Ad webview occlusion handling (#6116)

* wip: ad webview occlusion

* Ad webview window occlusion testing

* revert refresh test

apps/app/src/api/ads_occlusion_windows.rs

@@ -0,0 +1,193 @@
+use windows::Win32::Foundation::{HWND, POINT, RECT};
+use windows::Win32::Graphics::Dwm::{
+    DWMWA_CLOAKED, DWMWA_EXTENDED_FRAME_BOUNDS, DwmGetWindowAttribute,
+};
+use windows::Win32::Graphics::Gdi::ClientToScreen;
+use windows::Win32::UI::WindowsAndMessaging::{
+    GA_ROOT, GW_HWNDNEXT, GetAncestor, GetTopWindow, GetWindow, GetWindowRect,
+    GetWindowThreadProcessId, IsIconic, IsWindowVisible,
+};
+
+const OCCLUDED_AREA_THRESHOLD: f64 = 1.0;
+
+pub fn is_ads_webview_occluded(
+    main_hwnd: HWND,
+    x: i32,
+    y: i32,
+    width: u32,
+    height: u32,
+) -> bool {
+    let Some(ad_rect) = ad_rect_in_screen(main_hwnd, x, y, width, height)
+    else {
+        return false;
+    };
+
+    if is_empty_rect(&ad_rect) {
+        return false;
+    }
+
+    let ad_area = rect_area(&ad_rect);
+    if ad_area == 0 {
+        return false;
+    }
+
+    let mut occluded_area = 0u64;
+    let app_root = unsafe { GetAncestor(main_hwnd, GA_ROOT) };
+    let app_process_id = std::process::id();
+    let mut hwnd = match unsafe { GetTopWindow(None) } {
+        Ok(hwnd) => hwnd,
+        Err(_) => return false,
+    };
+
+    while !hwnd.is_invalid() {
+        let window_root = unsafe { GetAncestor(hwnd, GA_ROOT) };
+
+        if window_root == app_root {
+            return false;
+        }
+
+        if window_process_id(hwnd) == Some(app_process_id) {
+            hwnd = match unsafe { GetWindow(hwnd, GW_HWNDNEXT) } {
+                Ok(hwnd) => hwnd,
+                Err(_) => break,
+            };
+            continue;
+        }
+
+        if window_counts_as_occluder(hwnd)
+            && let Some(occluder_rect) = window_rect(hwnd)
+            && let Some(intersection) =
+                intersect_rects(&ad_rect, &occluder_rect)
+        {
+            occluded_area =
+                occluded_area.saturating_add(rect_area(&intersection));
+
+            if (occluded_area as f64 / ad_area as f64)
+                >= OCCLUDED_AREA_THRESHOLD
+            {
+                return true;
+            }
+        }
+
+        hwnd = match unsafe { GetWindow(hwnd, GW_HWNDNEXT) } {
+            Ok(hwnd) => hwnd,
+            Err(_) => break,
+        };
+    }
+
+    false
+}
+
+fn ad_rect_in_screen(
+    main_hwnd: HWND,
+    x: i32,
+    y: i32,
+    width: u32,
+    height: u32,
+) -> Option<RECT> {
+    let mut origin = POINT { x: 0, y: 0 };
+
+    if !unsafe { ClientToScreen(main_hwnd, &mut origin).as_bool() } {
+        return None;
+    }
+
+    let left = origin.x.saturating_add(x);
+    let top = origin.y.saturating_add(y);
+    let right = left.saturating_add(width as i32);
+    let bottom = top.saturating_add(height as i32);
+
+    Some(RECT {
+        left,
+        top,
+        right,
+        bottom,
+    })
+}
+
+fn window_counts_as_occluder(hwnd: HWND) -> bool {
+    if !unsafe { IsWindowVisible(hwnd).as_bool() } {
+        return false;
+    }
+
+    if unsafe { IsIconic(hwnd).as_bool() } {
+        return false;
+    }
+
+    if is_dwm_cloaked(hwnd) {
+        return false;
+    }
+
+    true
+}
+
+fn window_process_id(hwnd: HWND) -> Option<u32> {
+    let mut process_id = 0u32;
+
+    unsafe {
+        GetWindowThreadProcessId(hwnd, Some(&mut process_id));
+    }
+
+    (process_id != 0).then_some(process_id)
+}
+
+fn is_dwm_cloaked(hwnd: HWND) -> bool {
+    let mut cloaked = 0u32;
+
+    unsafe {
+        DwmGetWindowAttribute(
+            hwnd,
+            DWMWA_CLOAKED,
+            &mut cloaked as *mut u32 as *mut _,
+            std::mem::size_of::<u32>() as u32,
+        )
+    }
+    .is_ok()
+        && cloaked != 0
+}
+
+fn window_rect(hwnd: HWND) -> Option<RECT> {
+    let mut rect = RECT::default();
+
+    if unsafe {
+        DwmGetWindowAttribute(
+            hwnd,
+            DWMWA_EXTENDED_FRAME_BOUNDS,
+            &mut rect as *mut RECT as *mut _,
+            std::mem::size_of::<RECT>() as u32,
+        )
+    }
+    .is_err()
+        && unsafe { GetWindowRect(hwnd, &mut rect) }.is_err()
+    {
+        return None;
+    }
+
+    if is_empty_rect(&rect) {
+        return None;
+    }
+
+    Some(rect)
+}
+
+fn is_empty_rect(rect: &RECT) -> bool {
+    rect.right <= rect.left || rect.bottom <= rect.top
+}
+
+fn rect_area(rect: &RECT) -> u64 {
+    if is_empty_rect(rect) {
+        return 0;
+    }
+
+    (rect.right - rect.left) as u64 * (rect.bottom - rect.top) as u64
+}
+
+fn intersect_rects(a: &RECT, b: &RECT) -> Option<RECT> {
+    let rect = RECT {
+        left: a.left.max(b.left),
+        top: a.top.max(b.top),
+        right: a.right.min(b.right),
+        bottom: a.bottom.min(b.bottom),
+    };
+
+    (!is_empty_rect(&rect)).then_some(rect)
+}