/* Read a file using libMagick
 * 
 * 7/1/03 JC
 *	- from im_tiff2vips
 * 3/2/03 JC
 *	- some InitializeMagick() fail with NULL arg
 * 2/11/04
 *	- im_magick2vips_header() also checks sensible width/height
 * 28/10/05
 * 	- copy attributes to meta
 * 	- write many-frame images as a big column if all frames have identical
 * 	  width/height/bands/depth
 * 31/3/06
 * 	- test for magick attr support
 * 8/5/06
 * 	- set RGB16/GREY16 if appropriate
 * 10/8/07
 * 	- support 32/64 bit imagemagick too
 * 21/2/08 
 * 	- use MaxRGB if QuantumRange is missing (thanks Bob)
 * 	- look for MAGICKCORE_HDRI_SUPPORT (thanks Marcel)
 * 	- use image->attributes if GetNextImageAttribute() is missing
 */

/*

    This file is part of VIPS.
    
    VIPS is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

/*

    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk

 */

/* Turn on debugging output.
#define DEBUG
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>

#ifndef HAVE_MAGICK

#include <vips/vips.h>

int
im_magick2vips( const char *filename, IMAGE *im )
{
	im_error( "im_magick2vips", _( "libMagick support disabled" ) );
	return( -1 );
}

#else /*HAVE_MAGICK*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>

#include <vips/vips.h>
#include <vips/buf.h>
#include <vips/thread.h>

#include <magick/api.h>

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/

/* pre-float Magick used to call this MaxRGB.
 */
#if !defined(QuantumRange)
#  define QuantumRange MaxRGB
#endif

/* And this used to be UseHDRI.
 */
#if MAGICKCORE_HDRI_SUPPORT
#  define UseHDRI=1
#endif

/* What we track during a read call.
 */
typedef struct _Read {
	char *filename;
	IMAGE *im;

	Image *image;
	ImageInfo *image_info;
	ExceptionInfo exception;

	int n_frames;
	Image **frames;
	int frame_height;

	/* Mutex to serialise calls to libMagick during threaded read.
	 */
	GMutex *lock;
} Read;

static int
read_destroy( Read *read )
{
#ifdef DEBUG
	printf( "im_magick2vips: read_destroy: %s\n", read->filename );
#endif /*DEBUG*/

	IM_FREEF( DestroyImage, read->image );
	IM_FREEF( DestroyImageInfo, read->image_info ); 
	IM_FREE( read->frames );
	IM_FREE( read->filename );
	DestroyExceptionInfo( &read->exception );
	IM_FREEF( g_mutex_free, read->lock );
	im_free( read );

	return( 0 );
}

static Read *
read_new( const char *filename, IMAGE *im )
{
	Read *read;
	static int inited = 0;

	if( !inited ) {
		InitializeMagick( "" );
		inited = 1;
	}

	if( !(read = IM_NEW( NULL, Read )) )
		return( NULL );
	read->filename = im_strdup( NULL, filename );
	read->im = im;
	read->image = NULL;
	read->image_info = CloneImageInfo( NULL );
	GetExceptionInfo( &read->exception );
	read->n_frames = 0;
	read->frames = NULL;
	read->frame_height = 0;
	read->lock = g_mutex_new();

	if( im_add_close_callback( im,
		(im_callback_fn) read_destroy, read, NULL ) ) {
		read_destroy( read );
		return( NULL );
	}

	if( !read->filename || !read->image_info ) 
		return( NULL );

	im_strncpy( read->image_info->filename, filename, MaxTextExtent );

#ifdef DEBUG
	printf( "im_magick2vips: read_new: %s\n", read->filename );
#endif /*DEBUG*/

	return( read );
}

static int
get_bands( Image *image )
{
	int bands;

	switch( image->colorspace ) {
	case GRAYColorspace:
		bands = 1;
		break;

	case RGBColorspace:
		bands = 3;
		break;

	case sRGBColorspace:
		bands = 3;
		break;

	case CMYKColorspace:
		bands = 4;
		break;

	default:
		im_error( "im_magick2vips", _( "unsupported colorspace %d" ),
			(int) image->colorspace );
		return( -1 );
	}

	/* Alpha as well?
	 */
	if( image->matte ) {
		assert( image->colorspace != CMYKColorspace );
		bands += 1;
	}

	return( bands );
}

static int
parse_header( Read *read )
{
	IMAGE *im = read->im;
	Image *image = read->image;

