/******************************************************************************
 * $Id: coasp_dataset.cpp 33720 2016-03-15 00:39:53Z goatbar $
 *
 * Project:  DRDC Configurable Airborne SAR Processor (COASP) data reader
 * Purpose:  Support in GDAL for the DRDC COASP format data, both Metadata
 *	     and complex imagery.
 * Author:   Philippe Vachon <philippe@cowpig.ca>
 * Notes:    I have seen a grand total of 2 COASP scenes (3 sets of headers).
 *	     This is based on my best observations, some educated guesses and
 *	     such. So if you have a scene that doesn't work, send it to me
 *	     please and I will make it work... with violence.
 *
 ******************************************************************************
 * Copyright (c) 2007, Philippe Vachon
 * Copyright (c) 2009-2012, Even Rouault <even dot rouault at mines-paris dot org>
 *
 * 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 or substantial portions of the 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
 * DEALINGS IN THE SOFTWARE.
 ****************************************************************************/

#include "cpl_conv.h"
#include "cpl_port.h"
#include "cpl_string.h"
#include "cpl_vsi.h"
#include "gdal_frmts.h"
#include "gdal_priv.h"

CPL_CVSID("$Id: coasp_dataset.cpp 33720 2016-03-15 00:39:53Z goatbar $");

static const int TYPE_GENERIC = 0;
static const int TYPE_GEOREF = 1;

enum ePolarization {
	hh = 0,
	hv,
	vh,
	vv
};

/*******************************************************************
 * Declaration of the COASPMetadata classes                        *
 *******************************************************************/

class COASPMetadataItem;

class COASPMetadataReader
{
	VSILFILE *fp;
	char **papszMetadata;
	int nMetadataCount;
	int nCurrentItem;
public:
	COASPMetadataReader(char *pszFname);
        ~COASPMetadataReader();
	COASPMetadataItem *GetNextItem();
	COASPMetadataItem *GetItem(int nItem);
	int GotoMetadataItem(int nItemNumber);
	int GotoMetadataItem(const char *pszName);
	int GetCurrentItem() { return nCurrentItem; }
};

/* Your average metadata item */
class COASPMetadataItem
{
protected:
    char *pszItemName;
    char *pszItemValue;

public:
    COASPMetadataItem() : pszItemName(NULL), pszItemValue(NULL) { }
    COASPMetadataItem(char *pszItemName, char *pszItemValue);
    ~COASPMetadataItem();

    char *GetItemName();
    char *GetItemValue();
    int GetType() { return TYPE_GENERIC; }
};

/* Same as MetadataItem class except parses GCP properly and returns
 * a GDAL_GCP struct
 */
class COASPMetadataGeorefGridItem : public COASPMetadataItem
{
	int nId;
	int nPixels;
	int nLines;
	double ndLat;
	double ndLong;

public:
	COASPMetadataGeorefGridItem(int nId, int nPixels, int nLines,
		double ndLat, double ndLong);
	const char *GetItemName() { return "georef_grid"; }
	GDAL_GCP *GetItemValue();
	int GetType() { return TYPE_GEOREF; }
};

/********************************************************************
 * ================================================================ *
 * Implementation of the COASPMetadataItem Classes                  *
 * ================================================================ *
 ********************************************************************/

COASPMetadataItem::COASPMetadataItem(char *pszItemName_, char *pszItemValue_)
{
    pszItemName = VSIStrdup(pszItemName_);
    pszItemValue = VSIStrdup(pszItemValue_);
}

COASPMetadataItem::~COASPMetadataItem()
{
    CPLFree(pszItemName);
    CPLFree(pszItemValue);
}

char *COASPMetadataItem::GetItemName()
{
	return VSIStrdup(pszItemName);
}

char *COASPMetadataItem::GetItemValue()
{
	return VSIStrdup(pszItemValue);
}

COASPMetadataGeorefGridItem::COASPMetadataGeorefGridItem(int nIdIn, int nPixelsIn,
	int nLinesIn, double ndLatIn, double ndLongIn)
{
	this->nId = nIdIn;
	this->nPixels = nPixelsIn;
	this->nLines = nLinesIn;
	this->ndLat = ndLatIn;
	this->ndLong = ndLongIn;
        pszItemName = VSIStrdup("georef_grid");
}

GDAL_GCP *COASPMetadataGeorefGridItem::GetItemValue()
{
	return NULL;
}

/********************************************************************
 * ================================================================ *
 * Implementation of the COASPMetadataReader Class                  *
 * ================================================================ *
 ********************************************************************/

