package emu.grasscutter.server.dispatch;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.protobuf.ByteString;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpServer;
import com.sun.net.httpserver.HttpsConfigurator;
import com.sun.net.httpserver.HttpsServer;

import emu.grasscutter.Config;
import emu.grasscutter.Grasscutter;
import emu.grasscutter.database.DatabaseHelper;
import emu.grasscutter.game.Account;
import emu.grasscutter.net.proto.QueryCurrRegionHttpRspOuterClass.QueryCurrRegionHttpRsp;
import emu.grasscutter.net.proto.QueryRegionListHttpRspOuterClass.QueryRegionListHttpRsp;
import emu.grasscutter.net.proto.RegionInfoOuterClass.RegionInfo;
import emu.grasscutter.net.proto.RegionSimpleInfoOuterClass.RegionSimpleInfo;
import emu.grasscutter.server.dispatch.json.*;
import emu.grasscutter.server.dispatch.json.ComboTokenReqJson.LoginTokenData;
import emu.grasscutter.utils.FileUtils;
import emu.grasscutter.utils.Utils;

import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import java.io.*;
import java.net.InetSocketAddress;
import java.net.URI;
import java.net.URLDecoder;
import java.security.KeyStore;
import java.util.*;

public final class DispatchServer {
	public static String query_region_list = "";
	public static String query_cur_region = "";

	private final InetSocketAddress address;
	private final Gson gson;
	private final String defaultServerName = "os_usa";
	
	public String regionListBase64;
	public HashMap<String, RegionData> regions;

	public DispatchServer() {
		this.regions = new HashMap<String, RegionData>();
		this.address = new InetSocketAddress(Grasscutter.getConfig().getDispatchOptions().Ip, Grasscutter.getConfig().getDispatchOptions().Port);
		this.gson = new GsonBuilder().create();
		
		this.loadQueries();
		this.initRegion();
	}
	
	public InetSocketAddress getAddress() {
		return address;
	}
	
	public Gson getGsonFactory() {
		return gson;
	}

	public QueryCurrRegionHttpRsp getCurrRegion() {
		// Needs to be fixed by having the game servers connect to the dispatch server.
		if(Grasscutter.getConfig().RunMode.equalsIgnoreCase("HYBRID")) {
			return regions.get(defaultServerName).parsedRegionQuery;
		}

		Grasscutter.getLogger().warn("[Dispatch] Unsupported run mode for getCurrRegion()");
		return null;
	}
	
	public void loadQueries() {
		File file;
		
		file = new File(Grasscutter.getConfig().DATA_FOLDER + "query_region_list.txt");
		if (file.exists()) {
			query_region_list = new String(FileUtils.read(file));
		} else {
			Grasscutter.getLogger().warn("[Dispatch] query_region_list not found! Using default region list.");
		}
	
		file = new File(Grasscutter.getConfig().DATA_FOLDER + "query_cur_region.txt");
		if (file.exists()) {
			query_cur_region = new String(FileUtils.read(file));
		} else {
			Grasscutter.getLogger().warn("[Dispatch] query_cur_region not found! Using default current region.");
		}
	}

	private void initRegion() {
		try {
			byte[] decoded = Base64.getDecoder().decode(query_region_list);
			QueryRegionListHttpRsp rl = QueryRegionListHttpRsp.parseFrom(decoded);
			
			byte[] decoded2 = Base64.getDecoder().decode(query_cur_region);
			QueryCurrRegionHttpRsp regionQuery = QueryCurrRegionHttpRsp.parseFrom(decoded2);

			List<RegionSimpleInfo> servers = new ArrayList<RegionSimpleInfo>();
			List<String> usedNames = new ArrayList<String>(); // List to check for potential naming conflicts
			if(Grasscutter.getConfig().RunMode.equalsIgnoreCase("HYBRID")) { // Automatically add the game server if in hybrid mode
				RegionSimpleInfo server = RegionSimpleInfo.newBuilder()
						.setName("os_usa")
						.setTitle(Grasscutter.getConfig().getGameServerOptions().Name)
						.setType("DEV_PUBLIC")
						.setDispatchUrl("https://" + (Grasscutter.getConfig().getDispatchOptions().PublicIp.isEmpty() ? Grasscutter.getConfig().getDispatchOptions().Ip : Grasscutter.getConfig().getDispatchOptions().PublicIp) + ":" + getAddress().getPort() + "/query_cur_region_" + defaultServerName)
						.build();
				usedNames.add(defaultServerName);
				servers.add(server);