#ifdef HAVE_MAGICK_ATTR
	const ImageAttribute *attr;
#endif /*HAVE_MAGICK_ATTR*/
	Image *p;
	int i;

	im->Xsize = image->columns;
	im->Ysize = image->rows;
	read->frame_height = image->rows;
	if( (im->Bands = get_bands( image )) < 0 )
		return( -1 );

	switch( image->depth ) {
	case 8:
		im->BandFmt = IM_BANDFMT_UCHAR;
		im->Bbits = IM_BBITS_BYTE;
		break;

	case 16:
		im->BandFmt = IM_BANDFMT_USHORT;
		im->Bbits = IM_BBITS_SHORT;
		break;

#ifdef UseHDRI
	case 32:
		im->BandFmt = IM_BANDFMT_FLOAT;
		im->Bbits = IM_BBITS_FLOAT;
		break;

	case 64:
		im->BandFmt = IM_BANDFMT_DOUBLE;
		im->Bbits = IM_BBITS_DOUBLE;
		break;
#else /*!UseHDRI*/
	case 32:
		im->BandFmt = IM_BANDFMT_UINT;
		im->Bbits = IM_BBITS_INT;
		break;

	/* No 64-bit int format in VIPS.
	 */
#endif /*UseHDRI*/

	default:
		im_error( "im_magick2vips", _( "unsupported bit depth %d" ),
			(int) image->depth );
		return( -1 );
	}

	switch( image->colorspace ) {
	case GRAYColorspace:
		if( im->BandFmt == IM_BANDFMT_USHORT )
			im->Type = IM_TYPE_GREY16;
		else
			im->Type = IM_TYPE_B_W;
		break;

	case RGBColorspace:
		if( im->BandFmt == IM_BANDFMT_USHORT )
			im->Type = IM_TYPE_RGB16;
		else
			im->Type = IM_TYPE_RGB;
		break;

	case sRGBColorspace:
		if( im->BandFmt == IM_BANDFMT_USHORT )
			im->Type = IM_TYPE_RGB16;
		else
			im->Type = IM_TYPE_sRGB;
		break;

	case CMYKColorspace:
		im->Type = IM_TYPE_CMYK;
		break;

	default:
		im_error( "im_magick2vips", _( "unsupported colorspace %d" ),
			(int) image->colorspace );
		return( -1 );
	}

	switch( image->units ) {
	case PixelsPerInchResolution:
		im->Xres = image->x_resolution / 25.4;
		im->Yres = image->y_resolution / 25.4;
		break;

	case PixelsPerCentimeterResolution:
		im->Xres = image->x_resolution / 10.0;
		im->Yres = image->y_resolution / 10.0;
		break;

	default:
		im->Xres = 1.0;
		im->Yres = 1.0;
		break;
	}

	/* Other fields.
	 */
	im->Coding = IM_CODING_NONE;

#ifdef HAVE_MAGICK_ATTR
#ifdef HAVE_GETNEXTIMAGEATTRIBUTE
	/* Gah, magick6.something and later only. Attach any attributes.
	 */
	ResetImageAttributeIterator( image );
	while( (attr = GetNextImageAttribute( image )) ) {
#elif defined(HAVE_GETIMAGEATTRIBUTE)
	/* GraphicsMagick is missing the iterator: we have to loop ourselves.
	 * ->attributes is marked as private in the header, but there's no
	 * getter so we have to access it directly.
	 */
	for( attr = image->attributes; attr; attr = attr->next ) {
#else /*stuff*/
	#error attributes enabled, but no access funcs found
#endif
		char name_text[256];
		im_buf_t name;

		im_buf_init_static( &name, name_text, 256 );
		im_buf_appendf( &name, "magick-%s", attr->key );
		im_meta_set_string( im, im_buf_all( &name ), attr->value );

#ifdef DEBUG
		printf( "key = \"%s\", value = \"%s\"\n", 
			attr->key, attr->value );
#endif /*DEBUG*/
	}
#endif /*HAVE_MAGICK_ATTR*/

	/* Do we have a set of equal-sized frames? Append them.

