/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 "ultima/nuvie/core/nuvie_defs.h"
#include "ultima/nuvie/misc/u6_misc.h"
#include "ultima/nuvie/files/u6_lzw.h"
#include "ultima/nuvie/files/u6_lib_n.h"
#include "ultima/nuvie/files/nuvie_io.h"
#include "ultima/nuvie/files/u6_shape.h"
#include "common/endian.h"

namespace Ultima {
namespace Nuvie {

/*
 * Structure of shape file:
 * ========================
 *
 *      -> means input from file
 *      <- means storing pixel data
 *
 * .shp files are lzw compressed. After decompressing the file represents
 * following structure: -> file size (dword)
 *                      -> set of offsets (each word)
 *          -> set of shapes
 *
 * File size should be quite clear.
 *
 * Offsets are stored as unsigned words. The first offset in file is the
 * offset of the first object (simple, huh?). The number of offsets (objects)
 * in the file can be calculated as follows:
 *                      num_objects = (1st offset - 4) / 4.
 *
 * Frame structure:     -> num of pixels right from hot spot, X1 (word)
 *                      -> num of pixels left from hot spot, X2 (word)
 *                      -> num of pixels above hot spot, Y1 (word)
 *                      -> num of pixels below hot spot, Y2 (word)
 *                      -> set of pixel blocks
 *
 * The width of the shape can be calculated by adding X1 and X2 together and
 * height by adding Y1 and Y2 together. Coordinates for hot spot are X2 and Y1.
 *
 * Now the data it self is stored in pixel blocks which are quite complex:
 *                      -> number of pixels or repeats, num1 (word)
 *                      if (num1 and 1)
 *                         repeat num1 >> 1 times
 *                            -> temp value (unsigned byte)
 *                            if (temp value and 1)
 *                               -> pixel
 *                               <- store pixel temp value >> 1 times
 *                            else
 *                               <- read temp value >> 1 bytes
 *                         end
 *                     else
 *                         <- read num >> 1 bytes
 *
 * Color number 255 seems to be transperent.
 *
 * I hope this clears things up a bit.
 */


/*
 * =====================
 *  U6Shape::U6Shape();
 * =====================
 *
 * Just intializes all structures to 0.
 */
U6Shape::U6Shape() : raw(nullptr), hotx(0), hoty(0), width(0), height(0) {
}

/*
 * ======================
 *  U6Shape::~U6Shape();
 * ======================
 *
 * Frees all memory allocated by this instance of U6Shape class.
 */
U6Shape::~U6Shape(void) {
	if (raw)
		free(raw);
}

bool U6Shape::init(uint16 w, uint16 h, uint16 hx, uint16 hy) {
	width = w;
	height = h;
	hotx = hx;
	hoty = hy;
	raw = (uint8 *)malloc(width * height);

	if (raw == nullptr) {
		DEBUG(0, LEVEL_ERROR, "malloc failed to allocate space for shape\n");
		return false;
	}

	memset(raw, 0xff, width * height);

	return true;
}

bool U6Shape::load(const Common::Path &filename) {
	return false;
}

bool U6Shape::load(U6Lib_n *file, uint32 index) {
	unsigned char *buf = file->get_item(index);
	if (buf != nullptr) {
		if (load(buf)) {
			free(buf);
			return true;
		} else
			free(buf);
	}

	return false;
}

bool U6Shape::load_from_lzc(const Common::Path &filename, uint32 idx, uint32 sub_idx) {
	U6Lib_n lib_n;

	if (!lib_n.open(filename, 4, NUVIE_GAME_MD)) {
		return false;
	}

	if (idx >= lib_n.get_num_items()) {
		return false;
	}

	unsigned char *buf = lib_n.get_item(idx, nullptr);
	NuvieIOBuffer io;
	io.open(buf, lib_n.get_item_size(idx), false);
	U6Lib_n lib1;
	lib1.open(&io, 4, NUVIE_GAME_MD);

	if (sub_idx >= lib1.get_num_items()) {
		return false;
	}

	if (load(&lib1, (uint32)sub_idx)) {
		free(buf);
		return true;
	}

	free(buf);
	return false;
}

/*
 * =========================================
 *  bool U6Shape::load(unsigned char *buf);
 * =========================================
 *
 * Loads shape from buf
 * Returns true if successful, else returns false.
 */
bool U6Shape::load(unsigned char *buf) {
	/* A file already loaded. */
	if (raw != nullptr)
		return false;
	/* NOT REACHED */

	unsigned char *data = buf;

	/* Size and hot point. */
	width = READ_LE_UINT16(data);
	data += 2;
	width += hotx = READ_LE_UINT16(data);
	data += 2;

	height = hoty = READ_LE_UINT16(data);
	data += 2;
	height += READ_LE_UINT16(data);
	data += 2;

	width++;
	height++;

	/* Allocate memory for shape and make it all transperent. */
	raw = (unsigned char *)malloc(width * height);
	if (raw == nullptr) {
		DEBUG(0, LEVEL_ERROR, "malloc failed to allocate space for shape\n");
		return false;
	}
	memset(raw, 255, width * height);

