#include "kernel.h"
#include "scheduler.h"

static inline void zv_kernel_exec_process(
    zv_kernel_t *self,
    zv_process_t *target
) {
    bool was_interrupted = (target->state == ZV_INTERRUPTED);

    if (was_interrupted && self->interrupts > 0) {
        --self->interrupts;
    }

    target->state = ZV_WORKING;
    zv_state_t result = target->worker(self, target);

    if (result == ZV_WORKING || result == ZV_INTERRUPTED) {
        result = ZV_READY;
    }

    if (was_interrupted) {
        result = ZV_INTERRUPT_WAITING;
    }

    target->state = result;
}

static inline zv_process_t * zv_kernel_select_process(zv_kernel_t *self) {
    if (self->interrupts > 0) {
        zv_process_t *selected = zv_kernel_scheduler_select_interrupted(self);

        if (selected != NULL) {
            return selected;
        }       

        self->interrupts = 0;
    }

    return zv_kernel_scheduler_mode_selector(self);
}

void zv_kernel_scheduler_single_loop(zv_kernel_t *self) {
    zv_process_t *selected = zv_kernel_select_process(self);

    if (selected == NULL) {
        zv_kernel_idle_task();
        return;
    }

    zv_kernel_exec_process(self, selected);
    self->last = zv_kernel_get_pid(self, selected);
}

void zv_kernel_scheduler(zv_kernel_t *self) {
    while (true) {
        zv_kernel_scheduler_single_loop(self);
    }
}