#pragma once

#include <locks.hfa>
#include <limits.hfa>
#include <kernel.hfa>
#include <iofwd.hfa>
#include <virtual_dtor.hfa>

#ifdef __CFA_DEBUG__
#define CFA_DEBUG( stmt ) stmt
#else
#define CFA_DEBUG( stmt )
#endif // CFA_DEBUG

#define DEBUG_ABORT( cond, string ) CFA_DEBUG( if ( cond ) abort( string ) )

// Define the default number of processors created in the executor. Must be greater than 0.
#define __DEFAULT_EXECUTOR_PROCESSORS__ 2

// Define the default number of threads created in the executor. Must be greater than 0.
#define __DEFAULT_EXECUTOR_WORKERS__ 2

// Define the default number of executor request-queues (mailboxes) written to by actors and serviced by the
// actor-executor threads. Must be greater than 0.
#define __DEFAULT_EXECUTOR_RQUEUES__ 4

// Define if executor is created in a separate cluster
#define __DEFAULT_EXECUTOR_SEPCLUS__ false

#define __DEFAULT_EXECUTOR_BUFSIZE__ 10

#define __STEAL 1 // workstealing toggle. Disjoint from toggles above

// workstealing heuristic selection (only set one to be 1)
// #define RAND 0
#define SEARCH 1

// show stats
// #define ACTOR_STATS

// used to run and only track missed queue gulps
#ifdef ACTOR_STATS
#define ACTOR_STATS_QUEUE_MISSED
#endif

// forward decls
struct actor;
struct message;
struct executor;

enum allocation { Nodelete, Delete, Destroy, Finished }; // allocation status

typedef allocation (*__receive_fn)(actor &, message &, actor **, message **);
struct request {
	actor * receiver;
	message * msg;
	__receive_fn fn;
};

struct a_msg {
	int m;
};
static inline void ?{}( request & this ) {}
static inline void ?{}( request & this, actor * receiver, message * msg, __receive_fn fn ) {
	this.receiver = receiver;
	this.msg = msg;
	this.fn = fn;
}
static inline void ?{}( request & this, request & copy ) {
	this.receiver = copy.receiver;
	this.msg = copy.msg;
	this.fn = copy.fn;
}

// Vector-like data structure that supports O(1) queue operations with no bound on size
// assumes gulping behaviour (once a remove occurs, removes happen until empty beforw next insert)
struct copy_queue {
	request * buffer;
	size_t count, buffer_size, index, utilized, last_size;
};
static inline void ?{}( copy_queue & this ) {}
static inline void ?{}( copy_queue & this, size_t buf_size ) with(this) { 
	buffer_size = buf_size;
	buffer = aalloc( buffer_size );
	count = 0;
	utilized = 0;
	index = 0;
	last_size = 0;
}
static inline void ^?{}( copy_queue & this ) with(this) {
	DEBUG_ABORT( count != 0, "Actor system terminated with messages sent but not received\n" );
	adelete(buffer);
}

static inline void insert( copy_queue & this, request & elem ) with(this) {
	if ( count >= buffer_size ) { // increase arr size
		last_size = buffer_size;
		buffer_size = 2 * buffer_size;
		buffer = realloc( buffer, sizeof( request ) * buffer_size );
		/* paranoid */ verify( buffer );
	}
	memcpy( &buffer[count], &elem, sizeof(request) );
	count++;
}

// once you start removing you need to remove all elements
// it is not supported to call insert() before the array is fully empty
static inline request & remove( copy_queue & this ) with(this) {
	if ( count > 0 ) {
		count--;
		size_t old_idx = index;
		index = count == 0 ? 0 : index + 1;
		return buffer[old_idx];
	}
	request * ret = 0p;
	return *0p;
}

