/*
 * Copyright (c) 2016 Zibin Zheng <znbin@qq.com>
 * All rights reserved
 */

#include "multi_timer.h"

//timer handle list head.
static struct Timer* head_handle = NULL;

//Timer ticks
static uint32_t _timer_ticks = 0;

/**
  * @brief  Initializes the timer struct handle.
  * @param  handle: the timer handle strcut.
  * @param  timeout_cb: timeout callback.
  * @param  repeat: repeat interval time.
  * @retval None
  */
void timer_init (struct Timer* handle, void (*timeout_cb) (), uint32_t timeout, uint32_t repeat)
{
    // memset(handle, sizeof(struct Timer), 0);
    handle->timeout_cb = timeout_cb;
    handle->timeout    = _timer_ticks + timeout;
    handle->repeat     = repeat;
}

/**
  * @brief  Start the timer work, add the handle into work list.
  * @param  btn: target handle strcut.
  * @retval 0: succeed. -1: already exist.
  */
int timer_start (struct Timer* handle)
{
    struct Timer* target = head_handle;
    while (target)
    {
        if (target == handle)
        { return -1; }  //already exist.
        target = target->next;
    }
    handle->next = head_handle;
    head_handle  = handle;
    return 0;
}

/**
  * @brief  Stop the timer work, remove the handle off work list.
  * @param  handle: target handle strcut.
  * @retval None
  */
void timer_stop (struct Timer* handle)
{
    struct Timer** curr;
    for (curr = &head_handle; *curr;)
    {
        struct Timer* entry = *curr;
        if (entry == handle)
        {
            *curr = entry->next;
            //          free(entry);
        }
        else
        { curr = &entry->next; }
    }
}

/**
  * @brief  main loop.
  * @param  None.
  * @retval None
  */
void timer_loop()
{
    struct Timer* target;
    for (target = head_handle; target; target = target->next)
    {
        if (_timer_ticks >= target->timeout)
        {
            if (target->repeat == 0)
            {
                timer_stop (target);
            }
            else
            {
                target->timeout = _timer_ticks + target->repeat;
            }
            target->timeout_cb();
        }
    }
}

/**
  * @brief  background ticks, timer repeat invoking interval 1ms.
  * @param  None.
  * @retval None.
  */
void timer_ticks()
{
    _timer_ticks++;
}