import { createContext, useEffect, useMemo, useState } from "react";
import secureLocalStorageImport from "react-secure-storage";

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

type ThemeProviderProps = {
  children: React.ReactNode;
  defaultTheme?: Theme;
  storageKey?: string;
};

type ThemeProviderState = {
  theme: Theme;
  setTheme: (theme: Theme) => void;
};

const secureLocalStorage = (secureLocalStorageImport as any)?.default ?? secureLocalStorageImport;

const initialState: ThemeProviderState = {
  theme: "system",
  setTheme: () => null,
};

export const ThemeProviderContext = createContext<ThemeProviderState>(initialState);

export const ThemeProvider = ({
  children,
  defaultTheme = "system",
  storageKey = "vite-ui-theme",
  ...props
}: ThemeProviderProps) => {
  const [theme, setThemeState] = useState<Theme>(() => {
    try {
      const stored = secureLocalStorage?.getItem?.(storageKey);
      return (stored as Theme) || defaultTheme;
    } catch {
      return defaultTheme;
    }
  });

  useEffect(() => {
    const root = window.document.documentElement;
    root.classList.remove("light", "dark");

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

      root.classList.add(systemTheme);
      return;
    }

    root.classList.add(theme);
  }, [theme]);

  const value = useMemo(
    () => ({
      theme,
      setTheme: (nextTheme: Theme) => {
        try {
          secureLocalStorage?.setItem?.(storageKey, nextTheme);
        } catch {
          // fallback silencioso
        }
        setThemeState(nextTheme);
      },
    }),
    [theme, storageKey]
  );

  return (
    <ThemeProviderContext.Provider {...props} value={value}>
      {children}
    </ThemeProviderContext.Provider>
  );
};