/* 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 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL$
 * $Id$
 *
 */

/*
 * This code is based on Broken Sword 2.5 engine
 *
 * Copyright (c) Malte Thiesen, Daniel Queteschiner and Michael Elsdoerfer
 *
 * Licensed under GNU GPL v2
 *
 */

// -----------------------------------------------------------------------------
// Includes
// -----------------------------------------------------------------------------

#include "common/array.h"
#include "sword25/gfx/graphicengine.h"
#include "sword25/kernel/common.h"
#include "sword25/kernel/kernel.h"
#include "sword25/script/script.h"
#include "sword25/script/luabindhelper.h"

#include "sword25/math/geometry.h"
#include "sword25/math/region.h"
#include "sword25/math/regionregistry.h"
#include "sword25/math/walkregion.h"
#include "sword25/math/vertex.h"

// -----------------------------------------------------------------------------

namespace Sword25 {

// -----------------------------------------------------------------------------
// Constants
// -----------------------------------------------------------------------------

// These strings are defined as #defines to enable compile-time string composition
#define REGION_CLASS_NAME "Geo.Region"
#define WALKREGION_CLASS_NAME "Geo.WalkRegion"

// -----------------------------------------------------------------------------

// How luaL_checkudata, only without that no error is generated.
static void *my_checkudata(lua_State *L, int ud, const char *tname) {
	int top = lua_gettop(L);

	void *p = lua_touserdata(L, ud);
	if (p != NULL) { /* value is a userdata? */
		if (lua_getmetatable(L, ud)) { /* does it have a metatable? */
			// lua_getfield(L, LUA_REGISTRYINDEX, tname);  /* get correct metatable */
			BS_LuaBindhelper::GetMetatable(L, tname);
			/* does it have the correct mt? */
			if (lua_rawequal(L, -1, -2)) {
				lua_settop(L, top);
				return p;
			}
		}
	}

	lua_settop(L, top);
	return NULL;
}

// -----------------------------------------------------------------------------

static void NewUintUserData(lua_State *L, unsigned int Value) {
	void *UserData = lua_newuserdata(L, sizeof(Value));
	memcpy(UserData, &Value, sizeof(Value));
}

// -----------------------------------------------------------------------------

static bool IsValidPolygonDefinition(lua_State *L) {
#ifdef DEBUG
	int __startStackDepth = lua_gettop(L);
#endif

	// Ensure that we actually consider a table
	if (!lua_istable(L, -1)) {
		luaL_error(L, "Invalid polygon definition. Unexpected type, \"table\" needed.");
		return false;
	}

	int TableSize = luaL_getn(L, -1);

	// Make sure that there are at least three Vertecies
	if (TableSize < 6) {
		luaL_error(L, "Invalid polygon definition. At least three vertecies needed.");
		return false;
	}

	// Make sure that the number of table elements is divisible by two.
	// Since any two elements is a vertex, an odd number of elements is not allowed
	if ((TableSize % 2) != 0) {
		luaL_error(L, "Invalid polygon definition. Even number of table elements needed.");
		return false;
	}

	// Ensure that all elements in the table are of type Number
	for (int i = 1; i <= TableSize; i += 1) {
		lua_rawgeti(L, -1, i);
		if (!lua_isnumber(L, -1)) {
			luaL_error(L, "Invalid polygon definition. All table elements have to be numbers.");
			return false;
		}
		lua_pop(L, 1);
	}

#ifdef DEBUG
	BS_ASSERT(__startStackDepth == lua_gettop(L));
#endif

	return true;
}

// -----------------------------------------------------------------------------

static void TablePolygonToPolygon(lua_State *L, BS_Polygon &Polygon) {
#ifdef DEBUG
	int __startStackDepth = lua_gettop(L);
#endif

	// Ensure that a valid polygon definition is on the stack.
	// It is not necessary to catch the return value, since all errors are reported on luaL_error
	// End script.
	IsValidPolygonDefinition(L);

	int VertexCount = luaL_getn(L, -1) / 2;

	// Memory is reserved for Vertecies
	Common::Array<BS_Vertex> Vertecies;
	Vertecies.reserve(VertexCount);

	// Create Vertecies
	for (int i = 0; i < VertexCount; i++) {
		// X Value
		lua_rawgeti(L, -1, (i * 2) + 1);
		int X = static_cast<int>(lua_tonumber(L, -1));
		lua_pop(L, 1);

