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#include "asleep.h"

#include "task.h"

#include <assert.h>

#include <stdio.h>

#include <stdlib.h>

#include <errno.h>

#include <math.h>

#include <string.h>

#include "cor_platform.h"

typedef struct Loop_Timer {

    int64_t when;

    Future *who;

} Loop_Timer;

typedef struct _ASleep {

    _Cor_Mutex mutex;

    unsigned users;

    Loop_Timer *sleepers;

    int lo;

    int hi;

    int max;

    _Cor_Semaphore sem;

    bool sleeploop_cancel;

    pthread_t sleeploop;

    bool started;

} _ASleep;

static _ASleep asleep;

static void *ASleep_Sleeper(void *param);

static void ASleep_ctor(

    _ASleep *me

){

    int r;

    me->sleepers = NULL;

    me->lo = 0;

    me->hi = 0;

    me->max = 0;

    _Cor_Mutex_ctor(&me->mutex);

    _Cor_Semaphore_ctor(&me->sem);

    me->sleeploop_cancel = false;

    r = pthread_create(&me->sleeploop, NULL, ASleep_Sleeper, me);

    assert(r == 0);

    me->started = true;

}

static void ASleep_dtor(

    _ASleep *me

){

    int r;

    me->started = false;

    me->sleeploop_cancel = true;

    _Cor_Semaphore_Signal(&me->sem);

    r = pthread_join(me->sleeploop, NULL);

    assert(r == 0);

    _Cor_Sempahore_dtor(&me->sem);

    _Cor_Mutex_dtor(&me->mutex);

    free(me->sleepers);

}

void ASleep_StartSystem(){

    ASleep_ctor(&asleep);

}

void ASleep_StopSystem(){

    ASleep_dtor(&asleep);

}

static void ASleep_AddSleeper(

    _ASleep *me,

    int64_t when,

    Future *who

){

    _Cor_Mutex_Lock(&me->mutex);

    int nsleepers;

    if (me->lo <= me->hi){

        int nsleepers = me->hi - me->lo;

        // ensure there's always an empty slot so that lo == hi always means no sleepers

        if (nsleepers+1 >= me->max) {

            me->max = (me->max == 0) ? 4 : me->max * 2;

            me->sleepers = realloc(me->sleepers, me->max * sizeof(Loop_Timer));

            assert(me->sleepers);

}

    } else {

        nsleepers = me->hi + me->max - me->lo;

        // ensure there's always an empty slot so that lo == hi always means no sleepers

        if (nsleepers+1 >= me->max) {

            int oldmax = me->max;

            me->max = (me->max == 0) ? 4 : me->max * 2;

            me->sleepers = realloc(me->sleepers, me->max * sizeof(Loop_Timer));

            assert(me->sleepers);

            memmove(&me->sleepers[me->lo], &me->lo + me->max - oldmax, sizeof(*me->sleepers) * oldmax - me->lo);

            me->lo += me->max - oldmax;

}

    // insertion sort - we're assuming there's not going to be many sleepers active at once

    int i;

    int nexti;

    for (i = me->hi; i != me->lo; i = nexti){

        nexti = i-1;

        if (i < 0){

            nexti += me->max;

}

        if (me->sleepers[nexti].when <= when){

            break;

}

        me->sleepers[i] = me->sleepers[nexti];

}

    me->sleepers[i].when = when;

    me->sleepers[i].who = who;

    me->hi += 1;

    if (me->hi >= me->max){

        me->hi -= me->max;

}

    _Cor_Mutex_Unlock(&me->mutex);

    _Cor_Semaphore_Signal(&me->sem);

}

static void ASleep_RemoveSleeper(

    _ASleep *me,

    int64_t when,

    Future *who

){

    _Cor_Mutex_Lock(&me->mutex);

    int i;

    for (i = me->lo; i != me->hi; ){

        if (me->sleepers[i].when == when && me->sleepers[i].who == who){

            int previ = i;

            i += 1;

            if (i >= me->max){

                i -= me->max;

}

            for (; i != me->hi; ){

                me->sleepers[previ] = me->sleepers[i];

                previ = i;

                i += 1;

                if (i >= me->max){

                    i -= me->max;

