/*
 *  2ooM: The Master of Orion II Reverse Engineering Project
 *  Simple command-line tool to convert an LBX image to other formats.
 *  Copyright © 2006-2011, 2013-2014, 2021 Nick Bowler
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <limits.h>
#include <stdint.h>
#include <assert.h>
#include <getopt.h>
#include <errno.h>

#include "help.h"

#include "tools.h"
#include "image.h"
#include "error.h"
#include "lbx.h"

#include "imgoutput.h"

#define MIN(a, b) ((a) < (b) ? (a) : (b))

/* Global flags */
static int verbose = 0;
static char *outname = "out";
static int usepalette = 1;

#include "imgopts.h"
static const char sopts[] = SOPT_STRING;
static const struct option lopts[] = { LOPTS_INITIALIZER, {0} };

static void print_usage(FILE *f)
{
	const char *progname = tool_invocation();

	fprintf(f, "Usage: %s [options] [-i|-d] [frame ...]\n", progname);
	if (f != stdout)
		fprintf(f, "Try %s --help for more information.\n", progname);
}

static void print_help(void)
{
	const struct option *opt;

	print_usage(stdout);

	putchar('\n');
	puts("Options:");
	for (opt = lopts; opt->name; opt++) {
		struct lopt_help help;
		int w;

		if (!lopt_get_help(opt, &help))
			continue;

		help_print_option(opt, help.arg, help.desc, 20);
	}
	putchar('\n');

	puts("For more information, see the lbximg(1) man page.");
	putchar('\n');

	printf("Report bugs to <%s>.\n", PACKAGE_BUGREPORT);
}

enum {
	MODE_NONE,
	MODE_DECODE,
	MODE_IDENT,
};

static const struct img_format {
	img_output_func *output;
	char name[4];
	bool enabled;
} formats[] = {
#if HAVE_LIBPNG
	{ img_output_png, "png", 1 },
#endif
	{ img_output_pam, "pam", 1 },
	{ img_output_ppm, "ppm", 1 },
	{ img_output_pbm, "pbm", 1 },
};

static int lookup_format(const char *fmt)
{
	for (size_t i = 0; i < sizeof formats / sizeof formats[0]; i++) {
		assert(!formats[i].name[sizeof formats[i].name - 1]);

		if (!fmt && formats[i].enabled)
			return i;

		if (strcmp(formats[i].name, fmt))
			continue;

		if (!formats[i].enabled) {
			tool_err(-1, "%s support disabled at build time", fmt);
			return -1;
		}

		return i;
	}

	tool_err(-1, "unknown format %s", fmt);
	return -1;
}

bool img_is_masked(unsigned char *mask, unsigned width, unsigned height)
{
	unsigned long npixels = (unsigned long) width * height;
	unsigned long mask_sz = npixels / CHAR_BIT + (npixels % CHAR_BIT != 0);

	for (unsigned long i = 0; i < mask_sz; i++) {
		if (i+1 < mask_sz) {
			if (mask[i] != (unsigned char)-1)
				return true;
		} else {
			unsigned char test = (1u << npixels % CHAR_BIT) - 1;

			if ((mask[i] & test) != test)
				return true;
		}
	}

	return false;
}

int parserange(unsigned frames, char *str, unsigned char *bits)
{
	unsigned long start, end;
	unsigned int i;
	char *endptr;

	start = strtoul(str, &endptr, 0);
	if (start >= frames) {
		tool_err(-1, "frame %lu out of range.", start);
		return -1;
	}

	if (endptr == str) {
		tool_err(-1, "invalid frame range: %s.", str);
		return -1;
	}

	switch (*endptr) {
	case '\0':
		end = start;
		break;
	case '-':
		end = strtoul(endptr+1, &endptr, 0);
		if (end >= frames) {
			tool_err(-1, "frame %lu out of range.", end);
			return -1;
		}

		if (endptr == str)
			end = frames - 1;
		break;
	default:
		tool_err(-1, "invalid frame range: %s.", str);
		return -1;
	}

	if (end < start) {
		tool_err(-1, "invalid frame range: %s.", str);
		return -1;
	}

	for (i = start; i <= end; i++) {
		bits[i / CHAR_BIT] |= 1 << (i % CHAR_BIT);
	}

	return 0;
}

static int output(unsigned int frameno, const struct img_format *fmt,
                  unsigned char *pixels, unsigned char *pixel_mask,
                  unsigned int width, unsigned int height,
                  struct lbx_colour *palette)
{
	char name[strlen(outname) + sizeof ".65535.png"];
	FILE *of;
	int rc;

	assert(fmt->output != NULL);
	assert(frameno < 65536);
	snprintf(name, sizeof name, "%s.%03d.%s", outname, frameno, fmt->name);

	of = fopen(name, "wb");
	if (!of) {
		tool_err(0, "failed to open %s", name);
		return -1;
	}

	rc = fmt->output(of, name, width, height, pixels, pixel_mask, palette);
	if (rc < 0) {
		fclose(of);
		return -1;
	}

