#ifndef SNES_CONTROLLER_H
#define SNES_CONTROLLER_H

#include "../../io/GPIO.h"


/** https://fpgalover.com/images/manuals/SNES/time.JPG */

// Pinout on the chinese version
// left to right: gnd data latch clk +5v (also works with 3.3)
template <int PIN_LATCH, int PIN_DATA, int PIN_CLK> class SNESController {
	
public:

	union State {
		
		uint16_t raw;
		
		State() : raw(0) {}
		
		State(uint16_t raw) : raw(raw) {}
		
		struct {
			
			uint8_t dummy1 : 1;
			uint8_t dummy2 : 1;
			uint8_t dummy3 : 1;
			uint8_t dummy4 : 1;
			uint8_t r : 1;
			uint8_t l : 1;
			uint8_t x : 1;
			uint8_t a : 1;
			
			uint8_t right : 1;
			uint8_t left : 1;
			uint8_t down : 1;
			uint8_t up : 1;
			uint8_t start : 1;
			uint8_t select : 1;
			uint8_t y : 1;
			uint8_t b : 1;
			
		};
		
		bool operator != (const State o) const {return raw != o.raw;}
		
		/** write current state into the given 12+1 char* */
		void toString(char* dst) {
			dst[ 0] = !r		? 'R' : ' ';
			dst[ 1] = !l		? 'L' : ' ';
			dst[ 2] = !x		? 'X' : ' ';
			dst[ 3] = !a		? 'A' : ' ';
			dst[ 4] = !right	? 'r' : ' ';
			dst[ 5] = !left		? 'l' : ' ';
			dst[ 6] = !down		? 'd' : ' ';
			dst[ 7] = !up		? 'u' : ' ';
			dst[ 8] = !start	? 'S' : ' ';
			dst[ 9] = !select	? 's' : ' ';
			dst[10] = !y		? 'Y' : ' ';
			dst[11] = !b		? 'B' : ' ';
			dst[12] = 0;
		}
			
		
	};

public:

	/** ctor */
	SNESController() {
		MyGPIO::setInput(PIN_DATA);
		MyGPIO::setOutput(PIN_LATCH);
		MyGPIO::setOutput(PIN_CLK);		
	}
	
	
	/** read the current state from the controller */
	State read() {
		
		// latch the current data (remember state)
		latch();
		
		// read all 16 data bits
		uint16_t res = 0;
		for (uint8_t i = 0; i < 16; ++i) {
			res <<= 1;
			res |= readBit();
		}
		
		// wrap
		return State(res);	
		
	}
	
private:

	void latch() {
		
		// ensure CLK is HIGH
		MyGPIO::set(PIN_CLK);
		
		// send latch impulse
		MyGPIO::set(PIN_LATCH);
		wait();
		MyGPIO::clear(PIN_LATCH);
		wait();
		
	}
	
	uint8_t readBit() {
		MyGPIO::set(PIN_CLK);
		wait();
		MyGPIO::clear(PIN_CLK);
		uint8_t res = MyGPIO::get(PIN_DATA);
		wait();
		return res;
	}
	
	void wait() {
		for (uint8_t i = 0; i < 128; ++i) {asm("nop");}
	}
	
};

#endif