#include "memory/MemoryManager.h"
#include "sys/Syscall.h"
#include "thread/Scheduler.h"
#include <bits/rusage.h>

static void ticks_to_rusage(struct rusage* ru, u64 sticks, u64 uticks)
{
    ru->ru_stime.tv_sec = sticks / 1000;
    ru->ru_stime.tv_usec = (sticks % 1000) * 1000;
    ru->ru_utime.tv_sec = uticks / 1000;
    ru->ru_utime.tv_usec = (uticks % 1000) * 1000;
}

Result<u64> sys_getrusage(Registers*, SyscallArgs args)
{
    int who = (int)args[0];
    struct rusage* ru = (struct rusage*)args[1];

    auto* current = Scheduler::current();

    struct rusage kru;
    switch (who)
    {
    case RUSAGE_SELF: ticks_to_rusage(&kru, current->kernel_ticks_self, current->user_ticks_self); break;
    case RUSAGE_CHILDREN: ticks_to_rusage(&kru, current->kernel_ticks_children, current->user_ticks_children); break;
    default: return err(EINVAL);
    }

    if (!MemoryManager::copy_to_user_typed(ru, &kru)) return err(EFAULT);

    return 0;
}