#ifndef __THREAD_H
#define __THREAD_H

/**
 * @defgroup    thread  Threading
 * @ingroup     kernel
 * @{
 */

/**
 * @file
 * @author      Freie Universität Berlin, Computer Systems & Telematics, FeuerWhere project
 * @author      Kaspar Schleiser <kaspar@schleiser.de>
 */

#include <kernel.h>
#include <tcb.h>

/** Minimum stack size */
#define MINIMUM_STACK_SIZE	(sizeof(tcb_t))

/**
 * @brief Creates a new thread.
 * 
 * @param   stack Lowest address of preallocated stack space
 * @param   stacksize
 * @param   flags Options: 
 * YIELD: force context switch.
 * CREATE_SLEEPING: set new thread to sleeping state, thread must be woken up manually.
 * CREATE_STACKTEST: initialize stack with values needed for stack overflow testing.
 *
 * @param priority Priority of newly created thread. Lower number means higher
 * priority. 0 means highest possible priority. Lowest priority is
 * PRIORITY_IDLE-1, usually 30.
 *
 * @return  returns <0 on error, pid of newly created task else.
*/
int thread_create(char *stack, int stacksize, char priority, int flags, void (*function) (void), const char* name);

/**
 * @brief   returns the status of a process.
 * @return  STATUS_NOT_FOUND if pid is unknown
 */
unsigned int thread_getstatus(int pid);

/**
 * @brief   Puts the current thread into sleep mode. Has to be woken up externally.
 */
void thread_sleep();

/**
 * @brief   Wakes up a sleeping thread.
 * @param   pid The PID of the thread to be woken up
 * @return  STATUS_NOT_FOUND if pid is unknown or not sleeping
 */
int thread_wakeup(int pid);


/**
 * @brief   Returns the process ID of the currently running thread.
 * @return  Obviously you are not a golfer.
 */
int thread_getpid();

/**
 * @brief Measures the stack usage of a stack.
 * Only works if the thread was created with the flag CREATE_STACKTEST.
 *
 * @param stack The stack you want to measure. try active_thread->stack_start.
 */
int thread_measure_stack_usage(char* stack);

/* @} */
#endif /* __THREAD_H */