Create function to trigger Steam download

data/language/en-GB.txt

@@ -3843,3 +3843,6 @@ STR_7010    :Could not start replay, file ‘{STRING}’ doesn’t exist or isn
 STR_7011    :Could not start replay
 STR_7012    :Polish Złoty (PLN)
 STR_7013    :Drag areas of path
+STR_7014    :I own the game on Steam, but I haven’t installed it yet.
+STR_7015    :Please close Steam if it’s running, then click ‘OK’.
+STR_7016    :OpenRCT2 has tried to trigger a download in Steam. Please open Steam and let it download the game. When Steam is finished, click ‘OK’.

src/openrct2/config/Config.cpp

@@ -909,6 +909,7 @@ namespace OpenRCT2::Config
                 {
                     uiContext.ShowMessageBox(LanguageGetString(STR_NEEDS_RCT2_FILES));
                     std::string gog = LanguageGetString(STR_OWN_ON_GOG);
+                    std::string steam = LanguageGetString(STR_OWN_ON_STEAM);
                     std::string hdd = LanguageGetString(STR_INSTALLED_ON_HDD);
 
                     std::vector<std::string> options;
@@ -918,6 +919,7 @@ namespace OpenRCT2::Config
                     {
                         options.push_back(hdd);
                         options.push_back(gog);
+                        options.push_back(steam);
                         int optionIndex = uiContext.ShowMenuDialog(
                             options, LanguageGetString(STR_OPENRCT2_SETUP), LanguageGetString(STR_WHICH_APPLIES_BEST));
                         if (optionIndex < 0 || static_cast<uint32_t>(optionIndex) >= options.size())
@@ -975,6 +977,21 @@ namespace OpenRCT2::Config
                         possibleInstallPaths.emplace_back(dest);
                         possibleInstallPaths.emplace_back(Path::Combine(dest, u8"app"));
                     }
+                    else if (chosenOption == steam)
+                    {
+                        uiContext.ShowMessageBox(LanguageGetString(STR_PLEASE_CLOSE_STEAM));
+
+                        Platform::triggerSteamDownload();
+
+                        uiContext.ShowMessageBox(LanguageGetString(STR_WAIT_FOR_STEAM_DOWNLOAD));
+
+                        auto steamPath = FindRCT2SteamPath();
+                        if (!steamPath.empty())
+                        {
+                            Get().general.rct2Path = steamPath;
+                            return true;
+                        }
+                    }
                     if (possibleInstallPaths.empty())
                     {
                         return false;

src/openrct2/localisation/StringIds.h

@@ -1602,6 +1602,9 @@ enum : StringId
     STR_THIS_WILL_TAKE_A_FEW_MINUTES = 6407,
     STR_INSTALL_INNOEXTRACT = 6408,
     STR_NOT_THE_GOG_INSTALLER = 6409,
+    STR_OWN_ON_STEAM = 7014,
+    STR_PLEASE_CLOSE_STEAM = 7015,
+    STR_WAIT_FOR_STEAM_DOWNLOAD = 7016,
 
     STR_TILE_INSPECTOR_TOGGLE_INVISIBILITY_TIP = 6436,
 

src/openrct2/platform/Platform.Common.cpp

@@ -224,4 +224,32 @@ namespace OpenRCT2::Platform
             steamroot, downloadDepotFolder, "app_" + std::to_string(data.appId), "depot_" + std::to_string(data.depotId));
     }
 
+    bool triggerSteamDownload()
+    {
+        const auto steamPaths = GetSteamPaths();
+        if (!steamPaths.isSteamPresent() || steamPaths.manifests.empty())
+            return false;
+
+        const auto manifestsDir = Path::Combine(steamPaths.roots[0], steamPaths.manifests);
+        const std::array<SteamGameData, 3> gamesToTrigger = { kSteamRCT2Data, kSteamRCTCData, kSteamRCT1Data };
+        for (const auto& game : gamesToTrigger)
+        {
+            auto fullFilename = Path::Combine(manifestsDir, "appmanifest_" + std::to_string(game.appId) + ".acf");
+            // If the file exists, we assume a download has been triggered already.
+            if (File::Exists(fullFilename))
+                continue;
+
+            // clang-format off
+            auto buffer = u8string("\"AppState\"\r\n") + u8string("{\r\n")
+                + u8string("	\"AppID\"	\"" + std::to_string(game.appId) + "\"\r\n")
+                + u8string("	\"Universe\"	\"1\"\r\n")
+                + u8string("	\"installdir\"	\"" + game.nativeFolder + "\"\r\n")
+                + u8string("	\"StateFlags\"	\"1026\"\r\n") + u8string("}\r\n");
+            // clang-format on
+            File::WriteAllBytes(fullFilename, buffer.data(), buffer.size());
+        }
+
+        return true;
+    }
+
 } // namespace OpenRCT2::Platform

src/openrct2/platform/Platform.h

@@ -146,6 +146,7 @@ namespace OpenRCT2::Platform
     std::string GetUsername();
 
     SteamPaths GetSteamPaths();
+    bool triggerSteamDownload();
 #if defined(__unix__) || (defined(__APPLE__) && defined(__MACH__)) || defined(__FreeBSD__) || defined(__NetBSD__)
     std::string GetEnvironmentPath(const char* name);
     std::string GetHomePath();