				RegionInfo serverRegion = regionQuery.getRegionInfo().toBuilder()
						.setIp((Grasscutter.getConfig().getGameServerOptions().PublicIp.isEmpty() ? Grasscutter.getConfig().getGameServerOptions().Ip : Grasscutter.getConfig().getGameServerOptions().PublicIp))
						.setPort(Grasscutter.getConfig().getGameServerOptions().Port)
						.setSecretKey(ByteString.copyFrom(FileUtils.read(Grasscutter.getConfig().KEY_FOLDER + "dispatchSeed.bin")))
						.build();

				QueryCurrRegionHttpRsp parsedRegionQuery = regionQuery.toBuilder().setRegionInfo(serverRegion).build();
				regions.put(defaultServerName, new RegionData(parsedRegionQuery, Base64.getEncoder().encodeToString(parsedRegionQuery.toByteString().toByteArray())));

			} else {
				if(Grasscutter.getConfig().getDispatchOptions().getGameServers().length == 0) {
					Grasscutter.getLogger().error("[Dispatch] There are no game servers available. Exiting due to unplayable state.");
					System.exit(1);
				}
			}

			for (Config.DispatchServerOptions.RegionInfo regionInfo : Grasscutter.getConfig().getDispatchOptions().getGameServers()) {
				if(usedNames.contains(regionInfo.Name)) {
					Grasscutter.getLogger().error("Region name already in use.");
					continue;
				}
				RegionSimpleInfo server = RegionSimpleInfo.newBuilder()
						.setName(regionInfo.Name)
						.setTitle(regionInfo.Title)
						.setType("DEV_PUBLIC")
						.setDispatchUrl("https://" + (Grasscutter.getConfig().getDispatchOptions().PublicIp.isEmpty() ? Grasscutter.getConfig().getDispatchOptions().Ip : Grasscutter.getConfig().getDispatchOptions().PublicIp) + ":" + getAddress().getPort() + "/query_cur_region_" + regionInfo.Name)
						.build();
				usedNames.add(regionInfo.Name);
				servers.add(server);

				RegionInfo serverRegion = regionQuery.getRegionInfo().toBuilder()
						.setIp(regionInfo.Ip)
						.setPort(regionInfo.Port)
						.setSecretKey(ByteString.copyFrom(FileUtils.read(Grasscutter.getConfig().KEY_FOLDER + "dispatchSeed.bin")))
						.build();

				QueryCurrRegionHttpRsp parsedRegionQuery = regionQuery.toBuilder().setRegionInfo(serverRegion).build();
				regions.put(regionInfo.Name, new RegionData(parsedRegionQuery, Base64.getEncoder().encodeToString(parsedRegionQuery.toByteString().toByteArray())));
			}

			QueryRegionListHttpRsp regionList = QueryRegionListHttpRsp.newBuilder()
				.addAllServers(servers)
				.setClientSecretKey(rl.getClientSecretKey())
			    .setClientCustomConfigEncrypted(rl.getClientCustomConfigEncrypted())
			    .setEnableLoginPc(true)
				.build();

			this.regionListBase64 = Base64.getEncoder().encodeToString(regionList.toByteString().toByteArray());
		} catch (Exception e) {
			Grasscutter.getLogger().error("[Dispatch] Error while initializing region info!", e);
		}
	}

	public void start() throws Exception {
		HttpServer server;
		if (Grasscutter.getConfig().getDispatchOptions().UseSSL) {
			HttpsServer httpsServer;
			httpsServer = HttpsServer.create(getAddress(), 0);
			SSLContext sslContext = SSLContext.getInstance("TLS");
			try (FileInputStream fis = new FileInputStream(Grasscutter.getConfig().getDispatchOptions().KeystorePath)) {
				char[] keystorePassword = Grasscutter.getConfig().getDispatchOptions().KeystorePassword.toCharArray();
				KeyStore ks = KeyStore.getInstance("PKCS12");
				ks.load(fis, keystorePassword);
				KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
				kmf.init(ks, keystorePassword);
				
				sslContext.init(kmf.getKeyManagers(), null, null);
				
				httpsServer.setHttpsConfigurator(new HttpsConfigurator(sslContext));
				server = httpsServer;
			} catch (Exception e) {
				Grasscutter.getLogger().warn("[Dispatch] No SSL cert found! Falling back to HTTP server.");
				Grasscutter.getConfig().getDispatchOptions().UseSSL = false;
				server = HttpServer.create(getAddress(), 0);
			}
		} else {
			server = HttpServer.create(getAddress(), 0);
		}

		server.createContext("/", t -> responseHTML(t, "Hello"));
		