		// Y Value
		lua_rawgeti(L, -1, (i * 2) + 2);
		int Y = static_cast<int>(lua_tonumber(L, -1));
		lua_pop(L, 1);

		// Vertex
		Vertecies.push_back(BS_Vertex(X, Y));
	}
	BS_ASSERT((int)Vertecies.size() == VertexCount);

#ifdef DEBUG
	BS_ASSERT(__startStackDepth == lua_gettop(L));
#endif

	// Create polygon
	Polygon.Init(VertexCount, &Vertecies[0]);
}

// -----------------------------------------------------------------------------

static unsigned int TableRegionToRegion(lua_State *L, const char *ClassName) {
#ifdef DEBUG
	int __startStackDepth = lua_gettop(L);
#endif

	// You can define a region in Lua in two ways:
	// 1. A table that defines a polygon (polgon = table with numbers, which define
	// two consecutive numbers per vertex)
	// 2. A table containing more polygon definitions
	// Then the first polygon is the contour of the region, and the following are holes
	// defined in the first polygon.

	// It may be passed only one parameter, and this must be a table
	if (lua_gettop(L) != 1 || !lua_istable(L, -1)) {
		luaL_error(L, "First and only parameter has to be of type \"table\".");
		return 0;
	}

	unsigned int RegionHandle = 0;
	if (!strcmp(ClassName, REGION_CLASS_NAME)) {
		RegionHandle = BS_Region::Create(BS_Region::RT_REGION);
	} else if (!strcmp(ClassName, WALKREGION_CLASS_NAME)) {
		RegionHandle = BS_WalkRegion::Create(BS_Region::RT_WALKREGION);
	} else {
		BS_ASSERT(false);
	}

	BS_ASSERT(RegionHandle);

	// If the first element of the parameter is a number, then case 1 is accepted
	// If the first element of the parameter is a table, then case 2 is accepted
	// If the first element of the parameter has a different type, there is an error
	lua_rawgeti(L, -1, 1);
	int FirstElementType = lua_type(L, -1);
	lua_pop(L, 1);

	switch (FirstElementType) {
	case LUA_TNUMBER: {
		BS_Polygon Polygon;
		TablePolygonToPolygon(L, Polygon);
		BS_RegionRegistry::GetInstance().ResolveHandle(RegionHandle)->Init(Polygon);
	}
	break;

	case LUA_TTABLE: {
		lua_rawgeti(L, -1, 1);
		BS_Polygon Polygon;
		TablePolygonToPolygon(L, Polygon);
		lua_pop(L, 1);

		int PolygonCount = luaL_getn(L, -1);
		if (PolygonCount == 1)
			BS_RegionRegistry::GetInstance().ResolveHandle(RegionHandle)->Init(Polygon);
		else {
			Common::Array<BS_Polygon> Holes;
			Holes.reserve(PolygonCount - 1);

			for (int i = 2; i <= PolygonCount; i++) {
				lua_rawgeti(L, -1, i);
				Holes.resize(Holes.size() + 1);
				TablePolygonToPolygon(L, Holes.back());
				lua_pop(L, 1);
			}
			BS_ASSERT((int)Holes.size() == PolygonCount - 1);

			BS_RegionRegistry::GetInstance().ResolveHandle(RegionHandle)->Init(Polygon, &Holes);
		}
	}
	break;

	default:
		luaL_error(L, "Illegal region definition.");
		return 0;
	}

#ifdef DEBUG
	BS_ASSERT(__startStackDepth == lua_gettop(L));
#endif

	return RegionHandle;
}

// -----------------------------------------------------------------------------

static void NewUserdataRegion(lua_State *L, const char *ClassName) {
	// Region due to the Lua code to create
	// Any errors that occur will be intercepted to the luaL_error
	unsigned int RegionHandle = TableRegionToRegion(L, ClassName);
	BS_ASSERT(RegionHandle);

	NewUintUserData(L, RegionHandle);
	// luaL_getmetatable(L, ClassName);
	BS_LuaBindhelper::GetMetatable(L, ClassName);
	BS_ASSERT(!lua_isnil(L, -1));
	lua_setmetatable(L, -2);
}

// -----------------------------------------------------------------------------

static int NewRegion(lua_State *L) {
	NewUserdataRegion(L, REGION_CLASS_NAME);
	return 1;
}

