/*

 * Hedgewars, a free turn based strategy game

 * Copyright (C) 2012 Simeon Maxein <smaxein@googlemail.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

 */

#include "netbase.h"

#include "../util/buffer.h"

#include "../util/logging.h"

#include "../util/util.h"

#include "../socket.h"

#include <string.h>

#include <stdbool.h>

#include <stdlib.h>

#include <stdio.h>

#define NET_READBUFFER_LIMIT (1024*1024)

struct _flib_netbase {

    flib_vector *readBuffer;

    flib_tcpsocket *sock;

};

flib_netbase *flib_netbase_create(const char *server, uint16_t port) {

    if(log_badargs_if2(server==NULL, port==0)) {

        return NULL;

    }

    flib_netbase *result = NULL;

    flib_netbase *newNet =  flib_calloc(1, sizeof(flib_netbase));

    if(newNet) {

        newNet->readBuffer = flib_vector_create();

        newNet->sock = flib_socket_connect(server, port);

        if(newNet->readBuffer && newNet->sock) {

            flib_log_i("Connected to server %s:%u", server, (unsigned)port);

            result = newNet;

            newNet = NULL;

        }

    }

    flib_netbase_destroy(newNet);

    return result;

}

void flib_netbase_destroy(flib_netbase *net) {

    if(net) {

        flib_socket_close(net->sock);

        flib_vector_destroy(net->readBuffer);

        free(net);

    }

}

bool flib_netbase_connected(flib_netbase *net) {

    if(!log_badargs_if(net==NULL) && net->sock) {

        return true;

    }

    return false;

}

/**

 * Parses and returns a message, and removes it from the vector.

 */

static flib_netmsg *parseMessage(flib_vector *vec) {

    const uint8_t *partStart = flib_vector_data(vec);

    const uint8_t *end = partStart+flib_vector_size(vec);

    flib_netmsg *result = flib_netmsg_create();

    if(!result) {

        return NULL;

    }

    while(1) {

        const uint8_t *partEnd = memchr(partStart, '\n', end-partStart);

        if(!partEnd) {

            // message incomplete

            flib_netmsg_destroy(result);

            return NULL;

        } else if(partEnd-partStart == 0) {

            // Zero-length part, message end marker. Remove the message from the vector.

            uint8_t *vectorStart = flib_vector_data(vec);

            size_t msgLen = partEnd+1-vectorStart;

            memmove(vectorStart, partEnd+1, flib_vector_size(vec)-msgLen);

            flib_vector_resize(vec, flib_vector_size(vec)-msgLen);

            return result;

        } else {

            if(flib_netmsg_append_part(result, partStart, partEnd-partStart)) {

                flib_netmsg_destroy(result);

                return NULL;

            }

            partStart = partEnd+1; // Skip the '\n'

        }

    }

    return NULL; // Never reached

}

/**

 * Receive some bytes and add them to the buffer.

 * Returns the number of bytes received.

 * Automatically closes the socket if an error occurs

 * and sets sock=NULL.

 */

static int receiveToBuffer(flib_netbase *net) {

    uint8_t buffer[256];

    if(!net->sock) {

        return 0;

    } else if(flib_vector_size(net->readBuffer) > NET_READBUFFER_LIMIT) {

        flib_log_e("Net connection closed: Net message too big");

        flib_socket_close(net->sock);

        net->sock = NULL;

        return 0;

    } else {

        int size = flib_socket_nbrecv(net->sock, buffer, sizeof(buffer));

        if(size>=0 && !flib_vector_append(net->readBuffer, buffer, size)) {

            return size;

        } else {

            flib_socket_close(net->sock);

            net->sock = NULL;

            return 0;

        }

    }

}

flib_netmsg *flib_netbase_recv_message(flib_netbase *net) {

    if(log_badargs_if(net==NULL)) {

        return NULL;

    }

    flib_netmsg *msg;

    while(!(msg=parseMessage(net->readBuffer))

            && receiveToBuffer(net)) {}

    if(msg) {

        return msg;

    } else if(!net->sock && flib_vector_size(net->readBuffer)>0) {

        // Connection is down and we didn't get a complete message, just flush the rest.

        flib_vector_resize(net->readBuffer, 0);

    }

    return NULL;

}

static void logSentMsg(const uint8_t *data, size_t len) {

    if(flib_log_isActive(FLIB_LOGLEVEL_DEBUG)) {

        flib_log_d("[NET OUT][%03u]%*.*s",(unsigned)len, (unsigned)len, (unsigned)len, data);

    }

}

int flib_netbase_send_raw(flib_netbase *net, const void *data, size_t len) {

    if(log_badargs_if2(net==NULL, data==NULL && len>0)) {

        return -1;

    }

    if(!net->sock) {

        flib_log_w("flib_netbase_send_raw: Not connected.");

        return -1;

    }

    if(flib_socket_send(net->sock, data, len) == len) {

        logSentMsg(data, len);

        return 0;

    } else {

        flib_log_w("Failed or incomplete write: net connection lost.");

        flib_socket_close(net->sock);

        net->sock = NULL;

        return -1;

    }

}

int flib_netbase_send_message(flib_netbase *net, const flib_netmsg *msg) {

    if(log_badargs_if2(net==NULL, msg==NULL)) {

        return -1;

    }

    size_t totalSize = 0;

    for(int i=0; i<msg->partCount; i++) {

        totalSize += strlen(msg->parts[i]) + 1;

    }

    totalSize++; // Last part ends in two '\n' instead of one

    uint8_t *buffer = flib_malloc(totalSize);

    if(!buffer) {

        return -1;

    }

    size_t pos = 0;

    for(int i=0; i<msg->partCount; i++) {

        size_t partsize = strlen(msg->parts[i]);

        memcpy(buffer+pos, msg->parts[i], partsize);

        pos += partsize;

        buffer[pos++] = '\n';

    }

    buffer[pos++] = '\n';

    return flib_netbase_send_raw(net, buffer, pos);

}

int flib_netbase_sendf(flib_netbase *net, const char *format, ...) {

    int result = -1;

    if(!log_badargs_if2(net==NULL, format==NULL)) {

        va_list argp;

        va_start(argp, format);

        char *buffer = flib_vasprintf(format, argp);

        if(buffer) {

            result = flib_netbase_send_raw(net, buffer, strlen(buffer));

        }

        free(buffer);

        va_end(argp);

    }

    return result;

}

flib_netmsg *flib_netmsg_create() {

    flib_netmsg *result = flib_calloc(1, sizeof(flib_netmsg));

    if(result) {

        result->partCount = 0;

        result->parts = NULL;

        return result;

    } else {

        return NULL;

    }

}

void flib_netmsg_destroy(flib_netmsg *msg) {

    if(msg) {

        for(int i=0; i<msg->partCount; i++) {

            free(msg->parts[i]);

        }

        free(msg->parts);

        free(msg);

    }

}

int flib_netmsg_append_part(flib_netmsg *msg, const void *part, size_t partlen) {

    int result = -1;

    if(!log_badargs_if2(msg==NULL, part==NULL && partlen>0)) {

        char **newParts = realloc(msg->parts, (msg->partCount+1)*sizeof(*msg->parts));

        if(newParts) {

            msg->parts = newParts;

            msg->parts[msg->partCount] = flib_malloc(partlen+1);

            if(msg->parts[msg->partCount]) {

                memcpy(msg->parts[msg->partCount], part, partlen);

                msg->parts[msg->partCount][partlen] = 0;

                msg->partCount++;

                result = 0;

            }

        }

    }

    return result;

}