#include <xen/lib.h>
#include <xen/sched.h>
#include <xen/time.h>
#include <xen/sched-if.h>
#include <xen/softirq.h>
#include <xen/errno.h>
#include <xen/list.h>
#include <xen/timer.h>
#include <xen/randmd5.h>

int tot_vcpu=0;
MD5_CTX mdContext;

struct random_vcpu_info{
    struct list_head lista;
    struct vcpu *vcpu;
}*runnable;


void __init_runnable(void){
    runnable=xmalloc(struct random_vcpu_info);
    INIT_LIST_HEAD(&runnable->lista);
    printk("\nINIT runnable list\n");
}


static int random_vcpu_init(struct vcpu *v){
    struct random_vcpu_info *inf;
    inf= xmalloc(struct random_vcpu_info);
    if ( inf == NULL ) return -1;

    INIT_LIST_HEAD(&inf->lista);

    inf->vcpu=v;
    runnable->vcpu=v; 
    list_add(&inf->lista,&runnable->lista);
    tot_vcpu++; 
    printk("\n\nadd VCPU %d\n\n", v->vcpu_id);
    return 0;    
}

//destroy vcpu


struct task_slice random_schedule(s_time_t now){
    struct task_slice ret;
    struct random_vcpu_info *inf;
    int next_vcpu;

    printk("\n\nscheduling..\n");
    
    //MD5Final returns a random integer
    next_vcpu = (MD5Final (&mdContext)) % tot_vcpu;
    printk("\n\n\nnext_vcpu = %d",next_vcpu);
    inf = runnable;
    
    while (next_vcpu!=0){
        inf = list_entry(&runnable->lista, struct random_vcpu_info, lista );
        printk("runnable->v =%d", runnable->vcpu->vcpu_id);
        list_move_tail(&runnable->lista, &runnable->lista);
        next_vcpu--;
        printk("\nshifting list\n");   
    }
    ret.task= inf->vcpu;
    ret.time = MILLISECS(10);
    printk("\n\nI'm scheduling.. vcpi_id=%d , tot_vcpu=%d",inf->vcpu->vcpu_id,tot_vcpu);
    return ret;
}


static void __random_init(void){
    unsigned char digest[16];
    int i;
    long unsigned int mask= 0xFF;
    long unsigned int string_now = NOW();
    MD5Init (&mdContext);

    for (i=0;i<8;i++){
        digest[i]=(char) ((string_now & mask) >> 8*i);
        mask <<=8;
    }

    printk("Init Random Number Generator with word %x", (unsigned int) digest);
    MD5Update (&mdContext, (unsigned char*)prova, sizeof(s_time_t));
    printk("\n\nUpdating Random Generator\n");

}

static void random_vcpu_wake( struct vcpu *vc){
    printk("\n\nwake up!!!!!!!!!!!!\n\n");
    cpu_raise_softirq(smp_processor_id(),SCHEDULE_SOFTIRQ);
    __random_init();
    return;
}



struct scheduler sched_random_def = {
    .name           = "my Random Scheduler",
    .opt_name       = "random",
    .sched_id       = 17,
    .init_vcpu      = random_vcpu_init,
    .wake           = random_vcpu_wake,
    .destroy_vcpu   = NULL,
    .do_schedule    = random_schedule,

};