// try to reclaim some memory if less than half of buffer is utilized
static inline void reclaim( copy_queue & this ) with(this) {
	if ( utilized >= last_size || buffer_size <= 4 ) { utilized = 0; return; }
	utilized = 0;
	buffer_size--;
	buffer = realloc( buffer, sizeof( request ) * buffer_size ); // try to reclaim some memory
}

static inline bool is_empty( copy_queue & this ) with(this) { return count == 0; }

struct work_queue {
	__spinlock_t mutex_lock;
	copy_queue * owned_queue;							// copy queue allocated and cleaned up by this work_queue
	copy_queue * c_queue;								// current queue
	volatile bool being_processed;						// flag to prevent concurrent processing
	#ifdef ACTOR_STATS
	unsigned int id;
    #endif
    #ifdef ACTOR_STATS_QUEUE_MISSED
	size_t missed;										// transfers skipped due to being_processed flag being up
	#endif
}; // work_queue
static inline void ?{}( work_queue & this, size_t buf_size, unsigned int i ) with(this) { 
	owned_queue = alloc();								// allocated separately to avoid false sharing
	(*owned_queue){ buf_size };
	c_queue = owned_queue;
	being_processed = false;
	#ifdef ACTOR_STATS
	id = i;
	missed = 0;
	#endif
}

// clean up copy_queue owned by this work_queue
static inline void ^?{}( work_queue & this ) with(this) { delete( owned_queue ); }

static inline void insert( work_queue & this, request & elem ) with(this) {
	lock( mutex_lock __cfaabi_dbg_ctx2 );
	insert( *c_queue, elem );
	unlock( mutex_lock );
} // insert

static inline void transfer( work_queue & this, copy_queue ** transfer_to ) with(this) {
	lock( mutex_lock __cfaabi_dbg_ctx2 );
	#ifdef __STEAL

	// check if queue is being processed elsewhere
	if ( unlikely( being_processed ) ) {
		#ifdef ACTOR_STATS
		missed++;
		#endif
		unlock( mutex_lock );
		return;
	}

	being_processed = c_queue->count != 0;
	#endif // __STEAL

	c_queue->utilized = c_queue->count;

	// swap copy queue ptrs
	copy_queue * temp = *transfer_to;
	*transfer_to = c_queue;
	c_queue = temp;
	unlock( mutex_lock );
} // transfer

// needed since some info needs to persist past worker lifetimes
struct worker_info {
	volatile unsigned long long stamp;
	#ifdef ACTOR_STATS
	size_t stolen_from, try_steal, stolen, empty_stolen, failed_swaps, msgs_stolen;
	unsigned long long processed;
	size_t gulps;
	#endif
};
static inline void ?{}( worker_info & this ) {
	#ifdef ACTOR_STATS
	this.stolen_from = 0;
	this.try_steal = 0;									// attempts to steal
	this.stolen = 0;									// successful steals
	this.processed = 0;									// requests processed
	this.gulps = 0;										// number of gulps
	this.failed_swaps = 0;								// steal swap failures
	this.empty_stolen = 0;								// queues empty after steal
	this.msgs_stolen = 0;								// number of messages stolen
	#endif
	this.stamp = rdtscl();
}

// #ifdef ACTOR_STATS
// unsigned int * stolen_arr;
// unsigned int * replaced_queue;
// #endif
thread worker {
	work_queue ** request_queues;
	copy_queue * current_queue;
	executor * executor_;
	unsigned int start, range;
	int id;
};

#ifdef ACTOR_STATS
// aggregate counters for statistics
size_t __total_tries = 0, __total_stolen = 0, __total_workers, __all_gulps = 0, __total_empty_stolen = 0,
	__total_failed_swaps = 0, __all_processed = 0, __num_actors_stats = 0, __all_msgs_stolen = 0;
#endif
static inline void ?{}( worker & this, cluster & clu, work_queue ** request_queues, copy_queue * current_queue, executor * executor_,
	unsigned int start, unsigned int range, int id ) {
	((thread &)this){ clu };
	this.request_queues = request_queues;				// array of all queues
	this.current_queue = current_queue;					// currently gulped queue (start with empty queue to use in swap later)
	this.executor_ = executor_;							// pointer to current executor
	this.start = start;									// start of worker's subrange of request_queues
	this.range = range;									// size of worker's subrange of request_queues
	this.id = id;										// worker's id and index in array of workers
}

static bool no_steal = false;
struct executor {
	cluster * cluster;									// if workers execute on separate cluster
	processor ** processors;							// array of virtual processors adding parallelism for workers
	work_queue * request_queues;						// master array of work request queues
	copy_queue * local_queues;							// array of all worker local queues to avoid deletion race
	work_queue ** worker_req_queues;					// secondary array of work queues to allow for swapping
	worker ** workers;									// array of workers executing work requests
	worker_info * w_infos;								// array of info about each worker 
	unsigned int nprocessors, nworkers, nrqueues;		// number of processors/threads/request queues
	bool seperate_clus;									// use same or separate cluster for executor
	volatile bool is_shutdown;							// flag to communicate shutdown to worker threads
}; // executor

