import mem:*

__if_comp__ __C__ simple_passthrough(::"-pthread") 
"""
#include <pthread.h>
"""

fun pthread_create(thrd : *ulong, strt_routine : fun(*void) : *void, input : *void) : int {
    __if_comp__ __C__ { 
    simple_passthrough(thrd,strt_routine,input::) """
    pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
    //int ret = pthread_create((pthread_t*)thrd, &attr, strt_routine.func, strt_routine.data);
    int ret = pthread_create((pthread_t*)thrd, &attr, strt_routine.func, input);
    pthread_attr_destroy(&attr);
    return ret;
    """
    }
    return 0
}

fun pthread_join(thrd : *ulong) : int {
    __if_comp__ __C__ { simple_passthrough(thrd::) """
    pthread_t thread = *((pthread_t*)thrd);
    return pthread_join(thread, NULL);
    """
    }
    return 0
}

fun pthread_exit() : *void {
    __if_comp__ __C__ { simple_passthrough 
    """
    pthread_exit(NULL);
    """
    }
}



fun future<T>(in : fun() : T ) : future<T> {
    var out.construct(in) : future<T>
    return out
}

obj func_res { var func : *void; var result : *void; }

obj future<T> {
    var result : T
    var status : int
    var psy : fun() : T
    var wrapper : fun(*void) : * void;
    var thread : ulong

    fun construct(in : fun() : T) : *future<T> {
        status = 0
        psy = in
        wrapper = fun(in : *void) : *void {
            var triple = (in) cast *func_res;
            var func = (triple->func) cast *fun() : T;
            var res : *T = (triple->result) cast *T;
            (*res) = (*func)();
            pthread_exit();
            delete(in);
            return null<void>();
        }
        return this
    }

    fun run() {
        var in = new<func_res>();
        in->result = (&result) cast *void;
        in->func = (&psy) cast *void;
        status = pthread_create(&thread,wrapper,(in) cast *void)
    }

    fun get_status():int {
        return status
    }

    fun finish() : T {
        pthread_join(&thread)
        return result
    }
}