/******************************************************************************
 * $Id$
 *
 * Project:  GXF Reader
 * Purpose:  Handle GXF to PROJ.4 projection transformation.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 1998, Global Geomatics
 * Copyright (c) 1998, Frank Warmerdam
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "gxfopen.h"

#define SAFE_strcat(x, y)                                                      \
    snprintf(x + strlen(x), sizeof(x) - strlen(x), "%s", y)

/************************************************************************/
/*                     GXFGetMapProjectionAsPROJ4()                     */
/************************************************************************/

/**
 * Return the GXF Projection in PROJ.4 format.
 *
 * The returned string becomes owned by the caller, and should be freed
 * with CPLFree() or VSIFree().  The return value will be "unknown" if
 * no projection information is passed.
 *
 * The mapping of GXF projections to PROJ.4 format is not complete.  Please
 * see the gxf_proj4.c code to better understand limitations of this
 * translation.  In particular, PROJ.4 knows little about datums.
 *
 * For example, the following GXF definitions:
 * <pre>
 * #UNIT_LENGTH
 * m,1
 * #MAP_PROJECTION
 * "NAD83 / UTM zone 19N"
 * "GRS 1980",6378137,0.081819191,0
 * "Transverse Mercator",0,-69,0.9996,500000,0
 * </pre>
 *
 * Would translate to:
 * <pre>
 * +proj=tmerc +lat_0=0 +lon_0=-69 +k=0.9996 +x_0=500000 +y_0=0 +ellps=GRS80
 * </pre>
 *
 * @param hGXF handle to GXF file, as returned by GXFOpen().
 *
 * @return string containing PROJ.4 projection.
 */

char *GXFGetMapProjectionAsPROJ4(GXFHandle hGXF)

{
    GXFInfo_t *psGXF = (GXFInfo_t *)hGXF;
    char **papszMethods = NULL;
    char szPROJ4[512] = {0};

    /* -------------------------------------------------------------------- */
    /*      If there was nothing in the file return "unknown".              */
    /* -------------------------------------------------------------------- */
    if (CSLCount(psGXF->papszMapProjection) < 2)
        return (CPLStrdup("unknown"));

    /* -------------------------------------------------------------------- */
    /*      Parse the third line, looking for known projection methods.     */
    /* -------------------------------------------------------------------- */
    if (psGXF->papszMapProjection[2] != NULL)
    {
        if (strlen(psGXF->papszMapProjection[2]) > 80)
            return (CPLStrdup(""));
        papszMethods = CSLTokenizeStringComplex(psGXF->papszMapProjection[2],
                                                ",", TRUE, TRUE);
    }

    if (papszMethods == NULL || papszMethods[0] == NULL ||
        EQUAL(papszMethods[0], "Geographic"))
    {
        SAFE_strcat(szPROJ4, "+proj=longlat");
    }

#ifdef notdef
    else if (EQUAL(papszMethods[0], "Lambert Conic Conformal (1SP)") &&
             CSLCount(papszMethods) > 5)
    {
        /* notdef: It isn't clear that this 1SP + scale method is even
           supported by PROJ.4
           Later note: It is not. */

        SAFE_strcat(szPROJ4, "+proj=lcc");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);
    }
#endif
    else if (EQUAL(papszMethods[0], "Lambert Conic Conformal (2SP)") ||
             EQUAL(papszMethods[0], "Lambert Conformal (2SP Belgium)"))
    {
        /* notdef: Note we are apparently losing whatever makes the
           Belgium variant different than normal LCC, but hopefully
           they are close! */

