// terrasync.cxx -- "JIT" scenery fetcher
//
// Written by Curtis Olson, started November 2002.
//
// Copyright (C) 2002  Curtis L. Olson  - http://www.flightgear.org/~curt
// Copyright (C) 2008  Alexander R. Perry <alex.perry@ieee.org>
//
// 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.
//
// $Id$

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef HAVE_WINDOWS_H
#include <windows.h>
#endif

#ifdef __MINGW32__
#include <time.h>
#include <unistd.h>
#elif defined(_MSC_VER)
#include <io.h>
#endif

#include <stdlib.h>             // atoi() atof() abs() system()
#include <signal.h>             // signal()

#include <simgear/compiler.h>

#include <iostream>
#include <fstream>
#include <string>
#include <deque>
#include <map>

#include <simgear/io/raw_socket.hxx>
#include <simgear/bucket/newbucket.hxx>
#include <simgear/misc/sg_path.hxx>

#ifdef HAVE_SVN_CLIENT_H
#  ifdef HAVE_LIBSVN_CLIENT_1
#    include <svn_auth.h>
#    include <svn_client.h>
#    include <svn_cmdline.h>
#    include <svn_pools.h>
#  else
#    undef HAVE_SVN_CLIENT_H
#  endif
#endif

using namespace std;

const char* source_base = NULL;
const char* svn_base =
  "http://terrascenery.googlecode.com/svn/trunk/data/Scenery";
const char* rsync_base = "scenery.flightgear.org::Scenery";
const char* dest_base = "terrasyncdir";
const char* rsync_cmd = 
    "rsync --verbose --archive --delete --perms --owner --group";

#ifdef HAVE_SVN_CLIENT_H
bool use_svn = true;
#else
bool use_svn = false;
const char* svn_cmd = "svn checkout";
#endif

// display usage
static void usage( const string& prog ) {
    cout << 
"Usage:  terrasync [options]\n"
"Options:  \n"
" -d <dest>       destination directory [required]\n"
" -R              transport using pipe to rsync\n"
" -S              transport using built-in svn\n"
" -p <port>       listen on UDP port [default: 5501]\n"
" -s <source>     source base [default: '']\n"
" -pid <pidfile>  write PID to file\n"
" -v              be more verbose\n"
;

#ifdef HAVE_SVN_CLIENT_H
    cout << "    (defaults to the built in subversion)" << endl;
#else
    cout << "    (defaults to rsync, using external commands)" << endl;
#endif

  cout << "\nExample:\n"
"pid=$(cat $pidfile 2>/dev/null)\n"
"if test -n \"$pid\" && kill -0 $pid ; then\n"
"    echo \"terrasync already running: $pid\"\n"
"else\n"
"    nice /games/sport/fgs/utils/TerraSync/terrasync         \\\n"
"      -v -pid $pidfile -S -p 5500 -d /games/orig/terrasync &\n"
"fi" << endl;

}

deque<string> waitingTiles;
typedef map<string,time_t> CompletedTiles;
CompletedTiles completedTiles;
simgear::Socket theSocket;

#ifdef HAVE_SVN_CLIENT_H

// Things we need for doing subversion checkout - often
apr_pool_t *mysvn_pool = NULL;
svn_client_ctx_t *mysvn_ctx = NULL;
svn_opt_revision_t *mysvn_rev = NULL;
svn_opt_revision_t *mysvn_rev_peg = NULL;

static const svn_version_checklist_t mysvn_checklist[] = {
    { "svn_subr",   svn_subr_version },
    { "svn_client", svn_client_version },
    { NULL, NULL }
};