	   	FIXME ... there must be an attribute somewhere from dicom read 
		which says this is a volumetric image

	 */
	read->n_frames = 0;
	for( p = image; p; (p = GetNextImageInList( p )) ) {
		if( p->columns != im->Xsize ||
			p->rows != im->Ysize ||
			p->depth != im->Bbits ||
			get_bands( p ) != im->Bands )
			break;

		read->n_frames += 1;
	}
	if( p ) 
		/* Nope ... just do the first image in the list.
		 */
		read->n_frames = 1;

	/* Record frame pointers.
	 */
	im->Ysize *= read->n_frames;
	if( !(read->frames = IM_ARRAY( NULL, read->n_frames, Image * )) )
		return( -1 );
	p = image;
	for( i = 0; i < read->n_frames; i++ ) {
		read->frames[i] = p;
		p = GetNextImageInList( p );
	}

	return( 0 );
}

/* Divide by this to get 0 - MAX from a Quantum. Eg. consider QuantumRange ==
 * 65535, MAX == 255 (a Q16 ImageMagic representing an 8-bit image). Make sure
 * this can't be zero (if QuantumRange < MAX) .. can happen if we have a Q8
 * ImageMagick trying to represent a 16-bit image.
 */
#define SCALE( MAX ) \
	(QuantumRange < (MAX) ? \
		1 : \
		((QuantumRange + 1) / ((MAX) + 1)))

#define GRAY_LOOP( TYPE, MAX ) { \
	TYPE *q = (TYPE *) q8; \
	\
	for( x = 0; x < n; x++ ) \
		q[x] = pixels[x].green / SCALE( MAX ); \
}

#define GRAYA_LOOP( TYPE, MAX ) { \
	TYPE *q = (TYPE *) q8; \
	\
	for( x = 0; x < n; x++ ) { \
		q[0] = pixels[x].green / SCALE( MAX ); \
		q[1] = pixels[x].opacity / SCALE( MAX ); \
		\
		q += 2; \
	} \
}

#define RGB_LOOP( TYPE, MAX ) { \
	TYPE *q = (TYPE *) q8; \
	\
	for( x = 0; x < n; x++ ) { \
		q[0] = pixels[x].red / SCALE( MAX ); \
		q[1] = pixels[x].green / SCALE( MAX ); \
		q[2] = pixels[x].blue / SCALE( MAX ); \
		\
		q += 3; \
	} \
}

#define RGBA_LOOP( TYPE, MAX ) { \
	TYPE *q = (TYPE *) q8; \
	\
	for( x = 0; x < n; x++ ) { \
		q[0] = pixels[x].red / SCALE( MAX ); \
		q[1] = pixels[x].green / SCALE( MAX ); \
		q[2] = pixels[x].blue / SCALE( MAX ); \
		q[3] = pixels[x].opacity / SCALE( MAX ); \
		\
		q += 4; \
	} \
}

static void
unpack_pixels( IMAGE *im, PEL *q8, PixelPacket *pixels, int n )
{
	int x;

	switch( im->Bands ) {
	case 1:
		/* Gray.
		 */
		switch( im->BandFmt ) {
		case IM_BANDFMT_UCHAR:	
			GRAY_LOOP( unsigned char, 255 ); break;
		case IM_BANDFMT_USHORT: 
			GRAY_LOOP( unsigned short, 65535 ); break;
		case IM_BANDFMT_UINT:	
			GRAY_LOOP( unsigned int, 4294967295UL ); break;
		case IM_BANDFMT_DOUBLE:	
			GRAY_LOOP( double, QuantumRange ); break;

		default:
			assert( 0 );
		}
		break;

	case 2:
		/* Gray plus alpha.
		 */
		switch( im->BandFmt ) {
		case IM_BANDFMT_UCHAR:
			GRAYA_LOOP( unsigned char, 255 ); break;
		case IM_BANDFMT_USHORT:	
			GRAYA_LOOP( unsigned short, 65535 ); break;
		case IM_BANDFMT_UINT:	
			GRAYA_LOOP( unsigned int, 4294967295UL ); break;
		case IM_BANDFMT_DOUBLE:	
			GRAYA_LOOP( double, QuantumRange ); break;

		default:
			assert( 0 );
		}
		break;

	case 3:
		/* RGB.
		 */
		switch( im->BandFmt ) {
		case IM_BANDFMT_UCHAR:	
			RGB_LOOP( unsigned char, 255 ); break;
		case IM_BANDFMT_USHORT:	
			RGB_LOOP( unsigned short, 65535 ); break;
		case IM_BANDFMT_UINT:	
			RGB_LOOP( unsigned int, 4294967295UL ); break;
		case IM_BANDFMT_DOUBLE:	
			RGB_LOOP( double, QuantumRange ); break;

		default:
			assert( 0 );
		}
		break;

