// ATC-Main.cxx -- FGFS interface to ATC hardware
//
// Written by Curtis Olson, started January 2002
//
// Copyright (C) 2002  Curtis L. Olson - http://www.flightgear.org/~curt
//
// 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.
//
// $Id$


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

#include <simgear/compiler.h>

#include <stdlib.h>		// atoi() atof() abs()
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>              //snprintf
#if defined( _MSC_VER ) || defined(__MINGW32__)
#  include <io.h>                 //lseek, read, write
#endif

#include STL_STRING

#include <plib/ul.h>

#include <simgear/debug/logstream.hxx>
#include <simgear/io/iochannel.hxx>
#include <simgear/math/sg_types.hxx>
#include <simgear/misc/sg_path.hxx>
#include <simgear/props/props.hxx>

#include <Scripting/NasalSys.hxx>
#include <Main/fg_props.hxx>
#include <Main/globals.hxx>

#include "ATC-Main.hxx"

SG_USING_STD(string);


// Lock the ATC hardware
static int fgATCMainLock( int fd ) {
    // rewind
    lseek( fd, 0, SEEK_SET );

    char tmp[2];
    int result = read( fd, tmp, 1 );
    if ( result != 1 ) {
	SG_LOG( SG_IO, SG_DEBUG, "Lock failed" );
    }

    return result;
}


// Write a radios command
static int fgATCMainRelease( int fd ) {
    // rewind
    lseek( fd, 0, SEEK_SET );

    char tmp[2];
    tmp[0] = tmp[1] = 0;
    int result = write( fd, tmp, 1 );

    if ( result != 1 ) {
	SG_LOG( SG_IO, SG_DEBUG, "Release failed" );
    }

    return result;
}


void FGATCMain::init_config() {
#if defined( unix ) || defined( __CYGWIN__ )
    // Next check home directory for .fgfsrc.hostname file
    char *envp = ::getenv( "HOME" );
    if ( envp != NULL ) {
        SGPath atcsim_config( envp );
        atcsim_config.append( ".fgfs-atc610x.xml" );
        readProperties( atcsim_config.str(), globals->get_props() );
    }
#endif
}


// Open and initialize ATC hardware
bool FGATCMain::open() {
    if ( is_enabled() ) {
	SG_LOG( SG_IO, SG_ALERT, "This shouldn't happen, but the channel " 
		<< "is already in use, ignoring" );
	return false;
    }

    SG_LOG( SG_IO, SG_ALERT,
	    "Initializing ATC hardware, please wait ..." );

    // This loads the config parameters generated by "simcal"
    init_config();

    /////////////////////////////////////////////////////////////////////
    // Open the /proc files
    /////////////////////////////////////////////////////////////////////

    string lock0_file = "/proc/atc610x/board0/lock";
    string lock1_file = "/proc/atc610x/board1/lock";

    lock0_fd = ::open( lock0_file.c_str(), O_RDWR );
    if ( lock0_fd == -1 ) {
	SG_LOG( SG_IO, SG_ALERT, "errno = " << errno );
	char msg[256];
	snprintf( msg, 256, "Error opening %s", lock0_file.c_str() );
	perror( msg );
	exit( -1 );
    }

    lock1_fd = ::open( lock1_file.c_str(), O_RDWR );
    if ( lock1_fd == -1 ) {
	SG_LOG( SG_IO, SG_ALERT, "errno = " << errno );
	char msg[256];
	snprintf( msg, 256, "Error opening %s", lock1_file.c_str() );
	perror( msg );
	exit( -1 );
    }

    if ( input0_path.str().length() ) {
        input0 = new FGATCInput( 0, input0_path );
        input0->open();
    }
    if ( input1_path.str().length() ) {
        input1 = new FGATCInput( 1, input1_path );
        input1->open();
    }
    if ( output0_path.str().length() ) {
        output0 = new FGATCOutput( 0, output0_path );
        output0->open( lock0_fd );
    }
    if ( output1_path.str().length() ) {
        output1 = new FGATCOutput( 1, output1_path );
        output1->open( lock1_fd );
    }

    set_hz( 30 );		// default to processing requests @ 30Hz
    set_enabled( true );

    /////////////////////////////////////////////////////////////////////
    // Finished initing hardware
    /////////////////////////////////////////////////////////////////////

    SG_LOG( SG_IO, SG_ALERT,
	    "Done initializing ATC hardware." );

    return true;
}


bool FGATCMain::process() {
    // Lock the hardware, skip if it's not ready yet
    if ( fgATCMainLock( lock0_fd ) <= 0 ) {
        return false;
    }
    if ( fgATCMainLock( lock1_fd ) <= 0 ) {
        // lock0 will be locked here, so release before we return
	fgATCMainRelease( lock0_fd );
        return false;
    }

    // process the ATC inputs
    if ( input0 != NULL ) {
        input0->process();
    }
    if ( input1 != NULL ) {
        input1->process();
    }

    // run our custom nasal script.  This is a layer above the raw
    // hardware inputs.  It handles situations where there isn't a
    // direct 1-1 linear mapping between ATC functionality and FG
    // functionality, and handles situations where FG expects more
    // functionality from the interface than the ATC hardware can
    // directly provide.

    FGNasalSys *n = (FGNasalSys*)globals->get_subsystem("nasal");
    bool result = n->parseAndRun( "atcsim.do_hardware()" );
    if ( !result ) {
        SG_LOG( SG_GENERAL, SG_ALERT,
                "Nasal: atcsim.do_hardware() failed!" );
    }

    // process the ATC outputs
    if ( output0 != NULL ) {
        output0->process();
    }
    if ( output1 != NULL ) {
        output1->process();
    }

    fgATCMainRelease( lock0_fd );
    fgATCMainRelease( lock1_fd );

    return true;
}


bool FGATCMain::close() {
    int result;

    result = ::close( lock0_fd );
    if ( result == -1 ) {
	SG_LOG( SG_IO, SG_ALERT, "errno = " << errno );
	char msg[256];
	snprintf( msg, 256, "Error closing lock0_fd" );
	perror( msg );
	exit( -1 );
    }

    result = ::close( lock1_fd );
    if ( result == -1 ) {
	SG_LOG( SG_IO, SG_ALERT, "errno = " << errno );
	char msg[256];
	snprintf( msg, 256, "Error closing lock1_fd" );
	perror( msg );
	exit( -1 );
    }

    return true;
}