// Configure our subversion session
int mysvn_setup(void) {
    // Are we already prepared?
    if (mysvn_pool) return EXIT_SUCCESS;
    // No, so initialize svn internals generally
#ifdef _MSC_VER
    // there is a segfault when providing an error stream.
    //  Apparently, calling setvbuf with a nul buffer is
    //  not supported under msvc 7.1 ( code inside svn_cmdline_init )
    if (svn_cmdline_init("terrasync", 0) != EXIT_SUCCESS)
        return EXIT_FAILURE;
#else
    if (svn_cmdline_init("terrasync", stderr) != EXIT_SUCCESS)
        return EXIT_FAILURE;
#endif
    apr_pool_t *pool;
    apr_pool_create(&pool, NULL);
    svn_error_t *err = NULL;
    SVN_VERSION_DEFINE(mysvn_version);
    err = svn_ver_check_list(&mysvn_version, mysvn_checklist);
    if (err)
        return svn_cmdline_handle_exit_error(err, pool, "terrasync: ");
    err = svn_ra_initialize(pool);
    if (err)
        return svn_cmdline_handle_exit_error(err, pool, "terrasync: ");
    char *config_dir = NULL;
    err = svn_config_ensure(config_dir, pool);
    if (err)
        return svn_cmdline_handle_exit_error(err, pool, "terrasync: ");
    err = svn_client_create_context(&mysvn_ctx, pool);
    if (err)
        return svn_cmdline_handle_exit_error(err, pool, "terrasync: ");
    err = svn_config_get_config(&(mysvn_ctx->config),
        config_dir, pool);
    if (err)
        return svn_cmdline_handle_exit_error(err, pool, "terrasync: ");
    svn_config_t *cfg;
    cfg = ( svn_config_t*) apr_hash_get(
        mysvn_ctx->config,
    	SVN_CONFIG_CATEGORY_CONFIG,
        APR_HASH_KEY_STRING);
    if (err)
        return svn_cmdline_handle_exit_error(err, pool, "terrasync: ");
    svn_auth_baton_t *ab;
    err = svn_cmdline_setup_auth_baton(&ab,
        TRUE, NULL, NULL, config_dir, TRUE, cfg,
        mysvn_ctx->cancel_func, mysvn_ctx->cancel_baton, pool);
    if (err)
        return svn_cmdline_handle_exit_error(err, pool, "terrasync: ");
    mysvn_ctx->auth_baton = ab;
    mysvn_ctx->conflict_func = NULL;
    mysvn_ctx->conflict_baton = NULL;
    // Now our magic revisions
    mysvn_rev = (svn_opt_revision_t*) apr_palloc(pool, 
        sizeof(svn_opt_revision_t));
    if (!mysvn_rev)
        return EXIT_FAILURE;
    mysvn_rev_peg = (svn_opt_revision_t*) apr_palloc(pool, 
        sizeof(svn_opt_revision_t));
    if (!mysvn_rev_peg)
        return EXIT_FAILURE;
    mysvn_rev->kind = svn_opt_revision_head;
    mysvn_rev_peg->kind = svn_opt_revision_unspecified;
    // Success if we got this far
    mysvn_pool = pool;
    return EXIT_SUCCESS;
}

#endif

// sync one directory tree
void sync_tree(const char* dir) {
    int rc;
    char command[512];
    SGPath path( dest_base );

    path.append( dir );
    rc = path.create_dir( 0755 );
    if (rc) {
        cout << "Return code = " << rc << endl;
        exit(1);
    }

    if (use_svn) {
#ifdef HAVE_SVN_CLIENT_H
        cout << dir << " ... ";
	cout.flush();
        char dest_base_dir[512];
        snprintf( command, 512,
            "%s/%s", source_base, dir);
        snprintf( dest_base_dir, 512,
            "%s/%s", dest_base, dir);
	svn_error_t *err = NULL;
	if (mysvn_setup() != EXIT_SUCCESS)
	    exit(1);
	apr_pool_t *subpool = svn_pool_create(mysvn_pool);
	err = svn_client_checkout3(NULL,
	    command,
	    dest_base_dir,
	    mysvn_rev_peg,
	    mysvn_rev,
	    svn_depth_infinity,
	    0,
	    0,
	    mysvn_ctx,
	    subpool);
	if (err) {
	    // Report errors from the checkout attempt
	    cout << "failed: " << endl
	         << err->message << endl;
	    svn_error_clear(err);
	    return;
	} else {
	    cout << "done" << endl;
	}
	svn_pool_destroy(subpool);
	return;
#else

