/*       +------------------------------------+
 *       | Inspire Internet Relay Chat Daemon |
 *       +------------------------------------+
 *
 *  InspIRCd: (C) 2002-2007 InspIRCd Development Team
 * See: http://www.inspircd.org/wiki/index.php/Credits
 *
 * This program is free but copyrighted software; see
 *            the file COPYING for details.
 *
 * ---------------------------------------------------
 */

#include "inspircd.h"
#include "httpd.h"

/* $ModDesc: Provides HTTP serving facilities to modules */
/* $ModDep: httpd.h */

class ModuleHttpServer;

static ModuleHttpServer* HttpModule;
static bool claimed;

/** HTTP socket states
 */
enum HttpState
{
	HTTP_LISTEN = 0,
	HTTP_SERVE_WAIT_REQUEST = 1, /* Waiting for a full request */
	HTTP_SERVE_RECV_POSTDATA = 2, /* Waiting to finish recieving POST data */
	HTTP_SERVE_SEND_DATA = 3 /* Sending response */
};

class HttpServerSocket;

/** This class is used to handle HTTP socket timeouts
 */
class HttpServerTimeout : public Timer
{
 private:
	/** HttpServerSocket we are attached to
	 */
	HttpServerSocket* s;
	/** Socketengine the file descriptor is in
	 */
	SocketEngine* SE;
 public:
	/** Attach timeout to HttpServerSocket
	 */
	HttpServerTimeout(HttpServerSocket* sock, SocketEngine* engine);
	/** Handle timer tick
	 */
	void Tick(time_t TIME);
};

/** A socket used for HTTP transport
 */
class HttpServerSocket : public BufferedSocket
{
	FileReader* index;
	HttpState InternalState;
	
	HTTPHeaders headers;
	std::string reqbuffer;
	std::string postdata;
	unsigned int postsize;
	std::string request_type;
	std::string uri;
	std::string http_version;
	bool keepalive;
	
	HttpServerTimeout* Timeout;
	bool DataSinceLastTick;
	friend class HttpServerTimeout;
	
 public:

	HttpServerSocket(InspIRCd* SI, std::string host, int port, bool listening, unsigned long maxtime, FileReader* index_page) : BufferedSocket(SI, host, port, listening, maxtime), index(index_page), postsize(0)
	{
		InternalState = HTTP_LISTEN;
		Timeout = NULL;
	}

	HttpServerSocket(InspIRCd* SI, int newfd, char* ip, FileReader* ind) : BufferedSocket(SI, newfd, ip), index(ind), postsize(0), keepalive(false), DataSinceLastTick(false)
	{
		InternalState = HTTP_SERVE_WAIT_REQUEST;
		Timeout = new HttpServerTimeout(this, Instance->SE);
		Instance->Timers->AddTimer(Timeout);
	}

	FileReader* GetIndex()
	{
		return index;
	}

	~HttpServerSocket()
	{
		if (Timeout)
		{
			if (Instance->Time() < Timeout->GetTimer())
				Instance->Timers->DelTimer(Timeout);
			Timeout = NULL;
		}
	}
	
	void ResetRequest()
	{
		headers.Clear();
		postdata.clear();
		postsize = 0;
		request_type.clear();
		uri.clear();
		http_version.clear();
		InternalState = HTTP_SERVE_WAIT_REQUEST;
		
		if (reqbuffer.size())
			CheckRequestBuffer();
	}
	
	virtual int OnIncomingConnection(int newsock, char* ip)
	{
		if (InternalState == HTTP_LISTEN)
		{
			new HttpServerSocket(this->Instance, newsock, ip, index);
		}
		return true;
	}

