#include <string>
#include <iostream>
#include <sstream>
#include "ComputeThread.hh"
#include "DocumentThread.hh"
#include "GUIBase.hh"
#include "Actions.hh"
#include "InstallPrefix.hh"
#include "popen2.hh"
#include <sys/types.h>
#include <glibmm/spawn.h>
#include "internal/unistd.h"

typedef websocketpp::client<websocketpp::config::asio_client> client;

using namespace cadabra;

ComputeThread::ComputeThread(int server_port, std::string token, std::string ip_address)
	: gui(0), docthread(0), connection_is_open(false), restarting_kernel(false), server_pid(0),
	  server_stdout(0), server_stderr(0), forced_server_port(server_port), forced_server_token(token),
	  forced_server_ip_address(ip_address)
	{
	// The ComputeThread constructor (but _not_ the run() member!) is
	// always run on the gui thread, so we can grab the gui thread id
	// here.

	gui_thread_id=std::this_thread::get_id();
	}

ComputeThread::~ComputeThread()
	{
	if(server_stdout!=0) {
		close(server_stdout);
		// close(server_stderr);
		Glib::spawn_close_pid(server_pid);
		server_pid=0;
		server_stdout=0;
		server_stderr=0;
		}
	}

void ComputeThread::set_master(GUIBase *b, DocumentThread *d)
	{
	gui=b;
	docthread=d;
	}

void ComputeThread::init()
	{
	// Setup the WebSockets client.

	wsclient.init_asio();
	wsclient.start_perpetual();
	}

void ComputeThread::try_connect()
	{
	using websocketpp::lib::bind;

	// Make the resolver work when there is no network up at all, only localhost.
	// https://svn.boost.org/trac/boost/ticket/2456
	// Not sure why this works here, as the compiler claims this statement does
	// not have any effect.
	// No longer necessary with websocketpp-0.6.0.
	//
	// boost::asio::ip::resolver_query_base::flags(0);

	wsclient.clear_access_channels(websocketpp::log::alevel::all);
	wsclient.clear_error_channels(websocketpp::log::elevel::all);

	wsclient.set_open_handler(bind(&ComputeThread::on_open,
	                               this, websocketpp::lib::placeholders::_1));
	wsclient.set_fail_handler(bind(&ComputeThread::on_fail,
	                               this, websocketpp::lib::placeholders::_1));
	wsclient.set_close_handler(bind(&ComputeThread::on_close,
	                                this, websocketpp::lib::placeholders::_1));
	wsclient.set_message_handler(bind(&ComputeThread::on_message, this,
	                                  websocketpp::lib::placeholders::_1,
	                                  websocketpp::lib::placeholders::_2));

	std::ostringstream uristr;
	uristr << "ws://" << forced_server_ip_address << ":" << port;
	websocketpp::lib::error_code ec;
	connection = wsclient.get_connection(uristr.str(), ec);
	if (ec) {
		std::cerr << "cadabra-client: websocket connection error " << ec.message() << std::endl;
		return;
		}

	our_connection_hdl = connection->get_handle();
	wsclient.connect(connection);
	// std::cerr << "cadabra-client: connect done" << std::endl;
	}

void ComputeThread::run()
	{
	init();
	try_spawn_server();
	try_connect();

	// Enter run loop, which will never terminate anymore. The on_fail and on_close
	// handlers will re-try to establish connections when they go bad.

	wsclient.run();
	}

void ComputeThread::terminate()
	{
	wsclient.stop();

	// If we have started the server ourselves, stop it now so we do
	// not leave mess behind.
	// http://riccomini.name/posts/linux/2012-09-25-kill-subprocesses-linux-bash/

	if(server_pid!=0) {
		std::cerr << "cadabra-client: killing server" << std::endl;

		if(server_stdout!=0) {
			close(server_stdout);
			// close(server_stderr);
			Glib::spawn_close_pid(server_pid);
			server_pid=0;
			server_stdout=0;
			server_stderr=0;
			}
		//		kill(server_pid, SIGKILL);
		// 		if(server_stdout)
		//			pclose2(server_stdout, server_pid);
		}
	}

void ComputeThread::all_cells_nonrunning()
	{
	for(auto it: running_cells) {
		std::shared_ptr<ActionBase> rs_action =
		   std::make_shared<ActionSetRunStatus>(it.second->id(), false);
		docthread->queue_action(rs_action);
		}
	if(gui) {
		gui->process_data();
		gui->on_kernel_runstatus(false);
		}
	running_cells.clear();
	}

