From e69b4303fdd904f41357da16863dbd3b03853d2c Mon Sep 17 00:00:00 2001
From: Robin Linden <dev@robinlinden.eu>
Date: Sat, 21 Oct 2023 22:03:59 +0200
Subject: [PATCH] browser/gui: Display favicons if available

---
 browser/gui/app.cpp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/browser/gui/app.cpp b/browser/gui/app.cpp
index 2db9c1a73..548368921 100644
--- a/browser/gui/app.cpp
+++ b/browser/gui/app.cpp
@@ -11,6 +11,7 @@
 #include "render/render.h"
 #include "uri/uri.h"
 
+#include <SFML/Graphics/Image.hpp>
 #include <SFML/Window/Event.hpp>
 #include <fmt/format.h>
 #include <imgui-SFML.h>
@@ -24,6 +25,7 @@
 #include <cstdlib>
 #include <functional>
 #include <optional>
+#include <ranges>
 #include <sstream>
 #include <string_view>
 #include <utility>
@@ -327,6 +329,7 @@ int App::run() {
 }
 
 void App::navigate() {
+    // TODO(robinlinden): Unset favicon. May require us to have a Hastur icon.
     page_loaded_ = false;
     auto uri = uri::Uri::parse(url_buf_, engine_.uri());
     browse_history_.push(uri);
@@ -395,6 +398,27 @@ void App::on_page_loaded() {
         window_.setTitle(browser_title_);
     }
 
+    // TODO(robinlinden): Non-blocking load of favicon.
+    // https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel#icon
+    auto is_favicon_link = [](dom::Element const *v) {
+        auto rel = v->attributes.find("rel");
+        return rel != end(v->attributes) && rel->second == "icon" && v->attributes.contains("href");
+    };
+
+    for (auto const &link : dom::nodes_by_xpath(engine_.dom().html(), "/html/head/link")
+                    | std::views::filter(is_favicon_link) | std::views::reverse) {
+        auto uri = uri::Uri::parse(link->attributes.at("href"), engine_.uri());
+        auto icon = engine_.load(uri).response;
+        sf::Image favicon;
+        if (icon.err != protocol::Error::Ok || !favicon.loadFromMemory(icon.body.data(), icon.body.size())) {
+            spdlog::warn("Error loading favicon from '{}': {}", uri.uri, to_string(icon.err));
+            continue;
+        }
+
+        window_.setIcon(favicon.getSize().x, favicon.getSize().y, favicon.getPixelsPtr());
+        break;
+    }
+
     update_status_line();
     response_headers_str_ = engine_.response().headers.to_string();
     dom_str_ = dom::to_string(engine_.dom());