COASPMetadataReader::COASPMetadataReader(char *pszFname) :
    fp(NULL), papszMetadata(NULL), nMetadataCount(0), nCurrentItem(0)
{
    papszMetadata = CSLLoad(pszFname);
    nMetadataCount = CSLCount(papszMetadata);
}

COASPMetadataReader::~COASPMetadataReader()
{
    if (fp)
        VSIFCloseL(fp);
    CSLDestroy(papszMetadata);
}

COASPMetadataItem *COASPMetadataReader::GetNextItem()
{
	if (nCurrentItem >= nMetadataCount)
		return NULL;

        COASPMetadataItem *poMetadata;

        char **papszMDTokens
            = CSLTokenizeString2(papszMetadata[nCurrentItem], " ",
                                 CSLT_HONOURSTRINGS );
        char *pszItemName = papszMDTokens[0];
	if (STARTS_WITH_CI(pszItemName, "georef_grid")) {
		// georef_grid ( pixels lines ) ( lat long )
		// 0           1 2      3     4 5 6   7    8
                int nPixels = atoi(papszMDTokens[2]);
                int nLines = atoi(papszMDTokens[3]);
                double dfLat = CPLAtof(papszMDTokens[6]);
                double dfLong = CPLAtof(papszMDTokens[7]);
                poMetadata = new COASPMetadataGeorefGridItem(
                    nCurrentItem, nPixels, nLines, dfLat, dfLong);
	}
	else {
		int nCount = CSLCount(papszMDTokens);
                char *pszItemValue = CPLStrdup(papszMDTokens[1]);
		for (int i = 2; i < nCount; i++) {
			const size_t nSize = strlen(pszItemValue) + 1 + strlen(papszMDTokens[i]);
			pszItemValue = (char *)CPLRealloc(pszItemValue, nSize);
			snprintf(pszItemValue + strlen(pszItemValue),
                                 nSize - strlen(pszItemValue), " %s",
				papszMDTokens[i]);
		}

		poMetadata = new COASPMetadataItem(pszItemName,
			pszItemValue);

		CPLFree(pszItemValue);
	}
	CSLDestroy(papszMDTokens);
	nCurrentItem++;
	return poMetadata;
}

/* Goto a particular metadata item, listed by number */
int COASPMetadataReader::GotoMetadataItem(int nItemNumber)
{
	if (nItemNumber >= nMetadataCount || nItemNumber < 0) {
            nCurrentItem = 0;
	}
	else
            nCurrentItem = nItemNumber;
	return nCurrentItem;
}

/* Goto the first metadata item with a particular name */
int COASPMetadataReader::GotoMetadataItem(const char *pszName)
{
	nCurrentItem = CSLPartialFindString(papszMetadata, pszName);
	return nCurrentItem;
}

/*******************************************************************
 * Declaration of the COASPDataset class                           *
 *******************************************************************/


class COASPRasterBand;

/* A couple of observations based on the data I have available to me:
 * a) the headers don't really change, beyond indicating data sources
 *    and such. As such, I only read the first header specified by the
 *    user. Note that this is agnostic: you can specify hh, vv, vh, hv and
 *    all the data needed will be immediately available.
 * b) Lots of GCPs are present in the headers. This is most excellent.
 * c) There is no documentation on this format. All the knowledge contained
 *    herein is from harassing various Defence Scientists at DRDC Ottawa.
 */

class COASPDataset : public GDALDataset
{
	friend class COASPRasterBand;
	VSILFILE *fpHdr; /* File pointer for the header file */
	VSILFILE *fpBinHH; /* File pointer for the binary matrix */
	VSILFILE *fpBinHV;
	VSILFILE *fpBinVH;
	VSILFILE *fpBinVV;

	char *pszFileName; /* line and mission ID, mostly, i.e. l27p7 */

	int nGCPCount;
	GDAL_GCP *pasGCP;
public:
	static GDALDataset *Open( GDALOpenInfo * );
	static int Identify( GDALOpenInfo * poOpenInfo );
	int GetGCPCount();
	const GDAL_GCP *GetGCPs();
};

/********************************************************************
 * ================================================================ *
 * Declaration and implementation of the COASPRasterBand Class      *
 * ================================================================ *
 ********************************************************************/

class COASPRasterBand : public GDALRasterBand {
	VSILFILE *fp;
	int ePol;
public:
	COASPRasterBand( COASPDataset *poDS, GDALDataType eDataType, int ePol, VSILFILE *fp );
	virtual CPLErr IReadBlock( int nBlockXOff, int nBlockYOff,
		void *pImage);
};

