#ifndef __PT_H__
#define __PT_H__

typedef unsigned short lc_t;
#define LC_INIT(s) s = 0; // LC_INIT
#define LC_RESUME(s) switch(s) { case 0: // LC_RESUME
#define LC_SET(s) s = __LINE__; case __LINE__: // LC_SET line
#define LC_END(s) }  // LC_END

struct  pt { lc_t lc; };

#define PT_WAITING 0
#define PT_YIELDED 1
#define PT_EXITED  2
#define PT_ENDED   3
#define PT_INIT(pt)   LC_INIT((pt)->lc) // INIT
#define PT_THREAD(name_args) char name_args // THREAD
#define PT_BEGIN(pt) { char PT_YIELD_FLAG = 1; LC_RESUME((pt)->lc) // BEGIN
#define PT_END(pt) LC_END((pt)->lc);            \
        PT_YIELD_FLAG = 0;			\
        PT_INIT(pt); return PT_ENDED; }  // END
#define PT_WAIT_UNTIL(pt, condition)	        \
  do {						\
        LC_SET((pt)->lc);			\
        if(!(condition)) {		        \
          return PT_WAITING;			\
        }					\
  } while(0) // WAIT_UNTIL
#define PT_WAIT_WHILE(pt, cond)                 \
        PT_WAIT_UNTIL((pt), !(cond)) // WAIT_WHILE
#define PT_WAIT_THREAD(pt, thread)              \
        PT_WAIT_WHILE((pt), PT_SCHEDULE(thread)) // WAIT_THREAD
#define PT_SPAWN(pt, child, thread)		\
  do {						\
        PT_INIT((child));			\
        PT_WAIT_THREAD((pt), (thread));		\
  } while(0)                           // SPAWN
#define PT_RESTART(pt)				\
  do {						\
        PT_INIT(pt);				\
        return PT_WAITING;		        \
  } while(0)                          // RESTART
#define PT_EXIT(pt)				\
  do {						\
        PT_INIT(pt);				\
        return PT_EXITED;		        \
  } while(0) // EXIT
#define PT_SCHEDULE(f) ((f) < PT_EXITED) // SCHEDULE
#define PT_YIELD(pt)				\
  do {						\
        PT_YIELD_FLAG = 0;			\
        LC_SET((pt)->lc);			\
        if(PT_YIELD_FLAG == 0) {		\
          return PT_YIELDED;			\
        }					\
  } while(0)                           // YIELD
#define PT_YIELD_UNTIL(pt, cond)		\
  do {						\
        PT_YIELD_FLAG = 0;			\
        LC_SET((pt)->lc);			\
        if((PT_YIELD_FLAG == 0) || !(cond)) {	\
          return PT_YIELDED;			\
        }					\
  } while(0) // YIELD_UNTIL
// checked for n calls in a thread : seems OK
#define PT_DELAY(pt, ms)                        \
  do {			                        \
     static unsigned long _PTTTL_ ;             \
     _PTTTL_ = millis() + (unsigned int)(ms);   \
     PT_WAIT_UNTIL((pt), (millis() > _PTTTL_)); \
   } while(0)                          // DELAY
#define PT_SYNC(pt, mark, ms)                   \
  do {                                          \
     PT_WAIT_UNTIL((pt), (millis() - (mark) > (ms) )); \
  } while(0)                           // SYNC
#endif /* __PT_H__ */