	/* Get the pixel data. */
	uint16 num_pixels;
	while ((num_pixels = READ_LE_UINT16(data)) != 0) {

		data += 2;

		/* Coordinates relative to hot spot. */
		sint16 xpos = READ_LE_UINT16(data);
		data += 2;
		sint16 ypos = READ_LE_UINT16(data);
		data += 2;

		if (((hotx + xpos) >= width) || ((hoty + ypos) >= height)) {
			break;
		}
		/*
		 * Test if this block of pixels is encoded
		 * (bit0 is set).
		 */
		int encoded = num_pixels & 1;

		/* Divide it by 2. */
		num_pixels >>= 1;

		/* Normal pixel:
		 * =============
		 *
		 * Just fetch as many pixels as num_pixels suggests.
		 */
		if (!encoded) {
			memcpy(raw + (hotx + xpos) +
			       (hoty + ypos) * width, data, num_pixels);
			data += num_pixels;

			continue;
			/* NOT REACHED */
		}

		/* Encoded pixel:
		 * ==============
		 *
		 * Do as many repeats as num_pixels suggests.
		 */
		for (int j = 0; j < num_pixels;) {
			unsigned char num_pixels2 = *data++;
			int repeat = num_pixels2 & 1;

			num_pixels2 >>= 1;

			/*
			 * Repeat pixel value (data + 1) num_pixels2
			 * times.
			 */
			if (repeat) {
				memset(raw + (hotx + xpos) +
				       (hoty + ypos) * width + j,
				       *data++, num_pixels2);
			}


			/*
			 * Just fetch as many pixels as num_pixels2
			 * suggests.
			 */
			else {
				memcpy(raw + (hotx + xpos) +
				       (hoty + ypos) * width + j, data,
				       num_pixels2);
				data += num_pixels2;
			}
			j += num_pixels2;
		}

	}

	return true;
}

// TODO - allow for failure
bool U6Shape::load_WoU_background(const Configuration *config, nuvie_game_t game_type) {
	U6Lib_n file;
	Common::Path filename;

	if (game_type == NUVIE_GAME_MD)
		config_get_path(config, "mdscreen.lzc", filename);
	else // SE
		config_get_path(config, "screen.lzc", filename);

	file.open(filename, 4, game_type);
	unsigned char *temp_buf = file.get_item(0);
	load(temp_buf + 8);
	free(temp_buf);
	return true;
}

/*
 * =====================================
 *  unsigned char *U6Shape::get_data();
 * =====================================
 *
 * Returns raw data representing the shape or nullptr on failure.
 */
const unsigned char *U6Shape::get_data() const {
	return raw;
}

unsigned char *U6Shape::get_data() {
	return raw;
}

/*
 * ============================================
 *  Graphics::ManagedSurface *U6Shape::get_shape_surface();
 * ============================================
 *
 * Returns a Graphics::ManagedSurface representing the shape
 * or nullptr on failure. NOTE! user must free this
 * data.
 */
Graphics::ManagedSurface *U6Shape::get_shape_surface() {
	if (raw == nullptr)
		return nullptr;

	// Create the surface
	Graphics::ManagedSurface *surface = new Graphics::ManagedSurface(width, height,
		Graphics::PixelFormat::createFormatCLUT8());

	// Copy the raw pixels into it
	byte *dest = (byte *)surface->getPixels();
	Common::copy(raw, raw + width * height, dest);

	return surface;
}

/*
 * ====================================================
 *  bool U6Shape::get_hot_point(uint16 *x, uint16 *y);
 * ====================================================
 *
 * Puts the coordinates of the shape in x and y and
 * returns true or on failure just returns false.
 */
bool U6Shape::get_hot_point(uint16 *x, uint16 *y) {
	if (raw == nullptr)
		return false;
	/* NOT REACHED */

	*x = hotx;
	*y = hoty;

	return true;
}

/*
 * ===============================================
 *  bool U6Shape::get_size(uint16 *w, uint16 *h);
 * ===============================================
 *
 * Puts the size of the shape in w and h and
 * returns true or on failure just returns false.
 */
bool U6Shape::get_size(uint16 *w, uint16 *h) {
	if (raw == nullptr)
		return false;
	/* NOT REACHED */

	*w = width;
	*h = height;

	return true;
}

void U6Shape::draw_line(uint16 sx, uint16 sy, uint16 ex, uint16 ey, uint8 color) {
	if (raw == nullptr)
		return;

	draw_line_8bit(sx, sy, ex, ey, color, raw, width, height);
}

bool U6Shape::blit(U6Shape *shp, uint16 x, uint16 y) {
	if (shp == nullptr)
		return false;

	const unsigned char *src_data = shp->get_data();
	uint16 src_w = 0, src_h = 0;

	shp->get_size(&src_w, &src_h);

	if (x + src_w > width || y + src_h > height)
		return false;

	for (int i = 0; i < src_h; i++) {
		memcpy(&raw[x + y * width + i * width], &src_data[i * src_w], src_w);
	}

	return true;
}

void U6Shape::fill(uint8 color) {
	memset(raw, color, width * height);
}

} // End of namespace Nuvie
} // End of namespace Ultima