/*
 * pattern_sim.c
 *
 * Simulate diffraction patterns from small crystals
 *
 * (c) 2006-2010 Thomas White <taw@physics.org>
 *
 * Part of CrystFEL - crystallography with a FEL
 *
 */


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

#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <getopt.h>

#include "image.h"
#include "diffraction.h"
#include "diffraction-gpu.h"
#include "cell.h"
#include "utils.h"
#include "hdf5-file.h"
#include "detector.h"
#include "intensities.h"
#include "sfac.h"
#include "reflections.h"


static void show_help(const char *s)
{
	printf("Syntax: %s [options]\n\n", s);
	printf(
"Simulate diffraction patterns from small crystals probed with femtosecond\n"
"pulses of X-rays from a free electron laser.\n"
"\n"
" -h, --help                Display this help message.\n"
"     --simulation-details  Show technical details of the simulation.\n"
"     --gpu                 Use the GPU to speed up the calculation.\n"
"\n"
"     --near-bragg          Output h,k,l,I near Bragg conditions.\n"
" -n, --number=<N>          Generate N images.  Default 1.\n"
"     --no-images           Do not output any HDF5 files.\n"
" -r, --random-orientation  Use a randomly generated orientation\n"
"                            (a new orientation will be used for each image).\n"
"     --powder              Write a summed pattern of all images simulated by\n"
"                            this invocation to results/integr.h5.\n"
" -i, --intensities=<file>  Specify file containing reflection intensities\n"
"                            to use.\n"
"\n"
"By default, the simulation aims to be as accurate as possible.  For greater\n"
"speed, or for testing, you can choose to disable certain things using the\n"
"following options.\n"
"\n"
"     --no-water            Do not simulate water background.\n"
"     --no-noise            Do not calculate Poisson noise.\n"
);
}


static void show_details()
{
	printf(
"This program simulates diffraction patterns from small crystals illuminated\n"
"with femtosecond X-ray pulses from a free electron laser.\n"
"\n"
"The lattice transform from the specified number of unit cells is calculated\n"
"using the closed-form solution for a truncated lattice:\n"
"\n"
"F(q) =  sin(pi*na*q.a)/sin(pi*q.a)\n"
"      * sin(pi*nb*q.b)/sin(pi*q.b)\n"
"      * sin(pi*nc*q.c)/sin(pi*q.c)\n"
"\n"
"na = number of unit cells in 'a' direction (likewise nb, nc)\n"
" q = reciprocal vector (1/d convention, not 2pi/d)\n"
"\n"
"This square modulus of this value is take, and multiplied by the Bragg\n"
"intensitiy at the neares Bragg position.  That means that the gradient of\n"
"the underlying molecule transform is not included, for speed of calculation.\n"
"The Bragg intensities are taken from the file specified on the command line\n"
"with the --intensities option.\n"
"\n"
"Intensity from water is then added according to the first term of equation\n"
"5 from Phys Chem Chem Phys 2003 (5) 1981--1991.  This simulates the\n"
"coherent, elastic part of the diffuse scattering from the water jet only.\n"
"\n"
"Expected intensities at the CCD are then calculated using:\n"
"\n"
"I(q) = I0 * r^2 * |F(q)|^2 * S\n"
"\n"
"I0 = number of photons per unit area in the incident beam\n"
" r = Thomson radius\n"
" S = solid angle of corresponding pixel\n"
"where |F(q)|^2 is the value calculated as described above.\n"
"\n"
"Poisson counts are generated from the expected intensities using Knuth's\n"
"algorithm.  When the intensity is sufficiently high that Knuth's algorithm\n"
"would result in machine precision problems, a normal distribution with\n"
"standard deviation sqrt(I) is used instead.\n"
);
}


static struct quaternion read_quaternion()
{
	do {

		int r;
		float w, x, y, z;
		char line[1024];
		char *rval;

		printf("Please input quaternion: w x y z\n");
		rval = fgets(line, 1023, stdin);
		if ( rval == NULL ) return invalid_quaternion();
		chomp(line);

		r = sscanf(line, "%f %f %f %f", &w, &x, &y, &z);
		if ( r == 4 ) {

			struct quaternion quat;

			quat.w = w;
			quat.x = x;
			quat.y = y;
			quat.z = z;

			return quat;

		} else {
			ERROR("Invalid rotation '%s'\n", line);
		}

	} while ( 1 );
}


int main(int argc, char *argv[])
{
	int c;
	struct image image;
	struct gpu_context *gctx = NULL;
	double *powder;
	char *intfile = NULL;
	double *intensities;
	int config_simdetails = 0;
	int config_nearbragg = 0;
	int config_randomquat = 0;
	int config_noimages = 0;
	int config_nowater = 0;
	int config_nonoise = 0;
	int config_nosfac = 0;
	int config_gpu = 0;
	int config_powder = 0;
	int ndone = 0;    /* Number of simulations done (images or not) */
	int number = 1;   /* Number used for filename of image */
	int n_images = 1; /* Generate one image by default */
	int done = 0;
	UnitCell *cell;

