// Copyright (c) 2017 Ultimaker B.V.
// Cura is released under the terms of the LGPLv3 or higher.

import QtQuick 2.2
import QtQuick.Controls 1.2
import QtQuick.Layouts 1.1
import QtQuick.Controls.Styles 1.1

import UM 1.0 as UM
import Cura 1.0 as Cura

Item {
    id: sliderRoot

    // handle properties
    property real handleSize: 10
    property real handleRadius: handleSize / 2
    property real minimumRangeHandleSize: handleSize / 2
    property color upperHandleColor: "black"
    property color lowerHandleColor: "black"
    property color rangeHandleColor: "black"
    property color handleActiveColor: "white"
    property real handleLabelWidth: width
    property var activeHandle: upperHandle

    // track properties
    property real trackThickness: 4 // width of the slider track
    property real trackRadius: trackThickness / 2
    property color trackColor: "white"
    property real trackBorderWidth: 1 // width of the slider track border
    property color trackBorderColor: "black"

    // value properties
    property real maximumValue: 100
    property real minimumValue: 0
    property real minimumRange: 0 // minimum range allowed between min and max values
    property bool roundValues: true
    property real upperValue: maximumValue
    property real lowerValue: minimumValue

    property bool layersVisible: true

    function getUpperValueFromSliderHandle () {
        return upperHandle.getValue()
    }

    function setUpperValue (value) {
        upperHandle.setValue(value)
        updateRangeHandle()
    }

    function getLowerValueFromSliderHandle () {
        return lowerHandle.getValue()
    }

    function setLowerValue (value) {
        lowerHandle.setValue(value)
        updateRangeHandle()
    }

    function updateRangeHandle () {
        rangeHandle.height = lowerHandle.y - (upperHandle.y + upperHandle.height)
    }

    // set the active handle to show only one label at a time
    function setActiveHandle (handle) {
        activeHandle = handle
    }

    // slider track
    Rectangle {
        id: track

        width: sliderRoot.trackThickness
        height: sliderRoot.height - sliderRoot.handleSize
        radius: sliderRoot.trackRadius
        anchors.centerIn: sliderRoot
        color: sliderRoot.trackColor
        border.width: sliderRoot.trackBorderWidth
        border.color: sliderRoot.trackBorderColor
        visible: sliderRoot.layersVisible
    }

    // Range handle
    Item {
        id: rangeHandle

        y: upperHandle.y + upperHandle.height
        width: sliderRoot.handleSize
        height: sliderRoot.minimumRangeHandleSize
        anchors.horizontalCenter: sliderRoot.horizontalCenter
        visible: sliderRoot.layersVisible

        // set the new value when dragging
        function onHandleDragged () {

            upperHandle.y = y - upperHandle.height
            lowerHandle.y = y + height

            var upperValue = sliderRoot.getUpperValueFromSliderHandle()
            var lowerValue = sliderRoot.getLowerValueFromSliderHandle()

            // set both values after moving the handle position
            UM.SimulationView.setCurrentLayer(upperValue)
            UM.SimulationView.setMinimumLayer(lowerValue)
        }

        function setValue (value) {
            var range = sliderRoot.upperValue - sliderRoot.lowerValue
            value = Math.min(value, sliderRoot.maximumValue)
            value = Math.max(value, sliderRoot.minimumValue + range)

            UM.SimulationView.setCurrentLayer(value)
            UM.SimulationView.setMinimumLayer(value - range)
        }

        Rectangle {
            width: sliderRoot.trackThickness - 2 * sliderRoot.trackBorderWidth
            height: parent.height + sliderRoot.handleSize
            anchors.centerIn: parent
            color: sliderRoot.rangeHandleColor
        }

        MouseArea {
            anchors.fill: parent

            drag {
                target: parent
                axis: Drag.YAxis
                minimumY: upperHandle.height
                maximumY: sliderRoot.height - (rangeHandle.height + lowerHandle.height)
            }

            onPositionChanged: parent.onHandleDragged()
            onPressed: sliderRoot.setActiveHandle(rangeHandle)
        }

        SimulationSliderLabel {
            id: rangleHandleLabel

            height: sliderRoot.handleSize + UM.Theme.getSize("default_margin").height
            x: parent.x - width - UM.Theme.getSize("default_margin").width
            anchors.verticalCenter: parent.verticalCenter
            target: Qt.point(sliderRoot.width, y + height / 2)
            visible: sliderRoot.activeHandle == parent

            // custom properties
            maximumValue: sliderRoot.maximumValue
            value: sliderRoot.upperValue
            busy: UM.SimulationView.busy
            setValue: rangeHandle.setValue // connect callback functions
        }
    }

    // Upper handle
    Rectangle {
        id: upperHandle

        y: sliderRoot.height - (sliderRoot.minimumRangeHandleSize + 2 * sliderRoot.handleSize)
        width: sliderRoot.handleSize
        height: sliderRoot.handleSize
        anchors.horizontalCenter: sliderRoot.horizontalCenter
        radius: sliderRoot.handleRadius
        color: upperHandleLabel.activeFocus ? sliderRoot.handleActiveColor : sliderRoot.upperHandleColor
        visible: sliderRoot.layersVisible

        function onHandleDragged () {

            // don't allow the lower handle to be heigher than the upper handle
            if (lowerHandle.y - (y + height) < sliderRoot.minimumRangeHandleSize) {
                lowerHandle.y = y + height + sliderRoot.minimumRangeHandleSize
            }

            // update the range handle
            sliderRoot.updateRangeHandle()

            // set the new value after moving the handle position
            UM.SimulationView.setCurrentLayer(getValue())
        }

