leggen/frontend/src/contexts/ThemeContext.tsx

import React, { createContext, useContext, useEffect, useState } from "react";

type Theme = "light" | "dark" | "system";

interface ThemeContextType {
  theme: Theme;
  setTheme: (theme: Theme) => void;
  actualTheme: "light" | "dark";
}

const ThemeContext = createContext<ThemeContextType | undefined>(undefined);

// Theme colors for different modes
const THEME_COLORS = {
  light: "#0b74de", // Primary brand color
  dark: "#0f0f23", // Dark background color that matches typical dark themes
} as const;

export function ThemeProvider({ children }: { children: React.ReactNode }) {
  const [theme, setTheme] = useState<Theme>(() => {
    const stored = localStorage.getItem("theme") as Theme;
    return stored || "system";
  });

  const [actualTheme, setActualTheme] = useState<"light" | "dark">("light");

  useEffect(() => {
    const root = window.document.documentElement;

    const updateActualTheme = () => {
      let resolvedTheme: "light" | "dark";

      if (theme === "system") {
        resolvedTheme = window.matchMedia("(prefers-color-scheme: dark)")
          .matches
          ? "dark"
          : "light";
      } else {
        resolvedTheme = theme;
      }

      setActualTheme(resolvedTheme);

      // Remove previous theme classes
      root.classList.remove("light", "dark");

      // Add resolved theme class
      root.classList.add(resolvedTheme);

      // Update theme-color meta tags for PWA status bar
      const themeColor = THEME_COLORS[resolvedTheme];

      // Update theme-color meta tag
      const themeColorMeta = document.getElementById(
        "theme-color-meta",
      ) as HTMLMetaElement;
      if (themeColorMeta) {
        themeColorMeta.content = themeColor;
      }

      // Update Microsoft tile color
      const msThemeColorMeta = document.getElementById(
        "ms-theme-color-meta",
      ) as HTMLMetaElement;
      if (msThemeColorMeta) {
        msThemeColorMeta.content = themeColor;
      }

      // Update Apple status bar style for better iOS integration
      const appleStatusBarMeta = document.getElementById(
        "apple-status-bar-meta",
      ) as HTMLMetaElement;
      if (appleStatusBarMeta) {
        // Use 'black-translucent' for dark theme, 'default' for light theme
        appleStatusBarMeta.content =
          resolvedTheme === "dark" ? "black-translucent" : "default";
      }
    };

    updateActualTheme();

    // Listen for system theme changes
    const mediaQuery = window.matchMedia("(prefers-color-scheme: dark)");
    const handleChange = () => {
      if (theme === "system") {
        updateActualTheme();
      }
    };

    mediaQuery.addEventListener("change", handleChange);

    // Store theme preference
    localStorage.setItem("theme", theme);

    return () => mediaQuery.removeEventListener("change", handleChange);
  }, [theme]);

  return (
    <ThemeContext.Provider value={{ theme, setTheme, actualTheme }}>
      {children}
    </ThemeContext.Provider>
  );
}

export function useTheme() {
  const context = useContext(ThemeContext);
  if (context === undefined) {
    throw new Error("useTheme must be used within a ThemeProvider");
  }
  return context;
}