	virtual void OnClose()
	{
	}

	std::string Response(int response)
	{
		switch (response)
		{
			case 100:
				return "CONTINUE";
			case 101:
				return "SWITCHING PROTOCOLS";
			case 200:
				return "OK";
			case 201:
				return "CREATED";
			case 202:
				return "ACCEPTED";
			case 203:
				return "NON-AUTHORITATIVE INFORMATION";
			case 204:
				return "NO CONTENT";
			case 205:
				return "RESET CONTENT";
			case 206:
				return "PARTIAL CONTENT";
			case 300:
				return "MULTIPLE CHOICES";
			case 301:
				return "MOVED PERMENANTLY";
			case 302:
				return "FOUND";
			case 303:
				return "SEE OTHER";
			case 304:
				return "NOT MODIFIED";
			case 305:
				return "USE PROXY";
			case 307:
				return "TEMPORARY REDIRECT";
			case 400:
				return "BAD REQUEST";
			case 401:
				return "UNAUTHORIZED";
			case 402:
				return "PAYMENT REQUIRED";
			case 403:
				return "FORBIDDEN";
			case 404:
				return "NOT FOUND";
			case 405:
				return "METHOD NOT ALLOWED";
			case 406:
				return "NOT ACCEPTABLE";
			case 407:
				return "PROXY AUTHENTICATION REQUIRED";
			case 408:
				return "REQUEST TIMEOUT";
			case 409:
				return "CONFLICT";
			case 410:
				return "GONE";
			case 411:
				return "LENGTH REQUIRED";
			case 412:
				return "PRECONDITION FAILED";
			case 413:
				return "REQUEST ENTITY TOO LARGE";
			case 414:
				return "REQUEST-URI TOO LONG";
			case 415:
				return "UNSUPPORTED MEDIA TYPE";
			case 416:
				return "REQUESTED RANGE NOT SATISFIABLE";
			case 417:
				return "EXPECTATION FAILED";
			case 500:
				return "INTERNAL SERVER ERROR";
			case 501:
				return "NOT IMPLEMENTED";
			case 502:
				return "BAD GATEWAY";
			case 503:
				return "SERVICE UNAVAILABLE";
			case 504:
				return "GATEWAY TIMEOUT";
			case 505:
				return "HTTP VERSION NOT SUPPORTED";
			default:
				return "WTF";
			break;
				
		}
	}
	
	void SendHTTPError(int response)
	{
		HTTPHeaders empty;
		std::string data = "<html><head></head><body>Server error "+ConvToStr(response)+": "+Response(response)+"<br>"+
		                   "<small>Powered by <a href='http://www.inspircd.org'>InspIRCd</a></small></body></html>";
		
		SendHeaders(data.length(), response, empty);
		this->Write(data);
		
		if (keepalive)
			ResetRequest();
	}
	
	void SendHeaders(unsigned long size, int response, HTTPHeaders &rheaders)
	{

		this->Write(http_version + " "+ConvToStr(response)+" "+Response(response)+"\r\n");

		time_t local = this->Instance->Time();
		struct tm *timeinfo = gmtime(&local);
		char *date = asctime(timeinfo);
		date[strlen(date) - 1] = '\0';
		rheaders.CreateHeader("Date", date);
		
		rheaders.CreateHeader("Server", "InspIRCd/m_httpd.so/1.1");
		rheaders.SetHeader("Content-Length", ConvToStr(size));
		
		if (size)
			rheaders.CreateHeader("Content-Type", "text/html");
		else
			rheaders.RemoveHeader("Content-Type");
		
		if (rheaders.GetHeader("Connection") == "Close")
			keepalive = false;
		else if (rheaders.GetHeader("Connection") == "Keep-Alive" && !headers.IsSet("Connection"))
			keepalive = true;
		else if (!rheaders.IsSet("Connection") && !keepalive)
			rheaders.SetHeader("Connection", "Close");
		
		this->Write(rheaders.GetFormattedHeaders());
		this->Write("\r\n");
		
		if (!size && keepalive)
			ResetRequest();
	}

	virtual bool OnDataReady()
	{
		char* data = this->Read();

		/* Check that the data read is a valid pointer and it has some content */
		if (!data || !*data)
			return false;
		
		DataSinceLastTick = true;
		
		if (InternalState == HTTP_SERVE_RECV_POSTDATA)
		{
			postdata.append(data);
			if (postdata.length() >= postsize)
				ServeData();
		}
		else
		{
			reqbuffer.append(data);
			
			if (reqbuffer.length() >= 8192)
			{
				Instance->Log(DEBUG, "m_httpd dropped connection due to an oversized request buffer");
				reqbuffer.clear();
				return false;
			}
			
			if (InternalState == HTTP_SERVE_WAIT_REQUEST)
				CheckRequestBuffer();
		}
		
		return true;
	}
	
	void CheckRequestBuffer()
	{
		std::string::size_type reqend = reqbuffer.find("\r\n\r\n");
		if (reqend == std::string::npos)
			return;
		
		// We have the headers; parse them all
		std::string::size_type hbegin = 0, hend;
		while ((hend = reqbuffer.find("\r\n", hbegin)) != std::string::npos)
		{
			if (hbegin == hend)
				break;
			
			if (request_type.empty())
			{
				std::istringstream cheader(std::string(reqbuffer, hbegin, hend - hbegin));
				cheader >> request_type;
				cheader >> uri;
				cheader >> http_version;
				
				if (request_type.empty() || uri.empty() || http_version.empty())
				{
					SendHTTPError(400);
					return;
				}
				
				hbegin = hend + 2;
				continue;
			}
			
			std::string cheader = reqbuffer.substr(hbegin, hend - hbegin);
			
			std::string::size_type fieldsep = cheader.find(':');
			if ((fieldsep == std::string::npos) || (fieldsep == 0) || (fieldsep == cheader.length() - 1))
			{
				SendHTTPError(400);
				return;
			}
			