		// Dispatch
		server.createContext("/query_region_list", t -> {
			// Log
			Grasscutter.getLogger().info(String.format("[Dispatch] Client %s request: query_region_list", t.getRemoteAddress()));

			responseHTML(t, regionListBase64);
		});

		for (String regionName : regions.keySet()) {
			server.createContext("/query_cur_region_" + regionName, t -> {
				String regionCurrentBase64 = regions.get(regionName).Base64;
				// Log
				Grasscutter.getLogger().info(String.format("Client %s request: query_cur_region_%s", t.getRemoteAddress(), regionName));
				// Create a response form the request query parameters
				URI uri = t.getRequestURI();
				String response = "CAESGE5vdCBGb3VuZCB2ZXJzaW9uIGNvbmZpZw==";
				if (uri.getQuery() != null && uri.getQuery().length() > 0) {
					response = regionCurrentBase64;
				}
				responseHTML(t, response);
			});
		}

		// Login via account
		server.createContext("/hk4e_global/mdk/shield/api/login", t -> {
			// Get post data
			LoginAccountRequestJson requestData = null;
			try {
				String body = Utils.toString(t.getRequestBody());
				requestData = getGsonFactory().fromJson(body, LoginAccountRequestJson.class);
			} catch (Exception ignored) { }

			// Create response json
			if (requestData == null) {
				return;
			}
			LoginResultJson responseData = new LoginResultJson();

			Grasscutter.getLogger().info(String.format("[Dispatch] Client %s is trying to log in", t.getRemoteAddress()));
			
			// Login
			Account account = DatabaseHelper.getAccountByName(requestData.account);
			
			// Check if account exists, else create a new one.
			if (account == null) {
				// Account doesnt exist, so we can either auto create it if the config value is set
				if (Grasscutter.getConfig().getDispatchOptions().AutomaticallyCreateAccounts) {
					// This account has been created AUTOMATICALLY. There will be no permissions added.
					account = DatabaseHelper.createAccountWithId(requestData.account, 0);

					if (account != null) {
						responseData.message = "OK";
						responseData.data.account.uid = account.getId();
						responseData.data.account.token = account.generateSessionKey();
						responseData.data.account.email = account.getEmail();

						Grasscutter.getLogger().info(String.format("[Dispatch] Client %s failed to log in: Account %s created", t.getRemoteAddress(), responseData.data.account.uid));
					} else {
						responseData.retcode = -201;
						responseData.message = "Username not found, create failed.";

						Grasscutter.getLogger().info(String.format("[Dispatch] Client %s failed to log in: Account create failed", t.getRemoteAddress()));
					}
				} else {
					responseData.retcode = -201;
					responseData.message = "Username not found.";

					Grasscutter.getLogger().info(String.format("[Dispatch] Client %s failed to log in: Account no found", t.getRemoteAddress()));
				} 
			} else {
				// Account was found, log the player in
				responseData.message = "OK";
				responseData.data.account.uid = account.getId();
				responseData.data.account.token = account.generateSessionKey();
				responseData.data.account.email = account.getEmail();

				Grasscutter.getLogger().info(String.format("[Dispatch] Client %s logged in as %s", t.getRemoteAddress(), responseData.data.account.uid));
			}

			responseJSON(t, responseData);
		});
		// Login via token
		server.createContext("/hk4e_global/mdk/shield/api/verify", t -> {
			// Get post data
			LoginTokenRequestJson requestData = null;
			try {
				String body = Utils.toString(t.getRequestBody());
				requestData = getGsonFactory().fromJson(body, LoginTokenRequestJson.class);
			} catch (Exception ignored) { }

			// Create response json
			if (requestData == null) {
				return;
			}
			LoginResultJson responseData = new LoginResultJson();
			Grasscutter.getLogger().info(String.format("[Dispatch] Client %s is trying to log in via token", t.getRemoteAddress()));

			// Login
			Account account = DatabaseHelper.getAccountById(requestData.uid);
			
			// Test
			if (account == null || !account.getSessionKey().equals(requestData.token)) {
				responseData.retcode = -111;
				responseData.message = "Game account cache information error";

				Grasscutter.getLogger().info(String.format("[Dispatch] Client %s failed to log in via token", t.getRemoteAddress()));
			} else {
				responseData.message = "OK";
				responseData.data.account.uid = requestData.uid;
				responseData.data.account.token = requestData.token;
				responseData.data.account.email = account.getEmail();