        snprintf( command, 512,
            "%s %s/%s %s/%s", svn_cmd,
            source_base, dir,
	    dest_base, dir );
#endif
    } else {
        snprintf( command, 512,
            "%s %s/%s/ %s/%s/", rsync_cmd,
            source_base, dir,
	    dest_base, dir );
    }
    cout << command << endl;
    rc = system( command );
    if (rc) {
        cout << "Return code = " << rc << endl;
        if (rc == 5120) exit(1);
    }
}

#if defined(_MSC_VER) || defined(__MINGW32__)
typedef void (__cdecl * sighandler_t)(int);
#elif defined( __APPLE__ )
typedef sig_t sighandler_t;
#endif

bool terminating = false;
sighandler_t prior_signal_handlers[32];
int termination_triggering_signals[] = {
#if defined(_MSC_VER) || defined(__MINGW32__)
    SIGINT, SIGILL, SIGFPE, SIGSEGV, SIGTERM, SIGBREAK, SIGABRT,
#else
    SIGHUP, SIGINT, SIGQUIT, SIGKILL, SIGTERM,
#endif
    0};  // zero terminated

void terminate_request_handler(int param) {
    char msg[] = "\nReceived signal XX, intend to exit soon.\n"
         "repeat the signal to force immediate termination.\n";
    msg[17] = '0' + param / 10;
    msg[18] = '0' + param % 10;
    write(1, msg, sizeof(msg) - 1);
    terminating = true;
    signal(param, prior_signal_handlers[param]);
    theSocket.close();
}


const int nowhere = -9999;


// parse message
static void parse_message( const string &msg, int *lat, int *lon ) {
    double dlat, dlon;
    string text = msg;

    // find GGA string and advance to start of lat
    string::size_type pos = text.find( "$GPGGA" );
    if ( pos == string::npos )
    {
	*lat = nowhere;
	*lon = nowhere;
	return;
    }
    string tmp = text.substr( pos + 7 );
    pos = tmp.find( "," );
    tmp = tmp.substr( pos + 1 );
    // cout << "-> " << tmp << endl;

    // find lat then advance to start of hemisphere
    pos = tmp.find( "," );
    string lats = tmp.substr( 0, pos );
    dlat = atof( lats.c_str() ) / 100.0;
    tmp = tmp.substr( pos + 1 );

    // find N/S hemisphere and advance to start of lon
    if ( tmp.substr( 0, 1 ) == "S" ) {
        dlat = -dlat;
    }
    pos = tmp.find( "," );
    tmp = tmp.substr( pos + 1 );

    // find lon
    pos = tmp.find( "," );
    string lons = tmp.substr( 0, pos );
    dlon = atof( lons.c_str() ) / 100.0;
    tmp = tmp.substr( pos + 1 );

    // find E/W hemisphere and advance to start of lon
    if ( tmp.substr( 0, 1 ) == "W" ) {
        dlon = -dlon;
    }

    if ( dlat < 0 ) {
        *lat = (int)dlat - 1;
    } else {
        *lat = (int)dlat;
    }

    if ( dlon < 0 ) {
        *lon = (int)dlon - 1;
    } else {
        *lon = (int)dlon;
    }

    if ((dlon == 0) && (dlat == 0)) {
      *lon = nowhere;
      *lat = nowhere;
    }
}


