/* This file is part of Raul.
 * Copyright (C) 2007 Dave Robillard <http://drobilla.net>
 * 
 * Raul 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 2 of the License, or (at your option) any later
 * version.
 * 
 * Raul 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 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.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef RAUL_THREAD_H
#define RAUL_THREAD_H

#include <string>
#include <iostream>
#include <pthread.h>
#include <boost/utility.hpp>

namespace Raul {


/** Abstract base class for a thread.
 *
 * Extend this and override the _run method to easily create a thread
 * to perform some task.
 *
 * The current Thread can be accessed using the get() method.
 * 
 * \ingroup raul
 */
class Thread : boost::noncopyable
{
public:
	virtual ~Thread() { stop(); }

	static Thread* create(const std::string& name="")
		{ return new Thread(name); }
	
	/** Must be called from thread */
	static Thread* create_for_this_thread(const std::string& name="")
		{ return new Thread(pthread_self(), name); }
	
	/** Return the calling thread.
	 * The return value of this should NOT be cached unless the thread is
	 * explicitly user created with create().
	 */
	static Thread& get() {
		Thread* this_thread = reinterpret_cast<Thread*>(pthread_getspecific(_thread_key));
		if (!this_thread)
			this_thread = new Thread(); // sets thread-specific data

		return *this_thread;
	}

	/** Launch and start the thread. */
	virtual void start() {
		std::cout << "[" << _name << " Thread] Starting." << std::endl;

		pthread_attr_t attr;
		pthread_attr_init(&attr);
		pthread_attr_setstacksize(&attr, 1500000);

		pthread_create(&_pthread, &attr, _static_run, this);
		_pthread_exists = true;
	}

	/** Stop and terminate the thread. */
	virtual void stop() {
		if (_pthread_exists) {
			pthread_cancel(_pthread);
			pthread_join(_pthread, NULL);
			_pthread_exists = false;
		}
	}

	void set_scheduling(int policy, unsigned int priority) {
		sched_param sp;
		sp.sched_priority = priority;
		int result = pthread_setschedparam(_pthread, SCHED_FIFO, &sp);
		if (!result) {
			std::cout << "[" << _name << "] Set scheduling policy to ";
			switch (policy) {
				case SCHED_FIFO:  std::cout << "SCHED_FIFO";  break;
				case SCHED_RR:    std::cout << "SCHED_RR";    break;
				case SCHED_OTHER: std::cout << "SCHED_OTHER"; break;
				default:          std::cout << "UNKNOWN";     break;
			}
			std::cout << ", priority " << sp.sched_priority << std::endl;
		} else {
			std::cout << "[" << _name << "] Unable to set scheduling policy ("
				<< strerror(result) << ")" << std::endl;
		}
	}
	
	const std::string& name() { return _name; }
	void set_name(const std::string& name) { _name = name; }
	
	const unsigned context()                    { return _context; }
	void          set_context(unsigned context) { _context = context; }

protected:
	Thread(const std::string& name="") : _context(0), _name(name), _pthread_exists(false)
	{
		pthread_once(&_thread_key_once, thread_key_alloc);
		pthread_setspecific(_thread_key, this);
	}
	
	/** Must be called from thread */
	Thread(pthread_t thread, const std::string& name="")
	: _context(0), _name(name), _pthread_exists(true), _pthread(thread)
	{
		pthread_once(&_thread_key_once, thread_key_alloc);
		pthread_setspecific(_thread_key, this);
	}

	/** Thread function to execute.
	 *
	 * This is called once on start, and terminated on stop.
	 * Implementations likely want to put some infinite loop here.
	 */
	virtual void _run() {}

private:

	inline static void* _static_run(void* me) {
		pthread_setspecific(_thread_key, me);
		Thread* myself = (Thread*)me;
		myself->_run();
		return NULL; // and I
	}

	/** Allocate thread-specific data key */
	static void thread_key_alloc()
	{
		pthread_key_create(&_thread_key, NULL);
	}

	/* Key for the thread-specific buffer */
	static pthread_key_t _thread_key;
	
	/* Once-only initialisation of the key */
	static pthread_once_t _thread_key_once;

	unsigned    _context;
	std::string _name;
	bool        _pthread_exists;
	pthread_t   _pthread;
};


} // namespace Raul

#endif // RAUL_THREAD_H