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/* Copyright (C) 2019  C. McEnroe <june@causal.agency>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef STACK_H
#define STACK_H

#include <SDL_stdinc.h>
#include <assert.h>

struct Stack {
	Uint8 len;
	Sint8 cards[52];
};

static inline void stackClear(struct Stack *stack) {
	stack->len = 0;
}

static inline void stackPush(struct Stack *stack, Sint8 card) {
	assert(stack->len < 52);
	stack->cards[stack->len++] = card;
}

static inline Sint8 stackPop(struct Stack *stack) {
	if (!stack->len) return 0;
	return stack->cards[--stack->len];
}

static inline void stackFlipTo(struct Stack *dst, struct Stack *src, Uint8 n) {
	if (n > src->len) n = src->len;
	for (Uint8 i = 0; i < n; ++i) {
		stackPush(dst, -stackPop(src));
	}
}

static inline void stackMoveTo(struct Stack *dst, struct Stack *src, Uint8 n) {
	if (n > src->len) n = src->len;
	for (Uint8 i = 0; i < n; ++i) {
		stackPush(dst, src->cards[src->len - n + i]);
	}
	src->len -= n;
}

static inline void stackDeck(struct Stack *stack) {
	stackClear(stack);
	for (Sint8 i = 1; i <= 52; ++i) {
		stackPush(stack, -i);
	}
}

// FIXME: Use a portable random.
static inline void stackShuffle(struct Stack *stack) {
	for (Uint8 i = stack->len - 1; i > 0; --i) {
		Uint8 j = arc4random_uniform(i + 1);
		Sint8 x = stack->cards[i];
		stack->cards[i] = stack->cards[j];
		stack->cards[j] = x;
	}
}

#endif