#include "LuaPhysicsSetup.h"

#include "../CommonInterfaces/CommonMultiBodyBase.h"
#include "../Importers/ImportURDFDemo/BulletURDFImporter.h"
#include "../Importers/ImportURDFDemo/MyMultiBodyCreator.h"
#include "../Importers/ImportURDFDemo/URDF2Bullet.h"

struct LuaPhysicsSetup : public CommonMultiBodyBase
{
	LuaPhysicsSetup(GUIHelperInterface* helper);
	virtual ~LuaPhysicsSetup();

	virtual void initPhysics();

	virtual void exitPhysics();

	virtual void stepSimulation(float deltaTime)
	{
		m_guiHelper->autogenerateGraphicsObjects(m_dynamicsWorld);
		CommonMultiBodyBase::stepSimulation(deltaTime);
	}
};

#include "btBulletDynamicsCommon.h"
#include "LinearMath/btVector3.h"
#include <iostream>

extern "C"
{
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}

const char* sLuaFileName = "init_physics.lua";
static int upaxis = 1;

//const char* sLuaFileName = "init_urdf.lua";
//static int upaxis = 2;

static const float scaling = 0.35f;
static LuaPhysicsSetup* sLuaDemo = 0;

static btVector4 colors[4] =
	{
		btVector4(1, 0, 0, 1),
		btVector4(0, 1, 0, 1),
		btVector4(0, 1, 1, 1),
		btVector4(1, 1, 0, 1),
};

LuaPhysicsSetup::LuaPhysicsSetup(GUIHelperInterface* helper)
	: CommonMultiBodyBase(helper)
{
	sLuaDemo = this;
}

LuaPhysicsSetup::~LuaPhysicsSetup()
{
	sLuaDemo = 0;
}

//todo: allow to create solver, broadphase, multiple worlds etc.
static int gCreateDefaultDynamicsWorld(lua_State* L)
{
	sLuaDemo->createEmptyDynamicsWorld();
	btVector3 grav(0, 0, 0);
	grav[upaxis] = -10;

	sLuaDemo->m_dynamicsWorld->setGravity(grav);
	sLuaDemo->m_guiHelper->createPhysicsDebugDrawer(sLuaDemo->m_dynamicsWorld);
	lua_pushlightuserdata(L, sLuaDemo->m_dynamicsWorld);
	return 1;
}

static int gDeleteDynamicsWorld(lua_State* L)
{
	return 0;
}

ATTRIBUTE_ALIGNED16(struct)
CustomRigidBodyData
{
	int m_graphicsInstanceIndex;
};

static int gCreateCubeShape(lua_State* L)
{
	int argc = lua_gettop(L);
	if (argc == 4)
	{
		btVector3 halfExtents(1, 1, 1);
		if (!lua_isuserdata(L, 1))
		{
			std::cerr << "error: first argument to createCubeShape should be world";
			return 0;
		}
		//expect userdata = sLuaDemo->m_dynamicsWorld
		halfExtents = btVector3(lua_tonumber(L, 2), lua_tonumber(L, 3), lua_tonumber(L, 4));
		btCollisionShape* colShape = new btBoxShape(halfExtents);

		lua_pushlightuserdata(L, colShape);
		return 1;
	}
	else
	{
		std::cerr << "Error: invalid number of arguments to createCubeShape, expected 4 (world,halfExtentsX,halfExtentsY,halfExtentsX) but got " << argc;
	}
	return 0;
}

static int gCreateSphereShape(lua_State* L)
{
	int argc = lua_gettop(L);
	if (argc == 2)
	{
		btVector3 halfExtents(1, 1, 1);
		if (!lua_isuserdata(L, 1))
		{
			std::cerr << "error: first argument to createSphereShape should be world";
			return 0;
		}
		//expect userdata = sLuaDemo->m_dynamicsWorld
		btScalar radius = lua_tonumber(L, 2);
		btCollisionShape* colShape = new btSphereShape(radius);

		lua_pushlightuserdata(L, colShape);
		return 1;
	}
	else
	{
		std::cerr << "Error: invalid number of arguments to createSphereShape, expected 2 (world,radius) but got " << argc;
	}
	return 0;
}

int luaL_returnlen(lua_State* L, int index)
{
	lua_len(L, index);
	int len = lua_tointeger(L, -1);
	lua_pop(L, 1);
	return len;
}

btVector3 getLuaVectorArg(lua_State* L, int index)
{
	btVector3 pos(0, 0, 0);

