/* 
Copyright (c) 2011 by Simon Schneegans

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 3 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, see <http://www.gnu.org/licenses/>. 
*/

using GLib.Math;

namespace GnomePie {

/////////////////////////////////////////////////////////////////////////    
/// The delete sign, displayed in the upper right corner of each
/// Slice.
/////////////////////////////////////////////////////////////////////////

public class PiePreviewDeleteSign : GLib.Object {

    /////////////////////////////////////////////////////////////////////
    /// Called when the user clicked on this sign.
    /////////////////////////////////////////////////////////////////////

    public signal void on_clicked();
    
    /////////////////////////////////////////////////////////////////////
    /// The image used to display this oject.
    /////////////////////////////////////////////////////////////////////
    
    public Image icon { get; private set; }
    
    /////////////////////////////////////////////////////////////////////
    /// Some constants determining the look and behaviour of this Slice.
    /////////////////////////////////////////////////////////////////////
    
    private const int radius = 18;
    private const double globale_scale = 0.8;
    private const double click_cancel_treshold = 5;

    /////////////////////////////////////////////////////////////////////
    /// True, when the add sign is currently visible.
    /////////////////////////////////////////////////////////////////////

    private bool visible = false;
    
    /////////////////////////////////////////////////////////////////////
    /// Some AnimatedValues for smooth transitions.
    /////////////////////////////////////////////////////////////////////
    
    private AnimatedValue size;
    private AnimatedValue alpha; 
    private AnimatedValue activity; 
    private AnimatedValue clicked; 
    
    /////////////////////////////////////////////////////////////////////
    /// Storing the position where a mouse click was executed. Useful for
    /// canceling the click when the mouse moves some pixels.
    /////////////////////////////////////////////////////////////////////
    
    private double clicked_x = 0.0;
    private double clicked_y = 0.0;
    
    /////////////////////////////////////////////////////////////////////
    /// C'tor, sets everything up.
    /////////////////////////////////////////////////////////////////////

    public PiePreviewDeleteSign() {
        this.size = new AnimatedValue.cubic(AnimatedValue.Direction.OUT, 0, 0, 0, 2.0);
        this.alpha = new AnimatedValue.cubic(AnimatedValue.Direction.OUT, 0, 0, 0, 0.0);
        this.activity = new AnimatedValue.cubic(AnimatedValue.Direction.OUT, -3, -3, 0, 0.0);
        this.clicked = new AnimatedValue.cubic(AnimatedValue.Direction.OUT, 1, 1, 0, 0.0);
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Loads an Action. All members are initialized accordingly.
    /////////////////////////////////////////////////////////////////////

    public void load() {
        this.icon = new Icon("stock_delete", radius*2);
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Makes this object visible.
    /////////////////////////////////////////////////////////////////////
    
    public void show() {
        if (!this.visible) {
            this.visible = true;
            this.alpha.reset_target(1.0, 0.3);   
        }
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Makes this object invisible.
    /////////////////////////////////////////////////////////////////////
    
    public void hide() {
        if (this.visible) {
            this.visible = false;
            this.alpha.reset_target(0.0, 0.3);     
        }
    }

    /////////////////////////////////////////////////////////////////////
    /// Updates the size of this object. All transitions will be smooth.
    /////////////////////////////////////////////////////////////////////

    public void set_size(double size) {
        this.size.reset_target(size, 0.2);
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Draws the sign to the given context.
    /////////////////////////////////////////////////////////////////////

    public void draw(double frame_time, Cairo.Context ctx) {
        this.size.update(frame_time);
        this.alpha.update(frame_time);
        this.activity.update(frame_time);
        this.clicked.update(frame_time);
        
        if (this.alpha.val > 0) {
            ctx.save();
            
            // transform the context
            double scale = (this.size.val*this.clicked.val 
                         + this.activity.val*0.2 - 0.2)*globale_scale;
            ctx.scale(scale, scale);
        
            // paint the image
            icon.paint_on(ctx, this.alpha.val);
                
            ctx.restore();
        }
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Called when the mouse moves to another position.
    /////////////////////////////////////////////////////////////////////
    
    public bool on_mouse_move(double x, double y) {
        if (this.clicked.end == 0.9) {
            double dist = GLib.Math.pow(x-this.clicked_x, 2) + GLib.Math.pow(y-this.clicked_y, 2);
            if (dist > this.click_cancel_treshold*this.click_cancel_treshold)
                this.clicked.reset_target(1.0, 0.1);
        }
    
	    if (GLib.Math.fabs(x) <= radius*globale_scale && GLib.Math.fabs(y) <= radius*globale_scale) {
	        this.activity.reset_target(1.0, 0.2);
	        return true;
        } 
        
        this.activity.reset_target(0.0, 0.2);
        return false;
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Called when a button of the mouse is pressed.
    /////////////////////////////////////////////////////////////////////
    
    public bool on_button_press(double x, double y) {
        if (this.activity.end == 1.0) {
            this.clicked.reset_target(0.9, 0.1);
            this.clicked_x = x;
            this.clicked_y = y;
            return true;
        }
        return false;
    }
    
    /////////////////////////////////////////////////////////////////////
    /// Called when a button of the mouse is released.
    /////////////////////////////////////////////////////////////////////
    
    public bool on_button_release(double x, double y) {
        if (this.clicked.end == 0.9) {
            this.clicked.reset_target(1.0, 0.1);
            this.on_clicked();
            
            return true;
        }
        return false;
    }
}

}