import { DarkTheme, DefaultTheme, ThemeProvider } from '@react-navigation/native';
import { Stack, router, useRootNavigationState, useSegments } from 'expo-router';
import * as SplashScreen from 'expo-splash-screen';
import { StatusBar } from 'expo-status-bar';
import { useEffect, useRef } from 'react';
// import 'react-native-reanimated'; // Often causes issues on web if not configured perfectly, optional here
import { Platform, StyleSheet, View } from 'react-native';

import { LoadingSpinner } from '@/components/ui/LoadingSpinner';
import { ToastProvider } from '@/components/ui/Toast';
import { AuthProvider, useAuth } from '@/contexts/AuthContext';
import { BeneficiaryProvider } from '@/contexts/BeneficiaryContext';
import { useColorScheme } from '@/hooks/use-color-scheme';

// Polyfill for $ to prevent ReferenceError: Cannot access '$' before initialization
// This is a workaround for some web-specific bundling issues in this project.
if (Platform.OS === 'web' && typeof window !== 'undefined') {
    // @ts-ignore
    if (typeof window.$ === 'undefined') {
        // @ts-ignore
        window.$ = undefined;
    }
}

// Prevent auto-hide, ignore errors if splash not available
SplashScreen.preventAutoHideAsync().catch(() => { });

let splashHidden = false;

function RootLayoutNav() {
    const colorScheme = useColorScheme();
    const { isAuthenticated, isInitializing, setToken } = useAuth();
    const segments = useSegments();
    const navigationState = useRootNavigationState();

    // Track if initial redirect was done
    const hasInitialRedirect = useRef(false);

    useEffect(() => {
        // Check for token in URL query params (Web only feature)
        if (Platform.OS === 'web') {
            const url = new URL(window.location.href);
            const tokenParam = url.searchParams.get('token');
            if (tokenParam) {
                console.log('[Layout] Found token in URL, attempting login...');
                // Need a way to set token in AuthContext.
                // Since useAuth gives us setToken (assuming it does, or login logic), we can use it.
                // If AuthContext doesn't expose setToken directly, we might need to modify AuthContext 
                // or use specific login method. Assuming 'api.setToken' works and then we refresh auth.
                // actually useAuth usually exposes a way.
                // Let's assume for a moment we can use the injected setToken (if I added it) or just use api.

                // For now, let's try to set it via API and reload user?
                // Actually, best is if AuthContext handles it. 
                // But let's look at AuthContext later. For now I will try to use the api directly to verify constraint.
                const handleToken = async () => {
                    await setToken(tokenParam);
                    // Refresh the page to clear the token from URL
                    window.location.href = window.location.origin + window.location.pathname;
                };
                handleToken();
            }
        }
    }, []);

    useEffect(() => {
        if (!navigationState?.key) return;
        if (isInitializing) return;

        if (!splashHidden) {
            splashHidden = true;
            SplashScreen.hideAsync().catch(() => { });
        }

        const inAuthGroup = segments[0] === '(auth)';

        if (!hasInitialRedirect.current) {
            hasInitialRedirect.current = true;

            // URL Param Auth Check (Simple version)
            if (Platform.OS === 'web') {
                const url = new URL(window.location.href);
                const token = url.searchParams.get('token');
                if (token) {
                    // If we have a token, we might be authenticated now (race condition with AuthProvider).
                    // If isAuthenticated is true, good. If not, maybe we need to wait.
                    // But for now, let's allow the flow.
                }
            }

            if (!isAuthenticated && !inAuthGroup) {
                router.replace('/(auth)/login');
                return;
            }
        }

    }, [isAuthenticated, isInitializing, navigationState?.key]);

    if (isInitializing) {
        return <LoadingSpinner fullScreen message="Loading..." />;
    }

    return (
        <ThemeProvider value={colorScheme === 'dark' ? DarkTheme : DefaultTheme}>
            <View style={styles.webContainer}>
                <View style={styles.mobileWrapper}>
                    <Stack screenOptions={{ headerShown: false }}>
                        <Stack.Screen name="(auth)" />
                        <Stack.Screen name="(tabs)" />
                        <Stack.Screen name="modal" options={{ presentation: 'modal', title: 'Modal' }} />
                    </Stack>
                    <StatusBar style="auto" />
                </View>
            </View>
        </ThemeProvider>
    );
}

export default function RootLayout() {
    return (
        <AuthProvider>
            <BeneficiaryProvider>
                <ToastProvider>
                    <RootLayoutNav />
                </ToastProvider>
            </BeneficiaryProvider>
        </AuthProvider>
    );
}

const styles = StyleSheet.create({
    webContainer: {
        flex: 1,
        backgroundColor: '#e5e5e5', // Light gray background for desktop
        alignItems: 'center',
        justifyContent: 'center',
    },
    mobileWrapper: {
        flex: 1,
        width: '100%',
        maxWidth: 430, // Mobile width constraint
        backgroundColor: '#fff',
        shadowColor: '#000',
        shadowOffset: {
            width: 0,
            height: 2,
        },
        shadowOpacity: 0.25,
        shadowRadius: 3.84,
        elevation: 5,
        overflow: 'hidden', // Clip content to rounded corners if we want
    }
});