/* ScummVM - Scumm Interpreter
 * Copyright (C) 2004 The ScummVM project
 *
 * The ReInherit Engine is (C)2000-2003 by Daniel Balsom.
 *
 * 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 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 General Public License for more details.

 * You should have received a copy of the GNU 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.
 *
 * $Header$
 *
 */

// Object map / Object click-area module 

// Polygon Hit Test code ( HitTestPoly() ) adapted from code (C) Eric Haines
// appearing in Graphics Gems IV, "Point in Polygon Strategies."
// p. 24-46, code: p. 34-45
#include "saga/saga.h"

#include "saga/gfx.h"
#include "saga/cvar_mod.h"
#include "saga/console.h"
#include "saga/font.h"
#include "saga/objectmap.h"

namespace Saga {

// Initializes the object map module, creates module allocation context
ObjectMap::ObjectMap(SagaEngine *vm) : _vm(vm) {
	_objectsLoaded = false;
	_namesLoaded = false;
}

// Shuts down the object map module, destroys module allocation context
ObjectMap::~ObjectMap() {
	freeMem();
	freeNames();
}

// Loads an object map resource ( objects ( clickareas ( points ) ) ) 
int ObjectMap::load(const byte *om_res, size_t om_res_len) {
	R_OBJECTMAP_ENTRY *object_map;
	R_CLICKAREA *clickarea;
	Point *point;

	int i, k, m;

	MemoryReadStream readS(om_res, om_res_len);

	if (_objectsLoaded) {
		freeMem();
	}

	// Obtain object count N and allocate space for N objects
	_nObjects = readS.readUint16LE();

	_objectMaps = (R_OBJECTMAP_ENTRY *)malloc(_nObjects * sizeof *_objectMaps);

	if (_objectMaps == NULL) {
		warning("Error: Memory allocation failed");
		return R_MEM;
	}

	// Load all N objects
	for (i = 0; i < _nObjects; i++) {
		object_map = &_objectMaps[i];
		object_map->flags = readS.readByte();
		object_map->nClickareas = readS.readByte();
		object_map->defaultVerb = readS.readByte();
		readS.readByte();
		object_map->objectNum = readS.readUint16LE();
		object_map->scriptNum = readS.readUint16LE();
		object_map->clickareas = (R_CLICKAREA *)malloc(object_map->nClickareas * sizeof *(object_map->clickareas));

		if (object_map->clickareas == NULL) {
			warning("Error: Memory allocation failed");
			return R_MEM;
		}

		// Load all clickareas for this object
		for (k = 0; k < object_map->nClickareas; k++) {
			clickarea = &object_map->clickareas[k];
			clickarea->n_points = readS.readUint16LE();
			assert(clickarea->n_points != 0);

			clickarea->points = (Point *)malloc(clickarea->n_points * sizeof *(clickarea->points));
			if (clickarea->points == NULL) {
				warning("Error: Memory allocation failed");
				return R_MEM;
			}

			// Load all points for this clickarea
			for (m = 0; m < clickarea->n_points; m++) {
				point = &clickarea->points[m];
				point->x = readS.readSint16LE();
				point->y = readS.readSint16LE();
			}
			debug(2, "ObjectMap::load(): Read %d points for clickarea %d in object %d.",
					clickarea->n_points, k, object_map->objectNum);
		}
	}

	_objectsLoaded = true;

	return R_SUCCESS;
}

// Frees all storage allocated for the current object map data
int ObjectMap::freeMem() {
	R_OBJECTMAP_ENTRY *object_map;
	R_CLICKAREA *clickarea;

	int i, k;

	if (!_objectsLoaded) {
		return R_FAILURE;
	}

	for (i = 0; i < _nObjects; i++) {
		object_map = &_objectMaps[i];
		for (k = 0; k < object_map->nClickareas; k++) {
			clickarea = &object_map->clickareas[k];
			free(clickarea->points);
		}
		free(object_map->clickareas);
	}

	if (_nObjects) {
		free(_objectMaps);
	}

	_objectsLoaded = false;

	return R_SUCCESS;
}

// Loads an object name list resource
int ObjectMap::loadNames(const unsigned char *onl_res, size_t onl_res_len) {
	int table_len;
	int n_names;
	size_t name_offset;

	int i;

	MemoryReadStream readS(onl_res, onl_res_len);

	if (_namesLoaded) {
		freeNames();
	}

	table_len = readS.readUint16LE();

	n_names = table_len / 2 - 2;
	_nNames = n_names;

	debug(2, "ObjectMap::loadNames: Loading %d object names.", n_names);
	_names = (const char **)malloc(n_names * sizeof *_names);

	if (_names == NULL) {
		warning("Error: Memory allocation failed");
		return R_MEM;
	}

	for (i = 0; i < n_names; i++) {
		name_offset = readS.readUint16LE();
		_names[i] = (const char *)(onl_res + name_offset);

		debug(3, "Loaded object name string: %s", _names[i]);
	}

	_namesLoaded = true;

	return R_SUCCESS;
}

// Frees all storage allocated for the current object name list data
int ObjectMap::freeNames() {
	if (!_namesLoaded) {
		return R_FAILURE;
	}

	if (_nNames) {
		free(_names);
	}

	_namesLoaded = false;
	return R_SUCCESS;
}

// If 'object' is a valid object number in the currently loaded object 
// name list resource, the funciton sets '*name' to the descriptive string
// corresponding to 'object' and returns R_SUCCESS. Otherwise it returns
// R_FAILURE.
const char *ObjectMap::getName(int object) {
	assert(_namesLoaded);
	assert((object > 0) && (object <= _nNames));

	return _names[object - 1];
}

const uint16 ObjectMap::getFlags(int object) {
	int i;

