/****************************************************************************
 * This file is part of Terminal.
 *
 * Copyright (C) 2013 Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>
 *
 * Author(s):
 *    Pier Luigi Fiorini
 *
 * $BEGIN_LICENSE:GPL2+$
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 * $END_LICENSE$
 ***************************************************************************/

import QtQuick 2.1
import QtQuick.Window 2.1
import QtQuick.Controls 1.0
import QtGraphicalEffects 1.0

ApplicationWindow{
    id: mainwindow
    width: 1024
    height: 768

    title: qsTr("Terminal")

    visible: true

    ShaderSettings{
        id: shadersettings
    }

    ShaderEffectSource{
        id: theSource
        sourceItem: terminal
        sourceRect: Qt.rect(-20, -20, terminal.width + 40, terminal.height + 40)
    }

    ShaderEffect {
        id: shadercontainer
        anchors.fill: parent
        blending: false
        z: 2
        property color font_color: shadersettings.font_color
        property color background_color: shadersettings.background_color
        property variant source: theSource
        property size txt_Size: Qt.size(terminal.width, terminal.height)
        property real time: 0

        property real noise_strength: shadersettings.noise_strength
        property real screen_distorsion: shadersettings.screen_distortion
        property real glowing_line_strength: shadersettings.glowing_line_strength
        property real deltay: 1.0 / terminal.height
        property real deltax: 1.0 / terminal.width
        //property real faulty_screen_prob: shadersettings.faulty_screen_prob

        NumberAnimation on time{
            from: -1
            to: 100
            duration: 5000

            loops: Animation.Infinite
        }

        fragmentShader: "
                        uniform sampler2D source;
                        uniform highp float qt_Opacity;
                        uniform highp float time;
                        uniform highp vec2 txt_Size;
                        varying highp vec2 qt_TexCoord0;

                        uniform highp vec4 font_color;
                        uniform highp vec4 background_color;
                        uniform highp float noise_strength;
                        uniform highp float screen_distorsion;
                        uniform highp float glowing_line_strength;
                        uniform highp float deltax;
                        uniform highp float deltay;

                        float rand(vec2 co, float time){
                            return fract(sin(dot(co.xy ,vec2(0.37898 * time ,0.78233))) * 437.5875453);
                        }

                        float stepNoise(vec2 p){
                            vec2 newP = p * txt_Size*0.25;
                            return rand(floor(newP), time);
                        }

                        float getScanlineIntensity(vec2 pos){
                            return 0.5 + abs(sin(pos.y * txt_Size.y * 0.6)) * 0.5;
                        }

                        vec2 distortCoordinates(vec2 coords){
                            vec2 cc = coords - vec2(0.5);
                            float dist = dot(cc, cc) * screen_distorsion;
                            return (coords + cc * (1.0 + dist) * dist);
                        }

                        float randomPass(vec2 coords){
                            return fract(smoothstep(-0.2, 0.0, coords.y - time * 0.03)) * glowing_line_strength;
                        }

                        vec4 blurredColor(sampler2D source, vec2 coords){
                            vec4 sum = vec4(0.0);
                            sum += texture2D(source, coords - vec2(-deltax, -deltay)) * 0.11;
                            sum += texture2D(source, coords - vec2(-deltax, 0.0)) * 0.11;
                            sum += texture2D(source, coords - vec2(-deltax, +deltay)) * 0.11;
                            sum += texture2D(source, coords - vec2(0.0, -deltay)) * 0.11;
                            sum += texture2D(source, coords - vec2(0.0, 0.0)) * 0.11;
                            sum += texture2D(source, coords - vec2(0.0, +deltay)) * 0.11;
                            sum += texture2D(source, coords - vec2(+deltax, -deltay)) * 0.11;
                            sum += texture2D(source, coords - vec2(+deltax, 0.0)) * 0.11;
                            sum += texture2D(source, coords - vec2(+deltax, +deltay)) * 0.11;
                            return sum;
                        }

                        void main() {
                            vec2 coords = distortCoordinates(qt_TexCoord0);

                            //Emulate faulty screen
                            //coords.x = coords.x + sin(coords.y * 5.0) * 0.05 * step(faulty_screen_prob, rand(txt_Size, floor(time)));

                            //vec4 color = texture2D(source, coords);
                            vec4 color = blurredColor(source, coords);
                            float alpha = getScanlineIntensity(coords) * step(0.0, coords.x) * step(-1.0, -coords.x) * step(0.0, coords.y) * step(-1.0, -coords.y);
                            //float alpha = 1.0;
                            float noise = stepNoise(coords) * noise_strength;
                            float randomPass = randomPass(coords) * glowing_line_strength;
                            vec4 added_color = (noise + randomPass) * font_color;
                            vec4 finalColor = color + added_color;

                            gl_FragColor = mix(finalColor, background_color, 1.0 - alpha);
                        }"
    }

    TerminalScreen {
        id: terminal
        width: mainwindow.width
        height: mainwindow.height
        visible: false

        //FIXME: Ugly forced clear terminal at the beginning
        Component.onCompleted: terminal.screen.sendKey("l", 76, 67108864);
    }

    RadialGradient{
        z: 4
        anchors.fill: terminal
        cached: true
        opacity: 0.3
        gradient: Gradient{
            GradientStop{position: 0.0; color: shadersettings.font_color}
            GradientStop{position: 0.7; color: shadersettings.background_color}
        }
    }
}