/*
    Copyright (C) 2003-2006 Paul Davis 

    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.

    $Id$
*/

#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>

#include <gdkmm/rectangle.h>
#include <gtkmm2ext/fastmeter.h>
#include <gtkmm2ext/utils.h>

#define UINT_TO_RGB(u,r,g,b) { (*(r)) = ((u)>>16)&0xff; (*(g)) = ((u)>>8)&0xff; (*(b)) = (u)&0xff; }
#define UINT_TO_RGBA(u,r,g,b,a) { UINT_TO_RGB(((u)>>8),r,g,b); (*(a)) = (u)&0xff; }
using namespace Gtk;
using namespace Gdk;
using namespace Glib;
using namespace Gtkmm2ext;
using namespace std;


int FastMeter::min_pattern_metric_size = 10;
int FastMeter::max_pattern_metric_size = 1024;

FastMeter::PatternMap FastMeter::v_pattern_cache;
FastMeter::PatternMap FastMeter::h_pattern_cache;

int FastMeter::_clr0 = 0;
int FastMeter::_clr1 = 0;
int FastMeter::_clr2 = 0;
int FastMeter::_clr3 = 0;

FastMeter::FastMeter (long hold, unsigned long dimen, Orientation o, int len, int clr0, int clr1, int clr2, int clr3)
{
	orientation = o;
	hold_cnt = hold;
	hold_state = 0;
	current_peak = 0;
	current_level = 0;
	last_peak_rect.width = 0;
	last_peak_rect.height = 0;
	_clr0 = clr0;
	_clr1 = clr1;
	_clr2 = clr2;
	_clr3 = clr3;

	set_events (BUTTON_PRESS_MASK|BUTTON_RELEASE_MASK);

	pixrect.x = 0;
	pixrect.y = 0;

	if (orientation == Vertical) {
		if (!len) {
			len = 250;
		}
		pattern = request_vertical_meter(dimen, len);
		pixheight = len;
		pixwidth = dimen;
	} else {
		if (!len) {
			len = 186; // interesting size, eh?
		}
		pattern = request_horizontal_meter(len, dimen);
		pixheight = dimen;
		pixwidth = len;
	}

	if (orientation == Vertical) {
		pixrect.width = min (pixwidth, (gint) dimen);
		pixrect.height = pixheight;
	} else {
		pixrect.width = pixwidth;
		pixrect.height = min (pixheight, (gint) dimen);
	}

	request_width = pixrect.width;
	request_height= pixrect.height;
}

Cairo::RefPtr<Cairo::Pattern>
FastMeter::generate_meter_pattern (int width, int height)
{
	guint8 r0,g0,b0,r1,g1,b1,r2,g2,b2,r3,g3,b3,a;

	/* clr0: color at top of the meter 
	      1: color at the knee
              2: color half-way between bottom and knee
	      3: color at the bottom of the meter
	*/

	UINT_TO_RGBA (_clr0, &r0, &g0, &b0, &a);
	UINT_TO_RGBA (_clr1, &r1, &g1, &b1, &a);
	UINT_TO_RGBA (_clr2, &r2, &g2, &b2, &a);
	UINT_TO_RGBA (_clr3, &r3, &g3, &b3, &a);

	// fake log calculation copied from log_meter.h
	// actual calculation:
	// log_meter(0.0f) =
	//  def = (0.0f + 20.0f) * 2.5f + 50f
	//  return def / 115.0f

	const int knee = (int)floor((float)height * 100.0f / 115.0f);
	cairo_pattern_t* _p = cairo_pattern_create_linear (0.0, 0.0, width, height);

	/* cairo coordinate space goes downwards as y value goes up, so invert
	 * knee-based positions by using (1.0 - y)
	 * 
	 * also, double-stop the knee point, so that we get a hard transition 
	 */

	cairo_pattern_add_color_stop_rgb (_p, 0.0, r3/255.0, g3/255.0, b3/255.0); // bottom
	cairo_pattern_add_color_stop_rgb (_p, 1.0 - (knee/(2.0 * height)), r2/255.0, g2/255.0, b2/255.0); // mid-point to knee
	cairo_pattern_add_color_stop_rgb (_p, 1.0 - (knee/(double)height), r0/255.0, g0/255.0, b0/255.0); // knee
	cairo_pattern_add_color_stop_rgb (_p, 1.0 - (knee/(double)height), r1/255.0, g1/255.0, b1/255.0); // double-stop @ knee
	cairo_pattern_add_color_stop_rgb (_p, 1.0, r0/255.0, g0/255.0, b0/255.0); // top

	Cairo::RefPtr<Cairo::Pattern> p (new Cairo::Pattern (_p, false));

	return p;
}

Cairo::RefPtr<Cairo::Pattern>
FastMeter::request_vertical_meter(int width, int height)
{
	if (height < min_pattern_metric_size)
		height = min_pattern_metric_size;
	if (height > max_pattern_metric_size)
		height = max_pattern_metric_size;
	
	PatternMap::iterator i;

	if ((i = v_pattern_cache.find (height)) != v_pattern_cache.end()) {
		return i->second;
	}

