/*
    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 <boost/scoped_array.hpp>

#include "gtkmm2ext/utils.h"

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

double WaveView::_global_gradient_depth = 0.6;
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)
	, _gradient_depth (_global_gradient_depth)
	, _shape_independent (false)
	, _logscaled_independent (false)
	, _gradient_depth_independent (false)
	, _amplitude_above_axis (1.0)
	, _region_start (region->start())
	, _cache (0)
{
	VisualPropertiesChanged.connect_same_thread (invalidation_connection, boost::bind (&WaveView::handle_visual_property_change, this));
}

WaveView::~WaveView ()
{
	delete _cache;
	_cache = 0;
}

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 (!_gradient_depth_independent && (_gradient_depth != global_gradient_depth())) {
		_gradient_depth = global_gradient_depth();
		changed = true;
	}
	
	if (changed) {
		invalidate_image_cache ();
	}
}

void
WaveView::set_fill_color (Color c)
{
	if (c != _fill_color) {
		invalidate_image_cache ();
		Fill::set_fill_color (c);
	}
}

void
WaveView::set_outline_color (Color c)
{
	if (c != _outline_color) {
		invalidate_image_cache ();
		Outline::set_outline_color (c);
	}
}

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

		_samples_per_pixel = samples_per_pixel;
		
		_bounding_box_dirty = true;
		
		end_change ();
		
		invalidate_whole_cache ();
	}
}

static inline double
image_to_window (double wave_origin, double image_start)
{
	return wave_origin + image_start;
}

static inline double
window_to_image (double wave_origin, double image_start)
{
	return image_start - wave_origin;
}

void
WaveView::ensure_cache (framecnt_t start, framecnt_t end,
			framepos_t sample_start, framepos_t sample_end) const
{
	if (_cache && _cache->sample_start() <= sample_start && _cache->sample_end() >= sample_end) {
		/* cache already covers required range, do nothing */
		return;
	}

	if (_cache) {
		delete _cache;
		_cache = 0;
	}

	/* sample position is canonical here, and we want to generate
	 * an image that spans about twice the canvas width 
	 */
	
	const framepos_t center = sample_start + ((sample_end - sample_start) / 2);
	const framecnt_t canvas_samples = 2 * (_canvas->visible_area().width() * _samples_per_pixel);

	/* we can request data from anywhere in the Source, between 0 and its length
	 */

	sample_start = max ((framepos_t) 0, (center - canvas_samples));
	sample_end = min (center + canvas_samples, _region->source_length (0));

	if (sample_end <= sample_start) {
		cerr << "sample start = " << sample_start << endl;
		cerr << "center+ = " << center<< endl;
		cerr << "CS = " << canvas_samples << endl;
		cerr << "pui = " << center + canvas_samples << endl;
		cerr << "sl = " << _region->source_length (0) << endl;
		cerr << "st = " << _region->start () << endl;
		cerr << "END: " << sample_end << endl;
		assert (false);
	}
	
	start = floor (sample_start / (double) _samples_per_pixel);
	end = ceil (sample_end / (double) _samples_per_pixel);
	
	assert (end > start);

	cerr << name << " cache miss - new CE, span " << start << " .. " << end << " (" << sample_start << " .. " << sample_end << ")\n";
	_cache = new CacheEntry (this, start, end, sample_start, sample_end);
}

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

	if (!_region) {
		return;
	}

	Rect self = item_to_window (Rect (0.0, 0.0, floor (_region->length() / _samples_per_pixel), _height));
	boost::optional<Rect> d = self.intersection (area);

	if (!d) {
		return;
	}
	
	Rect draw = d.get();

	/* window coordinates - pixels where x=0 is the left edge of the canvas
	 * window. We round up and down in case we were asked to
	 * draw "between" pixels at the start and/or end.
	 */

	const double draw_start = floor (draw.x0);
	const double draw_end = ceil (draw.x1);

	// cerr << "Need to draw " << draw_start << " .. " << draw_end << endl;
	