// sync area
static void sync_area( int lat, int lon ) {
    if ( lat < -90 || lat > 90 || lon < -180 || lon > 180 )
        return;
    char NS, EW;
    int baselat, baselon;

    if ( lat < 0 ) {
        int base = (int)(lat / 10);
        if ( lat == base * 10 ) {
            baselat = base * 10;
        } else {
            baselat = (base - 1) * 10;
        }
        NS = 's';
    } else {
        baselat = (int)(lat / 10) * 10;
        NS = 'n';
    }
    if ( lon < 0 ) {
        int base = (int)(lon / 10);
        if ( lon == base * 10 ) {
            baselon = base * 10;
        } else {
            baselon = (base - 1) * 10;
        }
        EW = 'w';
    } else {
        baselon = (int)(lon / 10) * 10;
        EW = 'e';
    }

    const char* terrainobjects[3] = { "Terrain", "Objects", 0 };
    
    for (const char** tree = &terrainobjects[0]; *tree; tree++) {
	char dir[512];
	snprintf( dir, 512, "%s/%c%03d%c%02d/%c%03d%c%02d",
		*tree,
		EW, abs(baselon), NS, abs(baselat),
		EW, abs(lon), NS, abs(lat) );
	waitingTiles.push_back( dir );
    }
}


// sync areas
static void sync_areas( int lat, int lon, int lat_dir, int lon_dir ) {
    // do current 1x1 degree area first
    sync_area( lat, lon );

    if ( lat_dir == 0 && lon_dir == 0 ) {
        // now do surrounding 8 1x1 degree areas.
        for ( int i = lat - 1; i <= lat + 1; ++i ) {
            for ( int j = lon - 1; j <= lon + 1; ++j ) {
                if ( i != lat || j != lon ) {
                    sync_area( i, j );
                }
            }
        }
    } else {
        if ( lat_dir != 0 ) {
            sync_area( lat + lat_dir, lon );
            sync_area( lat + lat_dir, lon - 1 );
            sync_area( lat + lat_dir, lon + 1 );
        }
        if ( lon_dir != 0 ) {
            sync_area( lat, lon + lon_dir );
            sync_area( lat - 1, lon + lon_dir );
            sync_area( lat + 1, lon + lon_dir );
        }
    }
}

void getWaitingTile() {
    while ( !waitingTiles.empty() ) {
	CompletedTiles::iterator ii =
            completedTiles.find( waitingTiles.front() );
	time_t now = time(0);
	if ( ii == completedTiles.end() || ii->second + 600 < now ) {
	    sync_tree(waitingTiles.front().c_str());
	    completedTiles[ waitingTiles.front() ] = now;
	    waitingTiles.pop_front();
	    break;
	}
	waitingTiles.pop_front();
    }
}

int main( int argc, char **argv ) {
    int port = 5501;
    char host[256] = "localhost";
    bool testing = false;
    bool do_checkout(true);
    int verbose(0);
    const char* pidfn = "";

    // parse arguments
    int i = 1;
    while ( i < argc ) {
        if ( (string)argv[i] == "-p" ) {
            ++i;
            port = atoi( argv[i] );
        } else if ( string(argv[i]).find("-pid") == 0 ) {
            ++i;
            pidfn = argv[i];
            cout << "pidfn: " << pidfn << endl;
        } else if ( (string)argv[i] == "-s" ) {
            ++i;
            source_base = argv[i];
        } else if ( (string)argv[i] == "-d" ) {
            ++i;
            dest_base = argv[i];
        } else if ( (string)argv[i] == "-R" ) {
	    use_svn = false;
        } else if ( (string)argv[i] == "-S" ) {
	    use_svn = true;
        } else if ( (string)argv[i] == "-v" ) {
	    verbose++;
        } else if ( (string)argv[i] == "-T" ) {
	    testing = true;
        } else if ( (string)argv[i] == "-h" ) {
            usage( argv[0] );
            exit(0);
        } else {
            cerr << "Unrecognized verbiage '" << argv[i] << "'" << endl;
            usage( argv[0] );
            exit(-1);        
        }
        ++i;
    }

    if (*pidfn) {
      ofstream pidstream;
      pidstream.open(pidfn);
      if (!pidstream.good()) {
        cerr << "Cannot open pid file '" << pidfn << "': ";
        perror(0);
        exit(2);
      }
      pidstream << getpid() << endl;
      pidstream.close();
    }

