#include "kthread.h"
#include "list.h"
#include "alloc.h"
#include "klibc.h"

static struct kthread *currentThread;

void _kthread_exit(){
        //TODO 
        return;
}

int kthreadSetup(vaddr_t mainStack, size_t mainStackSize){
        struct kthread * current = (struct kthread *)malloc(sizeof(struct kthread));
        strzcpy(current->name, "[KINIT]", KTHREAD_NAME_MAX_LENGTH);
        current->stackAddr = mainStack;
        current->stackSize = mainStackSize;

        list_singleton(currentThread, current);

        return 0;
}

struct kthread *createKthread(const char *name, cpu_kstate_function_arg1_t func,
                              void *args)
{
        struct kthread *thread = (struct kthread *)malloc(sizeof(struct kthread));
        if (!thread)
                return NULL;

        thread->stackAddr = (vaddr_t) malloc(KTHREAD_DEFAULT_STACK_SIZE);
        thread->stackSize = KTHREAD_DEFAULT_STACK_SIZE;

        if(!thread->stackAddr)
                goto free_mem;

        if(name)
                strzcpy(thread->name, name, KTHREAD_NAME_MAX_LENGTH);
        else
                strzcpy(thread->name, "[UNKNOW]", KTHREAD_NAME_MAX_LENGTH);

        if(cpu_kstate_init(&thread->cpuState, (cpu_kstate_function_arg1_t *)func, (vaddr_t)args,
                    thread->stackAddr, thread->stackSize,
                    (cpu_kstate_function_arg1_t *)_kthread_exit, 0))
                goto free_mem;

        list_add_tail(currentThread, thread);
        return thread;
free_mem:
        free((void *)thread->stackAddr);
        free((void *)thread);
        return NULL;
}

void deleteKthread(struct kthread *thread){
        list_delete(currentThread, thread);

        free((void *)thread->stackAddr);
        free((void *)thread);
}

struct cpu_state *selectNextThread(struct cpu_state *prevCpu){
        currentThread->cpuState = prevCpu;
        struct kthread *nextThread = currentThread->next;
        currentThread = nextThread;
        return nextThread->cpuState;
}