        // get the upper value based on the slider position
        function getValue () {
            var result = y / (sliderRoot.height - (2 * sliderRoot.handleSize + sliderRoot.minimumRangeHandleSize))
            result = sliderRoot.maximumValue + result * (sliderRoot.minimumValue - (sliderRoot.maximumValue - sliderRoot.minimumValue))
            result = sliderRoot.roundValues ? Math.round(result) : result
            return result
        }

        // set the slider position based on the upper value
        function setValue (value) {

            UM.SimulationView.setCurrentLayer(value)

            var diff = (value - sliderRoot.maximumValue) / (sliderRoot.minimumValue - sliderRoot.maximumValue)
            var newUpperYPosition = Math.round(diff * (sliderRoot.height - (2 * sliderRoot.handleSize + sliderRoot.minimumRangeHandleSize)))
            y = newUpperYPosition

            // update the range handle
            sliderRoot.updateRangeHandle()
        }

        Keys.onUpPressed: upperHandleLabel.setValue(upperHandleLabel.value + ((event.modifiers & Qt.ShiftModifier) ? 10 : 1))
        Keys.onDownPressed: upperHandleLabel.setValue(upperHandleLabel.value - ((event.modifiers & Qt.ShiftModifier) ? 10 : 1))

        // dragging
        MouseArea {
            anchors.fill: parent

            drag {
                target: parent
                axis: Drag.YAxis
                minimumY: 0
                maximumY: sliderRoot.height - (2 * sliderRoot.handleSize + sliderRoot.minimumRangeHandleSize)
            }

            onPositionChanged: parent.onHandleDragged()
            onPressed: {
                sliderRoot.setActiveHandle(upperHandle)
                upperHandleLabel.forceActiveFocus()
            }
        }

        SimulationSliderLabel {
            id: upperHandleLabel

            height: sliderRoot.handleSize + UM.Theme.getSize("default_margin").height
            x: parent.x - width - UM.Theme.getSize("default_margin").width
            anchors.verticalCenter: parent.verticalCenter
            target: Qt.point(sliderRoot.width, y + height / 2)
            visible: sliderRoot.activeHandle == parent

            // custom properties
            maximumValue: sliderRoot.maximumValue
            value: sliderRoot.upperValue
            busy: UM.SimulationView.busy
            setValue: upperHandle.setValue // connect callback functions
        }
    }

    // Lower handle
    Rectangle {
        id: lowerHandle

        y: sliderRoot.height - sliderRoot.handleSize
        width: parent.handleSize
        height: parent.handleSize
        anchors.horizontalCenter: parent.horizontalCenter
        radius: sliderRoot.handleRadius
        color: lowerHandleLabel.activeFocus ? sliderRoot.handleActiveColor : sliderRoot.lowerHandleColor

        visible: sliderRoot.layersVisible

        function onHandleDragged () {

            // don't allow the upper handle to be lower than the lower handle
            if (y - (upperHandle.y + upperHandle.height) < sliderRoot.minimumRangeHandleSize) {
                upperHandle.y = y - (upperHandle.heigth + sliderRoot.minimumRangeHandleSize)
            }

            // update the range handle
            sliderRoot.updateRangeHandle()

            // set the new value after moving the handle position
            UM.SimulationView.setMinimumLayer(getValue())
        }

        // get the lower value from the current slider position
        function getValue () {
            var result = (y - (sliderRoot.handleSize + sliderRoot.minimumRangeHandleSize)) / (sliderRoot.height - (2 * sliderRoot.handleSize + sliderRoot.minimumRangeHandleSize));
            result = sliderRoot.maximumValue - sliderRoot.minimumRange + result * (sliderRoot.minimumValue - (sliderRoot.maximumValue - sliderRoot.minimumRange))
            result = sliderRoot.roundValues ? Math.round(result) : result
            return result
        }

        // set the slider position based on the lower value
        function setValue (value) {

            UM.SimulationView.setMinimumLayer(value)

            var diff = (value - sliderRoot.maximumValue) / (sliderRoot.minimumValue - sliderRoot.maximumValue)
            var newLowerYPosition = Math.round((sliderRoot.handleSize + sliderRoot.minimumRangeHandleSize) + diff * (sliderRoot.height - (2 * sliderRoot.handleSize + sliderRoot.minimumRangeHandleSize)))
            y = newLowerYPosition

            // update the range handle
            sliderRoot.updateRangeHandle()
        }

        Keys.onUpPressed: lowerHandleLabel.setValue(lowerHandleLabel.value + ((event.modifiers & Qt.ShiftModifier) ? 10 : 1))
        Keys.onDownPressed: lowerHandleLabel.setValue(lowerHandleLabel.value - ((event.modifiers & Qt.ShiftModifier) ? 10 : 1))

        // dragging
        MouseArea {
            anchors.fill: parent

            drag {
                target: parent
                axis: Drag.YAxis
                minimumY: upperHandle.height + sliderRoot.minimumRangeHandleSize
                maximumY: sliderRoot.height - parent.height
            }

            onPositionChanged: parent.onHandleDragged()
            onPressed: {
                sliderRoot.setActiveHandle(lowerHandle)
                lowerHandleLabel.forceActiveFocus()
            }
        }

        SimulationSliderLabel {
            id: lowerHandleLabel

            height: sliderRoot.handleSize + UM.Theme.getSize("default_margin").height
            x: parent.x - width - UM.Theme.getSize("default_margin").width
            anchors.verticalCenter: parent.verticalCenter
            target: Qt.point(sliderRoot.width, y + height / 2)
            visible: sliderRoot.activeHandle == parent

            // custom properties
            maximumValue: sliderRoot.maximumValue
            value: sliderRoot.lowerValue
            busy: UM.SimulationView.busy
            setValue: lowerHandle.setValue // connect callback functions
        }
    }
}