        SAFE_strcat(szPROJ4, "+proj=lcc");

        if (CSLCount(papszMethods) > 1)
        {
            SAFE_strcat(szPROJ4, " +lat_1=");
            SAFE_strcat(szPROJ4, papszMethods[1]);
        }

        if (CSLCount(papszMethods) > 2)
        {
            SAFE_strcat(szPROJ4, " +lat_2=");
            SAFE_strcat(szPROJ4, papszMethods[2]);
        }

        if (CSLCount(papszMethods) > 3)
        {
            SAFE_strcat(szPROJ4, " +lat_0=");
            SAFE_strcat(szPROJ4, papszMethods[3]);
        }

        if (CSLCount(papszMethods) > 4)
        {
            SAFE_strcat(szPROJ4, " +lon_0=");
            SAFE_strcat(szPROJ4, papszMethods[4]);
        }

        if (CSLCount(papszMethods) > 5)
        {
            SAFE_strcat(szPROJ4, " +x_0=");
            SAFE_strcat(szPROJ4, papszMethods[5]);
        }

        if (CSLCount(papszMethods) > 6)
        {
            SAFE_strcat(szPROJ4, " +y_0=");
            SAFE_strcat(szPROJ4, papszMethods[6]);
        }
    }

    else if (EQUAL(papszMethods[0], "Mercator (1SP)") &&
             CSLCount(papszMethods) > 5)
    {
        /* notdef: it isn't clear that +proj=merc support a scale of other
           than 1.0 in PROJ.4 */

        SAFE_strcat(szPROJ4, "+proj=merc");

        SAFE_strcat(szPROJ4, " +lat_ts=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);
    }

    else if (EQUAL(papszMethods[0], "Mercator (2SP)") &&
             CSLCount(papszMethods) > 4)
    {
        /* notdef: it isn't clear that +proj=merc support a scale of other
           than 1.0 in PROJ.4 */

        SAFE_strcat(szPROJ4, "+proj=merc");

        SAFE_strcat(szPROJ4, " +lat_ts=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);
    }

    else if (EQUAL(papszMethods[0], "Hotine Oblique Mercator") &&
             CSLCount(papszMethods) > 7)
    {
        /* Note that only the second means of specifying omerc is supported
           by this code in GXF. */
        SAFE_strcat(szPROJ4, "+proj=omerc");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lonc=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +alpha=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        if (CPLAtof(papszMethods[4]) < 0.00001)
        {
            SAFE_strcat(szPROJ4, " +not_rot");
        }
        else
        {
#ifdef notdef
            if (CPLAtof(papszMethods[4]) + CPLAtof(papszMethods[3]) < 0.00001)
                /* ok */;
            else
                /* notdef: no way to specify arbitrary angles! */;
#endif
        }

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[5]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[6]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[7]);
    }

    else if (EQUAL(papszMethods[0], "Laborde Oblique Mercator") &&
             CSLCount(papszMethods) > 6)
    {
        SAFE_strcat(szPROJ4, "+proj=labrd");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +azi=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[6]);
    }

    else if (EQUAL(papszMethods[0], "New Zealand Map Grid") &&
             CSLCount(papszMethods) > 4)
    {
        SAFE_strcat(szPROJ4, "+proj=nzmg");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);
    }

    else if (EQUAL(papszMethods[0], "New Zealand Map Grid") &&
             CSLCount(papszMethods) > 4)
    {
        SAFE_strcat(szPROJ4, "+proj=nzmg");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);
    }

    else if (EQUAL(papszMethods[0], "Oblique Stereographic") &&
             CSLCount(papszMethods) > 5)
    {
        /* there is an option to produce +lat_ts, which we ignore */

        SAFE_strcat(szPROJ4, "+proj=stere");

        SAFE_strcat(szPROJ4, " +lat_0=45");

        SAFE_strcat(szPROJ4, " +lat_ts=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);
    }

    else if (EQUAL(papszMethods[0], "Polar Stereographic") &&
             CSLCount(papszMethods) > 5)
    {
        /* there is an option to produce +lat_ts, which we ignore */

        SAFE_strcat(szPROJ4, "+proj=stere");

        SAFE_strcat(szPROJ4, " +lat_0=90");