	int sz = luaL_returnlen(L, index);  // get size of table
	{
		lua_rawgeti(L, index, 1);  // push t[i]
		pos[0] = lua_tonumber(L, -1);
		lua_pop(L, 1);
		lua_rawgeti(L, index, 2);  // push t[i]
		pos[1] = lua_tonumber(L, -1);
		lua_pop(L, 1);
		lua_rawgeti(L, index, 3);  // push t[i]
		pos[2] = lua_tonumber(L, -1);
		lua_pop(L, 1);
	}
	return pos;
}

btQuaternion getLuaQuaternionArg(lua_State* L, int index)
{
	btQuaternion orn(0, 0, 0, 1);

	int sz = luaL_returnlen(L, index);  // get size of table
	{
		lua_rawgeti(L, index, 1);  // push t[i]
		orn[0] = lua_tonumber(L, -1);
		lua_pop(L, 1);
		lua_rawgeti(L, index, 2);  // push t[i]
		orn[1] = lua_tonumber(L, -1);
		lua_pop(L, 1);
		lua_rawgeti(L, index, 3);  // push t[i]
		orn[2] = lua_tonumber(L, -1);
		lua_pop(L, 1);
		lua_rawgeti(L, index, 4);  // push t[i]
		orn[3] = lua_tonumber(L, -1);
		lua_pop(L, 1);
	}
	return orn;
}

static int gLoadMultiBodyFromUrdf(lua_State* L)
{
	int argc = lua_gettop(L);
	if (argc == 4)
	{
		if (!lua_isuserdata(L, 1))
		{
			std::cerr << "error: first argument to b3CreateRigidbody should be world";
			return 0;
		}

		luaL_checktype(L, 3, LUA_TTABLE);

		btVector3 pos = getLuaVectorArg(L, 3);

		btQuaternion orn = getLuaQuaternionArg(L, 4);

		btDiscreteDynamicsWorld* world = (btDiscreteDynamicsWorld*)lua_touserdata(L, 1);
		if (world != sLuaDemo->m_dynamicsWorld)
		{
			std::cerr << "error: first argument expected to be a world";
			return 0;
		}
		const char* fileName = lua_tostring(L, 2);
#if 1
		BulletURDFImporter u2b(sLuaDemo->m_guiHelper, 0);
		bool loadOk = u2b.loadURDF(fileName);
		if (loadOk)
		{
			b3Printf("loaded %s OK!", fileName);

			btTransform tr;
			tr.setIdentity();
			tr.setOrigin(pos);
			tr.setRotation(orn);
			int rootLinkIndex = u2b.getRootLinkIndex();
			//			printf("urdf root link index = %d\n",rootLinkIndex);
			MyMultiBodyCreator creation(sLuaDemo->m_guiHelper);
			bool m_useMultiBody = true;
			ConvertURDF2Bullet(u2b, creation, tr, sLuaDemo->m_dynamicsWorld, m_useMultiBody, u2b.getPathPrefix());
			btMultiBody* mb = creation.getBulletMultiBody();

			if (mb)
			{
				lua_pushlightuserdata(L, mb);
				return 1;
			}
		}
		else
		{
			b3Printf("can't find %s", fileName);
		}
#endif
	}

	return 0;
}

static int gCreateRigidBody(lua_State* L)
{
	int argc = lua_gettop(L);
	if (argc == 5)
	{
		btTransform startTransform;
		startTransform.setIdentity();

		if (!lua_isuserdata(L, 1))
		{
			std::cerr << "error: first argument to b3CreateRigidbody should be world";
			return 0;
		}
		btDiscreteDynamicsWorld* world = (btDiscreteDynamicsWorld*)lua_touserdata(L, 1);
		if (world != sLuaDemo->m_dynamicsWorld)
		{
			std::cerr << "error: first argument expected to be a world";
			return 0;
		}

		if (!lua_isuserdata(L, 2))
		{
			std::cerr << "error: second argument to b3CreateRigidbody should be collision shape";
			return 0;
		}

		btScalar mass = lua_tonumber(L, 3);

		luaL_checktype(L, 4, LUA_TTABLE);

		btVector3 pos = getLuaVectorArg(L, 4);

		btQuaternion orn = getLuaQuaternionArg(L, 5);

		btCollisionShape* colShape = (btCollisionShape*)lua_touserdata(L, 2);
		//expect userdata = sLuaDemo->m_dynamicsWorld

		btVector3 inertia(0, 0, 0);
		if (mass)
		{
			colShape->calculateLocalInertia(mass, inertia);
		}

		btRigidBody* body = new btRigidBody(mass, 0, colShape, inertia);
		body->getWorldTransform().setOrigin(pos);
		body->getWorldTransform().setRotation(orn);

