/* 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>
#include <stdlib.h>

#include "cards.h"

#ifndef STACK_CAP
#define STACK_CAP 52
#endif

typedef Sint8 Card;

static int cardSuit(Card card) {
	card = abs(card);
	if (card > Cards_Spade) {
		return Cards_Spade;
	} else if (card > Cards_Heart) {
		return Cards_Heart;
	} else if (card > Cards_Diamond) {
		return Cards_Diamond;
	} else {
		return Cards_Club;
	}
}

static int cardColor(Card card) {
	return cardSuit(card) == Cards_Diamond || cardSuit(card) == Cards_Heart;
}

static int cardRank(Card card) {
	return abs(card) - cardSuit(card);
}

struct Stack {
	Uint8 len;
	Card cards[STACK_CAP];
};

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

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

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

static inline Card stackTop(const struct Stack *stack) {
	if (!stack->len) return 0;
	return stack->cards[stack->len - 1];
}

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 int randUniform(int bound) {
	for (;;) {
		int r = rand();
		if (r >= RAND_MAX % bound) return r % bound;
	}
}

static inline void stackShuffle(struct Stack *stack) {
	for (Uint8 i = stack->len - 1; i > 0; --i) {
		Uint8 j = randUniform(i + 1);
		Card x = stack->cards[i];
		stack->cards[i] = stack->cards[j];
		stack->cards[j] = x;
	}
}

#endif