#ifndef AUDIO_H
#define AUDIO_H

#include "../io/Timer0.h"
#include "../io/SoftSPI.h"
#include "../io/IO.h"
#include "../ESP.h"

#include "../data/RingBuffer.h"
#include "../data/DoubleBuffer.h"

class Audio;

extern Audio audio;

class Audio {

private:

	static constexpr uint32_t Hz = 22050;

	RingBuffer<uint8_t, 1500> bufPlayback;
	DoubleBuffer<uint8_t, 512> bufRecord;

	Timer0 timer;
	SoftSPI spi;



public:

	Audio() {
		// NOT CALLED
		// CALL init() manually!
	}


	/** init the audio system */
	void init() {

		spi.init();

		bufPlayback.init();
		bufRecord.init();

		timer.attachInterrupt(&Audio::onInterrupt);
		timer.fireLoopHz(Hz);

	}

	bool needsFlush() const { return bufRecord.needsFlush(); }

	/** get the recording buffer */
	DoubleBuffer<uint8_t, 512>& getRecord() {return bufRecord;}

	/** get the playback buffer */
	RingBuffer<uint8_t, 1500>& getPlayback() {return bufPlayback;}

	void markFlushed() { bufRecord.markFlushed(); }


public:

	inline uint8_t playAndRecord8(const uint8_t out) {

		// start
		spi.chipSelect();

		// build output word for the DAC
		const uint16_t out16 = (0 << 15) | (1 << 13) | (1 << 12) | (((uint16_t)out) << 4);

		// read 12-bit sample from the ADC while sending the word to the DAC
		const uint16_t inp12 = (spi.readWriteWord(out16) & 0b0001111111111110) >> 1;

		//const uint16_t inp8 =  (inp12>>0) - (2048+128);
		//const uint16_t inp8 =  (inp12>>2) - (512-128);
		//const uint16_t inp8 =  (inp12>>3) - (256-128);
		const uint16_t inp8 =  (inp12>>4);

		//const int16_t sinp12 = (int16_t)inp12 - 2048 - 256;
		//const uint8_t inp8 = (sinp12 / 12) + 128;

		// done
		spi.chipDeselect();
		return inp8;

	}

	inline void process() {

		// loop-back
//		static volatile uint8_t inp;
//		inp = playAndRecord8(inp);
//		bufRecord.add(inp);

		// next sample to write [zero level (128) if none available]
		const uint8_t out = (bufPlayback.getNumUsed() < 200) ? (128) : (bufPlayback.get());

		// send output-sample and thereby read the input sample
		const uint8_t inp = playAndRecord8(out);

		// append sample for writing
		bufRecord.add(inp);

	}


//	uint8_t rand() {
//		static volatile uint8_t val = 131;
//		val *= 17;
//		val += 11;
//		return val;
//	}

private:

	static inline void onInterrupt() {
		//IO::toggleLED1();
		audio.process();
	}

};

#endif // AUDIO_H