	assert(_namesLoaded);
	assert((object > 0) && (object <= _nNames));

	for (i = 0; i < _nObjects; i++) {
		if (_objectMaps[i].objectNum == object) {
			return _objectMaps[i].flags;
		}
	}

	return 0;
}

// If 'object' is a valid object number in the currently loaded object 
// name list resource, the funciton sets '*ep_num' to the entrypoint number
// corresponding to 'object' and returns R_SUCCESS. Otherwise, it returns
// R_FAILURE.
const int ObjectMap::getEPNum(int object) {
	int i;

	assert(_namesLoaded);

	if ((object < 0) || (object > (_nObjects + 1)))
		return -1;

	for (i = 0; i < _nObjects; i++)
		if (_objectMaps[i].objectNum == object)
			return _objectMaps[i].scriptNum;

	return -1;
}

// Uses Gfx::drawLine to display all clickareas for each object in the 
// currently loaded object map resource.
int ObjectMap::draw(R_SURFACE *ds, Point *imouse_pt, int color, int color2) {
	R_OBJECTMAP_ENTRY *object_map;
	R_CLICKAREA *clickarea;

	char txt_buf[32];

	int draw_color = color;
	int draw_txt = 0;

	int hit_object = 0;
	int objectNum = 0;

	int pointcount = 0;
	int i, k;

	if (!_objectsLoaded) {
		return R_FAILURE;
	}

	if (imouse_pt != NULL) {
		if (hitTest(imouse_pt, &objectNum) == R_SUCCESS) {
			hit_object = 1;
		}
	}

	for (i = 0; i < _nObjects; i++) {
		draw_color = color;
		if (hit_object && (objectNum == _objectMaps[i].objectNum)) {
			snprintf(txt_buf, sizeof txt_buf, "obj %d: v %d, f %X",
					_objectMaps[i].objectNum,
					_objectMaps[i].defaultVerb,
					_objectMaps[i].flags);
			draw_txt = 1;
			draw_color = color2;
		}

		object_map = &_objectMaps[i];

		for (k = 0; k < object_map->nClickareas; k++) {
			clickarea = &object_map->clickareas[k];
			pointcount = 0;
			if (clickarea->n_points == 2) {
				// 2 points represent a box
				_vm->_gfx->drawFrame(ds, &clickarea->points[0], &clickarea->points[1], draw_color);
			} else if (clickarea->n_points > 2) {
				// Otherwise draw a polyline
				_vm->_gfx->drawPolyLine(ds, clickarea->points, clickarea->n_points, draw_color);
			}
		}
	}

	if (draw_txt) {
		_vm->_font->draw(SMALL_FONT_ID, ds, txt_buf, 0, 2, 2,
				_vm->_gfx->getWhite(), _vm->_gfx->getBlack(), FONT_OUTLINE);
	}

	return R_SUCCESS;
}

static bool MATH_HitTestPoly(Point *points, unsigned int npoints, Point test_point) {
	int yflag0;
	int yflag1;
	bool inside_flag = false;
	unsigned int pt;

	Point *vtx0 = &points[npoints - 1];
	Point *vtx1 = &points[0];

	yflag0 = (vtx0->y >= test_point.y);
	for (pt = 0; pt < npoints; pt++, vtx1++) {
		yflag1 = (vtx1->y >= test_point.y);
		if (yflag0 != yflag1) {
			if (((vtx1->y - test_point.y) * (vtx0->x - vtx1->x) >=
				(vtx1->x - test_point.x) * (vtx0->y - vtx1->y)) == yflag1) {
				inside_flag = !inside_flag;
			}
		}
		yflag0 = yflag1;
		vtx0 = vtx1;
	}

	return inside_flag;
}

int ObjectMap::hitTest(Point *imouse_pt, int *objectNum) {
	Point imouse;
	R_OBJECTMAP_ENTRY *object_map;
	R_CLICKAREA *clickarea;
	Point *points;
	int n_points;

	int i, k;

	assert((imouse_pt != NULL) && (objectNum != NULL));

	imouse.x = imouse_pt->x;
	imouse.y = imouse_pt->y;

	// Loop through all scene objects
	for (i = 0; i < _nObjects; i++) {
		object_map = &_objectMaps[i];

		// Hit-test all clickareas for this object
		for (k = 0; k < object_map->nClickareas; k++) {
			clickarea = &object_map->clickareas[k];
			n_points = clickarea->n_points;
			points = clickarea->points;

			if (n_points == 2) {
				// Hit-test a box region
				if ((imouse.x > points[0].x) && (imouse.x <= points[1].x) &&
					(imouse.y > points[0].y) &&
					(imouse.y <= points[1].y)) {
						*objectNum = object_map->objectNum;
						return R_SUCCESS;
				}
			} else if (n_points > 2) {
				// Hit-test a polygon
				if (MATH_HitTestPoly(points, n_points, imouse)) {
					*objectNum = object_map->objectNum;
					return R_SUCCESS;
				}
			}
		}
	}

	*objectNum = 0;

	return R_FAILURE;
}

void ObjectMap::info(void) {
	int i;

	_vm->_console->print("%d objects loaded.", _nObjects);

	for (i = 0; i < _nObjects; i++) {
		_vm->_console->print("%s:", _names[i]);
		_vm->_console->print("%d. verb: %d, flags: %X, name_i: %d, scr_n: %d, ca_ct: %d", i, 
					_objectMaps[i].defaultVerb,
					_objectMaps[i].flags,
					_objectMaps[i].objectNum,
					_objectMaps[i].scriptNum,
					_objectMaps[i].nClickareas);
	}

	return;
}

} // End of namespace Saga