// -----------------------------------------------------------------------------

static int NewWalkRegion(lua_State *L) {
	NewUserdataRegion(L, WALKREGION_CLASS_NAME);
	return 1;
}

// -----------------------------------------------------------------------------

static const char *GEO_LIBRARY_NAME = "Geo";

static const luaL_reg GEO_FUNCTIONS[] = {
	{"NewRegion", NewRegion},
	{"NewWalkRegion", NewWalkRegion},
	{0, 0}
};

// -----------------------------------------------------------------------------

static BS_Region *CheckRegion(lua_State *L) {
	// The first parameter must be of type 'userdata', and the Metatable class Geo.Region or Geo.WalkRegion
	unsigned int *RegionHandlePtr;
	if ((RegionHandlePtr = reinterpret_cast<unsigned int *>(my_checkudata(L, 1, REGION_CLASS_NAME))) != 0 ||
	        (RegionHandlePtr = reinterpret_cast<unsigned int *>(my_checkudata(L, 1, WALKREGION_CLASS_NAME))) != 0) {
		return BS_RegionRegistry::GetInstance().ResolveHandle(*RegionHandlePtr);
	} else {
		luaL_argcheck(L, 0, 1, "'" REGION_CLASS_NAME "' expected");
	}

	// Compilation fix. Execution never reaches this point
	return 0;
}

// -----------------------------------------------------------------------------

static int R_IsValid(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	lua_pushbooleancpp(L, pR->IsValid());
	return 1;
}

// -----------------------------------------------------------------------------

static int R_GetX(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	lua_pushnumber(L, pR->GetPosX());
	return 1;
}

// -----------------------------------------------------------------------------

static int R_GetY(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	lua_pushnumber(L, pR->GetPosY());
	return 1;
}

// -----------------------------------------------------------------------------

static int R_GetPos(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	BS_Vertex::VertexToLuaVertex(L, pR->GetPosition());
	return 1;
}

// -----------------------------------------------------------------------------

static int R_IsPointInRegion(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	BS_Vertex Vertex;
	BS_Vertex::LuaVertexToVertex(L, 2, Vertex);
	lua_pushbooleancpp(L, pR->IsPointInRegion(Vertex));
	return 1;
}

// -----------------------------------------------------------------------------

static int R_SetPos(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	BS_Vertex Vertex;
	BS_Vertex::LuaVertexToVertex(L, 2, Vertex);
	pR->SetPos(Vertex.X, Vertex.Y);

	return 0;
}

// -----------------------------------------------------------------------------

static int R_SetX(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	pR->SetPosX(static_cast<int>(luaL_checknumber(L, 2)));

	return 0;
}

// -----------------------------------------------------------------------------

static int R_SetY(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	pR->SetPosY(static_cast<int>(luaL_checknumber(L, 2)));

	return 0;
}

// -----------------------------------------------------------------------------

static void DrawPolygon(const BS_Polygon &Polygon, unsigned int Color, const BS_Vertex &Offset) {
	BS_GraphicEngine *pGE = static_cast<BS_GraphicEngine *>(BS_Kernel::GetInstance()->GetService("gfx"));
	BS_ASSERT(pGE);

	for (int i = 0; i < Polygon.VertexCount - 1; i++)
		pGE->DrawDebugLine(Polygon.Vertecies[i] + Offset, Polygon.Vertecies[i + 1] + Offset, Color);

	pGE->DrawDebugLine(Polygon.Vertecies[Polygon.VertexCount - 1] + Offset, Polygon.Vertecies[0] + Offset, Color);
}

// -----------------------------------------------------------------------------

static void DrawRegion(const BS_Region &Region, unsigned int Color, const BS_Vertex &Offset) {
	DrawPolygon(Region.GetContour(), Color, Offset);
	for (int i = 0; i < Region.GetHoleCount(); i++)
		DrawPolygon(Region.GetHole(i), Color, Offset);
}

// -----------------------------------------------------------------------------

static int R_Draw(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);

	switch (lua_gettop(L)) {
	case 3: {
		BS_Vertex Offset;
		BS_Vertex::LuaVertexToVertex(L, 3, Offset);
		DrawRegion(*pR, BS_GraphicEngine::LuaColorToARGBColor(L, 2), Offset);
	}
	break;

	case 2:
		DrawRegion(*pR, BS_GraphicEngine::LuaColorToARGBColor(L, 2), BS_Vertex(0, 0));
		break;

	default:
		DrawRegion(*pR, BS_RGB(255, 255, 255), BS_Vertex(0, 0));
	}

	return 0;
}

// -----------------------------------------------------------------------------

static int R_GetCentroid(lua_State *L) {
	BS_Region *RPtr = CheckRegion(L);
	BS_ASSERT(RPtr);

