package me.dablakbandit.dabcore.metrics;

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Timer;
import java.util.TimerTask;
import java.util.UUID;
import java.util.concurrent.Callable;
import java.util.logging.Level;
import java.util.zip.GZIPOutputStream;

import javax.net.ssl.HttpsURLConnection;

import org.bukkit.Bukkit;
import org.bukkit.configuration.file.YamlConfiguration;
import org.bukkit.entity.Player;
import org.bukkit.plugin.RegisteredServiceProvider;
import org.bukkit.plugin.ServicePriority;
import org.bukkit.plugin.java.JavaPlugin;

import me.dablakbandit.dabcore.json.JSONArray;
import me.dablakbandit.dabcore.json.JSONException;
import me.dablakbandit.dabcore.json.JSONObject;

/**
 * bStats collects some data for plugin authors.
 *
 * Check out https://bStats.org/ to learn more about bStats!
 */
public class Metrics{
	
	// The version of this bStats class
	public static final int			B_STATS_VERSION	= 1;
	
	// The url to which the data is sent
	private static final String		URL				= "https://bStats.org/submitData/bukkit";
	
	// Should failed requests be logged?
	private static boolean			logFailedRequests;
	
	// The uuid of the server
	private static String			serverUUID;
	
	// The plugin
	private final JavaPlugin		plugin;
	
	// A list with all custom charts
	private final List<CustomChart>	charts			= new ArrayList<>();
	
	/**
	 * Class constructor.
	 *
	 * @param plugin The plugin which stats should be submitted.
	 */
	public Metrics(JavaPlugin plugin){
		if(plugin == null){ throw new IllegalArgumentException("Plugin cannot be null!"); }
		this.plugin = plugin;
		
		// Get the config file
		File bStatsFolder = new File(plugin.getDataFolder().getParentFile(), "bStats");
		File configFile = new File(bStatsFolder, "config.yml");
		YamlConfiguration config = YamlConfiguration.loadConfiguration(configFile);
		
		// Check if the config file exists
		if(!config.isSet("serverUuid")){
			
			// Add default values
			config.addDefault("enabled", true);
			// Every server gets it's unique random id.
			config.addDefault("serverUuid", UUID.randomUUID().toString());
			// Should failed request be logged?
			config.addDefault("logFailedRequests", false);
			
			// Inform the server owners about bStats
			config	.options().header("bStats collects some data for plugin authors like how many servers are using their plugins.\n" + "To honor their work, you should not disable it.\n" + "This has nearly no effect on the server performance!\n" + "Check out https://bStats.org/ to learn more :)")
					.copyDefaults(true);
			try{
				config.save(configFile);
			}catch(IOException ignored){
			}
		}
		
		// Load the data
		serverUUID = config.getString("serverUuid");
		logFailedRequests = config.getBoolean("logFailedRequests", false);
		if(config.getBoolean("enabled", true)){
			boolean found = false;
			// Search for all other bStats Metrics classes to see if we are the first one
			for(Class<?> service : Bukkit.getServicesManager().getKnownServices()){
				try{
					service.getField("B_STATS_VERSION"); // Our identifier :)
					found = true; // We aren't the first
					break;
				}catch(NoSuchFieldException ignored){
				}
			}
			// Register our service
			Bukkit.getServicesManager().register(Metrics.class, this, plugin, ServicePriority.Normal);
			if(!found){
				// We are the first!
				startSubmitting();
			}
		}
	}
	
	/**
	 * Adds a custom chart.
	 *
	 * @param chart The chart to add.
	 */
	public void addCustomChart(CustomChart chart){
		if(chart == null){ throw new IllegalArgumentException("Chart cannot be null!"); }
		charts.add(chart);
	}
	
	/**
	 * Starts the Scheduler which submits our data every 30 minutes.
	 */
	private void startSubmitting(){
		final Timer timer = new Timer(true); // We use a timer cause the Bukkit scheduler is affected by server lags
		timer.scheduleAtFixedRate(new TimerTask(){
			@Override
			public void run(){
				if(!plugin.isEnabled()){ // Plugin was disabled
					timer.cancel();
					return;
				}
				// Nevertheless we want our code to run in the Bukkit main thread, so we have to use the Bukkit scheduler
				// Don't be afraid! The connection to the bStats server is still async, only the stats collection is sync ;)
				Bukkit.getScheduler().runTask(plugin, new Runnable(){
					@Override
					public void run(){
						submitData();
					}
				});
			}
		}, 1000 * 60 * 5, 1000 * 60 * 30);
		// Submit the data every 30 minutes, first time after 5 minutes to give other plugins enough time to start
		// WARNING: Changing the frequency has no effect but your plugin WILL be blocked/deleted!
		// WARNING: Just don't do it!
	}
	
