#include "main_stack.h"
#include <stdlib.h>

/**
 * Initialize main stack: Assign valid cards and shuffle it
 * @param[in,out] m Pointer to main stack
 */
void main_stack_init(main_stack_t *m)
{
	assert(m != NULL);

	// assign card values to main stack
	for(int i = 0; i < MAX_MAIN_STACK_CARDS; i++)
		m->cards[i] = i + 1;

	// shuffle stack
	for(int i = 0; i < 3 * MAX_MAIN_STACK_CARDS; i++)
	{
		uint32_t x = rand() % MAX_MAIN_STACK_CARDS;
		uint32_t y = rand() % MAX_MAIN_STACK_CARDS;
		card tmp = m->cards[x];
		m->cards[x] = m->cards[y];
		m->cards[y] = tmp;
	}
}

/**
 * Draw card on top of main stack and mark it as removed
 * @param[in,out] m Pointer to main stack
 * @return Card on top of stack
 */
card main_stack_remove_card(main_stack_t *m)
{
	assert(m != NULL);

	for(int i = 0; i < MAX_MAIN_STACK_CARDS; i++)
	{
		card c = m->cards[i];
		if(c == 0)
			continue;
		m->cards[i] = 0;
		return c;
	}
	return 0; // stack empty
}

/**
 * Returns number of cards remaining in main stack
 * @param[in] m Pointer to main stack
 * @return Number of cards in stack
 */
uint8_t main_stack_size(const main_stack_t *m)
{
	assert(m != NULL);

	uint8_t count = 0;

	for(uint8_t i = 0; i < MAX_MAIN_STACK_CARDS; i++)
	{
		if(m->cards[i] == 0)
			continue;
		count++;
	}

	return count;
}