feat: Added native custom theme support

lib/libimhex/source/api/theme_manager.cpp

@@ -0,0 +1,118 @@
+#include <hex/api/theme_manager.hpp>
+
+#include <hex/helpers/logger.hpp>
+#include <hex/helpers/utils.hpp>
+
+#include <nlohmann/json.hpp>
+
+namespace hex::api {
+
+    std::map<std::string, nlohmann::json> ThemeManager::s_themes;
+    std::map<std::string, std::function<void(std::string, std::string)>> ThemeManager::s_themeHandlers, ThemeManager::s_styleHandlers;
+    std::string ThemeManager::s_imagePostfix;
+
+    void ThemeManager::addThemeHandler(const std::string &name, const std::function<void(std::string, std::string)> &handler) {
+        s_themeHandlers[name] = handler;
+    }
+
+    void ThemeManager::addStyleHandler(const std::string &name, const std::function<void(std::string, std::string)> &handler) {
+        s_styleHandlers[name] = handler;
+    }
+
+    void ThemeManager::addTheme(const std::string &content) {
+        auto theme = nlohmann::json::parse(content);
+        if (theme.contains("name") && theme.contains("colors")) {
+            s_themes[theme["name"].get<std::string>()] = theme;
+        } else {
+            hex::log::error("Invalid theme file");
+        }
+    }
+
+    std::optional<ImColor> ThemeManager::parseColorString(const std::string &colorString) {
+        if (colorString.length() != 9 || colorString[0] != '#')
+            return std::nullopt;
+
+        u32 color = 0;
+
+        for (u32 i = 1; i < 9; i++) {
+            color <<= 4;
+            if (colorString[i] >= '0' && colorString[i] <= '9')
+                color |= colorString[i] - '0';
+            else if (colorString[i] >= 'A' && colorString[i] <= 'F')
+                color |= colorString[i] - 'A' + 10;
+            else if (colorString[i] >= 'a' && colorString[i] <= 'f')
+                color |= colorString[i] - 'a' + 10;
+            else
+                return std::nullopt;
+        }
+
+        return ImColor(hex::changeEndianess(color, std::endian::big));
+    }
+
+    void ThemeManager::changeTheme(std::string name) {
+        if (!s_themes.contains(name)) {
+            if (s_themes.empty()) {
+                hex::log::error("Theme '{}' does not exist and no other themes are available!", name);
+                return;
+            } else {
+                const std::string &defaultTheme = s_themes.begin()->first;
+                hex::log::error("Theme '{}' does not exist, using default theme '{}' instead!", name, defaultTheme);
+                name = defaultTheme;
+            }
+        }
+
+        const auto &theme = s_themes[name];
+
+        if (theme.contains("base")) {
+            if (theme["base"].is_string()) {
+                changeTheme(theme["base"].get<std::string>());
+            } else {
+                hex::log::error("Theme '{}' has invalid base theme!", name);
+            }
+        }
+
+        if (theme.contains("colors")) {
+            for (const auto&[type, content] : theme["colors"].items()) {
+                if (!s_themeHandlers.contains(type)) {
+                    log::warn("No theme handler found for '{}'", type);
+                    continue;
+                }
+
+                for (const auto &[key, value] : content.items())
+                    s_themeHandlers[type](key, value.get<std::string>());
+            }
+        }
+
+        if (theme.contains("styles")) {
+            for (const auto&[key, value] : theme["styles"].items()) {
+                if (!s_styleHandlers.contains(key)) {
+                    log::warn("No style handler found for '{}'", key);
+                    continue;
+                }
+
+                s_styleHandlers[key](name, value.get<std::string>());
+            }
+        }
+
+        if (theme.contains("image_postfix")) {
+            if (theme["image_postfix"].is_string()) {
+                s_imagePostfix = theme["image_postfix"].get<std::string>();
+            } else {
+                hex::log::error("Theme '{}' has invalid image postfix!", name);
+            }
+        }
+    }
+
+    const std::string &ThemeManager::getThemeImagePostfix() {
+        return s_imagePostfix;
+    }
+
+    std::vector<std::string> ThemeManager::getThemeNames() {
+        std::vector<std::string> themeNames;
+        for (const auto &[name, theme] : s_themes)
+            themeNames.push_back(name);
+
+        return themeNames;
+    }
+
+}