#include "drawing.h"
#include "sprites.h"
#include "maxCommands.h"

/* Draw sprite to screen 
 *
 *	layer:	16x8 bit buffer
 * 	x, y:	Position on screen
 * 	sprite:	Sprite to draw
 */
void drawSprite(uint8_t layer[], uint8_t x, uint8_t y, struct Sprite* sprite) {
	/* Check if in range */
	if( x + sprite->width > 8 || y + sprite->height > 16) 
		return;

	/* Or buffer with sprite */
	for (int i = y; i < sprite->height + y; i++) {
		layer[i] |= sprite->buff[i - y] >> x;
	}
}

/* Clear specified buffer */
void clearBuffer(uint8_t layer[] ) {
	for( int i = 0; i < BUFF_HEIGHT; i++ ) {
		layer[i] = 0;
	}
}

/* Render specfied screenbuffer
 *
 *	device:	Which screen
 *	where:	It render the next 8 bytes from this index
 */
void render(int display, unsigned int where, bool clean) {

	static uint8_t onScreen[BUFF_HEIGHT];

	int i;
	uint8_t toWrite;

	/* Will draw 8 lines from /where/. */
	for(i = where; i < (where + 8); i++) {
		toWrite = topLayer[i] | buttonLayer[i];

		/* Check if whats on screen is the same */
		if(onScreen[i] == toWrite && !clean) 
			continue;

		writeCommand(display, maxDIGIT_0 + i - where, toWrite);

		/* Keep track of whats on screen */
		onScreen[i] = toWrite;
	}
}

/* Renders all 16 bytes to screen */
void renderToSerial() {
	/* Send terminal clear characters(https://stackoverflow.com/questions/10105666/clearing-the-terminal-screen) */
	Serial.write(27);
	Serial.print("[2J");
	Serial.write(27);
	Serial.print("[H");

	/* For every line */
	for( int i = 0; i < 16; i++ ) {
		uint8_t toWrite = topLayer[i] | buttonLayer[i];

		/* For every bit in line */
		for( int bit = 0; bit < 8; bit++) 
			Serial.print( ( toWrite & ( 1 << 7 - bit ) ) > 0 );

		Serial.println();
		
	}
}

/* Write a register to specified display 
 *  A static function is only available in this file */
static void writeCommand(int display, uint8_t addr, uint8_t data) {
	/* Chip select low */
	digitalWrite(CS, LOW);

	/* Shift out the data, to the max shift registers
	 * MSBFIRST makes the MSB go first out */
	shiftOut(DATA_IN, CLK, MSBFIRST, addr);
	shiftOut(DATA_IN, CLK, MSBFIRST, data);

	/* If the device is number two, the commands should be shiftet through
	 * Each MAX, holds 16 bits(2 bytes) */
	serialPad(display * 2);

	digitalWrite(CS, HIGH);

	/* Before writing new commands, all the buffers should be cleaned */
	serialPad(NUM_DISPLAY * 2);

}

/* Init specified display */
void initDisplays(int display) {
	/* Clear all registers */
	for( int i = 0; i < 0x0F; i++)
		writeCommand(display, i, 0);

	/* Turn on(1 is shutdown disable) */
	writeCommand(display, maxSHUTDOWN_INV, 1);

	/* Darker please */
	writeCommand(display, maxINTENSITY, 0x00);

	/* Activate all lines */
	writeCommand(display, maxSCAN_LIMIT, 0x07);
}

/* Send x amount of empty bytes */
static void serialPad(int count) {
	for( int i = 0; i < count; i++ ) {
		shiftOut(DATA_IN, CLK, MSBFIRST, 0);
	}
}