COASPRasterBand::COASPRasterBand( COASPDataset *poDSIn, GDALDataType eDataTypeIn,
	int ePolIn, VSILFILE *fpIn)
{
	this->fp = fpIn;
	this->ePol = ePolIn;
	this->poDS = poDSIn;
	this->eDataType = eDataTypeIn;
        nBlockXSize = poDS->GetRasterXSize();
        nBlockYSize = 1;
}

CPLErr COASPRasterBand::IReadBlock( CPL_UNUSED int nBlockXOff,
                                    int nBlockYOff,
                                    void *pImage )
{
	if (this->fp == NULL) {
		CPLError(CE_Fatal, CPLE_AppDefined, "file pointer freed unexpectedly\n");
		return CE_Fatal;
	}

	/* 8 bytes per pixel: 4 bytes I, 4 bytes Q */
	unsigned long nByteNum = poDS->GetRasterXSize() * 8 * nBlockYOff;

	VSIFSeekL(this->fp, nByteNum, SEEK_SET);
	int nReadSize = (GDALGetDataTypeSize(eDataType)/8) * poDS->GetRasterXSize();
	VSIFReadL((char *)pImage, 1, nReadSize,
		this->fp);

#ifdef CPL_LSB
	GDALSwapWords( pImage, 4, nBlockXSize * 2, 4 );
#endif
	return CE_None;
}


/********************************************************************
 * ================================================================ *
 * Implementation of the COASPDataset Class                         *
 * ================================================================ *
 ********************************************************************/

/************************************************************************/
/*                            GetGCPCount()                             */
/************************************************************************/

int COASPDataset::GetGCPCount()
{
	return nGCPCount;
}

/************************************************************************/
/*                               GetGCPs()                              */
/************************************************************************/

const GDAL_GCP *COASPDataset::GetGCPs()
{
	return pasGCP;
}

/************************************************************************/
/*                              Identify()                              */
/************************************************************************/

int COASPDataset::Identify( GDALOpenInfo *poOpenInfo )
{
	if(poOpenInfo->fpL == NULL || poOpenInfo->nHeaderBytes < 256)
		return 0;

	/* With a COASP .hdr file, the first line or so is:
 	 * time_first_datarec
 	 */
	if(STARTS_WITH_CI((char *)poOpenInfo->pabyHeader, "time_first_datarec"))
		return 1;

	return 0;
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

GDALDataset *COASPDataset::Open( GDALOpenInfo *poOpenInfo )
{
	if (!COASPDataset::Identify(poOpenInfo))
		return NULL;

/* -------------------------------------------------------------------- */
/*      Confirm the requested access is supported.                      */
/* -------------------------------------------------------------------- */
    if( poOpenInfo->eAccess == GA_Update )
    {
        CPLError( CE_Failure, CPLE_NotSupported,
                  "The COASP driver does not support update access to existing"
                  " datasets.\n" );
        return NULL;
    }

    /* Create a fresh dataset for us to work with */
    COASPDataset *poDS = new COASPDataset();

	if (poDS == NULL)
		return NULL;

	/* Steal the file pointer for the header */
	poDS->fpHdr = poOpenInfo->fpL;
	poOpenInfo->fpL = NULL;

	/* Set the binary matrix file pointers to NULL, for now */
	poDS->fpBinHH = NULL;
	poDS->fpBinHV = NULL;
	poDS->fpBinVH = NULL;
	poDS->fpBinVV = NULL;
        poDS->nGCPCount = 0;
        poDS->pasGCP = NULL;

	poDS->pszFileName = VSIStrdup(poOpenInfo->pszFilename);

	/* determine the file name prefix */
	char *pszBaseName = VSIStrdup(CPLGetBasename(poDS->pszFileName));
	char *pszDir = VSIStrdup(CPLGetPath(poDS->pszFileName));
	const char *pszExt = "rc";
	int nNull = static_cast<int>(strlen(pszBaseName)) - 1;
	char *pszBase = (char *)CPLMalloc(nNull);
	strncpy(pszBase, pszBaseName, nNull);
	pszBase[nNull - 1] = '\0';
	free(pszBaseName);

	char *psChan = strstr(pszBase,"hh");;
	if (psChan == NULL) {
		psChan = strstr(pszBase, "hv");
	}
	if (psChan == NULL) {
		psChan = strstr(pszBase, "vh");
	}
	if (psChan == NULL) {
		psChan = strstr(pszBase, "vv");
	}

	if (psChan == NULL) {
		CPLError(CE_Fatal, CPLE_AppDefined, "unable to recognize file as COASP.\n");
		free(poDS->pszFileName);
		free(pszBase);
		free(pszDir);
		delete poDS;
		return NULL;
	}