void ComputeThread::on_fail(websocketpp::connection_hdl )
	{
	std::cerr << "cadabra-client: connection to server on port " << port << " failed" << std::endl;
	connection_is_open=false;
	all_cells_nonrunning();
	if(gui && server_pid!=0) {
		close(server_stdout);
		// close(server_stderr);
		Glib::spawn_close_pid(server_pid);
		//		kill(server_pid, SIGKILL);
		server_pid=0;
		server_stdout=0;
		server_stderr=0;
		gui->on_network_error();
		}

	try_spawn_server();
	try_connect();
	}

using SlotSpawnChildSetup = sigc::slot<void()>;

void ComputeThread::try_spawn_server()
	{
	// Startup the server. First generate a UUID, pass this to the
	// starting server, then use this UUID to get access to the server
	// port.

	// std::cerr << "cadabra-client: spawning server" << std::endl;

	if(forced_server_port!=0) {
		port=forced_server_port;
		authentication_token=forced_server_token;
		return;
		}

	std::vector<std::string> argv, envp;
#if defined(_WIN32) || defined(_WIN64)
	argv.push_back(cadabra::install_prefix()+"\\bin\\cadabra-server.exe");
#else
	argv.push_back("cadabra-server");
#endif
	Glib::Pid pid;
	std::string wd("");

	// See https://bugs.launchpad.net/inkscape/+bug/1662531 for things related to
	// the 'envp' argument in the call below.
	try {
		Glib::spawn_async_with_pipes(wd, argv, /* envp, WITH envp, Fedora 27 fails to start python properly */
		                             Glib::SPAWN_DEFAULT|Glib::SPAWN_SEARCH_PATH,
		                             sigc::slot<void>(),
		                             &pid,
		                             0,
		                             &server_stdout,
		                             0); // We need to see stderr on the console
		//										  &server_stderr);

		char buffer[100];
		FILE *f = fdopen(server_stdout, "r");
		if(fscanf(f, "%100s", buffer)!=1) {
			throw std::logic_error("Failed to read port from server.");
			}
		port = atoi(buffer);
		if(fscanf(f, "%100s", buffer)!=1) {
			throw std::logic_error("Failed to read authentication token from server.");
			}
		authentication_token=std::string(buffer);
		// std::cerr << "auth token: " << authentication_token << std::endl;
		}
	catch(Glib::SpawnError& err) {
		std::cerr << "Failed to start server " << argv[0] << ": " << err.what() << std::endl;
		// FIXME: cannot just fall through, the server is not up!
		}
	}

void ComputeThread::on_open(websocketpp::connection_hdl )
	{
	connection_is_open=true;
	restarting_kernel=false;
	if(gui)
		gui->on_connect();

	//	// now it is safe to use the connection
	//	std::string msg;
	//
	////	if(stopit) {
	////		msg =
	////			"{ \"header\":   { \"uuid\": \"none\", \"msg_type\": \"execute_interrupt\" },"
	////			"  \"content\":  { \"code\": \"print(42)\n\"} "
	////			"}";
	////		}
	////	else {
	//		msg =
	//			"{ \"header\":   { \"uuid\": \"none\", \"msg_type\": \"execute_request\" },"
	//			"  \"content\":  { \"code\": \"import time\nprint(42)\ntime.sleep(10)\n\"} "
	//			"}";
	////		}
	//
	////	c->send(hdl, "import time\nfor i in range(0,10):\n   print('this is python talking '+str(i))\nex=Ex('A_{m n}')\nprint(str(ex))", websocketpp::frame::opcode::text);
	//	c->send(hdl, msg, websocketpp::frame::opcode::text);
	}

void ComputeThread::on_close(websocketpp::connection_hdl )
	{
	// std::cerr << "cadabra-client: connection closed" << std::endl;
	connection_is_open=false;
	all_cells_nonrunning();
	if(gui) {
		if(restarting_kernel) gui->on_disconnect("restarting kernel");
		else                  gui->on_disconnect("not connected");
		}

	sleep(1); // do not cause a torrent...
	try_connect();
	}

void ComputeThread::cell_finished_running(DataCell::id_t id)
	{
	auto it=running_cells.find(id);
	if(it==running_cells.end()) {
		throw std::logic_error("Cannot find cell with id = "+std::to_string(id.id));
		}

