#ifndef RINGBUFFER_H
#define RINGBUFFER_H

#include "../Debug.h"

typedef void (*RingBufferFullCallback)();


template <typename Scalar, int size> class RingBuffer {

private:

	static constexpr const char* NAME = "RingBuffer";

	Scalar data[size];

	volatile size_t head;
	volatile size_t tail;
	volatile mutable size_t used;

public:

	RingBuffer() {
		init();
	}

	void init() {
		head = 0;
		tail = 0;
		used = 0;
	}

	void clear() {
		init();
	}

	/** add one value to the buffer. blocks until space is available */
	void addBlocking(const Scalar value) {
		while (used == size) {os_delay_us(1000);}
		data[head] = value;
		head = (head + 1) % size;
		++used;
	}

	/** add one value to the buffer, if there is enough space */
	void addOrIgnore(const Scalar value) {
		if (used == size) {return;}
		data[head] = value;
		head = (head + 1) % size;
		++used;
	}

	/** add one value to the buffer, or call the callback if there is no space available */
	void addOrCallback(const Scalar value, RingBufferFullCallback cb) {
		while(used == size) {cb();}
		data[head] = value;
		head = (head + 1) % size;
		++used;
	}


	/** add multiple values to the buffer. blocks until space is available */
	void addBlocking(const Scalar* value, const size_t len) {
		debugMod1(NAME, "addBlocking(%d)", len);
		for (size_t i = 0; i < len; ++i) {
			addBlocking(value[i]);
		}
		debugMod1(NAME, "used: %d", used);
	}

	/** add multiple values to the buffer, if there is enough space */
	void addOrIgnore(const Scalar* value, const size_t len) {
		debugMod1(NAME, "addOrIgnore(%d)", len);
		for (size_t i = 0; i < len; ++i) {
			addOrIgnore(value[i]);
		}
		debugMod1(NAME, "used: %d", used);
	}

	/** add multiple values to the buffer, if there is enough space */
	void addOrCallback(const Scalar* value, const size_t len, RingBufferFullCallback cb) {
		debugMod1(NAME, "addOrCallback(%d)", len);
		for (size_t i = 0; i < len; ++i) {
			addOrCallback(value[i], cb);
		}
		debugMod1(NAME, "used: %d", used);
	}

//	/** anything available? */
//	bool hasNext() const {
//		return used != 0;
//	}

	/** get the next value from the buffer */
	Scalar get() {
		const Scalar res = data[tail];
		tail = (tail + 1) % size;
		--used;
		return res;
	}

	const Scalar& getConst() const {
		const uint8_t idx = tail;
		tail = (tail + 1) % size;
		--used;
		return data[idx];
	}

	/** true if the buffer is currently empty */
	bool empty() const {
		return used == 0;
	}

	/** true if the buffer is currently full */
	bool full() const {
		return size == used;
	}

	/** get the number of used elements within the buffer */
	size_t getNumUsed() const {
		return used;
	}

	/** get the number of free elements within the buffer */
	size_t getNumFree() const {
		return size-used;
	}

};

#endif // RINGBUFFER_H