    // Use the appropriate default for the "-s" flag
    if (source_base == NULL) {
        if (use_svn)
	    source_base = svn_base;
	else
	    source_base = rsync_base;
    }
    
    // Must call this before any other net stuff
    simgear::Socket::initSockets();

    if ( ! theSocket.open( false ) ) {  // open a UDP socket
        printf("error opening socket\n");
        return -1;
    }

    if ( theSocket.bind( host, port ) == -1 ) {
        printf("error binding to port %d\n", port);
        return -1;
    }

    char msg[256];
    int maxlen = 256;
    int len;
    int lat, lon;
    int last_lat = nowhere;
    int last_lon = nowhere;
    bool recv_msg = false;

    char synced_other;
    if (do_checkout) {
        for ( synced_other = 'K'; synced_other <= 'Z'; synced_other++ ) {
            char dir[512];
            snprintf( dir, 512, "Airports/%c", synced_other );
            waitingTiles.push_back( dir );
        }
        for ( synced_other = 'A'; synced_other <= 'J'; synced_other++ ) {
            char dir[512];
            snprintf( dir, 512, "Airports/%c", synced_other );
            waitingTiles.push_back( dir );
        }
        if ( use_svn ) {
            waitingTiles.push_back( "Models" );
        }
    }


    for (int* sigp=termination_triggering_signals; *sigp; sigp++) {
        prior_signal_handlers[*sigp] =
            signal(*sigp, *terminate_request_handler);
        if (verbose) cout << "Intercepted signal " << *sigp << endl;
    }

    while ( !terminating ) {
        // main loop
        recv_msg = false;
        if ( testing ) {
            // No FGFS communications
            lat = 37;
            lon = -123;
            recv_msg = (lat != last_lat) || (lon != last_lon);
        } else {
            if (verbose && waitingTiles.empty()) {
                cout << "Idle; waiting for FlightGear position\n";
            }
            theSocket.setBlocking(waitingTiles.empty());
            len = theSocket.recv(msg, maxlen, 0);
            if (len >= 0) {
                msg[len] = '\0';
                recv_msg = true;
                if (verbose) cout << "recv length: " << len << endl;
                parse_message( msg, &lat, &lon );
            }
        }

        if ( recv_msg ) {
             // Ignore messages where the location does not change
             if ( lat != last_lat || lon != last_lon ) {
		cout << "pos in msg = " << lat << "," << lon << endl;
		deque<string> oldRequests;
		oldRequests.swap( waitingTiles );
                int lat_dir, lon_dir, dist;
                if ( last_lat == nowhere || last_lon == nowhere ) {
                    lat_dir = lon_dir = 0;
                } else {
                    dist = lat - last_lat;
                    if ( dist != 0 ) {
                        lat_dir = dist / abs(dist);
                    } else {
                        lat_dir = 0;
                    }
                    dist = lon - last_lon;
                    if ( dist != 0 ) {
                        lon_dir = dist / abs(dist);
                    } else {
                        lon_dir = 0;
                    }
                }
                cout << "lat = " << lat << " lon = " << lon << endl;
                cout << "lat_dir = " << lat_dir << "  "
		     << "lon_dir = " << lon_dir << endl;
                sync_areas( lat, lon, lat_dir, lon_dir );
		while ( !oldRequests.empty() ) {
		    waitingTiles.push_back( oldRequests.front() );
		    oldRequests.pop_front();
		}
                last_lat = lat;
                last_lon = lon;
            }
	}

        // No messages inbound, so process some pending work
        else if ( !waitingTiles.empty() ) {
	    getWaitingTile();
        }

	else if ( testing ) {
	    terminating = true;
	} else

        #ifdef _WIN32
                Sleep(1000);
#else
	        sleep(1);
#endif
    } // while !terminating
        
    return 0;
}