WorldBorder/src/main/java/com/wimbli/WorldBorder/UUID/UUIDFetcher.java

/*
 *  This code mostly taken from https://gist.github.com/Jofkos/d0c469528b032d820f42
 */

package com.wimbli.WorldBorder.UUID;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.UUID;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.function.Consumer;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;


public class UUIDFetcher {
	
	/**
	 * Date when name changes were introduced
	 * @see UUIDFetcher#getUUIDAt(String, long)
	 */
	public static final long FEBRUARY_2015 = 1422748800000L;
	
	
	private static Gson gson = new GsonBuilder().registerTypeAdapter(UUID.class, new UUIDTypeAdapter()).create();
	
	private static final String UUID_URL = "https://api.mojang.com/users/profiles/minecraft/%s?at=%d";
	private static final String NAME_URL = "https://api.mojang.com/user/profiles/%s/names";

	private static Map<String, UUID> uuidCache = new HashMap<String, UUID>();
	private static Map<UUID, String> nameCache = new HashMap<UUID, String>();

	private static ExecutorService pool = Executors.newCachedThreadPool();
	
	private String name;
	private UUID id;
		
	/**
	 * Fetches the uuid asynchronously and passes it to the consumer
	 * 
	 * @param name The name
	 * @param action Do what you want to do with the uuid her
	 */
	public static void getUUID(String name, Consumer<UUID> action) {
		pool.execute(() -> action.accept(getUUID(name)));
	}
	
	/**
	 * Fetches the uuid synchronously and returns it
	 * 
	 * @param name The name
	 * @return The uuid
	 */
	public static UUID getUUID(String name) {
		return getUUIDAt(name, System.currentTimeMillis());
	}
	
	/**
	 * Fetches the uuid synchronously for a specified name and time and passes the result to the consumer
	 * 
	 * @param name The name
	 * @param timestamp Time when the player had this name in milliseconds
	 * @param action Do what you want to do with the uuid her
	 */
	public static void getUUIDAt(String name, long timestamp, Consumer<UUID> action) {
		pool.execute(() -> action.accept(getUUIDAt(name, timestamp)));
	}
	
	/**
	 * Fetches the uuid synchronously for a specified name and time
	 * 
	 * @param name The name
	 * @param timestamp Time when the player had this name in milliseconds
	 * @see UUIDFetcher#FEBRUARY_2015
	 */
	public static UUID getUUIDAt(String name, long timestamp) {
		name = name.toLowerCase();
		if (uuidCache.containsKey(name)) {
			return uuidCache.get(name);
		}
		try {
			HttpURLConnection connection = (HttpURLConnection) new URL(String.format(UUID_URL, name, timestamp/1000)).openConnection();
			connection.setReadTimeout(5000);
			UUIDFetcher data = gson.fromJson(new BufferedReader(new InputStreamReader(connection.getInputStream())), UUIDFetcher.class);
			
			uuidCache.put(name, data.id);
			nameCache.put(data.id, data.name);

			return data.id;
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		return null;
	}
	
	/**
	 * Fetches the name asynchronously and passes it to the consumer
	 * 
	 * @param uuid The uuid
	 * @param action Do what you want to do with the name her
	 */
	public static void getName(UUID uuid, Consumer<String> action) {
		pool.execute(() -> action.accept(getName(uuid)));
	}

	/**
	 * Fetches the name synchronously and returns it
	 * 
	 * @param uuid The uuid
	 * @return The name
	 */
	public static String getName(UUID uuid) {
		if (nameCache.containsKey(uuid)) {
			return nameCache.get(uuid);
		}
		try {
			HttpURLConnection connection = (HttpURLConnection) new URL(String.format(NAME_URL, UUIDTypeAdapter.fromUUID(uuid))).openConnection();
			connection.setReadTimeout(5000);
			UUIDFetcher[] nameHistory = gson.fromJson(new BufferedReader(new InputStreamReader(connection.getInputStream())), UUIDFetcher[].class);
			UUIDFetcher currentNameData = nameHistory[nameHistory.length - 1];

			uuidCache.put(currentNameData.name.toLowerCase(), uuid);
			nameCache.put(uuid, currentNameData.name);

			return currentNameData.name;
		} catch (Exception e) {
			e.printStackTrace();
		}

		return null;
	}

	public static Map<UUID, String> getNameList(ArrayList<UUID> uuids) {
		Map<UUID, String> uuidStringMap = new HashMap<>();
		for (UUID uuid: uuids) 
		{
			uuidStringMap.put(uuid, getName(uuid));
		}
		return uuidStringMap;
	}
}