feat: complete Phase 0 Enterprise IAM

ui/src/theme/mod.rs

@@ -0,0 +1,91 @@
+//! Theme management (light / dark / system) with localStorage persistence.
+
+use gloo_storage::{LocalStorage, Storage};
+use std::fmt;
+
+const STORAGE_KEY: &str = "nx9-auth-theme";
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum ThemeMode {
+    Light,
+    Dark,
+    #[default]
+    System,
+}
+
+impl ThemeMode {
+    pub fn as_str(self) -> &'static str {
+        match self {
+            Self::Light => "light",
+            Self::Dark => "dark",
+            Self::System => "system",
+        }
+    }
+
+    pub fn from_str(s: &str) -> Self {
+        match s {
+            "light" => Self::Light,
+            "dark" => Self::Dark,
+            _ => Self::System,
+        }
+    }
+
+    pub fn cycle(self) -> Self {
+        match self {
+            Self::Light => Self::Dark,
+            Self::Dark => Self::System,
+            Self::System => Self::Light,
+        }
+    }
+
+    pub fn label(self) -> &'static str {
+        match self {
+            Self::Light => "Light",
+            Self::Dark => "Dark",
+            Self::System => "System",
+        }
+    }
+
+    pub fn icon(self) -> &'static str {
+        match self {
+            Self::Light => "☀",
+            Self::Dark => "☾",
+            Self::System => "◐",
+        }
+    }
+}
+
+impl fmt::Display for ThemeMode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+pub fn load_theme() -> ThemeMode {
+    LocalStorage::get::<String>(STORAGE_KEY)
+        .map(|s| ThemeMode::from_str(&s))
+        .unwrap_or_default()
+}
+
+pub fn save_theme(mode: ThemeMode) {
+    let _ = LocalStorage::set(STORAGE_KEY, mode.as_str());
+}
+
+/// Apply theme to `<html data-theme="...">`.
+pub fn apply_theme(mode: ThemeMode) {
+    if let Some(document) = web_sys::window().and_then(|w| w.document()) {
+        if let Some(el) = document.document_element() {
+            match mode {
+                ThemeMode::Light => {
+                    let _ = el.set_attribute("data-theme", "light");
+                }
+                ThemeMode::Dark => {
+                    let _ = el.set_attribute("data-theme", "dark");
+                }
+                ThemeMode::System => {
+                    let _ = el.remove_attribute("data-theme");
+                }
+            }
+        }
+    }
+}