	/* image coordnates: pixels where x=0 is the start of this waveview,
	 * wherever it may be positioned. thus image_start=N means "an image
	 * that beings N pixels after the start of region that this waveview is
	 * representing. 
	 */

	const framepos_t image_start = window_to_image (self.x0, draw_start);
	const framepos_t image_end = window_to_image (self.x0, draw_end);

	// cerr << "Image/WV space: " << image_start << " .. " << image_end << endl;

	/* sample coordinates - note, these are not subject to rounding error */
	framepos_t sample_start = _region_start + (image_start * _samples_per_pixel);
	framepos_t sample_end   = _region_start + (image_end * _samples_per_pixel);

	// cerr << "Sample space: " << sample_start << " .. " << sample_end << endl;

	ensure_cache (image_start, image_end, sample_start, sample_end);

	// cerr << "Cache contains " << _cache->pixel_start() << " .. " << _cache->pixel_end() << " / " 
	// << _cache->sample_start() << " .. " << _cache->sample_end()
	// << endl;

	double image_offset = (_cache->sample_start() - _region->start()) / _samples_per_pixel;

	// cerr << "Offset into image to place at zero: " << image_offset << endl;

	context->rectangle (draw_start, draw.y0, draw_end - draw_start, draw.height());
	context->set_source (_cache->image(), self.x0 + image_offset, self.y0);
	context->fill ();
}

void
WaveView::compute_bounding_box () const
{
	if (_region) {
		_bounding_box = Rect (0.0, 0.0, _region->length() / _samples_per_pixel, _height);
	} else {
		_bounding_box = boost::optional<Rect> ();
	}
	
	_bounding_box_dirty = false;
}
	
void
WaveView::set_height (Distance height)
{
	if (height != _height) {
		begin_change ();
		
		_height = height;
		
		_bounding_box_dirty = true;
		end_change ();
		
		invalidate_image_cache ();
	}
}

void
WaveView::set_channel (int channel)
{
	if (channel != _channel) {
		begin_change ();
		
		_channel = channel;
		
		_bounding_box_dirty = true;
		end_change ();
		
		invalidate_whole_cache ();
	}
}

void
WaveView::invalidate_whole_cache ()
{
	begin_visual_change ();
	delete _cache;
	_cache = 0;
	end_visual_change ();
}

void
WaveView::invalidate_image_cache ()
{
	invalidate_whole_cache ();
}

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

void
WaveView::gain_changed ()
{
	invalidate_whole_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_amplitude_above_axis (double a)
{
	if (_amplitude_above_axis != a) {
		_amplitude_above_axis = a;
		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::region_resized ()
{
	if (!_region) {
		return;
	}

	/* special: do not use _region->length() here to compute
	   bounding box because it will already have changed.
	   
	   if we have a bounding box, use it.
	*/

	_pre_change_bounding_box = _bounding_box;

	frameoffset_t s = _region->start();

	if (s != _region_start) {
		/* if the region start changes, the information we have 
		   in the image cache is out of date and not useful
		   since it will fragmented into little pieces. invalidate
		   the cache.
		*/
		_region_start = _region->start();
		invalidate_whole_cache ();
	}

	_bounding_box_dirty = true;
	compute_bounding_box ();

	end_change ();
}

WaveView::CacheEntry::CacheEntry (WaveView const * wave_view, double pixel_start, double pixel_end,
				  framepos_t sample_start,framepos_t sample_end)
	: _wave_view (wave_view)
	, _pixel_start (pixel_start)
	, _pixel_end (pixel_end)
	, _sample_start (sample_start)
	, _sample_end (sample_end)
	, _n_peaks (_pixel_end - _pixel_start)
{
	_peaks.reset (new PeakData[_n_peaks]);

	_wave_view->_region->read_peaks (_peaks.get(), _n_peaks, 
					 _sample_start, _sample_end - _sample_start,
					 _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);
}

struct LineTips {
    double top;
    double bot;
    bool clipped;
    
    LineTips() : top (0.0), bot (0.0), clipped (false) {}
};

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);

