import QtQuick 2.12
import QtCharts 2.3
import QtQuick.Shapes 1.12

import Controls 1.0 as Controls
import Utils 1.0

ChartView {
    id: chart

    antialiasing: true
    backgroundColor: Palette.backgroundColor
    margins.left: 20

    legend.visible: false
    legend.alignment: Qt.AlignRight
    legend.markerShape: Legend.MarkerShapeCircle

    property AbstractAxis xAxis: valueAxisX
    property AbstractAxis yAxis: valueAxisY

    property int defaultXMax: 10
    property int defaultYMax: 1
    property bool autoScaling: true
    property int selectedSeriesIndex: 0

    property string infoXMark: ""
    property string infoYMark: ""

    ValueAxis {
        id: valueAxisX
        min: 0
        max: chart.defaultXMax
        tickCount: 8
        gridVisible: false
        gridLineColor: Palette.borderColor
        labelsColor: Palette.contentTextColor
        labelsFont.pixelSize: 18
        color: Palette.borderColor
        titleVisible: false
    }

    ValueAxis {
        id: valueAxisY
        min: 0
        max: chart.defaultYMax
        tickCount: 6
        labelsColor: Palette.contentTextColor
        labelsFont.pixelSize: 18
        color: Palette.borderColor
        titleVisible: false
    }

    Shape {
        id: currentPointLine
        implicitWidth: 1
        implicitHeight: chart.plotArea.height
        x: chart.plotArea.x
        y: chart.plotArea.y

        ShapePath {
            strokeColor: Palette.borderColor
            strokeStyle: ShapePath.SolidLine
            startX: 0
            startY: 0
            PathLine { x: 0; y: currentPointLine.height }
        }
    }

    Rectangle {
        id: currentPointInfo

        width: currentPointInfoLabel.width
        height: currentPointInfoLabel.height
        color: Palette.backgroundColor
        border.width: 1
        border.color: Palette.borderColor
        opacity: 0.9
        radius: 6
        visible: false

        Controls.SubtitleLabel {
            id: currentPointInfoLabel
            horizontalAlignment: Text.AlignHCenter
            anchors.centerIn: parent
            padding: 10
        }
    }

    MouseArea {
        id: chartMouseArea
        anchors.fill: parent
        acceptedButtons: Qt.LeftButton
        hoverEnabled: true

        property real lastMouseX: 0
        property real lastMouseY: 0

        property real scrollThreshold: 0

        onMouseXChanged: {
            if ((mouse.buttons & Qt.LeftButton) == Qt.LeftButton) {
                if (mouseX - lastMouseX > scrollThreshold) {
                    chart.scrollLeft(mouseX - lastMouseX)
                } else if (mouseX - lastMouseX < scrollThreshold) {
                    chart.scrollRight(lastMouseX - mouseX)
                }
                lastMouseX = mouseX
                chart.autoScaling = false
            }

            updatePointInfo()
        }
        onMouseYChanged: {

            if ((mouse.buttons & Qt.LeftButton) == Qt.LeftButton) {
                if (mouseY - lastMouseY > scrollThreshold) {
                    chart.scrollUp(mouseY - lastMouseY)
                } else if (mouseY - lastMouseY < scrollThreshold) {
                    chart.scrollDown(lastMouseY - mouseY)
                }
                lastMouseY = mouseY
                chart.autoScaling = false
            }

            updatePointInfo()
        }
        onPressed: {
            if (mouse.button === Qt.LeftButton) {
                lastMouseX = mouseX
                lastMouseY = mouseY
            }
        }
        onWheel: {
            var scaleFactor = 0.75
            var area = chart.plotArea
            chart.autoScaling = false

            var yAxisPosition = mouseX <= chart.plotArea.x
            if (yAxisPosition) {
                if (wheel.angleDelta.y > 0) {
                    chart.zoomIn(Qt.rect(area.x, area.y + Math.round(area.height * (1 - scaleFactor) / 2), area.width, Math.round(area.height * scaleFactor)))
                } else {
                    chart.zoomIn(Qt.rect(area.x, area.y - Math.round((area.height / scaleFactor) * (1 - scaleFactor) / 2), area.width, Math.round(area.height / scaleFactor)))
                }
                return
            }

            var xAxisPosition = mouseY >= (chart.plotArea.y + chart.plotArea.height)
            if (xAxisPosition) {
                if (wheel.angleDelta.y > 0) {
                    chart.zoomIn(Qt.rect(area.x + area.width * (1 - scaleFactor) / 2, area.y, Math.round(area.width * scaleFactor), area.height))
                } else {
                    chart.zoomIn(Qt.rect(area.x - (area.width / scaleFactor) * (1 - scaleFactor) / 2, area.y, Math.round(area.width / scaleFactor), area.height))
                }
                return
            }

            if (wheel.angleDelta.y > 0) {
                let zoomedInArea = Qt.rect(area.x + Math.round((mouseX - area.x) * (1 - scaleFactor)),
                                           area.y + Math.round((mouseY - area.y) * (1 - scaleFactor)),
                                           Math.round(area.width * scaleFactor),
                                           Math.round(area.height * scaleFactor))
                chart.zoomIn(zoomedInArea)
            } else {
                let zoomedOutArea = Qt.rect(area.x - Math.floor((mouseX - area.x) * (1 - scaleFactor)),
                                            area.y - Math.floor((mouseY - area.y) * (1 - scaleFactor)),
                                            Math.round(area.width * (1 + (1 - scaleFactor))),
                                            Math.round(area.height * (1 + (1 - scaleFactor))))
                chart.zoomIn(zoomedOutArea)
            }

            updatePointInfo()
        }

        function updatePointInfo() {
            var currentPointVisibility = mouseX >= chart.plotArea.x && mouseX <= chart.plotArea.x + chart.plotArea.width &&
                    mouseY >= chart.plotArea.y && mouseY <= chart.plotArea.y + chart.plotArea.height

            currentPointInfo.visible = currentPointVisibility
            currentPointInfo.x = mouseX + 5
            currentPointInfo.y = mouseY - currentPointInfo.height - 5

            var currentX = Math.ceil(mapToValue(Qt.point(mouseX, mouseY), chart.series(selectedSeriesIndex)).x)
            var selectedPoint = Qt.point(0, 0)

            if (currentX < chart.series(selectedSeriesIndex).count && currentX > 0) {
                selectedPoint = chart.series(selectedSeriesIndex).at(currentX)
                currentPointInfoLabel.text = selectedPoint.x + " " + infoXMark + ", " + selectedPoint.y + " " + infoYMark
            } else {
                currentPointInfo.visible = false
            }

            currentPointLine.visible = currentPointVisibility
            currentPointLine.x = mouseX
        }
    }

    onSeriesAdded: if (count === 1) {
                       series.pointAdded.connect(function (index){ chartMouseArea.updatePointInfo() })
                   }
}