			headers.SetHeader(cheader.substr(0, fieldsep), cheader.substr(fieldsep + 2));
			
			hbegin = hend + 2;
		}
		
		reqbuffer.erase(0, reqend + 4);
		
		std::transform(request_type.begin(), request_type.end(), request_type.begin(), ::toupper);
		std::transform(http_version.begin(), http_version.end(), http_version.begin(), ::toupper);
		
		if ((http_version != "HTTP/1.1") && (http_version != "HTTP/1.0"))
		{
			SendHTTPError(505);
			return;
		}
		
		if (strcasecmp(headers.GetHeader("Connection").c_str(), "keep-alive") == 0)
			keepalive = true;
		
		if (headers.IsSet("Content-Length") && (postsize = atoi(headers.GetHeader("Content-Length").c_str())) != 0)
		{
			InternalState = HTTP_SERVE_RECV_POSTDATA;
			
			if (reqbuffer.length() >= postsize)
			{
				postdata = reqbuffer.substr(0, postsize);
				reqbuffer.erase(0, postsize);
			}
			else if (!reqbuffer.empty())
			{
				postdata = reqbuffer;
				reqbuffer.clear();
			}
			
			if (postdata.length() >= postsize)
				ServeData();
			
			return;
		}
		
		ServeData();
	}

	void ServeData()
	{
		InternalState = HTTP_SERVE_SEND_DATA;

		if ((request_type == "GET") && (uri == "/"))
		{
			HTTPHeaders empty;
			SendHeaders(index->ContentSize(), 200, empty);
			this->Write(index->Contents());
		}
		else
		{
			claimed = false;
			HTTPRequest httpr(request_type,uri,&headers,this,this->GetIP(),postdata);
			Event e((char*)&httpr, (Module*)HttpModule, "httpd_url");
			e.Send(this->Instance);
			if (!claimed)
			{
				SendHTTPError(404);
			}
		}
	}

	void Page(std::stringstream* n, int response, HTTPHeaders *headers)
	{
		SendHeaders(n->str().length(), response, *headers);
		this->Write(n->str());
		
		if (!keepalive)
		{
			Instance->SE->DelFd(this);
			this->Close();
		}
		else
			this->ResetRequest();
	}
};

HttpServerTimeout::HttpServerTimeout(HttpServerSocket* sock, SocketEngine* engine) : Timer(15, time(NULL), true), s(sock), SE(engine)
{
}

void HttpServerTimeout::Tick(time_t TIME)
{
	if (!s->DataSinceLastTick)
	{
		SE->DelFd(s);
		s->Close();
		s->Timeout = NULL;
		this->CancelRepeat();
	}
	else
		s->DataSinceLastTick = false;
}

class ModuleHttpServer : public Module
{
	std::vector<HttpServerSocket*> httpsocks;
 public:

	void ReadConfig()
	{
		int port;
		std::string host;
		std::string bindip;
		std::string indexfile;
		FileReader* index;
		HttpServerSocket* http;
		ConfigReader c(ServerInstance);

		httpsocks.clear();

		for (int i = 0; i < c.Enumerate("http"); i++)
		{
			host = c.ReadValue("http", "host", i);
			bindip = c.ReadValue("http", "ip", i);
			port = c.ReadInteger("http", "port", i, true);
			indexfile = c.ReadValue("http", "index", i);
			index = new FileReader(ServerInstance, indexfile);
			if (!index->Exists())
				throw ModuleException("Can't read index file: "+indexfile);
			http = new HttpServerSocket(ServerInstance, bindip, port, true, 0, index);
			httpsocks.push_back(http);
		}
	}

	ModuleHttpServer(InspIRCd* Me) : Module(Me)
	{
		ReadConfig();
		HttpModule = this;
		Implementation eventlist[] = { I_OnRequest };
		ServerInstance->Modules->Attach(eventlist, this, 1);
	}

	char* OnRequest(Request* request)
	{
		claimed = true;
		HTTPDocument* doc = (HTTPDocument*)request->GetData();
		HttpServerSocket* sock = (HttpServerSocket*)doc->sock;
		sock->Page(doc->GetDocument(), doc->GetResponseCode(), &doc->headers);
		return NULL;
	}

	void Implements(char* List)
	{
		List[I_OnRequest] = 1;
	}

	virtual ~ModuleHttpServer()
	{
		for (size_t i = 0; i < httpsocks.size(); i++)
		{
			ServerInstance->SE->DelFd(httpsocks[i]);
			httpsocks[i]->Close();
			delete httpsocks[i]->GetIndex();
		}
		ServerInstance->BufferedSocketCull();
	}

	virtual Version GetVersion()
	{
		return Version(1,1,0,0,VF_VENDOR|VF_SERVICEPROVIDER,API_VERSION);
	}
};

MODULE_INIT(ModuleHttpServer)