#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include "stm32f7xx_hal.h"
#include "nokia.h"
#define NUMBER_OF_LINES 20

typedef struct						// LINE STRUCTURE
{
	int8_t x1;						///< first point X pos
	int8_t y1;						///< first point y pos
	int8_t x2;						///< second point X pos
	int8_t y2;						///< second point Y pos
} LINE;
LINE lines[NUMBER_OF_LINES];		// the lines
uint32_t toClear,toDraw;

LINE directions =
{ 1, 2, 3, 4 };						// the point of lines directions




///////////////////////////////////////////////////////////////////////////////
/// \brief Calculate the new line X position
/// \param pos the pointer to new position
/// \param dir the pointer to the new direction
///////////////////////////////////////////////////////////////////////////////
static void CalcNewLineX(int8_t * pos, int8_t * dir)
{
	int8_t temp;

	temp = *pos + *dir; 				// new position calcul
	if ((temp > 83) || (temp < 0)) 		// check limit bounds
	{
		if (*dir > 0) 					// was going left to right
		{
			*dir = 0 - ((rand() * 3 / RAND_MAX) + 1); 	// change direction
		}
		else 							// was going right to left
		{
			*dir = (rand() * 3 / RAND_MAX) + 1; 		// change direction

		}
		temp = *pos + *dir; 			// recalculate new position
	}
	*pos = temp; 						// change position
}

///////////////////////////////////////////////////////////////////////////////
/// \brief Calculate the new line Y position
/// \param pos the pointer to new position
/// \param dir the pointer to the new direction
///////////////////////////////////////////////////////////////////////////////
static void CalcNewLineY(int8_t * pos, int8_t * dir)
{
	int8_t temp;

	temp = *pos + *dir; 				// new position calcul
	if ((temp > 47) || (temp < 0)) 		// check limit bounds
	{
		if (*dir > 0) 					// was going top to bottom
		{
			*dir = 0 - ((rand() * 1 / RAND_MAX) + 1); 	// change direction
		}
		else 							// was going bottom to top
		{
			*dir = (rand() * 1 / RAND_MAX) + 1;			 // change direction

		}
		temp = *pos + *dir; 			// recalculate new position
	}
	*pos = temp; 						// change position
}


void ScreenSaver(void)
{
		 toClear = (toDraw + 1)%NUMBER_OF_LINES; 	// next line to clear
		 //--------------------------------------------------------------------
		 // clear oldest line
		 NokiaDrawLine(lines[toClear].x1,lines[toClear].y1,
				lines[toClear].x2,lines[toClear].y2,0);
		 //--------------------------------------------------------------------
		 // draw newest line
		 NokiaDrawLine(lines[toDraw].x1,lines[toDraw].y1,
				lines[toDraw].x2,lines[toDraw].y2,1);
		 //--------------------------------------------------------------------
		 lines[toClear] = lines[toDraw]; // for calculation of new line
		 CalcNewLineX(&lines[toClear].x1,&directions.x1);
		 CalcNewLineX(&lines[toClear].x2,&directions.x2);
		 CalcNewLineY(&lines[toClear].y1,&directions.y1);
		 CalcNewLineY(&lines[toClear].y2,&directions.y2);
		 toDraw = toClear; 				// next line to draw
}