#include <kernel/object.h>
#include <kernel/sched.h>
#include <kernel/syscall.h>
#include <kernel/task.h>
#include <kernel/thread.h>
#include <kernel/wait.h>
#include <mango/status.h>
#include <mango/types.h>

kern_status_t sys_kern_object_wait(kern_wait_item_t *items, size_t nr_items)
{
	if (nr_items > KERN_WAIT_MAX_ITEMS) {
		return KERN_INVALID_ARGUMENT;
	}

	struct task *self = current_task();
	struct thread *self_thread = current_thread();
	if (!validate_access_rw(self, items, nr_items * sizeof *items)) {
		return KERN_MEMORY_FAULT;
	}

	self_thread->tr_state = THREAD_SLEEPING;

	kern_status_t status = KERN_OK;
	struct object *objects[KERN_WAIT_MAX_ITEMS];
	struct wait_item waiters[KERN_WAIT_MAX_ITEMS];
	unsigned long irq_flags = 0;

	size_t nr_retained = 0;
	bool signals_observed = false;
	for (nr_retained = 0; nr_retained < nr_items; nr_retained++) {
		kern_handle_t handle = items[nr_retained].w_handle;
		handle_flags_t flags;
		struct object *object = NULL;

		status = task_resolve_handle(self, handle, &object, &flags);
		if (status != KERN_OK) {
			break;
		}

		objects[nr_retained] = object;

		object_lock_irqsave(object, &irq_flags);
		wait_item_init(&waiters[nr_retained], self_thread);
		thread_wait_begin_nosleep(
			&waiters[nr_retained],
			&object->ob_wq);

		if (object->ob_signals & items[nr_retained].w_waitfor) {
			signals_observed = true;
			items[nr_retained].w_observed = object->ob_signals;
		}

		object_unlock_irqrestore(object, irq_flags);
	}

	if (signals_observed || status != KERN_OK) {
		goto cleanup;
	}

	schedule(SCHED_NORMAL);

	for (size_t i = 0; i < nr_retained; i++) {
		object_lock_irqsave(objects[i], &irq_flags);

		if (objects[i]->ob_signals & items[i].w_waitfor) {
			signals_observed = true;
			items[i].w_observed = objects[i]->ob_signals;
		}

		object_unlock_irqrestore(objects[i], irq_flags);
	}

cleanup:
	for (size_t i = 0; i < nr_retained; i++) {
		thread_wait_end_nosleep(&waiters[i], &objects[i]->ob_wq);
		object_unref(objects[i]);
	}

	self_thread->tr_state = THREAD_READY;
	return status;
}