// #ifdef ACTOR_STATS
// __spinlock_t out_lock;
// #endif
static inline void ^?{}( worker & mutex this ) with(this) { 
	#ifdef ACTOR_STATS
	__atomic_add_fetch(&__all_gulps, executor_->w_infos[id].gulps,__ATOMIC_SEQ_CST);
	__atomic_add_fetch(&__all_processed, executor_->w_infos[id].processed,__ATOMIC_SEQ_CST);
	__atomic_add_fetch(&__all_msgs_stolen, executor_->w_infos[id].msgs_stolen,__ATOMIC_SEQ_CST);
	__atomic_add_fetch(&__total_tries, executor_->w_infos[id].try_steal, __ATOMIC_SEQ_CST);
	__atomic_add_fetch(&__total_stolen, executor_->w_infos[id].stolen, __ATOMIC_SEQ_CST);
	__atomic_add_fetch(&__total_failed_swaps, executor_->w_infos[id].failed_swaps, __ATOMIC_SEQ_CST);
	__atomic_add_fetch(&__total_empty_stolen, executor_->w_infos[id].empty_stolen, __ATOMIC_SEQ_CST);

	// per worker steal stats (uncomment alongside the lock above this routine to print)
	// lock( out_lock __cfaabi_dbg_ctx2 );
	// printf("Worker id: %d, processed: %llu messages, attempted %lu, stole: %lu, stolen from: %lu\n", id, processed, try_steal, stolen, __atomic_add_fetch(&executor_->w_infos[id].stolen_from, 0, __ATOMIC_SEQ_CST) );
	// int count = 0;
	// int count2 = 0;
	// for ( i; range ) {
	//	 if ( replaced_queue[start + i] > 0 ){
	//		 count++;
	//		 // printf("%d: %u, ",i, replaced_queue[i]);
	//	 }
	//	 if (__atomic_add_fetch(&stolen_arr[start + i],0,__ATOMIC_SEQ_CST) > 0)
	//		 count2++;
	// }
	// printf("swapped with: %d of %u indices\n", count, executor_->nrqueues / executor_->nworkers );
	// printf("%d of %u indices were stolen\n", count2, executor_->nrqueues / executor_->nworkers );
	// unlock( out_lock );
	#endif
}

static inline void ?{}( executor & this, unsigned int nprocessors, unsigned int nworkers, unsigned int nrqueues, bool seperate_clus, size_t buf_size ) with(this) {
	if ( nrqueues < nworkers ) abort( "nrqueues needs to be >= nworkers\n" );
	this.nprocessors = nprocessors;
	this.nworkers = nworkers;
	this.nrqueues = nrqueues;
	this.seperate_clus = seperate_clus;
	this.is_shutdown = false;

	if ( nworkers == nrqueues )
		no_steal = true;
	
	#ifdef ACTOR_STATS
	// stolen_arr = aalloc( nrqueues );
	// replaced_queue = aalloc( nrqueues );
	__total_workers = nworkers;
	#endif

	if ( seperate_clus ) {
		this.cluster = alloc();
		(*cluster){};
	} else cluster = active_cluster();

	request_queues = aalloc( nrqueues );
	worker_req_queues = aalloc( nrqueues );
	for ( i; nrqueues ) {
		request_queues[i]{ buf_size, i };
		worker_req_queues[i] = &request_queues[i];
	}
	
	processors = aalloc( nprocessors );
	for ( i; nprocessors ) 
		(*(processors[i] = alloc())){ *cluster };

	local_queues = aalloc( nworkers );
	workers = aalloc( nworkers );
	w_infos = aalloc( nworkers );
	unsigned int reqPerWorker = nrqueues / nworkers, extras = nrqueues % nworkers;