#ifdef AREA_DRAW_AND_FILL

		/* 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 (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 (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) {
						y = position (alt_log_meter (fast_coefficient_to_dB (y)));
					} else if (y < 0.0) {
						y = position (-alt_log_meter (fast_coefficient_to_dB (-y)));
					} else {
						y = position (0.0);
					}
					context->line_to (i + 0.5, y);
				} 
			} else {
				for (int i = 0; i < _n_peaks; ++i) {
					context->line_to (i + 0.5, position (_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 (alt_log_meter (fast_coefficient_to_dB (y))));
					} else if (y < 0.0) {
						context->line_to (i + 0.5, position (-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 (_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 (_wave_view->gradient_depth() != 0.0) {
			
			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 *= 1.0 - _wave_view->gradient_depth();
			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 ();

#else
		cerr << "draw, logscaled = " << _wave_view->_logscaled << " global " << WaveView::_global_logscaled << endl;

		boost::scoped_array<LineTips> tips (new LineTips[_n_peaks]);

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

			/* each peak is a line from the bottom of the waveview
			 * to a point determined by max (_peaks[i].max,
			 * _peaks[i].min)
			 */

			if (_wave_view->_logscaled) {
				for (int i = 0; i < _n_peaks; ++i) {
					tips[i].bot = _wave_view->height();
					tips[i].top = position (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) {
					tips[i].bot = _wave_view->height();
					tips[i].top = position (max (fabs (_peaks[i].max), fabs (_peaks[i].min)));
				}
			}

		} else {

			if (_wave_view->_logscaled) {
				for (int i = 0; i < _n_peaks; ++i) {
					Coord top = _peaks[i].min;
					Coord bot = _peaks[i].max;

					if (top > 0.0) {
						top = position (alt_log_meter (fast_coefficient_to_dB (top)));
					} else if (top < 0.0) {
						top = position (-alt_log_meter (fast_coefficient_to_dB (-top)));
					} else {
						top = position (0.0);
					}

					if (bot > 0.0) {
						bot = position (alt_log_meter (fast_coefficient_to_dB (bot)));
					} else if (bot < 0.0) {
						bot = position (-alt_log_meter (fast_coefficient_to_dB (-bot)));
					} else {
						bot = position (0.0);
					}

					tips[i].top = top;
					tips[i].bot = bot;

				} 

			} else {
				for (int i = 0; i < _n_peaks; ++i) {
					tips[i].top = floor (position (_peaks[i].min));
					tips[i].bot = ceil (position (_peaks[i].max));
				}
			}
		}

		if (_wave_view->gradient_depth() != 0.0) {
			
			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 */
			v *= 1.0 - _wave_view->gradient_depth();
			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 {
			cerr << "\tno gradient\n";
			set_source_rgba (context, _wave_view->_fill_color);
		}

		context->set_line_width (0.5);

		/* draw the lines */
		
		if (_wave_view->_shape == WaveView::Rectified) {
			for (int i = 0; i < _n_peaks; ++i) {
				context->move_to (i + 0.5, tips[i].top + 0.5); /* down 1 pixel */
				context->line_to (i + 0.5, tips[i].bot);
				context->stroke ();
			}
		} else {
			for (int i = 0; i < _n_peaks; ++i) {
				context->move_to (i + 0.5, tips[i].top + 0.5); /* down 1 pixel */
				context->line_to (i + 0.5, tips[i].bot - 0.5); /* up 1 pixel */
				context->stroke ();
			}
		}

		/* now add dots to the top and bottom of each line (this is
		 * modelled on pyramix, except that we add clipping indicators.
		 */

		context->set_source_rgb (0, 0, 0);

		for (int i = 0; i < _n_peaks; ++i) {
			context->rectangle (i + 0.5, tips[i].top, 0.5, 0.5);
			context->fill ();
			if (_wave_view->_shape != WaveView::Rectified) {
				context->rectangle (i + 0.5, tips[i].bot, 0.5, 0.5);
				context->fill ();
			}
		}
#endif

		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 (1.0-s) * (_wave_view->_height / 2.0);
}

void
WaveView::CacheEntry::clear_image ()
{
	_image.clear ();
}
	    
void
WaveView::set_global_gradient_depth (double depth)
{
	if (_global_gradient_depth != depth) {
		_global_gradient_depth = depth;
		VisualPropertiesChanged (); /* EMIT SIGNAL */
	}
}