/*
    Copyright (C) 2011-2013 Paul Davis
    Author: Carl Hetherington <cth@carlh.net>

    This program 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.

    This program 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 more 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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <cmath>
#include <cairomm/cairomm.h>

#include "gtkmm2ext/utils.h"

#include "pbd/compose.h"
#include "pbd/signals.h"

#include "ardour/types.h"
#include "ardour/dB.h"
#include "ardour/audioregion.h"

#include "canvas/wave_view.h"
#include "canvas/utils.h"
#include "canvas/canvas.h"

#include <gdkmm/general.h>

using namespace std;
using namespace ARDOUR;
using namespace ArdourCanvas;

bool WaveView::_gradient_waveforms = true;
bool WaveView::_global_logscaled = false;
WaveView::Shape WaveView::_global_shape = WaveView::Normal;

PBD::Signal0<void> WaveView::VisualPropertiesChanged;

WaveView::WaveView (Group* parent, boost::shared_ptr<ARDOUR::AudioRegion> region)
	: Item (parent)
	, Outline (parent)
	, Fill (parent)
	, _region (region)
	, _channel (0)
	, _samples_per_pixel (0)
	, _height (64)
	, _wave_color (0xffffffff)
	, _show_zero (true)
	, _zero_color (0xff0000ff)
	, _clip_color (0xff0000ff)
	, _logscaled (_global_logscaled)
	, _shape (_global_shape)
	, _amplitude (1.0)
	, _shape_independent (false)
	, _logscaled_independent (false)
	, _region_start (0)
{
	VisualPropertiesChanged.connect_same_thread (invalidation_connection, boost::bind (&WaveView::handle_visual_property_change, this));
}

void
WaveView::handle_visual_property_change ()
{
	bool changed = false;

	if (!_shape_independent && (_shape != global_shape())) {
		_shape = global_shape();
		changed = true;
	}

	if (!_logscaled_independent && (_logscaled != global_logscaled())) {
		_logscaled = global_logscaled();
		changed = true;
	}

	if (changed) {
		invalidate_image_cache ();
	}
}

void
WaveView::set_samples_per_pixel (double samples_per_pixel)
{
	begin_change ();
	
	_samples_per_pixel = samples_per_pixel;

	_bounding_box_dirty = true;
	end_change ();

	invalidate_whole_cache ();
}

void
WaveView::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
{
	assert (_samples_per_pixel != 0);

	if (!_region) {
		return;
	}

	/* p, start and end are offsets from the start of the source.
	   area is relative to the position of the region.
	 */
	
	int const start = rint (area.x0 + _region_start / _samples_per_pixel);
	int const end   = rint (area.x1 + _region_start / _samples_per_pixel);

	int p = start;
	list<CacheEntry*>::iterator cache = _cache.begin ();

	while (p < end) {

		/* Step through cache entries that end at or before our current position, p */
		while (cache != _cache.end() && (*cache)->end() <= p) {
			++cache;
		}

		/* Now either:
		   1. we have run out of cache entries
		   2. the one we are looking at finishes after p but also starts after p.
		   3. the one we are looking at finishes after p and starts before p.

		   Set up a pointer to the cache entry that we will use on this iteration.
		*/

		CacheEntry* render = 0;

		if (cache == _cache.end ()) {

			/* Case 1: we have run out of cache entries, so make a new one for
			   the whole required area and put it in the list.
			*/
			
			CacheEntry* c = new CacheEntry (this, p, end);
			_cache.push_back (c);
			render = c;

		} else if ((*cache)->start() > p) {

			/* Case 2: we have a cache entry, but it starts after p, so we
			   need another one for the missing bit.
			*/

			CacheEntry* c = new CacheEntry (this, p, (*cache)->start());
			cache = _cache.insert (cache, c);
			++cache;
			render = c;

		} else {

			/* Case 3: we have a cache entry that will do at least some of what
			   we have left, so render it.
			*/

			render = *cache;
			++cache;

		}

		int const this_end = min (end, render->end ());
		
		Coord const left  =        p - _region_start / _samples_per_pixel;
		Coord const right = this_end - _region_start / _samples_per_pixel;
		
		context->save ();
		
		context->rectangle (left, area.y0, right, area.height());
		context->clip ();
		
		context->translate (left, 0);

		context->set_source (render->image(), render->start() - p, 0);
		context->paint ();
		
		context->restore ();

		p = min (end, render->end ());
	}
}

void
WaveView::compute_bounding_box () const
{
	if (_region) {
		_bounding_box = Rect (0, 0, _region->length() / _samples_per_pixel, _height);
	} else {
		_bounding_box = boost::optional<Rect> ();
	}
	
