/**
 ******************************************************************************
 * @addtogroup OpenPilotSystem OpenPilot System
 * @{
 * @addtogroup OpenPilotLibraries OpenPilot System Libraries
 * @{
 * @file       pios_task_monitor.h
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 * @brief      Task monitoring functions
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <pios.h>

#ifdef PIOS_INCLUDE_TASK_MONITOR

// Private variables
static xSemaphoreHandle  mLock;
static xTaskHandle      *mTaskHandles;
static uint32_t          mLastMonitorTime;
static uint16_t          mMaxTasks;

/**
 * Initialize the Task Monitor
 */
int32_t PIOS_TASK_MONITOR_Initialize(uint16_t max_tasks)
{
	mLock = xSemaphoreCreateRecursiveMutex();
	if (!mLock) { return -1; }

	mTaskHandles = (xTaskHandle*)pvPortMalloc(max_tasks * sizeof(xTaskHandle));
	if (!mTaskHandles) { return -1; }
	memset(mTaskHandles, 0, max_tasks * sizeof(xTaskHandle));

	mMaxTasks = max_tasks;
#if (configGENERATE_RUN_TIME_STATS == 1)
	mLastMonitorTime = portGET_RUN_TIME_COUNTER_VALUE();
#else
	mLastMonitorTime = 0;
#endif
	return 0;
}

/**
 * Register a task handle 
 */
int32_t PIOS_TASK_MONITOR_RegisterTask(uint16_t task_id, xTaskHandle handle)
{
	if (mTaskHandles && task_id < mMaxTasks) {
		xSemaphoreTakeRecursive(mLock, portMAX_DELAY);
		mTaskHandles[task_id] = handle;
		xSemaphoreGiveRecursive(mLock);
		return 0;
	} else {
		return -1;
	}
}

/**
 * Unregister a task handle
 */
int32_t PIOS_TASK_MONITOR_UnregisterTask(uint16_t task_id)
{
	if (mTaskHandles && task_id < mMaxTasks) {
		xSemaphoreTakeRecursive(mLock, portMAX_DELAY);
		mTaskHandles[task_id] = 0;
		xSemaphoreGiveRecursive(mLock);
		return 0;
	} else {
		return -1;
	}
}

/**
 * Query if a task is running
 */
bool PIOS_TASK_MONITOR_IsRunning(uint16_t task_id)
{
	return (mTaskHandles && task_id <= mMaxTasks && mTaskHandles[task_id]);
}

/**
 * Tell the caller the status of all tasks via a task-by-task callback
 */
void PIOS_TASK_MONITOR_ForEachTask(TaskMonitorTaskInfoCallback callback, void *context)
{
	if (!mTaskHandles) { return; }

	xSemaphoreTakeRecursive(mLock, portMAX_DELAY);

#if (configGENERATE_RUN_TIME_STATS == 1)
	/* Calculate the amount of elapsed run time between the last time we
	 * measured and now. Scale so that we can convert task run times
	 * directly to percentages. */
	uint32_t currentTime = portGET_RUN_TIME_COUNTER_VALUE();
	/* avoid divide-by-zero if the interval is too small */
	uint32_t deltaTime = ((currentTime - mLastMonitorTime)/100) ? : 1;
	mLastMonitorTime = currentTime;			
#endif
	/* Update all task information */
	for (uint16_t n = 0; n < mMaxTasks; ++n) {
		struct pios_task_info info;
		if (mTaskHandles[n]) {
			info.is_running = true;
#if defined(ARCH_POSIX) || defined(ARCH_WIN32)
			info.stack_remaining = 10000;
#else
			info.stack_remaining = uxTaskGetStackHighWaterMark(mTaskHandles[n]) * 4;
#endif
#if (configGENERATE_RUN_TIME_STATS == 1)
			/* Generate run time percentage stats */
			info.running_time_percentage = uxTaskGetRunTime(mTaskHandles[n])/deltaTime;
#else
			info.running_time_percentage = 0;
#endif		
		} else {
			info.is_running = false;
			info.stack_remaining = 0;
			info.running_time_percentage = 0;
		}
		/* Pass the information for this task back to the caller */
		callback(n, &info, context);
	}

	xSemaphoreGiveRecursive(mLock);
}

#endif // PIOS_INCLUDE_TASK_MONITOR