	Cairo::RefPtr<Cairo::Pattern> p = generate_meter_pattern (width, height);
	v_pattern_cache[height] = p;

	return p;
}

Cairo::RefPtr<Cairo::Pattern>
FastMeter::request_horizontal_meter(int width, int height)
{
	if (width < min_pattern_metric_size)
		width = min_pattern_metric_size;
	if (width > max_pattern_metric_size)
		width = max_pattern_metric_size;
	
	PatternMap::iterator i;

	if ((i = h_pattern_cache.find (height)) != h_pattern_cache.end()) {
		return i->second;
	}

	/* flip height/width so that we get the right pattern */

	Cairo::RefPtr<Cairo::Pattern> p = generate_meter_pattern (height, width);

	/* rotate to make it horizontal */

	cairo_matrix_t m;
	cairo_matrix_init_rotate (&m, -M_PI/2.0);
	cairo_pattern_set_matrix (p->cobj(), &m);

	h_pattern_cache[width] = p;

	return p;
}

FastMeter::~FastMeter ()
{
}

void
FastMeter::set_hold_count (long val)
{
	if (val < 1) {
		val = 1;
	}
	
	hold_cnt = val;
	hold_state = 0;
	current_peak = 0;
	
	queue_draw ();
}

void
FastMeter::on_size_request (GtkRequisition* req)
{
	if (orientation == Vertical) {

		req->height = request_height;
		req->height = max(req->height, min_pattern_metric_size);
		req->height = min(req->height, max_pattern_metric_size);

		req->width  = request_width;

	} else {

		req->width  = request_width;
		req->width  = max(req->width,  min_pattern_metric_size);
		req->width  = min(req->width,  max_pattern_metric_size);

		req->height = request_height;
	}

}

void
FastMeter::on_size_allocate (Gtk::Allocation &alloc)
{
	if (orientation == Vertical) {

		if (alloc.get_width() != request_width) {
			alloc.set_width (request_width);
		}

		int h = alloc.get_height();
		h = max (h, min_pattern_metric_size);
		h = min (h, max_pattern_metric_size);
		
		if (h != alloc.get_height()) {
			alloc.set_height (h);
		}

		if (pixheight != h) {
			pattern = request_vertical_meter (request_width, h);
			pixheight = h;
			pixwidth  = request_width;
		}

	} else {

		if (alloc.get_height() != request_height) {
			alloc.set_height(request_height);
		}

		int w = alloc.get_width();
		w = max (w, min_pattern_metric_size);
		w = min (w, max_pattern_metric_size);

		if (w != alloc.get_width()) {
			alloc.set_width (w);
		}

		if (pixwidth != w) {
			pattern = request_horizontal_meter (w, request_height);
			pixheight = request_height;
			pixwidth  = w;
		}
	}

	DrawingArea::on_size_allocate (alloc);
}

bool
FastMeter::on_expose_event (GdkEventExpose* ev)
{
	if (orientation == Vertical) {
		return vertical_expose (ev);
	} else {
		return horizontal_expose (ev);
	}
}

bool
FastMeter::vertical_expose (GdkEventExpose* ev)
{
	Glib::RefPtr<Gdk::Window> win = get_window ();
	gint top_of_meter;
	GdkRectangle intersection;
	GdkRectangle background;

	cairo_t* cr = gdk_cairo_create (get_window ()->gobj());
	cairo_rectangle (cr, ev->area.x, ev->area.y, ev->area.width, ev->area.height);
	cairo_clip (cr);

	top_of_meter = (gint) floor (pixheight * current_level);
	
	/* reset the height & origin of the rect that needs to show the pixbuf
	 */

	pixrect.height = top_of_meter;
	pixrect.y = pixheight - top_of_meter;

	background.x = 0;
	background.y = 0;
	background.width = pixrect.width;
	background.height = pixheight - top_of_meter;

	if (gdk_rectangle_intersect (&background, &ev->area, &intersection)) {
		cairo_set_source_rgb (cr, 0, 0, 0); // black 
		cairo_rectangle (cr, intersection.x, intersection.y, intersection.width, intersection.height);
		cairo_fill (cr);
	}

	if (gdk_rectangle_intersect (&pixrect, &ev->area, &intersection)) {
		// draw the part of the meter image that we need. the area we draw is bounded "in reverse" (top->bottom)
		cairo_set_source (cr, pattern->cobj());
		cairo_rectangle (cr, intersection.x, intersection.y, intersection.width, intersection.height);
		cairo_fill (cr);
	}

	// draw peak bar 

	if (hold_state) {
		last_peak_rect.x = 0;
		last_peak_rect.width = pixwidth;
		last_peak_rect.y = pixheight - (gint) floor (pixheight * current_peak);
		last_peak_rect.height = min(3, pixheight - last_peak_rect.y);

		cairo_set_source (cr, pattern->cobj());
		cairo_rectangle (cr, 0, last_peak_rect.y, pixwidth, last_peak_rect.height);
		cairo_fill (cr);