	_bounding_box_dirty = false;
}
	
void
WaveView::set_height (Distance height)
{
	begin_change ();

	_height = height;

	_bounding_box_dirty = true;
	end_change ();

	invalidate_image_cache ();
}

void
WaveView::set_channel (int channel)
{
	begin_change ();
	
	_channel = channel;

	_bounding_box_dirty = true;
	end_change ();

	invalidate_whole_cache ();
}

void
WaveView::invalidate_whole_cache ()
{
	for (list<CacheEntry*>::iterator i = _cache.begin(); i != _cache.end(); ++i) {
		delete *i;
	}

	_cache.clear ();
	_canvas->item_visual_property_changed (this);
}

void
WaveView::invalidate_image_cache ()
{
	for (list<CacheEntry*>::iterator i = _cache.begin(); i != _cache.end(); ++i) {
		(*i)->clear_image ();
	}
	_canvas->item_visual_property_changed (this);
}

void
WaveView::region_resized ()
{
	_bounding_box_dirty = true;
}

void
WaveView::set_logscaled (bool yn)
{
	if (_logscaled != yn) {
		_logscaled = yn;
		invalidate_image_cache ();
	}
}

void
WaveView::set_amplitude (double a)
{
	if (_amplitude != a) {
		_amplitude = a;
		invalidate_image_cache ();
	}
}

void
WaveView::set_zero_color (Color c)
{
	if (_zero_color != c) {
		_zero_color = c;
		invalidate_image_cache ();
	}
}

void
WaveView::set_clip_color (Color c)
{
	if (_clip_color != c) {
		_clip_color = c;
		invalidate_image_cache ();
	}
}

void
WaveView::set_show_zero_line (bool yn)
{
	if (_show_zero != yn) {
		_show_zero = yn;
		invalidate_image_cache ();
	}
}

void
WaveView::set_shape (Shape s)
{
	if (_shape != s) {
		_shape = s;
		invalidate_image_cache ();
	}
}

void
WaveView::set_global_shape (Shape s)
{
	if (_global_shape != s) {
		_global_shape = s;
		VisualPropertiesChanged (); /* EMIT SIGNAL */
	}
}

void
WaveView::set_global_logscaled (bool yn)
{
	if (_global_logscaled != yn) {
		_global_logscaled = yn;
		VisualPropertiesChanged (); /* EMIT SIGNAL */
		
	}
}

void
WaveView::set_region_start (frameoffset_t start)
{
	_region_start = start;
	_bounding_box_dirty = true;
}

/** Construct a new CacheEntry with peak data between two offsets
 *  in the source.
 */
WaveView::CacheEntry::CacheEntry (
	WaveView const * wave_view,
	int start,
	int end
	)
	: _wave_view (wave_view)
	, _start (start)
	, _end (end)
{
	_n_peaks = _end - _start;
	_peaks.reset (new PeakData[_n_peaks]);

	_wave_view->_region->read_peaks (
		_peaks.get(),
		_n_peaks,
		_start * _wave_view->_samples_per_pixel,
		(_end - _start) * _wave_view->_samples_per_pixel,
		_wave_view->_channel,
		_wave_view->_samples_per_pixel
		);
}

WaveView::CacheEntry::~CacheEntry ()
{
}

static inline float
_log_meter (float power, double lower_db, double upper_db, double non_linearity)
{
	return (power < lower_db ? 0.0 : pow((power-lower_db)/(upper_db-lower_db), non_linearity));
}

static inline float
alt_log_meter (float power)
{
	return _log_meter (power, -192.0, 0.0, 8.0);
}

Cairo::RefPtr<Cairo::ImageSurface>
WaveView::CacheEntry::image ()
{
	if (!_image) {

		_image = Cairo::ImageSurface::create (Cairo::FORMAT_ARGB32, _n_peaks, _wave_view->_height);
		Cairo::RefPtr<Cairo::Context> context = Cairo::Context::create (_image);

		/* Draw the edge of the waveform, top half first, the loop back
		 * for the bottom half to create a clockwise path
		 */

		context->begin_new_path();


		if (_wave_view->_shape == WaveView::Rectified) {

			/* top edge of waveform is based on max (fabs (peak_min, peak_max))
			 */

			if (_wave_view->_logscaled) {
				for (int i = 0; i < _n_peaks; ++i) {
					context->line_to (i + 0.5, position (_wave_view->amplitude() * 
									     alt_log_meter (fast_coefficient_to_dB (
												    max (fabs (_peaks[i].max), fabs (_peaks[i].min))))));
				}
			} else {
				for (int i = 0; i < _n_peaks; ++i) {
					context->line_to (i + 0.5, position (_wave_view->amplitude() * max (fabs (_peaks[i].max), fabs (_peaks[i].min))));
				}
			}