				Grasscutter.getLogger().info(String.format("[Dispatch] Client %s logged in via token as %s", t.getRemoteAddress(), responseData.data.account.uid));
			}

			responseJSON(t, responseData);
		});
		// Exchange for combo token
		server.createContext("/hk4e_global/combo/granter/login/v2/login", t -> {
			// Get post data
			ComboTokenReqJson requestData = null;
			try {
				String body = Utils.toString(t.getRequestBody());
				requestData = getGsonFactory().fromJson(body, ComboTokenReqJson.class);
			} catch (Exception ignored) { }

			// Create response json
			if (requestData == null || requestData.data == null) {
				return;
			}
			LoginTokenData loginData = getGsonFactory().fromJson(requestData.data, LoginTokenData.class); // Get login data
			ComboTokenResJson responseData = new ComboTokenResJson();

			// Login
			Account account = DatabaseHelper.getAccountById(loginData.uid);
			
			// Test
			if (account == null || !account.getSessionKey().equals(loginData.token)) {
				responseData.retcode = -201;
				responseData.message = "Wrong session key.";

				Grasscutter.getLogger().info(String.format("[Dispatch] Client %s failed to exchange combo token", t.getRemoteAddress()));
			} else {
				responseData.message = "OK";
				responseData.data.open_id = loginData.uid;
				responseData.data.combo_id = "157795300";
				responseData.data.combo_token = account.generateLoginToken();

				Grasscutter.getLogger().info(String.format("[Dispatch] Client %s succeed to exchange combo token", t.getRemoteAddress()));
			}

			responseJSON(t, responseData);
		});
		// Agreement and Protocol
		server.createContext( // hk4e-sdk-os.hoyoverse.com
				"/hk4e_global/mdk/agreement/api/getAgreementInfos", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"marketing_agreements\":[]}}")
		);
		server.createContext( // hk4e-sdk-os.hoyoverse.com
				"/hk4e_global/combo/granter/api/compareProtocolVersion", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"modified\":true,\"protocol\":{\"id\":0,\"app_id\":4,\"language\":\"en\",\"user_proto\":\"\",\"priv_proto\":\"\",\"major\":7,\"minimum\":0,\"create_time\":\"0\",\"teenager_proto\":\"\",\"third_proto\":\"\"}}}")
		);
		// Game data
		server.createContext( // hk4e-api-os.hoyoverse.com
				"/common/hk4e_global/announcement/api/getAlertPic", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"total\":0,\"list\":[]}}")
		);
		server.createContext( // hk4e-api-os.hoyoverse.com
				"/common/hk4e_global/announcement/api/getAlertAnn",
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"alert\":false,\"alert_id\":0,\"remind\":true}}")
		);
		server.createContext( // hk4e-api-os.hoyoverse.com
				"/common/hk4e_global/announcement/api/getAnnList", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"list\":[],\"total\":0,\"type_list\":[],\"alert\":false,\"alert_id\":0,\"timezone\":0,\"t\":\"" + System.currentTimeMillis() + "\"}}")
		);
		server.createContext( // hk4e-api-os-static.hoyoverse.com
				"/common/hk4e_global/announcement/api/getAnnContent", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"list\":[],\"total\":0}}")
		);
		server.createContext( // hk4e-sdk-os.hoyoverse.com
				"/hk4e_global/mdk/shopwindow/shopwindow/listPriceTier", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"suggest_currency\":\"USD\",\"tiers\":[]}}")
		);
		// Captcha
		server.createContext( // api-account-os.hoyoverse.com
				"/account/risky/api/check", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"id\":\"c8820f246a5241ab9973f71df3ddd791\",\"action\":\"\",\"geetest\":{\"challenge\":\"\",\"gt\":\"\",\"new_captcha\":0,\"success\":1}}}")
		);
		// Config	
		server.createContext( // sdk-os-static.hoyoverse.com
				"/combo/box/api/config/sdk/combo", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"vals\":{\"disable_email_bind_skip\":\"false\",\"email_bind_remind_interval\":\"7\",\"email_bind_remind\":\"true\"}}}")
		);
		server.createContext( // hk4e-sdk-os-static.hoyoverse.com
				"/hk4e_global/combo/granter/api/getConfig", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"protocol\":true,\"qr_enabled\":false,\"log_level\":\"INFO\",\"announce_url\":\"https://webstatic-sea.hoyoverse.com/hk4e/announcement/index.html?sdk_presentation_style=fullscreen\\u0026sdk_screen_transparent=true\\u0026game_biz=hk4e_global\\u0026auth_appid=announcement\\u0026game=hk4e#/\",\"push_alias_type\":2,\"disable_ysdk_guard\":false,\"enable_announce_pic_popup\":true}}")
		);
		server.createContext( // hk4e-sdk-os-static.hoyoverse.com
				"/hk4e_global/mdk/shield/api/loadConfig", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"message\":\"OK\",\"data\":{\"id\":6,\"game_key\":\"hk4e_global\",\"client\":\"PC\",\"identity\":\"I_IDENTITY\",\"guest\":false,\"ignore_versions\":\"\",\"scene\":\"S_NORMAL\",\"name\":\"原神海外\",\"disable_regist\":false,\"enable_email_captcha\":false,\"thirdparty\":[\"fb\",\"tw\"],\"disable_mmt\":false,\"server_guest\":false,\"thirdparty_ignore\":{\"tw\":\"\",\"fb\":\"\"},\"enable_ps_bind_account\":false,\"thirdparty_login_configs\":{\"tw\":{\"token_type\":\"TK_GAME_TOKEN\",\"game_token_expires_in\":604800},\"fb\":{\"token_type\":\"TK_GAME_TOKEN\",\"game_token_expires_in\":604800}}}}")
		);
		// Test api?
		server.createContext( // abtest-api-data-sg.hoyoverse.com
				"/data_abtest_api/config/experiment/list", 
				new DispatchHttpJsonHandler("{\"retcode\":0,\"success\":true,\"message\":\"\",\"data\":[{\"code\":1000,\"type\":2,\"config_id\":\"14\",\"period_id\":\"6036_99\",\"version\":\"1\",\"configs\":{\"cardType\":\"old\"}}]}")
		);
		// Log Server 
		server.createContext( // log-upload-os.mihoyo.com
				"/log/sdk/upload", 
				new DispatchHttpJsonHandler("{\"code\":0}")
		);
		server.createContext( // log-upload-os.mihoyo.com
				"/sdk/upload", 
				new DispatchHttpJsonHandler("{\"code\":0}")
		);
		server.createContext( // /perf/config/verify?device_id=xxx&platform=x&name=xxx
				"/perf/config/verify", 
				new DispatchHttpJsonHandler("{\"code\":0}")
		);
		
