .{ "new_event.button", "0" },
         .{ "new_event.x", "10" },
         .{ "new_event.y", "20" },
         .{ "new_event.screenX", "10" },
         .{ "new_event.screenY", "20" },
+        // MouseEvent Listener
+        .{ "let me = new MouseEvent('click')", "undefined" },
+        .{ "me instanceof Event", "true" },
+        .{ "var eevt = null; function ccbk(event) { eevt = event; }", "undefined" },
+        .{ "document.addEventListener('click', ccbk)", "undefined" },
+        .{ "document.dispatchEvent(me)", "true" },
+        .{ "eevt.type", "click" },
+        .{ "eevt instanceof MouseEvent", "true" },
     }, .{});
 }