/*
    Copyright (C) 2000-2007 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.

*/

#include <iostream>
#include <iomanip>
#include <cstring>

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

#include "gtkmm2ext/gui_thread.h"
#include "gtkmm2ext/gtk_ui.h"

#include "ardour/panner.h"
#include "stereo_panner.h"

#include "i18n.h"

using namespace std;
using namespace Gtk;

static const int pos_box_size = 10;
static const int lr_box_size = 18;
static const int step_down = 10;

StereoPanner::StereoPanner (boost::shared_ptr<PBD::Controllable> position, boost::shared_ptr<PBD::Controllable> width)
        : position_control (position)
        , width_control (width)
        , dragging (false)
        , dragging_position (false)
        , drag_start_x (0)
        , last_drag_x (0)
{
        position_control->Changed.connect (connections, invalidator(*this), boost::bind (&StereoPanner::value_change, this), gui_context());
        width_control->Changed.connect (connections, invalidator(*this), boost::bind (&StereoPanner::value_change, this), gui_context());
        set_tooltip ();

        add_events (Gdk::BUTTON_PRESS_MASK|Gdk::BUTTON_RELEASE_MASK|Gdk::SCROLL_MASK|Gdk::POINTER_MOTION_MASK);
}

StereoPanner::~StereoPanner ()
{
}

void
StereoPanner::set_tooltip ()
{
        Gtkmm2ext::UI::instance()->set_tip (this, string_compose (_("L:%1 R:%2 Width: %3%%"), 
                                                                  (int) floor (position_control->get_value() * 100.0),
                                                                  (int) floor ((1.0 - position_control->get_value() * 100)),
                                                                  (int) floor (width_control->get_value() * 100.0)).c_str());
}

void
StereoPanner::value_change ()
{
        set_tooltip ();
        queue_draw ();
}

bool
StereoPanner::on_expose_event (GdkEventExpose* ev)
{
	Glib::RefPtr<Gdk::Window> win (get_window());
	Glib::RefPtr<Gdk::GC> gc (get_style()->get_base_gc (get_state()));

        cairo_t* cr = gdk_cairo_create (win->gobj());
       
        int x1, x2;
        int width, height;
        double pos = position_control->get_value (); /* 0..1 */
        double swidth = width_control->get_value (); /* -1..+1 */
        const int border_width = 1;
        const int border = border_width * 2;


        width = get_width();
        height = get_height ();

        /* background */

        cairo_set_source_rgb (cr, 0.184, 0.172, 0.172);
        cairo_rectangle (cr, 0, 0, width, height);
        cairo_fill (cr);

        /* leave a border */

        width -= border_width;
        height -= border_width;

        /* compute where the central box is */

        x1 = (int) floor (width * pos);                      // center of widget 
        x2 = x1 - (int) floor ((fabs (swidth) * width)/2.0); // center, then back up half the swidth value
        x1 -= pos_box_size/2;                                // center, then back up by half width of position box

        /* compute & draw the line through the box */
        
        cairo_set_line_width (cr, 2);
	cairo_set_source_rgba (cr, 0.3137, 0.4431, 0.7843, 1.0);
        cairo_move_to (cr, border + x2, 4+(pos_box_size/2)+step_down);
        cairo_line_to (cr, border + x2, 4+(pos_box_size/2));
        cairo_line_to (cr, border + x2 + floor ((fabs (swidth * width))), 4+(pos_box_size/2));
        cairo_line_to (cr, border + x2 + floor ((fabs (swidth * width))), 4+(pos_box_size/2) + step_down);
        cairo_stroke (cr);

        /* left box */

        cairo_rectangle (cr, 
                         border+ x2 - lr_box_size/2, 
                         (lr_box_size/2)+step_down, 
                         lr_box_size, lr_box_size);
	cairo_set_source_rgba (cr, 0.3137, 0.4431, 0.7843, 1.0);
        cairo_stroke_preserve (cr);
	cairo_set_source_rgba (cr, 0.4509, 0.7686, 0.8627, 0.8);
	cairo_fill (cr);