	//	DTree::iterator ret = (*it).second;
	running_cells.erase(it);
	}

void ComputeThread::on_message(websocketpp::connection_hdl hdl, message_ptr msg)
	{
	client::connection_ptr con = wsclient.get_con_from_hdl(hdl);
	// std::cerr << "payload: " << msg->get_payload() << std::endl;

	// Parse the JSON message.
	nlohmann::json root;

	try {
		root=nlohmann::json::parse(msg->get_payload());
		}
	catch(nlohmann::json::exception& e) {
		std::cerr << "cadabra-client: cannot parse message." << std::endl;
		return;
		}
	if(root.count("header")==0) {
		std::cerr << "cadabra-client: received message without 'header'." << std::endl;
		return;
		}
	if(root.count("content")==0) {
		std::cerr << "cadabra-client: received message without 'content'." << std::endl;
		return;
		}
	const nlohmann::json& header  = root["header"];
	const nlohmann::json& content = root["content"];
	const std::string msg_type    = root.value("msg_type", "");

	DataCell::id_t parent_id;
	parent_id.id = header.value("parent_id", uint64_t(0));
	if(header.value("parent_origin", "")=="client")
		parent_id.created_by_client=true;
	else
		parent_id.created_by_client=false;
	DataCell::id_t cell_id;
	cell_id.id = header["cell_id"].get<uint64_t>();
	if(header.value("cell_origin", "")=="client")
		cell_id.created_by_client=true;
	else
		cell_id.created_by_client=false;
	// std::cerr << "received cell with id " << cell_id.id << std::endl;
	if (interactive_cells.find(parent_id.id) != interactive_cells.end()) {
		interactive_cells.insert(cell_id.id);
		docthread->on_interactive_output(root);
	}
	else if (interactive_cells.find(cell_id.id) != interactive_cells.end()) {
		docthread->on_interactive_output(root);
		}
	else if (msg_type.find("csl_") == 0) {
		root["header"]["from_server"] = true;
		docthread->on_interactive_output(root);
		}
	else if (msg_type == "progress_update") {
		std::string msg = content.value<std::string>("msg", "Idle");
		int n = content.value<int>("n", 0);
		int total = content.value<int>("total", 0);
		// FIXME: do something with 'pulse':
		// int pulse = content.value<bool>("pulse", false);
		docthread->set_progress(msg, n, total);
	}
	else if(msg_type=="completed") {
		// std::cerr << "received completion of " << content["original"] << " -> " << content["completed"] << std::endl;

		// Finally, the action to add the output cell.
		std::string toadd=content["completed"].get<std::string>();
		if(toadd.size()>0) {
			toadd=toadd.substr(content["original"].get<std::string>().size());
			int pos=content["position"].get<int>();
			int alternative=content["alternative"].get<int>();
			std::shared_ptr<ActionBase> action =
				std::make_shared<ActionCompleteText>(cell_id, pos, toadd, alternative);
			docthread->queue_action(action);
			}
		}
	else {
		try {
			bool finished = header["last_in_sequence"].get<bool>();

			if (finished) {
				std::shared_ptr<ActionBase> rs_action =
				   std::make_shared<ActionSetRunStatus>(parent_id, false);
				docthread->queue_action(rs_action);
				cell_finished_running(parent_id);
				}

			if (content.count("output")>0 && content["output"].get<std::string>().size() > 0) {
				if (msg_type == "output") {
					std::string output = "\\begin{verbatim}" + content["output"].get<std::string>() + "\\end{verbatim}";

					// Stick an AddCell action onto the stack. We instruct the
					// action to add this result output cell as a child of the
					// corresponding input cell.
					DataCell result(cell_id, DataCell::CellType::output, output);

					// Finally, the action to add the output cell.
					std::shared_ptr<ActionBase> action =
					   std::make_shared<ActionAddCell>(result, parent_id, ActionAddCell::Position::child);
					docthread->queue_action(action);
					}
				else if (msg_type == "verbatim") {
					std::string output = "\\begin{verbatim}" + content["output"].get<std::string>() + "\\end{verbatim}";

					// Stick an AddCell action onto the stack. We instruct the
					// action to add this result output cell as a child of the
					// corresponding input cell.
					DataCell result(cell_id, DataCell::CellType::verbatim, output);

