3 files changed, 100 insertions, 13 deletions

diff --git a/src/filesystem.cpp b/src/filesystem.cpp
new file mode 100644
index 0000000..4dfa183
--- /dev/null
+++ b/src/filesystem.cpp
@@ -0,0 +1,30 @@
+#include "filesystem.hpp"
+
+#include <boost/iterator/filter_iterator.hpp>
+
+#include <random>
+
+namespace wanda
+{
+
+std::optional<path_list> scan(std::filesystem::path source, bool(filter)(std::filesystem::path const &))
+{
+    if (!std::filesystem::is_directory(source))
+    {
+        return std::nullopt;
+    }
+
+    auto first = boost::make_filter_iterator(filter, std::filesystem::recursive_directory_iterator{source});
+    auto last = boost::make_filter_iterator(filter, std::filesystem::recursive_directory_iterator{});
+    return path_list{first, last};
+}
+
+std::filesystem::path random_pick(path_list const &paths)
+{
+    static auto generator = std::mt19937{std::random_device{}()};
+    auto distribution = std::uniform_int_distribution<std::size_t>{0, paths.size() - 1};
+
+    return paths[distribution(generator)];
+}
+
+} // namespace wanda
\ No newline at end of file
diff --git a/src/filesystem.hpp b/src/filesystem.hpp
new file mode 100644
index 0000000..bcc9e5e
--- /dev/null
+++ b/src/filesystem.hpp
@@ -0,0 +1,35 @@
+#ifndef WANDA_FILESYSTEM_HPP
+#define WANDA_FILESYSTEM_HPP
+
+#include <filesystem>
+#include <optional>
+#include <vector>
+
+namespace wanda
+{
+
+/**
+ * @brief Covenience alias for path lists
+ */
+using path_list = std::vector<std::filesystem::path>;
+
+/**
+ * @brief The default scan filter, allowing only regular files to pass
+ */
+constexpr inline auto default_filter = [](std::filesystem::path const &path) {
+    return is_regular_file(path);
+};
+
+/**
+ * @brief Scan the given folder for files
+ */
+std::optional<path_list> scan(std::filesystem::path folder, bool(filter)(std::filesystem::path const &) = default_filter);
+
+/**
+ * @brief Pick a random path from the given list
+ */
+std::filesystem::path random_pick(path_list const &paths);
+
+} // namespace wanda
+
+#endif
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index 38fdf7f..6d1353d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,28 +1,50 @@
+#include "filesystem.hpp"
 #include "setting.hpp"
 #include "optional.hpp"
 
 #include <iostream>
+#include <set>
 #include <string>
 
-#include <typeinfo>
+namespace
+{
 
-int main()
+void set_wallpaper(std::filesystem::path wallpaper)
 {
   using namespace wanda::literals;
   using namespace wanda::std_ext;
   using namespace std::string_literals;
 
-  with("org.gnome.desktop.background"_setting, [](auto &setting) {
-    with(setting["picture-uri"_key], [](auto &value) {
-      std::visit([](auto &&value) {
-        using ValueType = std::decay_t<decltype(value)>;
-        if constexpr (std::is_same_v<ValueType, std::string>)
-        {
-          std::cout << value << '\n';
-        }
-      },
-      *value);
-      std::cout << (value = "file:///"s) << '\n';
+  with("org.gnome.desktop.background"_setting, [&](auto &setting) {
+    with(setting["picture-uri"_key], [&](auto &value) {
+      value = "file://" + wallpaper.native();
     }) || [] { std::cerr << "No such key!\n"; };
   }) || [] { std::cerr << "No such setting!\n"; };
 }
+
+constexpr auto image_filter = [](auto const &path) {
+  static auto const extensions = std::set<std::filesystem::path>{
+      std::filesystem::path{".jpg"},
+      std::filesystem::path{".png"},
+  };
+
+  if (!std::filesystem::is_regular_file(path))
+  {
+    return false;
+  }
+
+  return extensions.find(path.extension()) != extensions.cend();
+};
+
+} // namespace
+
+int main()
+{
+  using namespace wanda::std_ext;
+
+  with(wanda::scan({"/usr/share/backgrounds"}, image_filter), [](auto const &list) {
+    auto wallpaper = wanda::random_pick(list);
+    std::cout << "changing wallpaper to " << wallpaper << '\n';
+    set_wallpaper(wallpaper);
+  }) || [] { std::cerr << "Directory does not exist\n"; };
+}