	/**
	 * Gets the plugin specific data.
	 * This method is called using Reflection.
	 *
	 * @return The plugin specific data.
	 */
	public JSONObject getPluginData(){
		JSONObject data = new JSONObject();
		
		String pluginName = plugin.getDescription().getName();
		String pluginVersion = plugin.getDescription().getVersion();
		try{
			data.put("pluginName", pluginName); // Append the name of the plugin
			data.put("pluginVersion", pluginVersion); // Append the version of the plugin
			JSONArray customCharts = new JSONArray();
			for(CustomChart customChart : charts){
				// Add the data of the custom charts
				JSONObject chart = customChart.getRequestJsonObject();
				if(chart == null){ // If the chart is null, we skip it
					continue;
				}
				customCharts.put(chart);
				
			}
			data.put("customCharts", customCharts);
		}catch(Exception e){
			e.printStackTrace();
		}
		return data;
	}
	
	/**
	 * Gets the server specific data.
	 *
	 * @return The server specific data.
	 */
	private JSONObject getServerData(){
		// Minecraft specific data
		int playerAmount;
		try{
			// Around MC 1.8 the return type was changed to a collection from an array,
			// This fixes java.lang.NoSuchMethodError: org.bukkit.Bukkit.getOnlinePlayers()Ljava/util/Collection;
			Method onlinePlayersMethod = Class.forName("org.bukkit.Server").getMethod("getOnlinePlayers");
			playerAmount = onlinePlayersMethod.getReturnType().equals(Collection.class) ? ((Collection<?>)onlinePlayersMethod.invoke(Bukkit.getServer())).size() : ((Player[])onlinePlayersMethod.invoke(Bukkit.getServer())).length;
		}catch(Exception e){
			playerAmount = Bukkit.getOnlinePlayers().size(); // Just use the new method if the Reflection failed
		}
		int onlineMode = Bukkit.getOnlineMode() ? 1 : 0;
		String bukkitVersion = org.bukkit.Bukkit.getVersion();
		bukkitVersion = bukkitVersion.substring(bukkitVersion.indexOf("MC: ") + 4, bukkitVersion.length() - 1);
		
		// OS/Java specific data
		String javaVersion = System.getProperty("java.version");
		String osName = System.getProperty("os.name");
		String osArch = System.getProperty("os.arch");
		String osVersion = System.getProperty("os.version");
		int coreCount = Runtime.getRuntime().availableProcessors();
		
		JSONObject data = new JSONObject();
		
		try{
			data.put("serverUUID", serverUUID);
			
			data.put("playerAmount", playerAmount);
			data.put("onlineMode", onlineMode);
			data.put("bukkitVersion", bukkitVersion);
			
			data.put("javaVersion", javaVersion);
			data.put("osName", osName);
			data.put("osArch", osArch);
			data.put("osVersion", osVersion);
			data.put("coreCount", coreCount);
		}catch(JSONException e){
			e.printStackTrace();
		}
		
		return data;
	}
	
	/**
	 * Collects the data and sends it afterwards.
	 */
	private void submitData(){
		final JSONObject data = getServerData();
		
		JSONArray pluginData = new JSONArray();
		// Search for all other bStats Metrics classes to get their plugin data
		for(Class<?> service : Bukkit.getServicesManager().getKnownServices()){
			try{
				service.getField("B_STATS_VERSION"); // Our identifier :)
				
				for(RegisteredServiceProvider<?> provider : Bukkit.getServicesManager().getRegistrations(service)){
					try{
						pluginData.put(provider.getService().getMethod("getPluginData").invoke(provider.getProvider()));
					}catch(NullPointerException | NoSuchMethodException | IllegalAccessException | InvocationTargetException ignored){
					}
				}
			}catch(NoSuchFieldException ignored){
			}
		}
		try{
			data.put("plugins", pluginData);
		}catch(Exception e){
			e.printStackTrace();
		}
		
		// Create a new thread for the connection to the bStats server
		new Thread(new Runnable(){
			@Override
			public void run(){
				try{
					// Send the data
					sendData(data);
				}catch(Exception e){
					// Something went wrong! :(
					if(logFailedRequests){
						plugin.getLogger().log(Level.WARNING, "Could not submit plugin stats of " + plugin.getName(), e);
					}
				}
			}
		}).start();
	}
	
	/**
	 * Sends the data to the bStats server.
	 *
	 * @param data The data to send.
	 * @throws Exception If the request failed.
	 */
	private static void sendData(JSONObject data) throws Exception{
		if(data == null){ throw new IllegalArgumentException("Data cannot be null!"); }
		if(Bukkit.isPrimaryThread()){ throw new IllegalAccessException("This method must not be called from the main thread!"); }
		HttpsURLConnection connection = (HttpsURLConnection)new URL(URL).openConnection();
		
