frontend-app/hooks/usePushNotifications.ts

import * as Device from "expo-device";
import * as Notifications from "expo-notifications";
import { useEffect, useState } from "react";
import { Platform } from "react-native";
import { version as packageVersion } from '../package.json';

type RegisterTokenParams = {
	apiKey?: string | null;
	backendUrl: string;
	appVersion?: string;
	locale?: string;
	topics?: string[];
};

export function usePushNotifications({
	apiKey,
	backendUrl,
	appVersion = packageVersion,
	locale,
	topics
}: RegisterTokenParams & { apiKey?: string | null }) {
	const [expoPushToken, setExpoPushToken] = useState<string | null>(null);
	const [registered, setRegistered] = useState(false);
	const [registrationError, setRegistrationError] = useState<string | null>(null);

	useEffect(() => {
		if (!apiKey) {
			console.log("No API key available, skipping registration");
			return;
		}

		const registerTokenWithBackend = async (token: string) => {
			console.log("Attempting to register token with backend...");
			const res = await fetch(`${backendUrl}/register-token`, {
				method: "POST",
				headers: { 
					"Content-Type": "application/json", 
					"X-API-Key": apiKey 
				},
				body: JSON.stringify({ 
					token, 
					platform: Platform.OS, 
					app_ver: appVersion, 
					locale,
					topics 
				})
			});

			if (!res.ok) {
				const errorText = await res.text();
				console.error("Backend registration failed:", res.status, errorText);
				throw new Error(`Failed to register token: ${res.status}`);
			}
			
			console.log("Push token registered with backend ✅");
		};

		(async () => {
			try {
				const token = await registerForPushNotificationsAsync();
				if (token) {
					console.log("Got push token:", token);
					setExpoPushToken(token);
					
					await registerTokenWithBackend(token);
					setRegistered(true);
					setRegistrationError(null);
				} else {
					console.log("No push token received");
					setRegistrationError("Could not get push token");
				}
			} catch (err) {
				console.error("Registration error:", err);
				setRegistered(false);
				setRegistrationError(err instanceof Error ? err.message : "Failed to register push token");
			}
		})();
	}, [apiKey, backendUrl, appVersion, locale, topics]);

	const unregisterToken = async () => {
		if (!expoPushToken || !apiKey) {
			console.log("Cannot unregister: missing token or API key");
			return;
		}

		try {
			console.log("Unregistering token from backend...");
			const res = await fetch(`${backendUrl}/unregister-token`, {
				method: "POST",
				headers: {
					"Content-Type": "application/json",
					"X-API-Key": apiKey,
				},
				body: JSON.stringify({
					token: expoPushToken,
					platform: Platform.OS,
					app_ver: appVersion,
					locale,
					topics
				})
			});

			if (!res.ok) {
				throw new Error(`Unregister failed: ${res.status}`);
			}
			
			console.log("Push token unregistered from backend ✅");
			setExpoPushToken(null);
			setRegistered(false);
		} catch (error) {
			console.error("Failed to unregister token:", error);
		}
	};

	return { expoPushToken, registered, registrationError, unregisterToken };
}

async function registerForPushNotificationsAsync() {
	if (!Device.isDevice) {
		console.log("Must use physical device for Push Notifications");
		return null;
	}

	const { status: existingStatus } = await Notifications.getPermissionsAsync();
	let finalStatus = existingStatus;

	if (existingStatus !== "granted") {
		const { status } = await Notifications.requestPermissionsAsync();
		finalStatus = status;
	}

	if (finalStatus !== "granted") {
		console.log("Permission not granted for push notifications.");
		return null;
	}

	const tokenData = await Notifications.getExpoPushTokenAsync();
	const token = tokenData.data;
	console.log("Expo Push Token:", token);

	// Android-specific setup
	if (Platform.OS === "android") {
		await Notifications.setNotificationChannelAsync("default", {
			name: "default",
			importance: Notifications.AndroidImportance.MAX,
			vibrationPattern: [0, 250, 250, 250],
			lightColor: "#FF231F7C"
		});
	}

	return token;
}