	case 4:
		/* RGBA or CMYK.
		 */
		switch( im->BandFmt ) {
		case IM_BANDFMT_UCHAR:
			RGBA_LOOP( unsigned char, 255 ); break;
		case IM_BANDFMT_USHORT:	
			RGBA_LOOP( unsigned short, 65535 ); break;
		case IM_BANDFMT_UINT:	
			RGBA_LOOP( unsigned int, 4294967295UL ); break;
		case IM_BANDFMT_DOUBLE:	
			RGBA_LOOP( double, QuantumRange ); break;

		default:
			assert( 0 );
		}
		break;

	default:
		assert( 0 );
	}
}

static PixelPacket *
get_pixels( Image *image, int left, int top, int width, int height )
{
	PixelPacket *pixels;
	
	if( !(pixels = GetImagePixels( image, left, top, width, height )) )
		return( NULL );

/* Can't happen if red/green/blue are doubles.
 */
#ifndef UseHDRI
	/* Unpack palette.
	 */
	if( image->storage_class == PseudoClass ) {
		IndexPacket *indexes = GetIndexes( image );
		int i;

		for( i = 0; i < width * height; i++ ) {
			IndexPacket x = indexes[i];

			if( x < image->colors ) {
				pixels[i].red = image->colormap[x].red;
				pixels[i].green = image->colormap[x].green;
				pixels[i].blue = image->colormap[x].blue;
			}
		}
	}
#endif /*UseHDRI*/

	return( pixels );
}

static int
magick_fill_region( REGION *out, void *seq, void *a, void *b )
{
	Read *read = (Read *) a;
	Rect *r = &out->valid;
	int y;

	for( y = 0; y < r->height; y++ ) {
		int top = r->top + y;
		int frame = top / read->frame_height;
		int line = top % read->frame_height;

		PixelPacket *pixels;

		g_mutex_lock( read->lock );
		pixels = get_pixels( read->frames[frame], 
			r->left, line, r->width, 1 );
		g_mutex_unlock( read->lock );

		if( !pixels ) {
			im_error( "im_magick2vips", 
				"%s", _( "unable to read pixels" ) );
			return( -1 );
		}

		unpack_pixels( read->im, 
			(PEL *) IM_REGION_ADDR( out, r->left, top ), 
			pixels, r->width );
	}

	return( 0 );
}

int
im_magick2vips( const char *filename, IMAGE *im )
{
	Read *read;

	if( !(read = read_new( filename, im )) )
		return( -1 );

	read->image = ReadImage( read->image_info, &read->exception );
	if( !read->image ) {
		im_error( "im_magick2vips", _( "unable to read file \"%s\"\n"
			"libMagick error: %s %s" ),
			filename, 
			read->exception.reason, read->exception.description );
		return( -1 );
	}

	if( parse_header( read ) ||
		im_poutcheck( im ) || 
		im_generate( im, NULL, magick_fill_region, NULL, read, NULL ) )
		return( -1 );

	return( 0 );
}

static int
magick2vips_header( const char *filename, IMAGE *im )
{
	Read *read;

	if( !(read = read_new( filename, im )) )
		return( -1 );

	read->image = PingImage( read->image_info, &read->exception );
	if( !read->image ) {
		im_error( "im_magick2vips", _( "unable to ping file "
			"\"%s\"\nlibMagick error: %s %s" ),
			filename, 
			read->exception.reason, read->exception.description );
		return( -1 );
	}

	if( parse_header( read ) ) 
		return( -1 );

	if( im->Xsize <= 0 || im->Ysize <= 0 ) {
		im_error( "im_magick2vips", "%s", _( "bad image size" ) );
		return( -1 );
	}

	return( 0 );
}

static int
ismagick( const char *filename )
{
	IMAGE *im;
	int result;

	if( !(im = im_open( "dummy", "p" )) )
		return( -1 );
	result = magick2vips_header( filename, im );
	im_error_clear();
	im_close( im );

	return( result == 0 );
}

static const char *magick_suffs[] = { NULL };

void
im__magick_register( void )
{
	im_format_t *format;

	format = im_format_register( 
		"magick",		/* internal name */
		_( "libMagick-supported" ),/* i18n'd visible name */
		magick_suffs,		/* Allowed suffixes */
		ismagick,		/* is_a */
		magick2vips_header,	/* Load header only */
		im_magick2vips,		/* Load */
		NULL,			/* Save */
		NULL			/* Flags */
	);
	im_format_set_priority( format, -1000 );
}

#endif /*HAVE_MAGICK*/