/***
The `qtm` module, for headtracking. New3ds only.
@module ctr.qtm
@usage local qtm = require("ctr.qtm")
@newonly
*/
#include <3ds.h>
#include <3ds/types.h>
#include <3ds/services/qtm.h>

#include <lapi.h>
#include <lauxlib.h>

#include <string.h>

typedef struct {
	QTM_HeadTrackingInfo *info;
} qtm_userdata;

static const struct luaL_Reg qtm_methods[];

/***
Initialize the QTM module.
@function init
@treturn[1] boolean `true` if everything went fine
@treturn[2] boolean `false` in case of error
@treturn[2] integer error code
*/
static int qtm_init(lua_State *L) {
	Result ret = qtmInit();
	if (ret) {
		lua_pushboolean(L, false);
		lua_pushinteger(L, ret);
		return 2;
	}
	
	lua_pushboolean(L, true);
	return 1;
}

/***
Disable the QTM module.
@function shutdown
*/
static int qtm_shutdown(lua_State *L) {
	qtmExit();

	return 0;
}

/***
Check if the module is initialized.
@function checkInitialized
@treturn boolean `true` if initialized.
*/
static int qtm_checkInitialized(lua_State *L) {
	bool isInit = qtmCheckInitialized();

	lua_pushboolean(L, isInit);
	return 1;
}

/***
Return informations about the headtracking
@function getHeadtrackingInfo
@treturn qtmInfos QTM informations
*/
static int qtm_getHeadtrackingInfo(lua_State *L) {
	qtm_userdata *data = lua_newuserdata(L, sizeof(*data));
	luaL_getmetatable(L, "LQTM");
	lua_setmetatable(L, -2);
	Result ret = QTM_GetHeadTrackingInfo(0, data->info);
	if (ret) {
		lua_pushnil(L);
		return 1;
	}
	return 1;
}

/***
Check if the head is fully detected
@function checkHeadFullyDetected
@tparam qtmInfos qtmInfos QTM informations
@treturn boolean `true` if fully detected
*/
static int qtm_checkHeadFullyDetected(lua_State *L) {
	qtm_userdata *info = luaL_checkudata(L, 1, "LQTM");
	lua_pushboolean(L, qtmCheckHeadFullyDetected(info->info));
	return 1;
}

static int qtm___index(lua_State *L) {
	qtm_userdata *info = luaL_checkudata(L, 1, "LQTM");
	if (lua_isinteger(L, 2)) { // index
		lua_Integer index = luaL_checkinteger(L, 2);
		index = index - 1; // Lua index begins at 1
		if (index > 3 || index < 0) {
			lua_pushnil(L);
			lua_pushnil(L);
			return 2;
		}
	
		lua_pushnumber(L, info->info->coords0[index].x);
		lua_pushnumber(L, info->info->coords0[index].y);
		return 2;
		
	} else if (lua_isstring(L, 2)) { //method
		const char *mname = luaL_checkstring(L, 2);
		for (u8 i=0;qtm_methods[i].name;i++) {
			if (strcmp(qtm_methods[i].name, mname) == 0) {
				lua_pushcfunction(L, qtm_methods[i].func);
				return 1;
			}
		}
	}
	lua_pushnil(L);
	return 1;
}

/***
Convert QTM coordinates to screen coordinates
@function convertCoordToScreen
@tparam qtmInfos qtmInfos QTM informations
@tparam number coordinates index
@tparam[opt=400] number screenWidth specify a screen width
@tparam[opt=320] number screenHeight specify a screen height
@treturn[1] number screen X coordinate
@treturn[1] number screen Y coordinate
@treturn[2] nil in case of error
@treturn[2] string error message
*/
static int qtm_convertCoordToScreen(lua_State *L) {
	qtm_userdata *info = luaL_checkudata(L, 1, "LQTM");
	lua_Integer index = luaL_checkinteger(L, 2);
	index = index - 1; // Lua index begins at 1
	if (index > 3 || index < 0) {
		lua_pushnil(L);
		lua_pushstring(L, "Index must be between 1 and 3");
		return 2;
	}
	float screenWidth = luaL_optnumber(L, 3, 400.0f);
	float screenHeight = luaL_optnumber(L, 4, 320.0f);
	
	u32 x, y = 0;
	qtmConvertCoordToScreen(&info->info->coords0[index], &screenWidth, &screenHeight, &x, &y);
	
	lua_pushinteger(L, x);
	lua_pushinteger(L, y);
	
	return 2;
}

/***
qtmInfos object
@section Methods
*/

/***
Check if the head is fully detected
@function :checkHeadFullyDetected
@treturn boolean `true` if fully detected
*/

/***
Convert QTM coordinates to screen coordinates
@function :convertCoordToScreen
@tparam number coordinates index
@tparam[opt=400] number screenWidth specify a screen width
@tparam[opt=320] number screenHeight specify a screen height
@treturn number screen X coordinate
@treturn number screen Y coordinate
*/

/***
When the object is indexed with a number from 1 to 4, it returns the coordinates
of one of the headtracker points.
@tfield number index coordinates, as two numbers (not a table)
@usage coordX, coordY = qtmInfos[index]
*/

// object
static const struct luaL_Reg qtm_methods[] = {
	{"checkHeadFullyDetected", qtm_checkHeadFullyDetected},
	{"convertCoordToScreen",   qtm_convertCoordToScreen  },
	{"__index",                qtm___index               },
	{NULL, NULL}
};

// module functions
static const struct luaL_Reg qtm_functions[] = {
	{"init",                   qtm_init                  },
	{"shutdown",               qtm_shutdown              },
	{"checkInitialized",       qtm_checkInitialized      },
	{"getHeadtrackingInfo",    qtm_getHeadtrackingInfo   },
	{"checkHeadFullyDetected", qtm_checkHeadFullyDetected},
	{"convertCoordToScreen",   qtm_convertCoordToScreen  },
	{NULL, NULL}
};

int luaopen_qtm_lib(lua_State *L) {
	luaL_newmetatable(L, "LQTM");
	lua_pushvalue(L, -1);
	lua_setfield(L, -2, "__index");
	luaL_setfuncs(L, qtm_methods, 0);
	
	luaL_newlib(L, qtm_functions);
	return 1;
}

void load_qtm_lib(lua_State *L) {
	luaL_requiref(L, "ctr.qtm", luaopen_qtm_lib, false);
}