	} else {
		last_peak_rect.width = 0;
		last_peak_rect.height = 0;
	}

	cairo_destroy (cr);

	return TRUE;
}

bool
FastMeter::horizontal_expose (GdkEventExpose* ev)
{
	Glib::RefPtr<Gdk::Window> win = get_window ();
	gint right_of_meter;
	GdkRectangle intersection;
	GdkRectangle background;

	cairo_t* cr = gdk_cairo_create (get_window ()->gobj());
	cairo_rectangle (cr, ev->area.x, ev->area.y, ev->area.width, ev->area.height);
	cairo_clip (cr);

	right_of_meter = (gint) floor (pixwidth * current_level);
	pixrect.width = right_of_meter;

	background.x = 0;
	background.y = 0;
	background.width  = pixwidth - right_of_meter;
	background.height = pixrect.height;

	if (gdk_rectangle_intersect (&background, &ev->area, &intersection)) {
		cairo_set_source_rgb (cr, 0, 0, 0); // black 
		cairo_rectangle (cr, intersection.x + right_of_meter, intersection.y, intersection.width, intersection.height);
		cairo_fill (cr);
	}

	if (gdk_rectangle_intersect (&pixrect, &ev->area, &intersection)) {
		// draw the part of the meter image that we need. the area we draw is bounded "in reverse" (top->bottom)
		cairo_matrix_t m;
		cairo_matrix_init_translate (&m, -intersection.x, -intersection.y);
		cairo_pattern_set_matrix (pattern->cobj(), &m);
		cairo_set_source (cr, pattern->cobj());
		cairo_rectangle (cr, intersection.x, intersection.y, pixrect.width, intersection.height);
		cairo_fill (cr);
	}

	// draw peak bar 
	// XXX: peaks don't work properly
	/*
	if (hold_state && intersection.height > 0) {
		gint x = (gint) floor(pixwidth * current_peak);

		get_window()->draw_pixbuf (get_style()->get_fg_gc(get_state()), pixbuf,
					   x, intersection.y,
					   x, intersection.y,
					   3, intersection.height,
					   Gdk::RGB_DITHER_NONE, 0, 0);
	}
	*/

	cairo_destroy (cr);
	
	return true;
}

void
FastMeter::set (float lvl)
{
	float old_level = current_level;
	float old_peak = current_peak;

	current_level = lvl;
	
	if (lvl > current_peak) {
		current_peak = lvl;
		hold_state = hold_cnt;
	}
	
	if (hold_state > 0) {
		if (--hold_state == 0) {
			current_peak = lvl;
		}
	}

	if (current_level == old_level && current_peak == old_peak && hold_state == 0) {
		return;
	}


	Glib::RefPtr<Gdk::Window> win;

	if ((win = get_window()) == 0) {
		queue_draw ();
		return;
	}

	if (orientation == Vertical) {
		queue_vertical_redraw (win, old_level);
	} else {
		queue_horizontal_redraw (win, old_level);
	}
}

void
FastMeter::queue_vertical_redraw (const Glib::RefPtr<Gdk::Window>& win, float old_level)
{
	GdkRectangle rect;
	
	gint new_top = (gint) floor (pixheight * current_level);
	
	rect.x = 0;
	rect.width = pixwidth;
	rect.height = new_top;
	rect.y = pixheight - new_top;

	if (current_level > old_level) {
		/* colored/pixbuf got larger, just draw the new section */
		/* rect.y stays where it is because of X coordinates */
		/* height of invalidated area is between new.y (smaller) and old.y
		   (larger).
		   X coordinates just make my brain hurt.
		*/
		rect.height = pixrect.y - rect.y;
	} else {
		/* it got smaller, compute the difference */
		/* rect.y becomes old.y (the smaller value) */
		rect.y = pixrect.y;
		/* rect.height is the old.y (smaller) minus the new.y (larger)
		*/
		rect.height = pixrect.height - rect.height;
	}

	GdkRegion* region = 0;
	bool queue = false;

	if (rect.height != 0) {

		/* ok, first region to draw ... */
		
		region = gdk_region_rectangle (&rect);
		queue = true;
	}

	/* redraw the last place where the last peak hold bar was;
	   the next expose will draw the new one whether its part of
	   expose region or not.
	*/
	
	if (last_peak_rect.width * last_peak_rect.height != 0) {
		if (!queue) {
			region = gdk_region_new ();
			queue = true; 
		}
		gdk_region_union_with_rect (region, &last_peak_rect);
	} 

	if (queue) {
		gdk_window_invalidate_region (win->gobj(), region, true);
	}
	if (region) {
		gdk_region_destroy(region);
		region = 0;
	}
}

void
FastMeter::queue_horizontal_redraw (const Glib::RefPtr<Gdk::Window>& /*win*/, float /*old_level*/)
{
	/* XXX OPTIMIZE (when we have some horizontal meters) */
	queue_draw ();
}

void
FastMeter::clear ()
{
	current_level = 0;
	current_peak = 0;
	hold_state = 0;
	queue_draw ();
}