package helloworld;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Collectors;

import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestHandler;

/**
 * Handler for requests to Lambda function.
 */
public class App implements RequestHandler<Object, Object> {

    static {
        Runtime.getRuntime().addShutdownHook(new Thread() {
            @Override
            public void run() {
                System.out.println("[runtime] ShutdownHook triggered");

                System.out.println("[runtime] Cleaning up");
                // perform actual clean up work here.
                try {
                    Thread.sleep(200);
                 } catch (Exception e) {
                    System.out.println(e);
                 }

                System.out.println("[runtime] exiting");
                System.exit(0);
            }
        });
    }

    public Object handleRequest(final Object input, final Context context) {
        Map<String, String> headers = new HashMap<>();
        headers.put("Content-Type", "application/json");
        headers.put("X-Custom-Header", "application/json");
        try {
            final String pageContents = this.getPageContents("https://checkip.amazonaws.com");
            String output = String.format("{ \"message\": \"hello world\", \"location\": \"%s\" }", pageContents);
            return new GatewayResponse(output, headers, 200);
        } catch (IOException e) {
            return new GatewayResponse("{}", headers, 500);
        }
    }

    private String getPageContents(String address) throws IOException {
        URL url = new URL(address);
        try (BufferedReader br = new BufferedReader(new InputStreamReader(url.openStream()))) {
            return br.lines().collect(Collectors.joining(System.lineSeparator()));
        }
    }
}