	if (fclose(of) == EOF) {
		tool_err(0, "error writing %s", name);
		return -1;
	}

	if (verbose)
		printf("wrote %s\n", name);

	return 0;
}

static int loadoverride(FILE *f, struct lbx_colour *palette)
{
	struct lbx_image *img;
	int rc, ret = 0;

	img = lbx_img_open(f, &lbx_default_fops, NULL);
	if (!img) {
		tool_err(-1, "failed to open override image: %s", lbx_errmsg());
		return -1;
	}

	rc = lbx_img_getpalette(img, palette);
	if (rc < 0) {
		tool_err(-1, "error reading override palette: %s", lbx_errmsg());
		ret = -1;
	} else if (rc == 0) {
		tool_err(-1, "override image has no palette.");
		ret = -1;
	}

	lbx_img_close(img);
	return ret;
}

static int loadpalette(struct lbx_image *img, FILE *palf, FILE *override,
                       struct lbx_colour *palette)
{
	int rc, ret = -1;

	/* Default the palette to a wonderful pink. */
	for (unsigned i = 0; i < 256; i++) {
		palette[i] = (struct lbx_colour){0x3f, 0x00, 0x3f};
	}

	/* Read the external palette, if any. */
	if (palf) {
		rc = lbx_img_loadpalette(palf, &lbx_default_fops, palette);
		if (rc < 0) {
			tool_err(-1, "error reading external palette: %s", lbx_errmsg());
			return -1;
		}

		ret = 0;
	}

	/* Read the embedded palette */
	rc = lbx_img_getpalette(img, palette);
	if (rc < 0) {
		tool_err(-1, "error reading embedded palette: %s", lbx_errmsg());
		return -1;
	} else if (rc > 0) {
		ret = 0;
	}

	/* Read the override palette, if any. */
	if (override) {
		rc = loadoverride(override, palette);
		if (rc < 0)
			return -1;
		ret = 0;
	}

	/* If we literally have no palette data at all, may as well fail. */
	if (ret < 0)
		tool_err(-1, "no palette available.");
	return ret;
}

/* Return true iff a divides b. */
static bool divides(unsigned a, unsigned b)
{
	if (b == 0)
		return true;
	if (a == 0)
		return false;

	return b % a == 0;
}

/* Set n bits starting from offset in the bitmap. */
static void
set_bits(unsigned char *bitmap, unsigned long offset, unsigned long n)
{
	if (offset % CHAR_BIT) {
		bitmap[offset/CHAR_BIT] |= (n >= CHAR_BIT ? -1u : (1u << n) - 1)
	                          << offset%CHAR_BIT;

		n -= MIN(n, CHAR_BIT - offset%CHAR_BIT);
		offset += CHAR_BIT - offset%CHAR_BIT;
	}

	if (n > CHAR_BIT) {
		memset(&bitmap[offset/CHAR_BIT], -1, n/CHAR_BIT);

		offset += n - n%CHAR_BIT;
		n %= CHAR_BIT;
	}

	if (n) {
		bitmap[offset/CHAR_BIT] |= (1u << n) - 1;
	}
}

static int decode_frame(struct lbx_image *img, unsigned n,
                        unsigned char *pixels, unsigned char *pixel_mask)
{
	unsigned x, y;
	long rc;

	rc = lbx_img_seek(img, n);
	if (rc < 0) {
		tool_err(-1, "frame %u: invalid frame: %s\n", n, lbx_errmsg());
		return -1;
	}

	while ((rc = lbx_img_read_row_header(img, &x, &y)) != 0) {
		unsigned long offset;

		if (rc < 0) {
			tool_err(-1, "frame %u: invalid row: %s", n, lbx_errmsg());
			return -1;
		}

		offset = (unsigned long) y * img->width + x;
		rc = lbx_img_read_row_data(img, pixels+offset);
		if (rc < 0) {
			tool_err(-1, "frame %u: error reading row: %s\n", n, lbx_errmsg());
			return -1;
		}

		set_bits(pixel_mask, offset, rc);
	}

	return 0;
}

static int
decode(struct lbx_image *img, FILE *palf, FILE *override, int fmt, char **argv)
{
	unsigned char *pixels = NULL, *pixel_mask = NULL, *framebits = NULL;
	struct lbx_colour palette[256];
	int rc, ret = EXIT_FAILURE;
	int extracted = 0;
	unsigned int i;
	size_t npixels, mask_sz;

	assert(fmt >= 0 && fmt < sizeof formats / sizeof formats[0]);

	npixels = img->width;
	if (img->height && npixels >= (size_t)-1 / img->height) {
		tool_err(-1, "image too large");
		goto err;
	}
	npixels *= img->height;

