"use client";

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

type Theme = "dark" | "light";

interface DashboardThemeContextType {
  theme: Theme;
  toggleTheme: () => void;
  setTheme: (theme: Theme) => void;
}

const DashboardThemeContext = createContext<DashboardThemeContextType | undefined>(undefined);

export function DashboardThemeProvider({ children }: { children: React.ReactNode }) {
  const [theme, setThemeState] = useState<Theme>("light");
  const [mounted, setMounted] = useState(false);

  useEffect(() => {
    // Read from localStorage on mount
    const savedTheme = localStorage.getItem("dashboard-theme") as Theme | null;
    if (savedTheme) {
      setThemeState(savedTheme);
    } else if (window.matchMedia("(prefers-color-scheme: dark)").matches) {
      // Optional: follow system preference if no manual setting
      // setThemeState("dark"); 
    }
    setMounted(true);
  }, []);

  useEffect(() => {
    if (!mounted) return;

    // Apply/Remove the dark class on documentElement
    // This ensures Portals (which attach to body) also see the dark mode
    if (theme === "dark") {
      document.documentElement.classList.add("dark");
    } else {
      document.documentElement.classList.remove("dark");
    }

    // Persist choice
    localStorage.setItem("dashboard-theme", theme);

    // Cleanup function: When the Dashboard layout unmounts, we revert to light mode
    return () => {
      document.documentElement.classList.remove("dark");
    };
  }, [theme, mounted]);

  const toggleTheme = () => {
    setThemeState((prev) => (prev === "dark" ? "light" : "dark"));
  };

  const setTheme = (newTheme: Theme) => {
    setThemeState(newTheme);
  };

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

export function useDashboardTheme() {
  const context = useContext(DashboardThemeContext);
  if (context === undefined) {
    throw new Error("useDashboardTheme must be used within a DashboardThemeProvider");
  }
  return context;
}