        
        /* add text */

        cairo_move_to (cr, 
                       border + x2 - lr_box_size/2 + 4,
                       (lr_box_size/2) + step_down + 13);
	cairo_set_source_rgba (cr, 0.129, 0.054, 0.588, 1.0);
        cairo_select_font_face (cr, "sans-serif", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
        cairo_show_text (cr, "L");

        /* right box */

        cairo_rectangle (cr, 
                         border + x2 + (int) floor ((fabs (swidth * width))) - lr_box_size/2, 
                         (lr_box_size/2)+step_down, 
                         lr_box_size, lr_box_size);
	cairo_set_source_rgba (cr, 0.3137, 0.4431, 0.7843, 1.0);
        cairo_stroke_preserve (cr);
	cairo_set_source_rgba (cr, 0.4509, 0.7686, 0.8627, 0.8);
	cairo_fill (cr);

        /* add text */

        cairo_move_to (cr, 
                       border + x2 + (int) floor ((fabs (swidth * width))) - lr_box_size/2 + 4, 
                       (lr_box_size/2)+step_down + 13);
	cairo_set_source_rgba (cr, 0.129, 0.054, 0.588, 1.0);
        cairo_show_text (cr, "R");

        /* draw the central box */

        cairo_set_line_width (cr, 1);
	cairo_rectangle (cr, border + x1, 4, pos_box_size, pos_box_size);
	cairo_set_source_rgba (cr, 0.3137, 0.4431, 0.7843, 1.0);
        cairo_stroke_preserve (cr);
	cairo_set_source_rgba (cr, 0.4509, 0.7686, 0.8627, 0.8);
	cairo_fill (cr);

        /* done */

        cairo_destroy (cr);
	return true;
}

bool
StereoPanner::on_button_press_event (GdkEventButton* ev)
{
        drag_start_x = ev->x;
        last_drag_x = ev->x;

        /* center 8 pixels are for position drag */

        int w = get_width();
        double pos = position_control->get_value ();

        if ((ev->x >= (int) floor ((pos * w)-(pos_box_size/2))) && (ev->x <= (int) floor ((pos * w)+(pos_box_size/2)))) {
                dragging_position = true;
        } else {
                dragging_position = false;
        }

        if (ev->type == GDK_2BUTTON_PRESS) {
                if (dragging_position) {
                        cerr << "Reset pos\n";
                        position_control->set_value (0.5); // reset position to center
                } else {
                        cerr << "Reset width\n";
                        width_control->set_value (1.0); // reset position to full, LR
                }
                dragging = false;
        } else {
                dragging = true;
        }

        return true;
}

bool
StereoPanner::on_button_release_event (GdkEventButton* ev)
{
        dragging = false;
        dragging_position = false;
        return true;
}

bool
StereoPanner::on_motion_notify_event (GdkEventMotion* ev)
{
        if (!dragging) {
                return false;
        }

        int w = get_width();
        float delta = (abs (ev->x - last_drag_x)) / (double) (w/2);

        if (!dragging_position) {
                double wv = width_control->get_value();        
                
                if (((drag_start_x < w/2) && ev->x > last_drag_x) || // start left of center, move towards it
                    ((drag_start_x > w/2) && ev->x < last_drag_x)) { // start right of center, move towards it
                        wv = wv  * (1.0 - delta);
                } else {
                        /* moving out, so increase the width */
                        wv = wv * (1.0 + delta);
                }
                
                width_control->set_value (wv);

        } else {

                double pv = position_control->get_value(); // 0..1.0 ; 0 = left
                
                if (ev->x > last_drag_x) { // increasing 
                        pv = pv * (1.0 + delta);
                } else {
                        pv = pv * (1.0 - delta);
                }

                position_control->set_value (pv);
        }

        last_drag_x = ev->x;
        return true;
}