}

            me->hi = previ;

            break;

}

        i += 1;

        if (i >= me->max){

            i -= me->max;

}

    _Cor_Mutex_Unlock(&me->mutex);

    _Cor_Semaphore_Signal(&me->sem);

}

static void *ASleep_Sleeper(

    void *param

){

    _ASleep *me = (_ASleep *)param;

    while (!me->sleeploop_cancel){

        _Cor_Mutex_Lock(&me->mutex);

        bool got_one;

        if (me->lo != me->hi){

            int64_t when = me->sleepers[0].when;

            _Cor_Mutex_Unlock(&me->mutex);

            got_one = _Cor_Semaphore_Wait(&me->sem, when);

        } else {

            _Cor_Mutex_Unlock(&me->mutex);

            got_one = _Cor_Semaphore_Wait(&me->sem, -1);

}

        if (!got_one){

// timed out, so...

// issue any due timers

            int64_t now = _Cor_Realtime_Now();

            while(me->lo != me->hi && me->sleepers[me->lo].when <= now) {

                Future *fut = me->sleepers[me->lo].who;

                me->lo += 1;

                if (me->lo >= me->max){

                    me->lo -= me->max;

}

                _Cor_Mutex_Unlock(&me->mutex);

                Future_SetResult(fut, false, NULL);

                _Cor_Mutex_Lock(&me->mutex);

                now = _Cor_Realtime_Now();

}

            _Cor_Mutex_Unlock(&me->mutex);

}

    return NULL;

}

// value is a pointer to a float delay in seconds

bool ASleep(

    float delay,

    void **value

){

    assert(current_task && asleep.started);

    if (delay < 0){

        delay = 0;

}

    int64_t endtime = _Cor_Realtime_Now() + (int64_t)(delay * 1000000000);

    Future fut;

    Future_ctor(&fut);

    ASleep_AddSleeper(&asleep, endtime, &fut);

    bool res = Future_Await(&fut, value);

    ASleep_RemoveSleeper(&asleep, endtime, &fut);

    Future_dtor(&fut);

    return res;

}

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#include "asleep.h"

#include "task.h"

#include <assert.h>

#include <stdio.h>

#include <stdlib.h>

#include <errno.h>

#include <math.h>

#include <string.h>

#include "cor_platform.h"

typedef struct Loop_Timer {

    int64_t when;

    Future *who;

} Loop_Timer;

typedef struct _ASleep {

    _Cor_Mutex mutex;

    unsigned users;

    Loop_Timer *sleepers;

    int lo;

    int hi;

    int max;

    _Cor_Semaphore sem;

    bool sleeploop_cancel;

    _Cor_Thread sleeploop;

    bool started;

} _ASleep;

static _ASleep asleep;

static void *ASleep_Sleeper(void *param);

static void ASleep_ctor(

    _ASleep *me

){

    me->sleepers = NULL;

    me->lo = 0;

    me->hi = 0;

    me->max = 0;

    _Cor_Mutex_ctor(&me->mutex);

    _Cor_Semaphore_ctor(&me->sem);

    me->sleeploop_cancel = false;

    _Cor_Thread_ctor(&me->sleeploop, ASleep_Sleeper, me);

    me->started = true;

}

static void ASleep_dtor(

    _ASleep *me

){

    me->started = false;

    me->sleeploop_cancel = true;

    _Cor_Semaphore_Signal(&me->sem);

    _Cor_Thread_Join(&me->sleeploop);

    _Cor_Thread_dtor(&me->sleeploop);

    _Cor_Sempahore_dtor(&me->sem);

    _Cor_Mutex_dtor(&me->mutex);

    free(me->sleepers);

}

void ASleep_StartSystem(){

    ASleep_ctor(&asleep);

}

void ASleep_StopSystem(){

    ASleep_dtor(&asleep);

}

static void ASleep_AddSleeper(

    _ASleep *me,

    int64_t when,

    Future *who

){

    _Cor_Mutex_Lock(&me->mutex);

    int nsleepers;

    if (me->lo <= me->hi){

        int nsleepers = me->hi - me->lo;