        SAFE_strcat(szPROJ4, " +lat_ts=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);
    }

    else if (EQUAL(papszMethods[0], "Swiss Oblique Cylindrical") &&
             CSLCount(papszMethods) > 4)
    {
        /* notdef: geotiff's geo_ctrans.inc says this is the same as
           ObliqueMercator_Rosenmund, which GG's geotiff support just
           maps directly to +proj=omerc, though I find that questionable. */

        SAFE_strcat(szPROJ4, "+proj=omerc");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lonc=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);
    }

    else if (EQUAL(papszMethods[0], "Transverse Mercator") &&
             CSLCount(papszMethods) > 5)
    {
        /* notdef: geotiff's geo_ctrans.inc says this is the same as
           ObliqueMercator_Rosenmund, which GG's geotiff support just
           maps directly to +proj=omerc, though I find that questionable. */

        SAFE_strcat(szPROJ4, "+proj=tmerc");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);
    }

    else if (EQUAL(papszMethods[0], "Transverse Mercator (South Oriented)") &&
             CSLCount(papszMethods) > 5)
    {
        /* notdef: I don't know how south oriented is different from
           normal, and I don't find any mention of it in Geotiff;s geo_ctrans.
           Translating as tmerc, but that is presumably wrong. */

        SAFE_strcat(szPROJ4, "+proj=tmerc");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);
    }

    else if (EQUAL(papszMethods[0], "*Equidistant Conic") &&
             CSLCount(papszMethods) > 6)
    {
        SAFE_strcat(szPROJ4, "+proj=eqdc");

        SAFE_strcat(szPROJ4, " +lat_1=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lat_2=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[3]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[6]);
    }

    else if (EQUAL(papszMethods[0], "*Polyconic") && CSLCount(papszMethods) > 5)
    {
        SAFE_strcat(szPROJ4, "+proj=poly");

        SAFE_strcat(szPROJ4, " +lat_0=");
        SAFE_strcat(szPROJ4, papszMethods[1]);

        SAFE_strcat(szPROJ4, " +lon_0=");
        SAFE_strcat(szPROJ4, papszMethods[2]);

#ifdef notdef
        /*not supported by PROJ.4 */
        SAFE_strcat(szPROJ4, " +k=");
        SAFE_strcat(szPROJ4, papszMethods[3]);
#endif
        SAFE_strcat(szPROJ4, " +x_0=");
        SAFE_strcat(szPROJ4, papszMethods[4]);

        SAFE_strcat(szPROJ4, " +y_0=");
        SAFE_strcat(szPROJ4, papszMethods[5]);
    }

    else
    {
        SAFE_strcat(szPROJ4, "unknown");
    }

    CSLDestroy(papszMethods);

    /* -------------------------------------------------------------------- */
    /*      Now get the ellipsoid parameters.  For a bunch of common        */
    /*      ones we preserve the name.  For the rest we just carry over     */
    /*      the parameters.                                                 */
    /* -------------------------------------------------------------------- */
    if (CSLCount(psGXF->papszMapProjection) > 1)
    {
        char **papszTokens;

        if (strlen(psGXF->papszMapProjection[1]) > 80)
            return CPLStrdup("");

        papszTokens = CSLTokenizeStringComplex(psGXF->papszMapProjection[1],
                                               ",", TRUE, TRUE);

