Initial better mod browser link implementation

Signed-off-by: TheKodeToad <TheKodeToad@proton.me>

launcher/ui/pages/modplatform/ModPage.cpp

@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 TheKodeToad <TheKodeToad@proton.me>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -37,6 +38,7 @@
 #include "Application.h"
 #include "ui_ModPage.h"
 
+#include <QDesktopServices>
 #include <QKeyEvent>
 #include <memory>
 
@@ -80,6 +82,8 @@ ModPage::ModPage(ModDownloadDialog* dialog, BaseInstance* instance, ModAPI* api)
 
     ui->packView->setItemDelegate(new ProjectItemDelegate(this));
     ui->packView->installEventFilter(this);
+
+    connect(ui->packDescription, &QTextBrowser::anchorClicked, this, &ModPage::openUrl);
 }
 
 ModPage::~ModPage()
@@ -158,8 +162,8 @@ void ModPage::triggerSearch()
 {
     auto changed = m_filter_widget->changed();
     m_filter = m_filter_widget->getFilter();
-    
-    if(changed){
+
+    if (changed) {
         ui->packView->clearSelection();
         ui->packDescription->clear();
         ui->versionSelectionBox->clear();
@@ -241,6 +245,54 @@ void ModPage::onModSelected()
     ui->packView->adjustSize();
 }
 
+void ModPage::openUrl(const QUrl& url)
+{
+    // do not allow other url schemes for security reasons
+    if (!(url.scheme() == "http" || url.scheme() == "https")) {
+        qWarning() << "Unsupported scheme" << url.scheme();
+        return;
+    }
+
+    // detect mod URLs and search instead
+    int prefixLength;
+    const char* page;
+
+    if ((url.host() == "modrinth.com" || url.host() == "www.modrinth.com")
+            && url.path().startsWith("/mod/")) {
+        prefixLength = 5;
+        page = "modrinth";
+    }
+    else if (APPLICATION->capabilities() & Application::SupportsFlame
+            && url.host() == "www.curseforge.com"
+            && url.path().toLower().startsWith("/minecraft/mc-mods/")) {
+        prefixLength = 19;
+        page = "curseforge";
+    }
+    else
+        prefixLength = 0;
+
+    if (prefixLength != 0) {
+        QString slug = url.path().mid(prefixLength);
+
+        // remove trailing slash(es)
+        while (slug.endsWith('/'))
+            slug.remove(slug.length() - 1, 1);
+
+        // ensure that the path doesn't contain any further slashes,
+        // and the user isn't opening the same mod; they probably
+        // intended to view in their web browser
+        if (!slug.isEmpty() && !slug.contains('/') && slug != current.slug) {
+            ui->searchEdit->setText(slug);
+            dialog->selectPage(page);
+            triggerSearch();
+            return;
+        }
+    }
+
+    // open in the user's web browser
+    QDesktopServices::openUrl(url);
+}
+
 
 /******** Make changes to the UI ********/
 
@@ -270,8 +322,8 @@ void ModPage::updateModVersions(int prev_count)
         if ((valid || m_filter->versions.empty()) && !optedOut(version))
             ui->versionSelectionBox->addItem(version.version, QVariant(i));
     }
-    if (ui->versionSelectionBox->count() == 0 && prev_count != 0) { 
-        ui->versionSelectionBox->addItem(tr("No valid version found!"), QVariant(-1)); 
+    if (ui->versionSelectionBox->count() == 0 && prev_count != 0) {
+        ui->versionSelectionBox->addItem(tr("No valid version found!"), QVariant(-1));
         ui->modSelectionButton->setText(tr("Cannot select invalid version :("));
     }
 
@@ -317,8 +369,7 @@ void ModPage::updateUi()
         text += "<br>" + tr(" by ") + authorStrs.join(", ");
     }
 
-    
-    if(current.extraDataLoaded) {
+    if (current.extraDataLoaded) {
         if (!current.extraData.donate.isEmpty()) {
             text += "<br><br>" + tr("Donate information: ");
             auto donateToStr = [](ModPlatform::DonationData& donate) -> QString {