/*
# This file is part of the Astrometry.net suite.
# Licensed under a 3-clause BSD style license - see LICENSE
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <math.h>

#include "tycho2-fits.h"
#include "starutil.h"
#include "mathutil.h"
#include "an-endian.h"

#define OPTIONS "ho:"

static void print_help(char* progname) {
    printf("usage:\n"
		   "  %s -o <output-filename>\n"
		   "  <input-file> [<input-file> ...]\n\n"
		   "Input files must be Tycho-2 FITS files.\n"
		   "Output file will be in Stellarium format.\n\n",
		   progname);
}

static int write_32(FILE* fout, void* p) {
	if (fwrite(p, 1, 4, fout) != 4) {
		fprintf(stderr, "Failed to write 32-bit quantity: %s\n", strerror(errno));
		return -1;
	}
	return 0;
}
static int write_16(FILE* fout, void* p) {
	if (fwrite(p, 1, 2, fout) != 2) {
		fprintf(stderr, "Failed to write 16-bit quantity: %s\n", strerror(errno));
		return -1;
	}
	return 0;
}
static int write_8(FILE* fout, void* p) {
	if (fwrite(p, 1, 1, fout) != 1) {
		fprintf(stderr, "Failed to write 8-bit quantity: %s\n", strerror(errno));
		return -1;
	}
	return 0;
}


int main(int argc, char** args) {
	char* outfn = NULL;
	int c;
	int startoptind;
	FILE* fout;

    while ((c = getopt(argc, args, OPTIONS)) != -1) {
        switch (c) {
		case '?':
        case 'h':
			print_help(args[0]);
			exit(0);
		case 'o':
			outfn = optarg;
			break;
		}
    }

	if (!outfn || (optind == argc)) {
		print_help(args[0]);
		exit(-1);
	}

	fout = fopen(outfn, "wb");
	if (!fout) {
		fprintf(stderr, "Failed to open output file: %s\n", strerror(errno));
		exit(-1);
	}

	//qfits_err_register(qfits_dispfn);
	//qfits_err_statset(1);

	startoptind = optind;
	for (; optind<argc; optind++) {
		tycho2_fits* tycho = NULL;
		qfits_header* hdr;
		anbool is_tycho = FALSE;
		int i, N;
		uint32_t ui;
		char* infn;

		infn = args[optind];
		printf("Opening catalog file %s...\n", infn);
		hdr = qfits_header_read(infn);
		if (!hdr) {
			fprintf(stderr, "Couldn't read FITS header in file %s.\n", infn);
			exit(-1);
		}
		is_tycho = qfits_header_getboolean(hdr, "TYCHO_2", 0);
		if (!is_tycho) {
			fprintf(stderr, "File %s doesn't have TYCHO_2 FITS header.  Skipping file.\n", infn);
			continue;
		}
		tycho = tycho2_fits_open(infn);
		if (!tycho) {
			fprintf(stderr, "Couldn't open Tycho-2 catalog: %s\n", infn);
			exit(-1);
		}

		N = tycho2_fits_count_entries(tycho);

		fprintf(stderr, "Reading %i entries...\n", N);

		// Stellarium header: how many stars in the catalog
		// (32-bit uint).
		ui = u32_htole(N);
		if (write_32(fout, &ui)) exit(-1);

		for (i=0; i<N; i++) {
			tycho2_entry* e;
			float ra, dec, distance, mag;
			int nmag;
			int tmpmag;
			uint16_t imag;
			uint8_t type;

			e = tycho2_fits_read_entry(tycho);
			if (!e) {
				fprintf(stderr, "Failed to read a Tycho-2 entry.\n");
				exit(-1);
			}

			ra = e->RA;
			dec = e->DEC;
			// just avg the available magnitudes.
			nmag = 0;
			mag = 0.0;
			// in Tycho-2, mag 0.0 means it's unavailable.
			if (e->mag_BT != 0.0) {
				mag += e->mag_BT;
				nmag++;
			}
			if (e->mag_VT != 0.0) {
				mag += e->mag_VT;
				nmag++;
			}
			if (e->mag_HP != 0.0) {
				mag += e->mag_HP;
				nmag++;
			}
			if (nmag)
				mag /= (float)nmag;

			// ra: degrees -> hours
			ra *= 24.0 / 360.0;
			// dec: degrees -> degrees
			// imag: 256 * mag - 5

			// distance info isn't in Tycho-2.
			distance = 1.0;

			tmpmag = (int)rint(256.0 * mag);
			if (tmpmag < 0)
				tmpmag += 0x10000;
			imag = tmpmag;

			//type = 12; // "other"
			type = 0; // "other"

            v32_htole(&ra);
            v32_htole(&dec);
            v16_htole(&imag);
            v32_htole(&distance);

			write_32(fout, &ra);
			write_32(fout, &dec);
			write_16(fout, &imag);
			write_8 (fout, &type);
			write_32(fout, &distance);

		}
		tycho2_fits_close(tycho);
	}

	if (fclose(fout)) {
		fprintf(stderr, "Failed to close output file: %s\n", strerror(errno));
		exit(-1);
	}

	return 0;
}