/*
** Copyright (C) 2020  Johannes Kepler University Linz, Institute of Networks and Security
** Copyright (C) 2020  CDL Digidow <https://www.digidow.eu/>
**
** Licensed under the EUPL, Version 1.2 or – as soon they will be approved by
** the European Commission - subsequent versions of the EUPL (the "Licence").
** You may not use this work except in compliance with the Licence.
** 
** You should have received a copy of the European Union Public License along
** with this program.  If not, you may obtain a copy of the Licence at:
** <https://joinup.ec.europa.eu/software/page/eupl>
** 
** Unless required by applicable law or agreed to in writing, software
** distributed under the Licence is distributed on an "AS IS" basis,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the Licence for the specific language governing permissions and
** limitations under the Licence.
**
*/

#include "server.h"

int server_open(int16_t port) {
    struct sockaddr_in servaddr;
    int connfd = 0;

    connfd = socket(AF_INET, SOCK_STREAM, 0);
    if (-1 == connfd) {
        printf("server_open: failed to create endpoint.\n");
        return -1;
    }
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(port);

    if (0 != bind(connfd, (const struct sockaddr *) &servaddr, sizeof(servaddr))) {
        printf("server_open: failed to bind socket\n");
        close(connfd);
        return -1;
    }
    return connfd;
}

int server_start(conn_handler handler, int16_t port) {
    struct sockaddr_in client;
    unsigned int client_len = 0;
    int connfd = 0;
    int clientfd = 0;
    int len = 0;
    int ret = 0;    //<0 .. failure, 0 .. continue, 1 .. exit, 2 .. shutdown
    char buffer[MAX_BUFSIZE];

    if(NULL == handler) {
        printf("server_start: received empty handler, stopping\n");
        return -1;
    }
    connfd = server_open(port);
    if(-1 == connfd) {
        printf("server_start: could not open port, stopping\n");
        return -1;
    }
    if (0 != listen(connfd, MAX_CLIENTS)) {
        printf("server_start: listen failed, stopping\n");
        return -1;
    }
    printf("server_start: listening\n");
    for(ret = 1; 1 == ret;) {
        client_len = sizeof(client);
        clientfd = accept(connfd, (struct sockaddr *) &client, &client_len);
        if (0 >= clientfd) {
            printf("server_start: connection to client failed\n");
            ret = -1;
        } else {
            for(ret = 0; 0 == ret;) {
                bzero(buffer, MAX_BUFSIZE);
                len = 0;
		do {
                    ret = read(clientfd, &buffer[len], sizeof(buffer)-len);
		    len += ret;
                } while(0 < ret && buffer[len-1] != '\n');

                if (0 > ret) {
                    printf("server_start: cannot read from socket\n");
                    ret = -1;
                } else if(0 == ret) {
                    printf("server_start: client closed connection\n");
                    ret = 1;
                } else {
                    ret = handler(buffer);
                }

                if (0 == ret && 0 >= write(clientfd, buffer, strlen(buffer))) {
                    printf("server_start: cannot write to socket\n");
                    ret = 1;
                }
            }
            if (0 != close(clientfd)) {
                printf("server_start: failed to close client connection properly\n");
                ret = -1;
            }
        }
    }
    printf("server_start: closing connection\n");
    if (0 != close(connfd)) {
        printf("server_start: failed to close server port properly\n");
        ret = -1;
    }
    return ret;
}