	BS_Vertex::VertexToLuaVertex(L, RPtr->GetCentroid());

	return 1;
}

// -----------------------------------------------------------------------------

static int R_Delete(lua_State *L) {
	BS_Region *pR = CheckRegion(L);
	BS_ASSERT(pR);
	delete pR;
	return 0;
}

// -----------------------------------------------------------------------------

static const luaL_reg REGION_METHODS[] = {
	{"SetPos", R_SetPos},
	{"SetX", R_SetX},
	{"SetY", R_SetY},
	{"GetPos", R_GetPos},
	{"IsPointInRegion", R_IsPointInRegion},
	{"GetX", R_GetX},
	{"GetY", R_GetY},
	{"IsValid", R_IsValid},
	{"Draw", R_Draw},
	{"GetCentroid", R_GetCentroid},
	{0, 0}
};

// -----------------------------------------------------------------------------

static BS_WalkRegion *CheckWalkRegion(lua_State *L) {
	// The first parameter must be of type 'userdate', and the Metatable class Geo.WalkRegion
	unsigned int RegionHandle;
	if ((RegionHandle = *reinterpret_cast<unsigned int *>(my_checkudata(L, 1, WALKREGION_CLASS_NAME))) != 0) {
		return reinterpret_cast<BS_WalkRegion *>(BS_RegionRegistry::GetInstance().ResolveHandle(RegionHandle));
	} else {
		luaL_argcheck(L, 0, 1, "'" WALKREGION_CLASS_NAME "' expected");
	}

	// Compilation fix. Execution never reaches this point
	return 0;
}

// -----------------------------------------------------------------------------

static int WR_GetPath(lua_State *L) {
	BS_WalkRegion *pWR = CheckWalkRegion(L);
	BS_ASSERT(pWR);

	BS_Vertex Start;
	BS_Vertex::LuaVertexToVertex(L, 2, Start);
	BS_Vertex End;
	BS_Vertex::LuaVertexToVertex(L, 3, End);
	BS_Path Path;
	if (pWR->QueryPath(Start, End, Path)) {
		lua_newtable(L);
		BS_Path::const_iterator it = Path.begin();
		for (; it != Path.end(); it++) {
			lua_pushnumber(L, (it - Path.begin()) + 1);
			BS_Vertex::VertexToLuaVertex(L, *it);
			lua_settable(L, -3);
		}
	} else
		lua_pushnil(L);

	return 1;
}

// -----------------------------------------------------------------------------

static const luaL_reg WALKREGION_METHODS[] = {
	{"GetPath", WR_GetPath},
	{0, 0}
};

// -----------------------------------------------------------------------------

bool BS_Geometry::_RegisterScriptBindings() {
	BS_Kernel *pKernel = BS_Kernel::GetInstance();
	BS_ASSERT(pKernel);
	BS_ScriptEngine *pScript = static_cast<BS_ScriptEngine *>(pKernel->GetService("script"));
	BS_ASSERT(pScript);
	lua_State *L = static_cast< lua_State *>(pScript->GetScriptObject());
	BS_ASSERT(L);

	if (!BS_LuaBindhelper::AddMethodsToClass(L, REGION_CLASS_NAME, REGION_METHODS)) return false;
	if (!BS_LuaBindhelper::AddMethodsToClass(L, WALKREGION_CLASS_NAME, REGION_METHODS)) return false;
	if (!BS_LuaBindhelper::AddMethodsToClass(L, WALKREGION_CLASS_NAME, WALKREGION_METHODS)) return false;

	if (!BS_LuaBindhelper::SetClassGCHandler(L, REGION_CLASS_NAME, R_Delete)) return false;
	if (!BS_LuaBindhelper::SetClassGCHandler(L, WALKREGION_CLASS_NAME, R_Delete)) return false;

	if (!BS_LuaBindhelper::AddFunctionsToLib(L, GEO_LIBRARY_NAME, GEO_FUNCTIONS)) return false;

	return true;
}

} // End of namespace Sword25