        // ensure there's always an empty slot so that lo == hi always means no sleepers

        if (nsleepers+1 >= me->max) {

            me->max = (me->max == 0) ? 4 : me->max * 2;

            me->sleepers = realloc(me->sleepers, me->max * sizeof(Loop_Timer));

            assert(me->sleepers);

}

    } else {

        nsleepers = me->hi + me->max - me->lo;

        // ensure there's always an empty slot so that lo == hi always means no sleepers

        if (nsleepers+1 >= me->max) {

            int oldmax = me->max;

            me->max = (me->max == 0) ? 4 : me->max * 2;

            me->sleepers = realloc(me->sleepers, me->max * sizeof(Loop_Timer));

            assert(me->sleepers);

            memmove(&me->sleepers[me->lo], &me->lo + me->max - oldmax, sizeof(*me->sleepers) * oldmax - me->lo);

            me->lo += me->max - oldmax;

}

    // insertion sort - we're assuming there's not going to be many sleepers active at once

    int i;

    int nexti;

    for (i = me->hi; i != me->lo; i = nexti){

        nexti = i-1;

        if (i < 0){

            nexti += me->max;

}

        if (me->sleepers[nexti].when <= when){

            break;

}

        me->sleepers[i] = me->sleepers[nexti];

}

    me->sleepers[i].when = when;

    me->sleepers[i].who = who;

    me->hi += 1;

    if (me->hi >= me->max){

        me->hi -= me->max;

}

    _Cor_Mutex_Unlock(&me->mutex);

    _Cor_Semaphore_Signal(&me->sem);

}

static void ASleep_RemoveSleeper(

    _ASleep *me,

    int64_t when,

    Future *who

){

    _Cor_Mutex_Lock(&me->mutex);

    int i;

    for (i = me->lo; i != me->hi; ){

        if (me->sleepers[i].when == when && me->sleepers[i].who == who){

            int previ = i;

            i += 1;

            if (i >= me->max){

                i -= me->max;

}

            for (; i != me->hi; ){

                me->sleepers[previ] = me->sleepers[i];

                previ = i;

                i += 1;

                if (i >= me->max){

                    i -= me->max;

}

            me->hi = previ;

            break;

}

        i += 1;

        if (i >= me->max){

            i -= me->max;

}

    _Cor_Mutex_Unlock(&me->mutex);

    _Cor_Semaphore_Signal(&me->sem);

}

static void *ASleep_Sleeper(

    void *param

){

    _ASleep *me = (_ASleep *)param;

    while (!me->sleeploop_cancel){

        _Cor_Mutex_Lock(&me->mutex);

        bool got_one;

        if (me->lo != me->hi){

            int64_t when = me->sleepers[0].when;

            _Cor_Mutex_Unlock(&me->mutex);

            got_one = _Cor_Semaphore_Wait(&me->sem, when);

        } else {

            _Cor_Mutex_Unlock(&me->mutex);

            got_one = _Cor_Semaphore_Wait(&me->sem, -1);

}

        if (!got_one){

// timed out, so...

// issue any due timers

            int64_t now = _Cor_Realtime_Now();

            while(me->lo != me->hi && me->sleepers[me->lo].when <= now) {

                Future *fut = me->sleepers[me->lo].who;

                me->lo += 1;

                if (me->lo >= me->max){

                    me->lo -= me->max;

}

                _Cor_Mutex_Unlock(&me->mutex);

                Future_SetResult(fut, false, NULL);

                _Cor_Mutex_Lock(&me->mutex);

                now = _Cor_Realtime_Now();

}

            _Cor_Mutex_Unlock(&me->mutex);

}

    return NULL;

}

// value is a pointer to a float delay in seconds

bool ASleep(

    float delay,

    void **value

){

    assert(current_task && asleep.started);

    if (delay < 0){

        delay = 0;

}

    int64_t endtime = _Cor_Realtime_Now() + (int64_t)(delay * 1000000000);

    Future fut;

    Future_ctor(&fut);

    ASleep_AddSleeper(&asleep, endtime, &fut);

    bool res = Future_Await(&fut, value);

    ASleep_RemoveSleeper(&asleep, endtime, &fut);

    Future_dtor(&fut);

    return res;

}