	for ( i; nworkers ) {
		w_infos[i]{};
		local_queues[i]{ buf_size };
	}

	for ( unsigned int i = 0, start = 0, range; i < nworkers; i += 1, start += range ) {
		range = reqPerWorker + ( i < extras ? 1 : 0 );
		(*(workers[i] = alloc())){ *cluster, worker_req_queues, &local_queues[i], &this, start, range, i };
	} // for
}
static inline void ?{}( executor & this, unsigned int nprocessors, unsigned int nworkers, unsigned int nrqueues, bool seperate_clus ) { this{ nprocessors, nworkers, nrqueues, seperate_clus, __DEFAULT_EXECUTOR_BUFSIZE__ }; }
static inline void ?{}( executor & this, unsigned int nprocessors, unsigned int nworkers, unsigned int nrqueues ) { this{ nprocessors, nworkers, nrqueues, __DEFAULT_EXECUTOR_SEPCLUS__ }; }
static inline void ?{}( executor & this, unsigned int nprocessors, unsigned int nworkers ) { this{ nprocessors, nworkers, __DEFAULT_EXECUTOR_RQUEUES__ }; }
static inline void ?{}( executor & this, unsigned int nprocessors ) { this{ nprocessors, __DEFAULT_EXECUTOR_WORKERS__ }; }
static inline void ?{}( executor & this ) { this{ __DEFAULT_EXECUTOR_PROCESSORS__ }; }

static inline void ^?{}( executor & this ) with(this) {
	is_shutdown = true;

	for ( i; nworkers )
		delete( workers[i] );

	for ( i; nprocessors ) {
		delete( processors[i] );
	} // for

	#ifdef ACTOR_STATS_QUEUE_MISSED
	size_t misses = 0;
	for ( i; nrqueues ) {
		misses += worker_req_queues[i]->missed;
	}
	// adelete( stolen_arr );
	// adelete( replaced_queue );
	#endif

	adelete( workers );
	adelete( w_infos );
	adelete( local_queues );
	adelete( request_queues );
	adelete( worker_req_queues );
	adelete( processors );
	if ( seperate_clus ) delete( this.cluster );

	#ifdef ACTOR_STATS // print formatted stats
	printf("	Actor System Stats:\n");
	printf("\tActors Created:\t\t\t\t%lu\n\tMessages Sent:\t\t\t\t%lu\n", __num_actors_stats, __all_processed);
	size_t avg_gulps = __all_gulps == 0 ? 0 : __all_processed / __all_gulps;
	printf("\tGulps:\t\t\t\t\t%lu\n\tAverage Gulp Size:\t\t\t%lu\n\tMissed gulps:\t\t\t\t%lu\n", __all_gulps, avg_gulps, misses);
	printf("\tSteal attempts:\t\t\t\t%lu\n\tSteals:\t\t\t\t\t%lu\n\tSteal failures (no candidates):\t\t%lu\n\tSteal failures (failed swaps):\t\t%lu\t Empty steals:\t\t%lu\n", 
		__total_tries, __total_stolen, __total_tries - __total_stolen - __total_failed_swaps, __total_failed_swaps, __total_empty_stolen);
	size_t avg_steal = __total_stolen == 0 ? 0 : __all_msgs_stolen / __total_stolen;
	printf("\tMessages stolen:\t\t\t%lu\n\tAverage steal size:\t\t\t%lu\n", __all_msgs_stolen, avg_steal);
	#endif

    #ifndef ACTOR_STATS
    #ifdef ACTOR_STATS_QUEUE_MISSED
    printf("\t%lu", misses);
    #endif
    #endif
		
}

// this is a static field of executor but have to forward decl for get_next_ticket
static size_t __next_ticket = 0; 

static inline size_t __get_next_ticket( executor & this ) with(this) {
	#ifdef __CFA_DEBUG__
	size_t temp = __atomic_fetch_add( &__next_ticket, 1, __ATOMIC_SEQ_CST) % nrqueues;

	// reserve MAX for dead actors
	if ( unlikely( temp == MAX ) ) temp = __atomic_fetch_add( &__next_ticket, 1, __ATOMIC_SEQ_CST) % nrqueues;
	return temp;
	#else
	return __atomic_fetch_add( &__next_ticket, 1, __ATOMIC_RELAXED) % nrqueues;
	#endif
} // tickets