		// Compress the data to save bandwidth
		byte[] compressedData = compress(data.toString());
		
		// Add headers
		connection.setRequestMethod("POST");
		connection.addRequestProperty("Accept", "application/json");
		connection.addRequestProperty("Connection", "close");
		connection.addRequestProperty("Content-Encoding", "gzip"); // We gzip our request
		connection.addRequestProperty("Content-Length", String.valueOf(compressedData.length));
		connection.setRequestProperty("Content-Type", "application/json"); // We send our data in JSON format
		connection.setRequestProperty("User-Agent", "MC-Server/" + B_STATS_VERSION);
		
		// Send data
		connection.setDoOutput(true);
		DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream());
		outputStream.write(compressedData);
		outputStream.flush();
		outputStream.close();
		
		connection.getInputStream().close(); // We don't care about the response - Just send our data :)
	}
	
	/**
	 * Gzips the given String.
	 *
	 * @param str The string to gzip.
	 * @return The gzipped String.
	 * @throws IOException If the compression failed.
	 */
	private static byte[] compress(final String str) throws IOException{
		if(str == null){ return null; }
		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
		GZIPOutputStream gzip = new GZIPOutputStream(outputStream);
		gzip.write(str.getBytes("UTF-8"));
		gzip.close();
		return outputStream.toByteArray();
	}
	
	/**
	 * Represents a custom chart.
	 */
	public static abstract class CustomChart{
		
		// The id of the chart
		final String chartId;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 */
		CustomChart(String chartId){
			if(chartId == null || chartId.isEmpty()){ throw new IllegalArgumentException("ChartId cannot be null or empty!"); }
			this.chartId = chartId;
		}
		
		private JSONObject getRequestJsonObject(){
			JSONObject chart = new JSONObject();
			try{
				chart.put("chartId", chartId);
				JSONObject data = getChartData();
				if(data == null){
					// If the data is null we don't send the chart.
					return null;
				}
				chart.put("data", data);
			}catch(Throwable t){
				if(logFailedRequests){
					Bukkit.getLogger().log(Level.WARNING, "Failed to get data for custom chart with id " + chartId, t);
				}
				return null;
			}
			return chart;
		}
		
		protected abstract JSONObject getChartData() throws Exception;
		
	}
	
	/**
	 * Represents a custom simple pie.
	 */
	public static class SimplePie extends CustomChart{
		
		private final Callable<String> callable;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 * @param callable The callable which is used to request the chart data.
		 */
		public SimplePie(String chartId, Callable<String> callable){
			super(chartId);
			this.callable = callable;
		}
		
		@Override
		protected JSONObject getChartData() throws Exception{
			JSONObject data = new JSONObject();
			String value = callable.call();
			if(value == null || value.isEmpty()){
				// Null = skip the chart
				return null;
			}
			data.put("value", value);
			return data;
		}
	}
	
	/**
	 * Represents a custom advanced pie.
	 */
	public static class AdvancedPie extends CustomChart{
		
		private final Callable<Map<String, Integer>> callable;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 * @param callable The callable which is used to request the chart data.
		 */
		public AdvancedPie(String chartId, Callable<Map<String, Integer>> callable){
			super(chartId);
			this.callable = callable;
		}
		
		@Override
		protected JSONObject getChartData() throws Exception{
			JSONObject data = new JSONObject();
			JSONObject values = new JSONObject();
			Map<String, Integer> map = callable.call();
			if(map == null || map.isEmpty()){
				// Null = skip the chart
				return null;
			}
			boolean allSkipped = true;
			for(Map.Entry<String, Integer> entry : map.entrySet()){
				if(entry.getValue() == 0){
					continue; // Skip this invalid
				}
				allSkipped = false;
				values.put(entry.getKey(), entry.getValue());
			}
			if(allSkipped){
				// Null = skip the chart
				return null;
			}
			data.put("values", values);
			return data;
		}
	}
	
	/**
	 * Represents a custom drilldown pie.
	 */
	public static class DrilldownPie extends CustomChart{
		
		private final Callable<Map<String, Map<String, Integer>>> callable;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 * @param callable The callable which is used to request the chart data.
		 */
		public DrilldownPie(String chartId, Callable<Map<String, Map<String, Integer>>> callable){
			super(chartId);
			this.callable = callable;
		}
		