	/* Long options */
	const struct option longopts[] = {
		{"help",               0, NULL,               'h'},
		{"simulation-details", 0, &config_simdetails,  1},
		{"gpu",                0, &config_gpu,         1},
		{"near-bragg",         0, &config_nearbragg,   1},
		{"random-orientation", 0, NULL,               'r'},
		{"number",             1, NULL,               'n'},
		{"no-images",          0, &config_noimages,    1},
		{"no-water",           0, &config_nowater,     1},
		{"no-noise",           0, &config_nonoise,     1},
		{"intensities",        0, NULL,               'i'},
		{"powder",             0, &config_powder,      1},
		{0, 0, NULL, 0}
	};

	/* Short options */
	while ((c = getopt_long(argc, argv, "hrn:", longopts, NULL)) != -1) {

		switch (c) {
		case 'h' : {
			show_help(argv[0]);
			return 0;
		}

		case 'r' : {
			config_randomquat = 1;
			break;
		}

		case 'n' : {
			n_images = atoi(optarg);
			break;
		}

		case 'i' : {
			intfile = strdup(optarg);
			break;
		}

		case 0 : {
			break;
		}

		default : {
			return 1;
		}
		}

	}

	if ( config_simdetails ) {
		show_details();
		return 0;
	}

	if ( (!config_nowater) && config_gpu ) {
		ERROR("Cannot simulate water scattering on the GPU.\n");
		ERROR("Please try again with the --no-water option.\n");
		return 1;
	}

	if ( intfile == NULL ) {
		/* Gentle reminder */
		STATUS("You didn't specify the file containing the ");
		STATUS("reflection intensities (with --intensities).\n");
		STATUS("I'll simulate a flat intensity distribution.\n");
		intensities = NULL;
	} else {
		intensities = read_reflections(intfile);
		free(intfile);
	}

	/* Define image parameters */
	image.width = 1024;
	image.height = 1024;
	image.lambda = ph_en_to_lambda(eV_to_J(1790.0));  /* Wavelength */
	cell = load_cell_from_pdb("molecule.pdb");

	#include "geometry-lcls.tmp"

	powder = calloc(image.width*image.height, sizeof(*powder));

	/* Splurge a few useful numbers */
	STATUS("Wavelength is %f nm\n", image.lambda/1.0e-9);

	do {

		int na, nb, nc;
		double a, b, c, d;

		//na = 8*random()/RAND_MAX + 4;
		//nb = 8*random()/RAND_MAX + 4;
		//nc = 16*random()/RAND_MAX + 30;
		na = 24;
		nb = 24;
		nc = 40;

		/* Read quaternion from stdin */
		if ( config_randomquat ) {
			image.orientation = random_quaternion();
		} else {
			image.orientation = read_quaternion();
		}

		STATUS("Orientation is %5.3f %5.3f %5.3f %5.3f\n",
		       image.orientation.w, image.orientation.x,
		       image.orientation.y, image.orientation.z);

		if ( !quaternion_valid(image.orientation) ) {
			ERROR("Orientation modulus is not zero!\n");
			return 1;
		}

		/* Ensure no residual information */
		image.data = NULL;
		image.twotheta = NULL;

		cell_get_parameters(cell, &a, &b, &c, &d, &d, &d);
		STATUS("Particle size = %i x %i x %i (=%5.2f x %5.2f x %5.2f nm)\n",
	               na, nb, nc, na*a/1.0e-9, nb*b/1.0e-9, nc*c/1.0e-9);

		if ( config_gpu ) {
			if ( gctx == NULL ) {
				gctx = setup_gpu(config_nosfac, &image,
				                 intensities);
			}
			get_diffraction_gpu(gctx, &image, na, nb, nc, cell);
		} else {
			get_diffraction(&image, na, nb, nc, intensities, cell,
			                !config_nowater);
		}
		if ( image.data == NULL ) {
			ERROR("Diffraction calculation failed.\n");
			goto skip;
		}

		record_image(&image, !config_nonoise);

		if ( config_nearbragg ) {
			output_intensities(&image, cell);
		}

		if ( config_powder ) {

			int x, y, w;

			w = image.width;

			for ( x=0; x<image.width; x++ ) {
			for ( y=0; y<image.height; y++ ) {
				powder[x+w*y] += (double)image.data[x+w*y];
			}
			}

			if ( !(ndone % 10) ) {
				hdf5_write("results/integr.h5", powder,
				           image.width, image.height,
				           H5T_NATIVE_DOUBLE);
			}
		}

		if ( !config_noimages ) {

			char filename[1024];

			snprintf(filename, 1023, "results/sim-%i.h5", number);
			number++;

			/* Write the output file */
			hdf5_write(filename, image.data,
			           image.width, image.height, H5T_NATIVE_FLOAT);

		}

		/* Clean up */
		free(image.data);
		free(image.twotheta);

skip:
		ndone++;

		if ( n_images && (ndone >= n_images) ) done = 1;

	} while ( !done );

	if ( gctx != NULL ) {
		cleanup_gpu(gctx);
	}

	free(image.det.panels);
	free(powder);
	free(cell);
	free(intensities);

	return 0;
}