    /* Read Metadata, set GCPs as is appropriate */
    COASPMetadataReader *poReader = new COASPMetadataReader(
        poDS->pszFileName);

    /* Get Image X and Y widths */
    poReader->GotoMetadataItem("number_lines");
    COASPMetadataItem *poItem = poReader->GetNextItem();
    char *nValue = poItem->GetItemValue();
    poDS->nRasterYSize = atoi(nValue);
    free(nValue);

    poReader->GotoMetadataItem("number_samples");
    delete poItem;
    poItem = poReader->GetNextItem();
    nValue = poItem->GetItemValue();
    poDS->nRasterXSize = atoi(nValue);
    free(nValue);


	/* Horizontal transmit, horizontal receive */
	psChan[0] = 'h';
	psChan[1] = 'h';
     const char *pszFilename = CPLFormFilename(pszDir, pszBase, pszExt);

	poDS->fpBinHH = VSIFOpenL(pszFilename, "r");

	if (poDS->fpBinHH != NULL) {
		/* Set raster band */
		poDS->SetBand(1, new COASPRasterBand(poDS, GDT_CFloat32,
			hh , poDS->fpBinHH));
	}

	/* Horizontal transmit, vertical receive */
    psChan[0] = 'h';
    psChan[1] = 'v';
    pszFilename = CPLFormFilename(pszDir, pszBase, pszExt);

	poDS->fpBinHV = VSIFOpenL(pszFilename, "r");

	if (poDS->fpBinHV != NULL) {
		poDS->SetBand(2, new COASPRasterBand(poDS, GDT_CFloat32,
			hv, poDS->fpBinHV));
	}

	/* Vertical transmit, horizontal receive */
    psChan[0] = 'v';
    psChan[1] = 'h';
    pszFilename = CPLFormFilename(pszDir, pszBase, pszExt);

	poDS->fpBinVH = VSIFOpenL(pszFilename, "r");

	if (poDS->fpBinVH != NULL) {
    	poDS->SetBand(3, new COASPRasterBand(poDS, GDT_CFloat32,
			vh, poDS->fpBinVH));
	}

	/* Vertical transmit, vertical receive */
    psChan[0] = 'v';
    psChan[1] = 'v';
    pszFilename = CPLFormFilename(pszDir, pszBase, pszExt);

	poDS->fpBinVV = VSIFOpenL(pszFilename, "r");

	if (poDS->fpBinVV != NULL) {
		poDS->SetBand(4, new COASPRasterBand(poDS, GDT_CFloat32,
			vv, poDS->fpBinVV));
	}


	/* Oops, missing all the data? */

	if (poDS->fpBinHH == NULL && poDS->fpBinHV == NULL
		&& poDS->fpBinVH == NULL && poDS->fpBinVV == NULL)
	{
		CPLError(CE_Fatal,CPLE_AppDefined,"Unable to find any data! Aborting.");
		free(pszBase);
		free(pszDir);
		delete poDS;
                delete poItem;
                delete poReader;
		return NULL;
	}

    if ( poDS->GetRasterCount() == 4 ) {
        poDS->SetMetadataItem( "MATRIX_REPRESENTATION", "SCATTERING" );
    }

	free(pszBase);
	free(pszDir);

	delete poItem;
	delete poReader;

	return poDS;
}

/************************************************************************/
/*                         GDALRegister_COASP()                         */
/************************************************************************/

void GDALRegister_COASP()
{
    if( GDALGetDriverByName( "COASP" ) != NULL )
        return;

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription( "COASP" );
    poDriver->SetMetadataItem( GDAL_DCAP_RASTER, "YES" );
    poDriver->SetMetadataItem( GDAL_DMD_LONGNAME,
                               "DRDC COASP SAR Processor Raster" );
    poDriver->SetMetadataItem( GDAL_DMD_EXTENSION,
                               "hdr" );
    // poDriver->SetMetadataItem( GDAL_DMD_HELPTOPIC, "frmt_coasp.html");
    poDriver->pfnIdentify = COASPDataset::Identify;
    poDriver->pfnOpen = COASPDataset::Open;
    GetGDALDriverManager()->RegisterDriver( poDriver );
}