import QtQuick 2.0
import QtQuick.Particles 2.0

Item {
    id: root

    property alias text: textItem.text
    property bool checked: false
    property string onText: "On"
    property string offText: "Off"

    QtObject {
        id: priv
        property alias checkedPriv: root.checked
        onCheckedPrivChanged: {
            if (checkedPriv) switchEffectAnimation.restart();
        }

        function releaseSwitch() {
            if (knob.x == 48) switchEffectAnimation.restart();
            // Don't switch if we are in correct side
            if ((knob.x == -2 && !checked) || (knob.x == 48 && checked)) {
                return;
            }
            checked = !checked;
        }
    }

    width: parent ? parent.width : 200
    height: 80

    MouseArea {
        width: parent.width
        height: parent.height
        onClicked: {
            root.checked = !root.checked
        }
    }

    Text {
        id: textItem
        anchors.verticalCenter: parent.verticalCenter
        anchors.left: parent.left
        anchors.leftMargin: 22
        anchors.right: switchBackgroundImage.left
        elide: Text.ElideRight
        font.pixelSize: 20
        color: "#ffffff"
    }

    Image {
        id: switchBackgroundImage
        source: "images/switch_background.png"
        anchors.verticalCenter: parent.verticalCenter
        anchors.right: parent.right
        anchors.rightMargin: 22
    }
    Image {
        id: switchFrameImage
        source: "images/switch_frame.png"
        anchors.verticalCenter: parent.verticalCenter
        anchors.right: parent.right
        anchors.rightMargin: 21
        z: 10
    }

    Item {
        id: switchItem
        anchors.fill: switchBackgroundImage

        SequentialAnimation {
            id: switchEffectAnimation
            PropertyAction { target: particleSystem; property: "paused"; value: "false" }
            ScriptAction { script: particleEmitter.pulse(3000) }
        }

        Image {
            id: switchOnImage
            anchors.right: knob.right
            anchors.rightMargin: 2
            source: "images/switch_on.png"
            opacity: knob.x / 48

            // Stars effect
            ParticleSystem {
                id: particleSystem
                anchors.fill: parent
                paused: true
                onEmptyChanged: if (empty) particleSystem.pause();
                ImageParticle {
                    source: "images/star.png"
                    rotationVariation: 180
                    color:"#ffffff"
                }
                Emitter {
                    id: particleEmitter
                    width: parent.width
                    height: 8
                    emitRate: 16
                    lifeSpan: 2000
                    size: 32
                    sizeVariation: 16
                    endSize: 8
                    velocity: PointDirection{ y: 20; x:-2; xVariation: 5; yVariation: 10 }
                    enabled: false

                }
                Turbulence {
                    width: parent.width
                    height: (parent.height / 2)
                    strength: 8
                }
            }
        }

        Text {
            anchors.verticalCenter: parent.verticalCenter
            anchors.right: knob.left
            anchors.rightMargin: 6
            color: "#000000"
            font.pixelSize: 18
            font.bold: true
            text: onText
        }
        Text {
            anchors.verticalCenter: parent.verticalCenter
            anchors.left: knob.right
            anchors.leftMargin: 4
            color: "#ffffff"
            font.pixelSize: 18
            font.bold: true
            text: offText
        }

        Image {
            id: knob
            source: "images/switch_thumb.png"
            x: checked ? 48 : -2
            opacity: 0.4
            MouseArea {
                anchors.fill: parent
                drag.target: knob; drag.axis: Drag.XAxis; drag.minimumX: -2; drag.maximumX: 48
                onClicked: checked = !checked
                onReleased: priv.releaseSwitch();
            }
            Behavior on x {
                NumberAnimation { duration: 250; easing.type: Easing.InOutQuad }
            }
        }
    }

    // Mask out switch parts which should be hidden
    ShaderEffect {
        id: shaderItem
        property variant source: ShaderEffectSource { sourceItem: switchItem; hideSource: true }
        property variant maskSource: ShaderEffectSource { sourceItem: switchBackgroundImage; hideSource: true }

        anchors.fill: switchBackgroundImage

        fragmentShader: "
            varying highp vec2 qt_TexCoord0;
            uniform highp float qt_Opacity;
            uniform sampler2D source;
            uniform sampler2D maskSource;
            void main(void) {
                gl_FragColor = texture2D(source, qt_TexCoord0.st) * (texture2D(maskSource, qt_TexCoord0.st).a) * qt_Opacity;
            }
        "
    }
}