		world->addRigidBody(body);

		lua_pushlightuserdata(L, body);
		return 1;
	}
	else
	{
		std::cerr << "Error: invalid number of arguments to createRigidBody, expected 5 (world,shape,mass,pos,orn) but got " << argc;
	}
	return 0;
}

static int gSetBodyPosition(lua_State* L)
{
	int argc = lua_gettop(L);
	if (argc == 3)
	{
		if (!lua_isuserdata(L, 1))
		{
			std::cerr << "error: first argument needs to be a world";
			return 0;
		}
		if (!lua_isuserdata(L, 2))
		{
			std::cerr << "error: second argument needs to be a body";
			return 0;
		}
		btRigidBody* body = (btRigidBody*)lua_touserdata(L, 2);
		btVector3 pos = getLuaVectorArg(L, 3);

		btTransform& tr = body->getWorldTransform();
		tr.setOrigin(pos);
		body->setWorldTransform(tr);
	}
	else
	{
		std::cerr << "error: setBodyPosition expects 6 arguments like setBodyPosition(world,body,0,1,0)";
	}
	return 0;
}

static int gSetBodyOrientation(lua_State* L)
{
	int argc = lua_gettop(L);
	if (argc == 3)
	{
		if (!lua_isuserdata(L, 1))
		{
			std::cerr << "error: first argument needs to be a world";
			return 0;
		}
		if (!lua_isuserdata(L, 2))
		{
			std::cerr << "error: second argument needs to be a body";
			return 0;
		}
		btRigidBody* body = (btRigidBody*)lua_touserdata(L, 2);
		btQuaternion orn = getLuaQuaternionArg(L, 3);
		btTransform& tr = body->getWorldTransform();
		tr.setRotation(orn);
		body->setWorldTransform(tr);
	}
	else
	{
		std::cerr << "error: setBodyOrientation expects 3 arguments like setBodyOrientation(world,body,orn)";
	}
	return 0;
}

//b3CreateConvexShape(world, points)

//b3CreateHingeConstraint(world,bodyA,bodyB,...)

static void report_errors(lua_State* L, int status)
{
	if (status != 0)
	{
		std::cerr << "-- " << lua_tostring(L, -1) << std::endl;
		lua_pop(L, 1);  // remove error message
	}
}

void LuaPhysicsSetup::initPhysics()
{
	m_guiHelper->setUpAxis(upaxis);
	const char* prefix[] = {"./", "./data/", "../data/", "../../data/", "../../../data/", "../../../../data/"};
	int numPrefixes = sizeof(prefix) / sizeof(const char*);
	char relativeFileName[1024];
	FILE* f = 0;
	int result = 0;

	for (int i = 0; !f && i < numPrefixes; i++)
	{
		sprintf(relativeFileName, "%s%s", prefix[i], sLuaFileName);
		f = fopen(relativeFileName, "rb");
	}
	if (f)
	{
		fclose(f);

		lua_State* L = luaL_newstate();

		luaopen_io(L);  // provides io.*
		luaopen_base(L);
		luaopen_table(L);
		luaopen_string(L);
		luaopen_math(L);
		//luaopen_package(L);
		luaL_openlibs(L);

		// make my_function() available to Lua programs
		lua_register(L, "createDefaultDynamicsWorld", gCreateDefaultDynamicsWorld);
		lua_register(L, "deleteDynamicsWorld", gDeleteDynamicsWorld);
		lua_register(L, "createCubeShape", gCreateCubeShape);
		lua_register(L, "createSphereShape", gCreateSphereShape);
		lua_register(L, "loadMultiBodyFromUrdf", gLoadMultiBodyFromUrdf);

		lua_register(L, "createRigidBody", gCreateRigidBody);
		lua_register(L, "setBodyPosition", gSetBodyPosition);
		lua_register(L, "setBodyOrientation", gSetBodyOrientation);

		int s = luaL_loadfile(L, relativeFileName);

		if (s == 0)
		{
			// execute Lua program
			s = lua_pcall(L, 0, LUA_MULTRET, 0);
		}

		report_errors(L, s);
		lua_close(L);
	}
	else
	{
		b3Error("Cannot find Lua file%s\n", sLuaFileName);
	}
}

void LuaPhysicsSetup::exitPhysics()
{
	CommonMultiBodyBase::exitPhysics();
}

class CommonExampleInterface* LuaDemoCreateFunc(struct CommonExampleOptions& options)
{
	return new LuaPhysicsSetup(options.m_guiHelper);
}