        if (EQUAL(papszTokens[0], "WGS 84"))
            SAFE_strcat(szPROJ4, " +ellps=WGS84");
        else if (EQUAL(papszTokens[0], "*WGS 72"))
            SAFE_strcat(szPROJ4, " +ellps=WGS72");
        else if (EQUAL(papszTokens[0], "*WGS 66"))
            SAFE_strcat(szPROJ4, " +ellps=WGS66");
        else if (EQUAL(papszTokens[0], "*WGS 60"))
            SAFE_strcat(szPROJ4, " +ellps=WGS60");
        else if (EQUAL(papszTokens[0], "Clarke 1866"))
            SAFE_strcat(szPROJ4, " +ellps=clrk66");
        else if (EQUAL(papszTokens[0], "Clarke 1880"))
            SAFE_strcat(szPROJ4, " +ellps=clrk80");
        else if (EQUAL(papszTokens[0], "GRS 1980"))
            SAFE_strcat(szPROJ4, " +ellps=GRS80");
        else if (CSLCount(papszTokens) > 2)
        {
            snprintf(szPROJ4 + strlen(szPROJ4),
                     sizeof(szPROJ4) - strlen(szPROJ4), " +a=%s +e=%s",
                     papszTokens[1], papszTokens[2]);
        }

        CSLDestroy(papszTokens);
    }

    /* -------------------------------------------------------------------- */
    /*      Extract the units specification.                                */
    /* -------------------------------------------------------------------- */
    if (psGXF->pszUnitName != NULL)
    {
        if (EQUAL(psGXF->pszUnitName, "ft"))
        {
            SAFE_strcat(szPROJ4, " +units=ft");
        }
        else if (EQUAL(psGXF->pszUnitName, "ftUS"))
        {
            SAFE_strcat(szPROJ4, " +units=us-ft");
        }
        else if (EQUAL(psGXF->pszUnitName, "km"))
        {
            SAFE_strcat(szPROJ4, " +units=km");
        }
        else if (EQUAL(psGXF->pszUnitName, "mm"))
        {
            SAFE_strcat(szPROJ4, " +units=mm");
        }
        else if (EQUAL(psGXF->pszUnitName, "in"))
        {
            SAFE_strcat(szPROJ4, " +units=in");
        }
        else if (EQUAL(psGXF->pszUnitName, "ftInd"))
        {
            SAFE_strcat(szPROJ4, " +units=ind-ft");
        }
        else if (EQUAL(psGXF->pszUnitName, "lk"))
        {
            SAFE_strcat(szPROJ4, " +units=link");
        }
    }

    return (CPLStrdup(szPROJ4));
}

/************************************************************************/
/*                        GXFGetPROJ4Position()                         */
/*                                                                      */
/*      Get the same information as GXFGetPosition(), but adjust        */
/*      to units to meters if we don't ``know'' the indicated           */
/*      units.                                                          */
/************************************************************************/

CPLErr GXFGetPROJ4Position(GXFHandle hGXF, double *pdfXOrigin,
                           double *pdfYOrigin, double *pdfXPixelSize,
                           double *pdfYPixelSize, double *pdfRotation)

{
    GXFInfo_t *psGXF = (GXFInfo_t *)hGXF;
    char *pszProj;

    /* -------------------------------------------------------------------- */
    /*      Get the raw position.                                           */
    /* -------------------------------------------------------------------- */
    if (GXFGetPosition(hGXF, pdfXOrigin, pdfYOrigin, pdfXPixelSize,
                       pdfYPixelSize, pdfRotation) == CE_Failure)
        return (CE_Failure);

    /* -------------------------------------------------------------------- */
    /*      Do we know the units in PROJ.4?  Get the PROJ.4 string, and     */
    /*      check for a +units definition.                                  */
    /* -------------------------------------------------------------------- */
    pszProj = GXFGetMapProjectionAsPROJ4(hGXF);
    if (strstr(pszProj, "+unit") == NULL && psGXF->pszUnitName != NULL)
    {
        if (pdfXOrigin != NULL)
            *pdfXOrigin *= psGXF->dfUnitToMeter;
        if (pdfYOrigin != NULL)
            *pdfYOrigin *= psGXF->dfUnitToMeter;
        if (pdfXPixelSize != NULL)
            *pdfXPixelSize *= psGXF->dfUnitToMeter;
        if (pdfYPixelSize != NULL)
            *pdfYPixelSize *= psGXF->dfUnitToMeter;
    }
    CPLFree(pszProj);

    return (CE_None);
}