		@Override
		public JSONObject getChartData() throws Exception{
			JSONObject data = new JSONObject();
			JSONObject values = new JSONObject();
			Map<String, Map<String, Integer>> map = callable.call();
			if(map == null || map.isEmpty()){
				// Null = skip the chart
				return null;
			}
			boolean reallyAllSkipped = true;
			for(Map.Entry<String, Map<String, Integer>> entryValues : map.entrySet()){
				JSONObject value = new JSONObject();
				boolean allSkipped = true;
				for(Map.Entry<String, Integer> valueEntry : map.get(entryValues.getKey()).entrySet()){
					value.put(valueEntry.getKey(), valueEntry.getValue());
					allSkipped = false;
				}
				if(!allSkipped){
					reallyAllSkipped = false;
					values.put(entryValues.getKey(), value);
				}
			}
			if(reallyAllSkipped){
				// Null = skip the chart
				return null;
			}
			data.put("values", values);
			return data;
		}
	}
	
	/**
	 * Represents a custom single line chart.
	 */
	public static class SingleLineChart extends CustomChart{
		
		private final Callable<Integer> callable;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 * @param callable The callable which is used to request the chart data.
		 */
		public SingleLineChart(String chartId, Callable<Integer> callable){
			super(chartId);
			this.callable = callable;
		}
		
		@Override
		protected JSONObject getChartData() throws Exception{
			JSONObject data = new JSONObject();
			int value = callable.call();
			if(value == 0){
				// Null = skip the chart
				return null;
			}
			data.put("value", value);
			return data;
		}
		
	}
	
	/**
	 * Represents a custom multi line chart.
	 */
	public static class MultiLineChart extends CustomChart{
		
		private final Callable<Map<String, Integer>> callable;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 * @param callable The callable which is used to request the chart data.
		 */
		public MultiLineChart(String chartId, Callable<Map<String, Integer>> callable){
			super(chartId);
			this.callable = callable;
		}
		
		@Override
		protected JSONObject getChartData() throws Exception{
			JSONObject data = new JSONObject();
			JSONObject values = new JSONObject();
			Map<String, Integer> map = callable.call();
			if(map == null || map.isEmpty()){
				// Null = skip the chart
				return null;
			}
			boolean allSkipped = true;
			for(Map.Entry<String, Integer> entry : map.entrySet()){
				if(entry.getValue() == 0){
					continue; // Skip this invalid
				}
				allSkipped = false;
				values.put(entry.getKey(), entry.getValue());
			}
			if(allSkipped){
				// Null = skip the chart
				return null;
			}
			data.put("values", values);
			return data;
		}
		
	}
	
	/**
	 * Represents a custom simple bar chart.
	 */
	public static class SimpleBarChart extends CustomChart{
		
		private final Callable<Map<String, Integer>> callable;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 * @param callable The callable which is used to request the chart data.
		 */
		public SimpleBarChart(String chartId, Callable<Map<String, Integer>> callable){
			super(chartId);
			this.callable = callable;
		}
		
		@Override
		protected JSONObject getChartData() throws Exception{
			JSONObject data = new JSONObject();
			JSONObject values = new JSONObject();
			Map<String, Integer> map = callable.call();
			if(map == null || map.isEmpty()){
				// Null = skip the chart
				return null;
			}
			for(Map.Entry<String, Integer> entry : map.entrySet()){
				JSONArray categoryValues = new JSONArray();
				categoryValues.put(entry.getValue());
				values.put(entry.getKey(), categoryValues);
			}
			data.put("values", values);
			return data;
		}
		
	}
	
	/**
	 * Represents a custom advanced bar chart.
	 */
	public static class AdvancedBarChart extends CustomChart{
		
		private final Callable<Map<String, int[]>> callable;
		
		/**
		 * Class constructor.
		 *
		 * @param chartId The id of the chart.
		 * @param callable The callable which is used to request the chart data.
		 */
		public AdvancedBarChart(String chartId, Callable<Map<String, int[]>> callable){
			super(chartId);
			this.callable = callable;
		}
		
		@Override
		protected JSONObject getChartData() throws Exception{
			JSONObject data = new JSONObject();
			JSONObject values = new JSONObject();
			Map<String, int[]> map = callable.call();
			if(map == null || map.isEmpty()){
				// Null = skip the chart
				return null;
			}
			boolean allSkipped = true;
			for(Map.Entry<String, int[]> entry : map.entrySet()){
				if(entry.getValue().length == 0){
					continue; // Skip this invalid
				}
				allSkipped = false;
				JSONArray categoryValues = new JSONArray();
				for(int categoryValue : entry.getValue()){
					categoryValues.put(categoryValue);
				}
				values.put(entry.getKey(), categoryValues);
			}
			if(allSkipped){
				// Null = skip the chart
				return null;
			}
			data.put("values", values);
			return data;
		}
		
	}
}