// TODO: update globals in this file to be static fields once the static fields project is done
static executor * __actor_executor_ = 0p;
static bool __actor_executor_passed = false;			// was an executor passed to actor_start
static size_t __num_actors_ = 0;						// number of actor objects in system
static struct thread$ * __actor_executor_thd = 0p;		// used to wake executor after actors finish
struct actor {
	size_t ticket;										// executor-queue handle
	allocation alloc;									// allocation action
	inline virtual_dtor;
};

static inline void ?{}( actor & this ) with(this) {
	// Once an actor is allocated it must be sent a message or the actor system cannot stop. Hence, its receive
	// member must be called to end it
	DEBUG_ABORT( __actor_executor_ == 0p, "Creating actor before calling actor_start() can cause undefined behaviour.\n" );
	alloc = Nodelete;
	ticket = __get_next_ticket( *__actor_executor_ );
	__atomic_fetch_add( &__num_actors_, 1, __ATOMIC_RELAXED );
	#ifdef ACTOR_STATS
	__atomic_fetch_add( &__num_actors_stats, 1, __ATOMIC_SEQ_CST );
	#endif
}

static inline void check_actor( actor & this ) {
	if ( this.alloc != Nodelete ) {
		switch( this.alloc ) {
			case Delete: delete( &this ); break;
			case Destroy:
				CFA_DEBUG( this.ticket = MAX; );		// mark as terminated
				^?{}(this);
				break;
			case Finished:
				CFA_DEBUG( this.ticket = MAX; );		// mark as terminated
				break;
			default: ;									// stop warning
		}

		if ( unlikely( __atomic_add_fetch( &__num_actors_, -1, __ATOMIC_RELAXED ) == 0 ) ) { // all actors have terminated
			unpark( __actor_executor_thd );
		}
	}
}

struct message {
	allocation alloc;									// allocation action
	inline virtual_dtor;
};

static inline void ?{}( message & this ) {
	this.alloc = Nodelete;
}
static inline void ?{}( message & this, allocation alloc ) {
	memcpy( &this.alloc, &alloc, sizeof(allocation) );	// optimization to elide ctor
	CFA_DEBUG( if ( this.alloc == Finished ) this.alloc = Nodelete; );
}
static inline void ^?{}( message & this ) with(this) {
	CFA_DEBUG(
		if ( alloc == Nodelete ) {
			printf( "CFA warning (UNIX pid:%ld) : program terminating with message %p allocated but never sent.\n",
					(long int)getpid(), &this );
		}
	)
}

static inline void check_message( message & this ) {
	switch ( this.alloc ) {						// analyze message status
		case Nodelete: CFA_DEBUG( this.alloc = Finished ); break;
		case Delete: delete( &this ); break;
		case Destroy: ^?{}( this ); break;
		case Finished: break;
	} // switch
}
static inline allocation set_allocation( message & this, allocation state ) {
	CFA_DEBUG( if ( state == Nodelete ) state = Finished; );
	allocation prev = this.alloc;
	this.alloc = state;
	return prev;
}
static inline allocation get_allocation( message & this ) {
	return this.alloc;
}

static inline void deliver_request( request & this ) {
	DEBUG_ABORT( this.receiver->ticket == (unsigned long int)MAX, "Attempted to send message to deleted/dead actor\n" );
	actor * base_actor;
	message * base_msg;
	allocation temp = this.fn( *this.receiver, *this.msg, &base_actor, &base_msg );
	memcpy( &base_actor->alloc, &temp, sizeof(allocation) ); // optimization to elide ctor
	check_message( *base_msg );
	check_actor( *base_actor );
}

// tries to atomically swap two queues and returns 0p if the swap failed
// returns ptr to newly owned queue if swap succeeds
static inline work_queue * try_swap_queues( worker & this, unsigned int victim_idx, unsigned int my_idx ) with(this) {
	work_queue * my_queue = request_queues[my_idx];
	work_queue * other_queue = request_queues[victim_idx];

	// if either queue is 0p then they are in the process of being stolen
	if ( other_queue == 0p ) return 0p;

	// try to set our queue ptr to be 0p. If it fails someone moved our queue so return false
	if ( !__atomic_compare_exchange_n( &request_queues[my_idx], &my_queue, 0p, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST ) )
		return 0p;

