#include "MultiTimer.h"
#include <stdio.h>

/* Timer handle list head. */
static MultiTimer* timerList = NULL;

/* Timer tick */
static PlatformTicksFunction_t platformTicksFunction = NULL;

int MultiTimerInstall(PlatformTicksFunction_t ticksFunc)
{
    platformTicksFunction = ticksFunc;
    return 0;
}

int MultiTimerStart(MultiTimer* timer, uint64_t timing, MultiTimerCallback_t callback, void* userData, uint8_t is_repeated)
{
    if (!timer || !callback ) {
        return -1;
    }
    MultiTimer** nextTimer = &timerList;
    /* Remove the existing target timer. */
    for (; *nextTimer; nextTimer = &(*nextTimer)->next) {
        if (timer == *nextTimer) {
            *nextTimer = timer->next; /* remove from list */
            break;
        }
    }

    /* Init timer. */
    timer->deadline = platformTicksFunction() + timing;
    timer->timeout = timing;
    timer->callback = callback;
    timer->userData = userData;
    timer->is_repeated = is_repeated;

    /* Insert timer. */
    for (nextTimer = &timerList;; nextTimer = &(*nextTimer)->next) {
        if (!*nextTimer) {
            timer->next = NULL;
            *nextTimer = timer;
            break;
        }
        if (timer->deadline < (*nextTimer)->deadline) {
            timer->next = *nextTimer;
            *nextTimer = timer;
            break;
        }
    }
    return 0;
}

int MultiTimerStop(MultiTimer* timer)
{
    MultiTimer** nextTimer = &timerList;
    timer->is_repeated = 0;
    /* Find and remove timer. */
    for (; *nextTimer; nextTimer = &(*nextTimer)->next) {
        MultiTimer* entry = *nextTimer;
        if (entry == timer) {
            *nextTimer = timer->next;
            break;
        }
    }
    return 0;
}

int MultiTimerYield(void)
{
    MultiTimer* entry = timerList;
    for (; entry; entry = entry->next) {
        /* Sorted list, just process with the front part. */
        if (platformTicksFunction() < entry->deadline) {
            return (int)(entry->deadline - platformTicksFunction());
        }
        /* remove expired timer from list */
        timerList = entry->next;

        /* call callback */
        if (entry->callback) {
            entry->callback(entry, entry->userData);
            if(entry->is_repeated == 1) {
                MultiTimerStart(entry, entry->timeout, entry->callback, entry->userData, 1);
            }
        }
    }
    return 0;
}