/*
 * Copyright 2013 (c) Anna Schumaker.
 */
#include <callback.h>
#include <queue.h>
#include <random.h>

#include <algorithm>
#include <sstream>

#define O_MINUTES (60)
#define O_HOURS   (60 * O_MINUTES)
#define O_DAYS    (24 * O_HOURS)

Queue :: Queue()
	 : _cur(-1), _flags(0), _length(0)
{
}

Queue :: Queue(unsigned int f)
	 : _cur(-1), _flags(f & Q_FLAG_MASK), _length(0)
{
}

Queue :: ~Queue()
{
}

void Queue :: write(File &f)
{
	f << _flags << " " << _tracks.size();
	for (unsigned int i = 0; i < _tracks.size(); i++)
		f << " " << _tracks[i];
}

void Queue :: read(File &f)
{
	unsigned int n, id;
	f >> _flags >> n;
	_tracks.resize(n);
	for (unsigned int i = 0; i < n; i++) {
		f >> id;
		_tracks[i] = tagdb :: lookup(id);
	}
}

void Queue :: set_flag(queue_flags f)
{
	_flags |= f;
}

void Queue :: unset_flag(queue_flags f)
{
	_flags &= ~f;
}

bool Queue :: has_flag(queue_flags f)
{
	return (_flags & f) == (unsigned int)f;
}

/*
 * std::string.compare() returns
 *	  0: Strings are equal
 *	< 0: a < b
 *	> 0: a > b
 */
static inline int track_compare(Track *lhs, Track *rhs, sort_t field)
{
	int ret = lhs->less_than(rhs, field);
	if (field == SORT_YEAR && ret == 0)
		ret = lhs->less_than(rhs, SORT_ALBUM);
	return ret;
}

static bool track_less_than(Track *lhs, Track *rhs, std::list<sort_info> &order)
{
	std::list<sort_info>::iterator it;
	int res;

	for (it = order.begin(); it != order.end(); it++) {
		if (it->ascending == true)
			res = track_compare(lhs, rhs, it->field);
		else
			res = track_compare(rhs, lhs, it->field);
		if (res != 0)
			return res < 0;
	}
	return res;
}

unsigned int Queue :: find_sorted_id(Track *rhs)
{
	Track *lhs;
	unsigned int begin = 0, end = (_tracks.size() - 1), mid;

	if (_tracks.size() == 0)
		return 0;

	while (end > begin) {
		mid = begin + ((end - begin) / 2);
		lhs = _tracks[mid];
		if (track_less_than(lhs, rhs, _sort_order))
			begin = mid + 1;
		else {
			if (mid == begin)
				return begin;
			else
				end = mid - 1;
		}
	}

	lhs = _tracks[begin];
	if (track_less_than(lhs, rhs, _sort_order))
		return begin + 1;
	return begin;
}

unsigned int Queue :: _add_at(Track *track, unsigned int pos)
{
	_tracks.insert(_tracks.begin() + pos, track);
	_length += track->length;
	get_callbacks()->on_queue_track_add(this, pos);
	if (!(_flags & Q_DISABLE_CHANGED_SIZE))
		get_callbacks()->on_queue_changed();
	return pos;
}

void Queue :: _del_at(Track *track, unsigned int pos)
{
	_tracks.erase(_tracks.begin() + pos);
	_length -= track->length;
	get_callbacks()->on_queue_track_del(this, pos);
	if (!(_flags & Q_DISABLE_CHANGED_SIZE))
		get_callbacks()->on_queue_changed();
}

unsigned int Queue :: add(Track *track)
{
	unsigned int id = _tracks.size();
	if (_sort_order.size() > 0)
		id = find_sorted_id(track);
	return _add_at(track, id);
}

void Queue :: del(Track *track)
{
	for (unsigned int i = 0; i < _tracks.size(); i++) {
		if (_tracks[i] == track)
			_del_at(track, i);
	}
}

void Queue :: del(unsigned int id)
{
	_del_at(_tracks[id], id);
}

void Queue :: updated(Track *track)
{
	for (unsigned int i = 0; i < _tracks.size(); i++) {
		if (_tracks[i] == track)
			get_callbacks()->on_queue_track_changed(this, i);
	}
}

Track *Queue :: next()
{
	Track *res;

	if (_tracks.size() == 0)
		return NULL;
	else if (_tracks.size() == 1)
		_cur = 0;
	else if (_flags & Q_RANDOM)
		_cur += random(1, _tracks.size() / 2);
	else
		_cur++;

	_cur %= _tracks.size();
	res = _tracks[_cur];
	if (!(_flags & Q_REPEAT)) {
		del(_cur);
		_cur--;
	}
	return res;
}

unsigned int Queue :: size()
{
	return _tracks.size();
}

const std::string Queue :: size_str()
{
	std::stringstream ss;
	ss << size();
	return ss.str();
}

const std::string Queue :: length_str()
{
	std::stringstream ss;
	unsigned int factor[4] = { O_DAYS, O_HOURS, O_MINUTES, 1 };
	std::string  fields[4] = { "day",  "hour",  "minute",  "second" };
	unsigned int len = _length;

	for (unsigned int i = 0; i < 4; i++) {
		unsigned int dur = len / factor[i];
		len -= dur * factor[i];

		if (dur > 0) {
			ss << dur << " " << fields[i];
			if (dur > 1)
				ss << "s";
			if (len > 0)
				ss << ", ";
		}
	}

	return ss.str();
}



/* Sorting function */
class SortTracks {
private:
	std::list<sort_info> fields;
public:
	SortTracks(std::list<sort_info> f) : fields(f) {}
	bool operator()(Track *a, Track *b)
	{
		Track *lhs = a;
		Track *rhs = b;
		return track_less_than(lhs, rhs, fields);
	}
};

void Queue :: _add_sort(sort_t field, bool ascending)
{
	struct sort_info info;
	std::list<sort_info>::iterator it;

	/* Is field already in the sort_order? */
	for (it = _sort_order.begin(); it != _sort_order.end(); it++) {
		if (it->field == field) {
			it->ascending = !it->ascending;
			return;
		}
	}

	info.field = field;
	info.ascending = ascending;
	_sort_order.push_back(info);
	if (_sort_order.size() >= 4)
		_sort_order.erase(_sort_order.begin());
}

void Queue :: add_sort(sort_t field, bool ascending)
{
	if (_flags & Q_NO_SORT)
		return;

	_add_sort(field, ascending);
	std::stable_sort(_tracks.begin(), _tracks.end(), SortTracks(_sort_order));

	for (unsigned int i = 0; i < _tracks.size(); i++)
		get_callbacks()->on_queue_track_changed(this, i);
	get_callbacks()->on_queue_changed();
}

void Queue :: reset_sort(sort_t field, bool ascending)
{
	if (_flags & Q_NO_SORT)
		return;
	if (_sort_order.front().field != field)
		_sort_order.clear();
	add_sort(field, ascending);
}

void Queue :: force_clear_sort()
{
	_sort_order.clear();
}

std::list<sort_info> &Queue :: get_sort_order()
{
	return _sort_order;
}

Track *Queue :: operator[](unsigned int i)
{
	return _tracks[i];
}

void Queue :: set_cur(unsigned int c)
{
	_cur = c;
}

void Queue :: path_selected(unsigned int id)
{
	_cur = id;
	if (!(_flags &Q_REPEAT)) {
		del(_cur);
		_cur--;
	}
}

#ifdef CONFIG_TEST
void Queue :: reset()
{
	_tracks.clear();
	set_cur(0);
}
#endif /* CONFIG_TEST */