/* splitgpx -- split GPX on waypoints   Copyright (C) 2011 Frans Faase

   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., 675 Mass Ave, Cambridge, MA 02139, USA.

GNU General Public License:
   http://www.iwriteiam.nl/GNU.txt

Description:
   This program when run as pipe command, processes a GPX file
   saved with @Trip PC such that the single track is split with
   the enclosed waypoints in tracks where the name of the track
   is determined by the times mentiones in the waypoints.
   
   This is a rather low-level implementation, which does not
   really parse the GPX as XML, as it should, but it works for
   my purpose.
   
   This program is mentioned on http://www.iwriteiam.nl/D1109.html#10b
*/
#include <stdio.h>
#include <strings.h>

char buffer[2001];

void getLine(FILE* f)
{
    if (!fgets(buffer, 2000, f))
        buffer[0] = '\n';
    else
    {
        int len = strlen(buffer);
        while (len > 0 && (buffer[len-1] < ' '))
            buffer[--len] = '\0';
    }
}

class Waypoint
{
public:
    Waypoint() : next(0) {}
    char coord[200];
    char ele[200];
    char time[200];
    Waypoint *next;
};

Waypoint* all_waypoints = 0;

Waypoint* newWaypoint()
{
    static Waypoint** ref_last = &all_waypoints;

    Waypoint* n = new Waypoint();
    (*ref_last) = n;
    ref_last = &n->next;
    return n;
}

int main(int argc, char* argv)
{
    FILE *f = stdin;
    
    getLine(f);
    printf("%s\n", buffer);
    getLine(f);
    printf("%s\n", buffer);
    getLine(f);
    while (strncmp(buffer, "<wpt ", 5) == 0)
    {
        Waypoint *n = newWaypoint();
        strcpy(n->coord, buffer+5);
        getLine(f);
        strcpy(n->ele, buffer);
        getLine(f);
        strcpy(n->time, buffer);
        getLine(f);
        getLine(f);
        getLine(f);
        getLine(f);
        getLine(f);
    }
    if (strcmp(buffer, "<trk>") != 0)
        return 0;
    getLine(f);
    getLine(f);
    getLine(f);
    getLine(f);
    Waypoint* next_waypoint = all_waypoints;
    bool in_trk = false;
    while (strncmp(buffer, "<trkpt ", 7) == 0)
    {
        char coord[200];
        strcpy(coord, buffer);
        getLine(f);
        char ele[200];
        strcpy(ele, buffer);
        getLine(f);
        char time[200];
        strcpy(time, buffer);
        getLine(f);
        getLine(f);
        if (next_waypoint && strcmp(time, next_waypoint->time) > 0)
        {
            if (in_trk)
                printf("<trkpt %s\n%s\%s\n<speed>0.00</speed>\n</trkpt>\n</trkseg>\n</trk>\n",
                    next_waypoint->coord, next_waypoint->ele, next_waypoint->time);
            in_trk = false;
        }
        if (!in_trk)
        {
            printf("<trk>\n<name>%8.8s-%8.8s</name>\n<desc>Color:004000ff</desc>\n<trkseg>\n",
                next_waypoint->time+17, next_waypoint->next == 0 ? "" : next_waypoint->next->time+17);

            printf("<trkpt %s\n%s\%s\n<speed>0.00</speed>\n</trkpt>\n",
                next_waypoint->coord, next_waypoint->ele, next_waypoint->time);
        
            in_trk = true;
            next_waypoint = next_waypoint->next;
        }
        printf("%s\n%s\%s\n<speed>0.00</speed>\n</trkpt>\n",
            coord, ele, time);
        getLine(f);
    }
    if (in_trk)
    {
        if (next_waypoint)
            printf("<trkpt %s\n%s\%s\n<speed>0.00</speed>\n</trkpt>\n",
                next_waypoint->coord, next_waypoint->ele, next_waypoint->time);
        printf("</trkseg>\n</trk>\n");
    }
    printf("</gpx>\n");
    return 0;
}