import { Stack } from "expo-router/stack";
import { ConvexProvider, ConvexReactClient } from "convex/react";
import { useState, createContext, useContext, useEffect, useCallback, Component, type ReactNode, type ErrorInfo } from "react";
import { View, Text, Pressable, ScrollView } from "react-native";
import AsyncStorage from "@react-native-async-storage/async-storage";
import { ThemeProvider, useTheme } from "../components/theme";
import { ToastProvider } from "../components/ui/toast";

const CONVEX_URL = process.env.EXPO_PUBLIC_CONVEX_URL;

function getConvexClient(): ConvexReactClient | null {
  if (!CONVEX_URL) {
    console.error("Missing EXPO_PUBLIC_CONVEX_URL environment variable");
    return null;
  }
  try {
    return new ConvexReactClient(CONVEX_URL);
  } catch (e) {
    console.error("Failed to create Convex client:", e);
    return null;
  }
}

const convex = getConvexClient();

type AuthState = {
  token: string | null;
  userId: string | null;
  isAuthenticated: boolean;
  login: (token: string, userId: string) => Promise<void>;
  logout: () => Promise<void>;
};

const AuthContext = createContext<AuthState>({
  token: null,
  userId: null,
  isAuthenticated: false,
  login: async () => {},
  logout: async () => {},
});

export function useAuth() {
  return useContext(AuthContext);
}

const TOKEN_KEY = "mojmajstor_auth_token";
const USER_ID_KEY = "mojmajstor_auth_userId";

class ErrorBoundary extends Component<{ children: ReactNode }, { hasError: boolean; error: Error | null }> {
  state: { hasError: boolean; error: Error | null } = { hasError: false, error: null };

  static getDerivedStateFromError(error: Error) {
    return { hasError: true, error };
  }

  reset = () => {
    this.setState({ hasError: false, error: null });
  };

  render() {
    if (this.state.hasError) {
      return <ErrorFallback error={this.state.error!} onReset={this.reset} />;
    }
    return this.props.children;
  }
}

function ErrorFallback({ error, onReset }: { error: Error; onReset: () => void }) {
  const theme = useTheme();
  return (
    <View style={{ flex: 1, justifyContent: "center", alignItems: "center", padding: 24, backgroundColor: theme.colors.background }}>
      <Text style={{ fontSize: 48, marginBottom: 16 }}>⚠️</Text>
      <Text style={{ fontSize: 20, fontWeight: "700", color: theme.colors.text, marginBottom: 8, textAlign: "center" }}>
        Настана грешка
      </Text>
      <Text style={{ fontSize: 14, color: theme.colors.textSecondary, textAlign: "center", marginBottom: 8 }}>
        Приложението наиде на неочекувана грешка.
      </Text>
      {__DEV__ && error?.message ? (
        <ScrollView style={{ maxHeight: 120, marginBottom: 16 }} contentContainerStyle={{ padding: 12, backgroundColor: theme.colors.surface, borderRadius: 8 }}>
          <Text style={{ fontSize: 12, color: theme.colors.error, fontFamily: "monospace" }}>
            {error.message}
          </Text>
        </ScrollView>
      ) : null}
      <Pressable
        accessible
        accessibilityLabel="Обиди се повторно"
        accessibilityRole="button"
        onPress={onReset}
        style={{ backgroundColor: theme.colors.primary, borderRadius: 14, paddingVertical: 13, paddingHorizontal: 32, ...theme.shadows.sm }}
      >
        <Text style={{ color: theme.colors.textInverse, fontWeight: "600", fontSize: 16 }}>Обиди се повторно</Text>
      </Pressable>
    </View>
  );
}

function ThemedNavigator() {
  const theme = useTheme();

  return (
    <Stack
      screenOptions={{
        headerShown: false,
        headerStyle: { backgroundColor: theme.colors.surface },
        headerTintColor: theme.colors.text,
        headerTitleStyle: { color: theme.colors.text, fontWeight: "600", fontSize: 18 },
        headerShadowVisible: false,
        headerBackButtonDisplayMode: "minimal",
        contentStyle: { backgroundColor: theme.colors.background },
      }}
    >
      <Stack.Screen name="(auth)" />
      <Stack.Screen name="(tabs)" />
      <Stack.Screen name="ad/[id]" options={{ presentation: "card" }} />
      <Stack.Screen name="ad/create" options={{ presentation: "modal" }} />
      <Stack.Screen name="post/[id]" options={{ presentation: "card" }} />
      <Stack.Screen name="post/create" options={{ presentation: "modal" }} />
      <Stack.Screen name="chat/[id]" options={{ presentation: "card" }} />
      <Stack.Screen name="review/create" options={{ presentation: "modal" }} />
    </Stack>
  );
}

export default function RootLayout() {
  const [token, setToken] = useState<string | null>(null);
  const [userId, setUserId] = useState<string | null>(null);
  const [loaded, setLoaded] = useState(false);

  useEffect(() => {
    Promise.all([
      AsyncStorage.getItem(TOKEN_KEY),
      AsyncStorage.getItem(USER_ID_KEY),
    ]).then(([t, u]) => {
      if (t) setToken(t);
      if (u) setUserId(u);
      setLoaded(true);
    });
  }, []);

  const login = useCallback(async (newToken: string, newUserId: string) => {
    await AsyncStorage.setItem(TOKEN_KEY, newToken);
    await AsyncStorage.setItem(USER_ID_KEY, newUserId);
    setToken(newToken);
    setUserId(newUserId);
  }, []);

  const logout = useCallback(async () => {
    await AsyncStorage.removeItem(TOKEN_KEY);
    await AsyncStorage.removeItem(USER_ID_KEY);
    setToken(null);
    setUserId(null);
  }, []);

  if (!loaded) return null;

  if (!convex) {
    return (
      <ThemeProvider>
        <MissingConfigScreen />
      </ThemeProvider>
    );
  }

  return (
    <ConvexProvider client={convex}>
      <ThemeProvider>
        <AuthContext.Provider
          value={{ token, userId, isAuthenticated: !!token, login, logout }}
        >
          <ErrorBoundary>
            <ToastProvider>
              <ThemedNavigator />
            </ToastProvider>
          </ErrorBoundary>
        </AuthContext.Provider>
      </ThemeProvider>
    </ConvexProvider>
  );
}

function MissingConfigScreen() {
  const theme = useTheme();
  return (
    <View style={{ flex: 1, justifyContent: "center", alignItems: "center", padding: 24, backgroundColor: theme.colors.background }}>
      <Text style={{ fontSize: 48, marginBottom: 16 }}>⚙️</Text>
      <Text style={{ ...theme.typography.h2, color: theme.colors.text, marginBottom: 8, textAlign: "center" }}>
        Конфигурациска грешка
      </Text>
      <Text style={{ ...theme.typography.body, color: theme.colors.textSecondary, textAlign: "center", marginBottom: 24 }}>
        Недостасува EXPO_PUBLIC_CONVEX_URL. Проверете ја конфигурацијата за изградба.
      </Text>
    </View>
  );
}