/**********************************************************************
 * $Id$
 *
 * Project:  MapServer
 * Purpose:  Implementation of utility functions related to the PROJ4 library
 * Author:   DM Solutions Group (assefa@dmsolutions.ca)
 *
 **********************************************************************
 * Copyright (c) 2001,  Y. Assefa, DM Solutions Group Inc
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in 
 * all copies of this Software or works derived from this Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 ****************************************************************************/

#include <string.h>
#include "mapserver.h"

/************************************************************************/
/*                        ConvertProjUnitStringToMS                     */
/*                                                                      */
/*       Returns mapserver's unit code corresponding to the proj        */
/*      unit passed as argument.                                        */
/*       Please refer to ./src/pj_units.c file in the Proj.4 module.    */
/************************************************************************/
#ifdef USE_PROJ 
static int ConvertProjUnitStringToMS(const char *pszProjUnit)
{
    if (strcmp(pszProjUnit, "m") ==0)
    {
        return MS_METERS;
    }
    else if (strcmp(pszProjUnit, "km") ==0)
    {
        return MS_KILOMETERS;
    }
    else if (strcmp(pszProjUnit, "mi") ==0 || strcmp(pszProjUnit, "us-mi") ==0)
    {
        return MS_MILES;
    }
    else if (strcmp(pszProjUnit, "in") ==0 || strcmp(pszProjUnit, "us-in") ==0 )
    {
        return MS_INCHES;
    }
    else if (strcmp(pszProjUnit, "ft") ==0 || strcmp(pszProjUnit, "us-ft") ==0)
    {
        return MS_FEET;
    }
    else if (strcmp(pszProjUnit, "kmi") == 0)
    {
        return MS_NAUTICALMILES;
    }
    
    return -1;              
}
#endif /* def USE_PROJ */

/************************************************************************/
/*           int GetMapserverUnitUsingProj(projectionObj *psProj)       */
/*                                                                      */
/*      Return a mapserver unit corresponding to the projection         */
/*      passed. Retunr -1 on failure                                    */
/************************************************************************/
int GetMapserverUnitUsingProj(projectionObj *psProj)
{
#ifdef USE_PROJ
    char *proj_str;

    if( pj_is_latlong( psProj->proj ) )
        return MS_DD;

    proj_str = pj_get_def( psProj->proj, 0 );

/* -------------------------------------------------------------------- */
/*      Handle case of named units.                                     */
/* -------------------------------------------------------------------- */
    if( strstr(proj_str,"units=") != NULL )
    {
        char units[32];
        char *blank;

        strlcpy( units, (strstr(proj_str,"units=")+6), sizeof(units) );
        pj_dalloc( proj_str );

        blank = strchr(units, ' ');
        if( blank != NULL )
            *blank = '\0';

        return ConvertProjUnitStringToMS( units );
    }

/* -------------------------------------------------------------------- */
/*      Handle case of to_meter value.                                  */
/* -------------------------------------------------------------------- */
    if( strstr(proj_str,"to_meter=") != NULL )
    {
        char to_meter_str[32];
        char *blank;
        double to_meter;

        strlcpy(to_meter_str,(strstr(proj_str,"to_meter=")+9),
                sizeof(to_meter_str));
        pj_dalloc( proj_str );

        blank = strchr(to_meter_str, ' ');
        if( blank != NULL )
            *blank = '\0';

        to_meter = atof(to_meter_str);

        if( fabs(to_meter-1.0) < 0.0000001 )
            return MS_METERS;
        else if( fabs(to_meter-1000.0) < 0.00001 )
            return MS_KILOMETERS;
        else if( fabs(to_meter-0.3048) < 0.0001 )
            return MS_FEET;
        else if( fabs(to_meter-0.0254) < 0.0001 )
            return MS_INCHES;
        else if( fabs(to_meter-1609.344) < 0.001 )
            return MS_MILES;
        else if( fabs(to_meter-1852.0) < 0.1 )
            return MS_NAUTICALMILES;
        else
            return -1;
    }

    pj_dalloc( proj_str );
#endif
    return -1;
}