		} else {
			if (_wave_view->_logscaled) {
				for (int i = 0; i < _n_peaks; ++i) {
					Coord y = _peaks[i].max;
					if (y > 0.0) {
						context->line_to (i + 0.5, position (_wave_view->amplitude() * alt_log_meter (fast_coefficient_to_dB (y))));
					} else if (y < 0.0) {
						context->line_to (i + 0.5, position (_wave_view->amplitude() * -alt_log_meter (fast_coefficient_to_dB (-y))));
					} else {
						context->line_to (i + 0.5, position (0.0));
					}
				} 
			} else {
				for (int i = 0; i < _n_peaks; ++i) {
					context->line_to (i + 0.5, position (_wave_view->amplitude() * _peaks[i].max));
				}
			}
		}

		/* from final top point, move out of the clip zone */

		context->line_to (_n_peaks + 10, position (0.0));

	
		/* bottom half, in reverse */
	
		if (_wave_view->_shape == WaveView::Rectified) {
			
			/* lower half: drop to the bottom, then a line back to
			 * beyond the left edge of the clip region 
			 */

			context->line_to (_n_peaks + 10, _wave_view->_height);
			context->line_to (-10.0, _wave_view->_height);

		} else {

			if (_wave_view->_logscaled) {
				for (int i = _n_peaks-1; i >= 0; --i) {
					Coord y = _peaks[i].min;
					if (y > 0.0) {
						context->line_to (i + 0.5, position (_wave_view->amplitude() * alt_log_meter (fast_coefficient_to_dB (y))));
					} else if (y < 0.0) {
						context->line_to (i + 0.5, position (_wave_view->amplitude() * -alt_log_meter (fast_coefficient_to_dB (-y))));
					} else {
						context->line_to (i + 0.5, position (0.0));
					}
				} 
			} else {
				for (int i = _n_peaks-1; i >= 0; --i) {
					context->line_to (i + 0.5, position (_wave_view->amplitude() * _peaks[i].min));
				}
			}
		
			/* from final bottom point, move out of the clip zone */
			
			context->line_to (-10.0, position (0.0));
		}

		context->close_path ();

		if (WaveView::gradient_waveforms()) {

			Cairo::RefPtr<Cairo::LinearGradient> gradient (Cairo::LinearGradient::create (0, 0, 0, _wave_view->_height));
			
			double stops[3];
			
			double r, g, b, a;
			
			if (_wave_view->_shape == Rectified) {
				stops[0] = 0.1;
				stops[0] = 0.3;
				stops[0] = 0.9;
			} else {
				stops[0] = 0.1;
				stops[1] = 0.5;
				stops[2] = 0.9;
			}

			color_to_rgba (_wave_view->_fill_color, r, g, b, a);
			gradient->add_color_stop_rgba (stops[0], r, g, b, a);
			gradient->add_color_stop_rgba (stops[2], r, g, b, a);
			
			/* generate a new color for the middle of the gradient */
			double h, s, v;
			color_to_hsv (_wave_view->_fill_color, h, s, v);
			/* tone down the saturation */
			s *= 0.60;
			Color center = hsv_to_color (h, s, v, a);
			color_to_rgba (center, r, g, b, a);
			gradient->add_color_stop_rgba (stops[1], r, g, b, a);
			
			context->set_source (gradient);
		} else {
			set_source_rgba (context, _wave_view->_fill_color);
		}

		context->fill_preserve ();
		_wave_view->setup_outline_context (context);
		context->stroke ();

		if (_wave_view->show_zero_line()) {
			set_source_rgba (context, _wave_view->_zero_color);
			context->move_to (0, position (0.0));
			context->line_to (_n_peaks, position (0.0));
			context->stroke ();
		}
	}

	return _image;
}


Coord
WaveView::CacheEntry::position (double s) const
{
	switch (_wave_view->_shape) {
	case Rectified:
		return _wave_view->_height - (s * _wave_view->_height);
	default:
		break;
	}
	return (s+1.0) * (_wave_view->_height / 2.0);
}

void
WaveView::CacheEntry::clear_image ()
{
	_image.clear ();
}
	    
void
WaveView::set_gradient_waveforms (bool yn)
{
	if (_gradient_waveforms != yn) {
		_gradient_waveforms = yn;
		VisualPropertiesChanged (); /* EMIT SIGNAL */
	}
}