#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h> 

#include "tcpnet.h"


void error(const char *msg) {
	// perror(msg);
	throw std::runtime_error(msg);
}

// TODO do it as RAII
TcpNet::TcpNet() {}


#define TCPNET_BUFFER_SIZE 16256


int TcpNet::server(int portno, std::function<std::pair<bool, std::string>(std::string)> process_request) const {
	int sockfd, newsockfd;
	socklen_t clilen;

	char buffer[TCPNET_BUFFER_SIZE];
 	struct sockaddr_in serv_addr, cli_addr;
 
 	int n;
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd < 0) 
		error("ERROR opening socket");

 	bzero((char *) &serv_addr, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	serv_addr.sin_addr.s_addr = INADDR_ANY;
	serv_addr.sin_port = htons(portno);

	// this allows immediate bind after exit of ml
	int reuse = 1;
	if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (const char*)&reuse, sizeof(reuse)) < 0)
		error("setsockopt(SO_REUSEADDR) failed");
#ifdef SO_REUSEPORT
	if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEPORT, (const char*)&reuse, sizeof(reuse)) < 0) 
		error("setsockopt(SO_REUSEPORT) failed");
#endif

	if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) 
		error("ERROR on binding");

	listen(sockfd,5);
	clilen = sizeof(cli_addr);

	int requests_processed = 0;
	bool shutdown = false;
	while (!shutdown) {
		newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
		if (newsockfd < 0) 
			error("ERROR on accept");
	
		while (true) {
			bzero(buffer,TCPNET_BUFFER_SIZE);
			n = read(newsockfd,buffer,TCPNET_BUFFER_SIZE - 1);
			if (n == 0) break;	// nothing to read from client anymore
			if (n < 0) error("ERROR reading from socket");

			std::string request{buffer};
			std::pair<bool, std::string> response = process_request(request);

			shutdown = response.first;
			std::string response_str = response.second;

			n = write(newsockfd, response_str.c_str(), response_str.size());
			if (n < 0)
				error("ERROR writing to socket");

			requests_processed++;
		}	

		close(newsockfd);
	}

	close(sockfd);

	return requests_processed; 
}


std::vector<std::string> TcpNet::client(const std::string &address, int portno, const std::vector<std::string> &requests) const {
	int sockfd, n;
	struct sockaddr_in serv_addr;
	struct hostent *server;
	std::vector<std::string> responses;

    	char buffer[TCPNET_BUFFER_SIZE];
    
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (sockfd < 0) 
		error("ERROR opening socket");

 	server = gethostbyname(address.c_str());
	if (server == NULL) {
		fprintf(stderr,"ERROR, no such host\n");
		exit(0);
	}

	bzero((char *) &serv_addr, sizeof(serv_addr));
	serv_addr.sin_family = AF_INET;
	bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length);
	serv_addr.sin_port = htons(portno);
	
	if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
 		error("ERROR connecting");
    

	responses.reserve(requests.size());
	for(const auto &req : requests) {
		n = write(sockfd, req.c_str(), strlen(req.c_str()));
		if (n < 0) 
			error("ERROR writing to socket");
			
		bzero(buffer, TCPNET_BUFFER_SIZE);
		n = read(sockfd,buffer, TCPNET_BUFFER_SIZE - 1);
		if (n < 0)
			error("ERROR reading from socket");

		responses.push_back(std::string(buffer));
	}

	close(sockfd);

	return responses;
}


std::string TcpNet::client(const std::string &address, int portno, const std::string &request) const {
	std::vector<std::string> c{request};
	auto response = client(address, portno, c);

	return response[0];
}