					// Finally, the action to add the output cell.
					std::shared_ptr<ActionBase> action =
					   std::make_shared<ActionAddCell>(result, parent_id, ActionAddCell::Position::child);
					docthread->queue_action(action);
					}
				else if (msg_type == "latex_view") {
					// std::cerr << "received latex cell " << content["output"].asString() << std::endl;
					DataCell result(cell_id, DataCell::CellType::latex_view, content["output"].get<std::string>());
					std::shared_ptr<ActionBase> action =
					   std::make_shared<ActionAddCell>(result, parent_id, ActionAddCell::Position::child);
					docthread->queue_action(action);
					}
				else if (msg_type == "input_form") {
					DataCell result(cell_id, DataCell::CellType::input_form, content["output"].get<std::string>());
					std::shared_ptr<ActionBase> action =
					   std::make_shared<ActionAddCell>(result, parent_id, ActionAddCell::Position::child);
					docthread->queue_action(action);
					}
				else if (msg_type == "error") {
					std::string error = "{\\color{red}{\\begin{verbatim}" + content["output"].get<std::string>()
					                    + "\\end{verbatim}}}";
					if (msg_type == "fault") {
						error = "{\\color{red}{Kernel fault}}\\begin{small}" + error + "\\end{small}";
						}

					// Stick an AddCell action onto the stack. We instruct the
					// action to add this result output cell as a child of the
					// corresponding input cell.
					DataCell result(cell_id, DataCell::CellType::error, error);

					// Finally, the action.
					std::shared_ptr<ActionBase> action =
					   std::make_shared<ActionAddCell>(result, parent_id, ActionAddCell::Position::child);
					docthread->queue_action(action);

					// Position the cursor in the cell that generated the error. All other cells on
					// the execute queue have been cancelled by the server.
					std::shared_ptr<ActionBase> actionpos =
					   std::make_shared<ActionPositionCursor>(parent_id, ActionPositionCursor::Position::in);
					docthread->queue_action(actionpos);

					// FIXME: iterate over all cells and set the running flag to false.
					}
				else if (msg_type == "image_png") {
					DataCell result(cell_id, DataCell::CellType::image_png, content["output"].get<std::string>());
					std::shared_ptr<ActionBase> action =
					   std::make_shared<ActionAddCell>(result, parent_id, ActionAddCell::Position::child);
					docthread->queue_action(action);
					}
				else {
					std::cerr << "cadabra-client: received cell we did not expect: "
					          << msg_type << std::endl;
					}
				}
			}
		catch (std::logic_error& ex) {
			// WARNING: if the server sends
			std::cerr << "cadabra-client: trouble processing server response: " << ex.what() << std::endl;
			}
		}

	// Update kernel busy indicator depending on number of running cells.
	if(number_of_cells_executing()>0)
		gui->on_kernel_runstatus(true);
	else
		gui->on_kernel_runstatus(false);

	gui->process_data();
	}

void ComputeThread::execute_interactive(uint64_t id, const std::string& code)
	{
	assert(gui_thread_id == std::this_thread::get_id());

	if (!connection_is_open)
		return;

	if (code.substr(0, 7) == "reset()")
		return restart_kernel();

	nlohmann::json req, header, content;

	header["msg_type"]    = "execute_request";
	header["cell_id"]     = id;
	header["interactive"] = true;
	content["code"]       = code.c_str();

	req["auth_token"] = authentication_token;
	req["header"]     = header;
	req["content"]    = content;

	std::ostringstream oss;
	oss << req << std::endl;
	wsclient.send(our_connection_hdl, oss.str(), websocketpp::frame::opcode::text);
	interactive_cells.insert(id);
	}

void ComputeThread::execute_cell(DTree::iterator it)
	{
	// This absolutely has to be run on the main GUI thread.
	assert(gui_thread_id==std::this_thread::get_id());

	if(connection_is_open==false)
		return;

	const DataCell& dc=(*it);

	// std::cout << "cadabra-client: ComputeThread going to execute " << dc.textbuf << std::endl;

	if((it->textbuf).substr(0,7)=="reset()") {
		restart_kernel();

		std::shared_ptr<ActionBase> action =
		   std::make_shared<ActionPositionCursor>(it->id(), ActionPositionCursor::Position::next);

		docthread->queue_action(action);
		return;
		}

	// Position the cursor in the next cell so this one will not
	// accidentally get executed twice.
	std::shared_ptr<ActionBase> actionpos =
	   std::make_shared<ActionPositionCursor>(it->id(), ActionPositionCursor::Position::next);
	docthread->queue_action(actionpos);
	gui->process_data();