		// Logging servers
		server.createContext( // overseauspider.yuanshen.com
				"/log",
				new DispatchHttpJsonHandler("{\"code\":0}")
		);

		server.createContext( // log-upload-os.mihoyo.com
				"/crash/dataUpload",
				new DispatchHttpJsonHandler("{\"code\":0}")
		);
		server.createContext("/gacha", t -> responseHTML(t, "<!doctype html><html lang=\"en\"><head><title>Gacha</title></head><body></body></html>"));

		// Start server
		server.start();
		Grasscutter.getLogger().info("[Dispatch] Dispatch server started on port " + getAddress().getPort());
	}

	private void responseJSON(HttpExchange t, Object data) throws IOException {
		// Create a response
		String response = getGsonFactory().toJson(data);
		// Set the response header status and length
		t.getResponseHeaders().put("Content-Type", Collections.singletonList("application/json"));
		t.sendResponseHeaders(200, response.getBytes().length);
		// Write the response string
		OutputStream os = t.getResponseBody();
		os.write(response.getBytes());
		os.close();
	}

	private void responseHTML(HttpExchange t, String response) throws IOException {
		// Set the response header status and length
		t.getResponseHeaders().put("Content-Type", Collections.singletonList("text/html; charset=UTF-8"));
		t.sendResponseHeaders(200, response.getBytes().length);
		//Write the response string
		OutputStream os = t.getResponseBody();
		os.write(response.getBytes());
		os.close();
	}
	
	private Map<String, String> parseQueryString(String qs) {
		Map<String, String> result = new HashMap<>();
		if (qs == null) {
			return result;
		}

		int last = 0, next, l = qs.length();
		while (last < l) {
			next = qs.indexOf('&', last);
			if (next == -1) {
				next = l;
			}

			if (next > last) {
				int eqPos = qs.indexOf('=', last);
				try {
					if (eqPos < 0 || eqPos > next) {
						result.put(URLDecoder.decode(qs.substring(last, next), "utf-8"), "");
					} else {
						result.put(URLDecoder.decode(qs.substring(last, eqPos), "utf-8"), URLDecoder.decode(qs.substring(eqPos + 1, next), "utf-8"));
					}
				} catch (UnsupportedEncodingException e) {
					throw new RuntimeException(e); // will never happen, utf-8 support is mandatory for java
				}
			}
			last = next + 1;
		}
		return result;
	}

	public static class RegionData {

		QueryCurrRegionHttpRsp parsedRegionQuery;
		String Base64;

		public RegionData(QueryCurrRegionHttpRsp prq, String b64) {
			this.parsedRegionQuery = prq;
			this.Base64 = b64;
		}
	}
}