	/* Ensure there is at least 1 byte to allocate */
	if (npixels == 0)
		npixels = 1;

	framebits = calloc(1, img->frames / CHAR_BIT + 1);
	if (!framebits) {
		tool_err(0, "failed to allocate memory");
		goto err;
	}

	pixels = calloc(img->width, img->height);
	if (!pixels) {
		tool_err(0, "failed to allocate memory");
		goto err;
	}

	mask_sz = npixels / CHAR_BIT + (npixels % CHAR_BIT != 0);
	pixel_mask = malloc(mask_sz);
	if (!pixel_mask) {
		tool_err(0, "failed to allocate memory");
		goto err;
	}

	/* Figure out what images we're extracting. */
	if (!argv[0]) {
		/* extract all images by default. */
		memset(framebits, -1, img->frames / CHAR_BIT + 1);
	} else {
		for (i = 0; argv[i]; i++) {
			parserange(img->frames, argv[i], framebits);
		}
	}

	if (usepalette) {
		if (loadpalette(img, palf, override, palette) == -1) {
			ret = EXIT_FAILURE;
			goto err;
		}
	}

	/* Extract the images, in order. */
	ret = EXIT_SUCCESS;
	for (i = 0; i < img->frames; i++) {
		if (divides(img->chunk, i))
			memset(pixel_mask, 0, mask_sz);

		rc = decode_frame(img, i, pixels, pixel_mask);
		if (rc < 0) {
			ret = EXIT_FAILURE;
			goto err;
		}

		if (framebits[i / CHAR_BIT] & (1u << (i % CHAR_BIT))) {
			rc = output(i, &formats[fmt], pixels, pixel_mask,
			            img->width, img->height,
				    usepalette ? palette : NULL);

			if (rc == 0) {
				extracted = 1;
			}
		}
	}

	if (!extracted) {
		tool_err(-1, "no frames extracted.");
		ret = EXIT_FAILURE;
	}
err:
	free(pixels);
	free(pixel_mask);
	free(framebits);
	return ret;
}

int main(int argc, char **argv)
{
	int mode = MODE_NONE, fmt, opt, rc = EXIT_FAILURE;
	struct lbx_pipe_state stdin_handle = { .f = stdin };
	const char *file = NULL, *fmtstring = NULL;
	const char *ext_palette = NULL, *ovr_palette = NULL;
	FILE *palf = NULL, *overf = NULL;
	struct lbx_image *img;

	tool_init("lbximg", argc, argv);
	while ((opt = getopt_long(argc, argv, sopts, lopts, NULL)) != -1) {
		switch(opt) {
		case 'i':
			mode = MODE_IDENT;
			break;
		case 'd':
			mode = MODE_DECODE;
			break;
		case 'v':
			verbose = 1;
			break;
		case 'F':
			fmtstring = optarg;
			break;
		case 'f':
			file = optarg;
			break;
		case 'n':
			usepalette = 0;
			break;
		case 'p':
			ext_palette = optarg;

			break;
		case 'O':
			ovr_palette = optarg;
			break;
		case LOPT_OUTPUT_PREFIX:
			outname = optarg;
			break;
		case 'V':
			tool_version();
			return EXIT_SUCCESS;
		case 'H':
			print_help();
			return EXIT_SUCCESS;
		default:
			return EXIT_FAILURE;
		}
	}

	if (mode == MODE_NONE) {
		tool_err(-1, "you must specify a mode.");
		return EXIT_FAILURE;
	}

	fmt = lookup_format(fmtstring);
	if (fmt < 0)
		return EXIT_FAILURE;

	if (file)
		img = lbx_img_fopen(file);
	else
		img = lbx_img_open(&stdin_handle, &lbx_pipe_fops, NULL);

	if (!img) {
		tool_err(-1, "failed to open image: %s.", lbx_errmsg());
		return EXIT_FAILURE;
	}

	if (ext_palette && !(palf = fopen(ext_palette, "rb"))) {
		tool_err(0, "failed to open %s", optarg);
		return EXIT_FAILURE;
	}

	if (ovr_palette && !(overf = fopen(ovr_palette, "rb"))) {
		tool_err(0, "failed to open %s", optarg);
		return EXIT_FAILURE;
	}

	if (verbose || mode == MODE_IDENT) {
		int palette_count;

		if (!file)
			file = "stdin";

		palette_count = lbx_img_getpalette(img, NULL);
		if (palette_count < 0) {
			tool_err(-1, "error reading image: %s", lbx_errmsg());
			return EXIT_FAILURE;
		}

		printf("%s is %hux%hu LBX image, %hhu frame(s)%s%s%s\n",
		       file, img->width, img->height, img->frames,
		       palette_count ? ", embedded palette" : "",
		       img->chunk    ? ", chunked" : "",
		       img->leadin+1 < img->frames ? ", loops" : "");
	}

	switch (mode) {
	case MODE_IDENT:
		rc = 0;
		break;
	case MODE_DECODE:
		rc = decode(img, palf, overf, fmt, &argv[optind]);
		break;
	}

	lbx_img_close(img);
	if (palf)
		fclose(palf);
	if (overf)
		fclose(overf);
	return rc;
}