	// For a code cell, construct a server request message and then
	// send the cell to the server.
	if(it->cell_type==DataCell::CellType::python) {
		running_cells[dc.id()]=it;

		// Schedule an action to update the running status of this cell.
		std::shared_ptr<ActionBase> rs_action =
		   std::make_shared<ActionSetRunStatus>(it->id(), true);
		docthread->queue_action(rs_action);

		nlohmann::json req, header, content;
		header["uuid"]="none";
		header["cell_id"]=dc.id().id;
		if(dc.id().created_by_client)
			header["cell_origin"]="client";
		else
			header["cell_origin"]="server";
		header["msg_type"]="execute_request";
		req["auth_token"]=authentication_token;
		req["header"]=header;
		content["code"]=dc.textbuf;
		req["content"]=content;

		gui->on_kernel_runstatus(true);
		std::ostringstream str;
		str << req << std::endl;
		wsclient.send(our_connection_hdl, str.str(), websocketpp::frame::opcode::text);
		// NOTE: we can get a return message in on_message at any point after this,
		// it will come in on a different thread!
		}

	// For a LaTeX cell, immediately request a new latex output cell to be displayed.
	if(it->cell_type==DataCell::CellType::latex) {
		// Stick an AddCell action onto the stack. We instruct the
		// action to add this result output cell as a child of the
		// corresponding input cell.
		DataCell result(DataCell::CellType::latex_view, it->textbuf);

		std::shared_ptr<ActionBase> action =
		   std::make_shared<ActionAddCell>(result, it->id(), ActionAddCell::Position::child);
		docthread->queue_action(action);
		}
	}

int ComputeThread::number_of_cells_executing() const
	{
	return running_cells.size();
	}

void ComputeThread::stop()
	{
	if(connection_is_open==false)
		return;

	nlohmann::json req, header, content;
	header["uuid"]="none";
	header["msg_type"]="execute_interrupt";
	req["auth_token"]=authentication_token;
	req["header"]=header;

	std::ostringstream str;
	str << req << std::endl;

	//	std::cerr << str.str() << std::endl;

	server_pid=0;
	wsclient.send(our_connection_hdl, str.str(), websocketpp::frame::opcode::text);
	}

void ComputeThread::restart_kernel()
	{
	if(connection_is_open==false)
		return;

	restarting_kernel=true;

	// Restarting the kernel means all previously running blocks have stopped running.
	// Inform the GUI about this.
	// FIXME: set all running flags to false
	gui->on_kernel_runstatus(false);

	// std::cerr << "cadabra-client: restarting kernel" << std::endl;
	nlohmann::json req, header, content;
	header["uuid"]="none";
	header["msg_type"]="exit";
	header["from_server"] = true;
	req["auth_token"]=authentication_token;
	req["header"]=header;

	std::ostringstream str;
	str << req << std::endl;

	//	std::cerr << str.str() << std::endl;

	wsclient.send(our_connection_hdl, str.str(), websocketpp::frame::opcode::text);
	docthread->on_interactive_output(req);
	}

bool ComputeThread::complete(DTree::iterator it, int pos, int alternative)
	{
	if(connection_is_open==false)
		return false;

	const DataCell& dc=(*it);

	nlohmann::json req, header, content;
	header["uuid"]="none";
	header["cell_id"]=dc.id().id;
	if(dc.id().created_by_client)
		header["cell_origin"]="client";
	else
		header["cell_origin"]="server";
	header["msg_type"]="complete";
	req["auth_token"]=authentication_token;
	req["header"]=header;
	std::string todo = it->textbuf.substr(0,pos);
//	if(todo.size()>0 && todo[todo.size()-1]=='\n')
//		todo=todo.substr(0, todo.size()-1);
	// std::cerr << "to complete full: " << todo << std::endl;
	size_t lst=todo.find_last_of("\n(){}[]:\t ");
	if(lst!=std::string::npos)
		todo=todo.substr(lst+1);
	// std::cerr << "to complete strip: " << todo << std::endl;

	if(todo.size()==0)
		return false;

	req["string"]=todo;
	req["position"]=pos;
	req["alternative"]=alternative;

	std::ostringstream str;
	str << req << std::endl;

	// std::cerr << str.str() << std::endl;

	server_pid=0;
	wsclient.send(our_connection_hdl, str.str(), websocketpp::frame::opcode::text);

	return true;
	}