#ifndef KERNEL_SCHED_H_
#define KERNEL_SCHED_H_

#include <kernel/btree.h>
#include <kernel/handle.h>
#include <kernel/locks.h>
#include <kernel/queue.h>
#include <kernel/types.h>
#include <mango/status.h>

#define PRIO_MAX 32

#ifdef __cplusplus
extern "C" {
#endif

struct channel;
struct runqueue;

enum sched_priority {
	PRIO_IDLE = 4,
	PRIO_SUBNORMAL = 6,
	PRIO_NORMAL = 10,
	PRIO_SUPERNORMAL = 14,
	PRIO_HIGH = 18,
	PRIO_REALTIME = 24,
};

enum sched_mode {
	/* used when calling from non-interrupt context.
	   threads that aren't in state THREAD_READY are
	   removed from the runqueue. */
	SCHED_NORMAL = 0,
	/* used when calling from interrupt context.
	   threads that aren't in state THREAD_READY are
	   still added to the runqueue. */
	SCHED_IRQ = 1,
};

struct runqueue {
	struct queue rq_queues[PRIO_MAX];
	uint32_t rq_readybits;
	spin_lock_t rq_lock;
	unsigned int rq_nthreads;

	struct thread *rq_cur, *rq_idle;
};

struct timer {
	struct queue_entry t_entry;
	struct cpu_data *t_cpu;
	struct thread *t_owner;
	unsigned long t_expiry;
	void (*t_callback)(struct timer *);
};

extern kern_status_t sched_init(void);
extern void schedule(enum sched_mode mode);
extern void preempt_disable(void);
extern void preempt_enable(void);

extern void rq_init(struct runqueue *rq);
extern struct thread *rq_dequeue(struct runqueue *rq);
extern void rq_enqueue(struct runqueue *rq, struct thread *thr);
static inline void rq_lock(struct runqueue *rq, unsigned long *flags)
{
	spin_lock_irqsave(&rq->rq_lock, flags);
}
static inline void rq_unlock(struct runqueue *rq, unsigned long flags)
{
	spin_unlock_irqrestore(&rq->rq_lock, flags);
}
extern void rq_remove_thread(struct runqueue *rq, struct thread *thr);
extern struct runqueue *cpu_rq(unsigned int cpu);

extern cycles_t default_quantum(void);

extern bool need_resched(void);
extern struct task *current_task(void);
extern struct thread *current_thread(void);

extern struct runqueue *select_rq_for_thread(struct thread *thr);
extern void schedule_thread_on_cpu(struct thread *thr);

extern void start_charge_period(void);
extern void end_charge_period(void);

extern void add_timer(struct timer *timer);
extern void remove_timer(struct timer *timer);
extern unsigned long schedule_timeout(unsigned long clock_ticks);
extern unsigned long milli_sleep(unsigned long ms);
extern void sleep_forever(void);

#ifdef __cplusplus
}
#endif

#endif