/* Copyright (C) 2021,2022 fef <owo@fef.moe>.  All rights reserved. */

#pragma once

#include <arch/cpufunc.h>
#include <arch/trap.h>

#include <gay/cdefs.h>
#include <gay/irq.h>
#include <gay/sched.h>
#include <gay/types.h>

/**
 * @brief Print an error message and halt the system immediately.
 *
 * @param fmt printf style format string
 */
void panic(const char *fmt, ...) __noreturn __printflike(1, 2);
#define panic_if(condition, msg, ...) do {	\
	if (__predict_false(condition))		\
		panic(msg, ##__VA_ARGS__);	\
} while (0)

void print_regs(const trap_frame_t *ctx);

#ifdef DEBUG
/**
 * @brief Assert that statement `x` is true.
 * If it is not and debugging is enabled, the kernel panics.
 */
#define KASSERT(x) do {						\
	if ( __predict_false(!(x)) ) {				\
		panic("Assertion \"%s\" failed!\n"		\
		      "  in function %s()\n"			\
		      "  in file %s, line %u\n",		\
		      #x, __func__, __FILENAME__, __LINE__);	\
	}							\
} while (0)
#else
#define KASSERT(x) do { } while (0)
#endif

/**
 * @brief Enter a critical section, meaning preemption gets disabled.
 * Critical sections should be kept as short as possible for performance.
 * Cannot be called from irq context because irqs always run atomically.
 *
 * @see `critical_leave()`
 */
static inline void critical_enter(void)
{
	KASSERT(!in_irq());

	struct task *tsk = current;
	tsk->critnest++;
}

/**
 * @brief Leave a critical section.
 * Cannot be called from irq context.
 *
 * @see `critical_enter()`
 */
static inline void critical_leave(void)
{
	KASSERT(!in_irq());

	struct task *tsk = current;
	tsk->critnest--;

	KASSERT(tsk->critnest >= 0);
}

static inline bool in_critical(void)
{
	if (in_irq() || !intr_enabled())
		return true;
	return current->critnest > 0;
}