	// try to set other queue ptr to be our queue ptr. If it fails someone moved the other queue so fix up then return false
	if ( !__atomic_compare_exchange_n( &request_queues[victim_idx], &other_queue, my_queue, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST ) ) {
		/* paranoid */ verify( request_queues[my_idx] == 0p );
		request_queues[my_idx] = my_queue; // reset my queue ptr back to appropriate val
		return 0p;
	}

	// we have successfully swapped and since our queue is 0p no one will touch it so write back new queue ptr non atomically
	request_queues[my_idx] = other_queue; // last write does not need to be atomic
	return other_queue;
}

// once a worker to steal from has been chosen, choose queue to steal from
static inline void choose_queue( worker & this, unsigned int victim_id, unsigned int swap_idx ) with(this) {
	// have to calculate victim start and range since victim may be deleted before us in shutdown
	const unsigned int queues_per_worker = executor_->nrqueues / executor_->nworkers;
	const unsigned int extras = executor_->nrqueues % executor_->nworkers;
	unsigned int vic_start, vic_range;
	if ( extras > victim_id  ) {
		vic_range = queues_per_worker + 1;
		vic_start = vic_range * victim_id;
	} else {
		vic_start = extras + victim_id * queues_per_worker;
		vic_range = queues_per_worker;
	}
	unsigned int start_idx = prng( vic_range );

	unsigned int tries = 0;
	work_queue * curr_steal_queue;

	for ( unsigned int i = start_idx; tries < vic_range; i = (i + 1) % vic_range ) {
		tries++;
		curr_steal_queue = request_queues[ i + vic_start ];
		// avoid empty queues and queues that are being operated on
		if ( curr_steal_queue == 0p || curr_steal_queue->being_processed || is_empty( *curr_steal_queue->c_queue ) )
			continue;

		#ifdef ACTOR_STATS
		curr_steal_queue = try_swap_queues( this, i + vic_start, swap_idx );
		if ( curr_steal_queue ) {
			executor_->w_infos[id].msgs_stolen += curr_steal_queue->c_queue->count;
			executor_->w_infos[id].stolen++;
			if ( is_empty( *curr_steal_queue->c_queue ) ) executor_->w_infos[id].empty_stolen++;
			// __atomic_add_fetch(&executor_->w_infos[victim_id].stolen_from, 1, __ATOMIC_RELAXED);
			// replaced_queue[swap_idx]++;
			// __atomic_add_fetch(&stolen_arr[ i + vic_start ], 1, __ATOMIC_RELAXED);
		} else {
			executor_->w_infos[id].failed_swaps++;
		}
		#else
		curr_steal_queue = try_swap_queues( this, i + vic_start, swap_idx );
		#endif // ACTOR_STATS

		return;
	}

	return;
}

// choose a worker to steal from
static inline void steal_work( worker & this, unsigned int swap_idx ) with(this) {
	#if RAND
	unsigned int victim = prng( executor_->nworkers );
	if ( victim == id ) victim = ( victim + 1 ) % executor_->nworkers;
	choose_queue( this, victim, swap_idx );
	#elif SEARCH
	unsigned long long min = MAX; // smaller timestamp means longer since service
	int min_id = 0; // use ints not uints to avoid integer underflow without hacky math
	int n_workers = executor_->nworkers;
	unsigned long long curr_stamp;
	int scount = 1;
	for ( int i = (id + 1) % n_workers; scount < n_workers; i = (i + 1) % n_workers, scount++ ) {
		curr_stamp = executor_->w_infos[i].stamp;
		if ( curr_stamp < min ) {
			min = curr_stamp;
			min_id = i;
		}
	} 
	choose_queue( this, min_id, swap_idx );
	#endif
}

#define CHECK_TERMINATION if ( unlikely( executor_->is_shutdown ) ) break Exit
void main( worker & this ) with(this) {
	// #ifdef ACTOR_STATS
	// for ( i; executor_->nrqueues ) {
	//	 replaced_queue[i] = 0;
	//	 __atomic_store_n( &stolen_arr[i], 0, __ATOMIC_SEQ_CST );
	// }
	// #endif

	// threshold of empty queues we see before we go stealing
	const unsigned int steal_threshold = 2 * range;

	// Store variable data here instead of worker struct to avoid any potential false sharing
	unsigned int empty_count = 0;
	request & req;
	work_queue * curr_work_queue;

	Exit:
	for ( unsigned int i = 0;; i = (i + 1) % range ) {	// cycle through set of request buffers
		curr_work_queue = request_queues[i + start];

        #ifndef __STEAL
        CHECK_TERMINATION;
        #endif
		
		// check if queue is empty before trying to gulp it
		if ( is_empty( *curr_work_queue->c_queue ) ) {
			#ifdef __STEAL
			empty_count++;
			if ( empty_count < steal_threshold ) continue;
			#else
			continue;
			#endif
		}
		transfer( *curr_work_queue, &current_queue );
		#ifdef ACTOR_STATS
		executor_->w_infos[id].gulps++;
		#endif // ACTOR_STATS
		#ifdef __STEAL
		if ( is_empty( *current_queue ) ) {
			if ( unlikely( no_steal ) ) { CHECK_TERMINATION; continue; }
			empty_count++;
			if ( empty_count < steal_threshold ) continue;
			empty_count = 0;

			CHECK_TERMINATION; // check for termination

			__atomic_store_n( &executor_->w_infos[id].stamp, rdtscl(), __ATOMIC_RELAXED );
			
			#ifdef ACTOR_STATS
			executor_->w_infos[id].try_steal++;
			#endif // ACTOR_STATS
			
			steal_work( this, start + prng( range ) );
			continue;
		}
		#endif // __STEAL
		while ( ! is_empty( *current_queue ) ) {
			#ifdef ACTOR_STATS
			executor_->w_infos[id].processed++;
			#endif
			&req = &remove( *current_queue );
			if ( !&req ) continue;
			deliver_request( req );
		}
		#ifdef __STEAL
		curr_work_queue->being_processed = false;		// set done processing
		empty_count = 0; // we found work so reset empty counter
		#endif

		CHECK_TERMINATION;
		
		// potentially reclaim some of the current queue's vector space if it is unused
		reclaim( *current_queue );
	} // for
}

static inline void send( executor & this, request & req, unsigned long int ticket ) with(this) {
	insert( request_queues[ticket], req);
}

static inline void send( actor & this, request & req ) {
	DEBUG_ABORT( this.ticket == (unsigned long int)MAX, "Attempted to send message to deleted/dead actor\n" );
	send( *__actor_executor_, req, this.ticket );
}

static inline void __reset_stats() {
	#ifdef ACTOR_STATS
	__total_tries = 0;
	__total_stolen = 0;
	__all_gulps = 0;
	__total_failed_swaps = 0;
	__total_empty_stolen = 0;
	__all_processed = 0;
	__num_actors_stats = 0;
	__all_msgs_stolen = 0;
	#endif
}

static inline void actor_start( size_t num_thds ) {
	__reset_stats();
	__actor_executor_thd = active_thread();
	__actor_executor_ = alloc();
	(*__actor_executor_){ 0, num_thds, num_thds == 1 ? 1 : num_thds * 16 };
}

static inline void actor_start() { actor_start( get_proc_count( *active_cluster() ) ); }

static inline void actor_start( executor & this ) {
	__reset_stats();
	__actor_executor_thd = active_thread();
	__actor_executor_ = &this;
	__actor_executor_passed = true;
}

static inline void actor_stop() {
	park();												// unparked when actor system is finished

	if ( !__actor_executor_passed ) delete( __actor_executor_ );
	__actor_executor_ = 0p;
	__actor_executor_thd = 0p;
	__next_ticket = 0;
	__actor_executor_passed = false;
}

// Default messages to send to any actor to change status
// assigned at creation to __base_msg_finished to avoid unused message warning
message __base_msg_finished @= { .alloc = Finished };
struct delete_msg_t { inline message; } delete_msg = __base_msg_finished;
struct destroy_msg_t { inline message; } destroy_msg = __base_msg_finished;
struct finished_msg_t { inline message; } finished_msg = __base_msg_finished;

allocation receive( actor & this, delete_msg_t & ) { return Delete; }
allocation receive( actor & this, destroy_msg_t & ) { return Destroy; }
allocation receive( actor & this, finished_msg_t & ) { return Finished; }

// Default messages used all the time.
struct start_msg_t { inline message; } start_msg = __base_msg_finished; // start actor
struct stop_msg_t { inline message; } stop_msg = __base_msg_finished; // terminate actor