/*
 *  SPDX-FileCopyrightText: 2018 Marco Martin <mart@kde.org>
 *
 *  SPDX-License-Identifier: LGPL-2.0-or-later
 */

import QtQuick
import QtQuick.Layouts
import QtQuick.Controls as QQC2
import org.kde.kirigami as Kirigami

/*!
  This Component is used as the header of GlobalDrawer and as the header
  of Card, It can be accessed there as a grouped property but can never
  be instantiated directly.
  \internal
 */
Kirigami.ShadowedImage {
    id: root

//BEGIN properties
    /*!
      \brief This property holds an icon to be displayed alongside the title.

      It can be a QIcon, a FreeDesktop-compatible icon name, or any URL understood by QtQuick.Image.
     */
    property alias titleIcon: headingIcon.source

    /*!
      \brief This property holds the title's text which is to be displayed on top.
      of the image.
     */
    property alias title: heading.text

    /*!
      \brief This property holds the title's position.

      default: Qt.AlignTop | Qt.AlignLeft
     */
    property int titleAlignment: Qt.AlignTop | Qt.AlignLeft

    /*!
      \brief This property holds the title's level.

      Available text size values range from 1 (largest) to 5 (smallest).

      default: 1

      \sa Heading::level
     */
    property alias titleLevel: heading.level

    /*!
      \brief This property holds the title's wrap mode.

      default: Text.NoWrap

      \sa Text::wrapMode
     */
    property alias titleWrapMode: heading.wrapMode

    /*!
      \brief This property holds whether the title is part of an item considered
      checkable.

      If true, a checkbox will appear in the top-right corner of the title area.

      default: false
     */
    property bool checkable: false

    /*!
      \brief This property holds whether the title's checkbox is currently checked.

      If using this outside of a GlobalDrawer or a Card, you must manually bind
      this to the checked condition of the parent item, or whatever else in your
      UI signals checkability. You must also handle the `toggled` signal when
      the user manually clicks the checkbox.

      default: false
     */
    property bool checked: false

    property int leftPadding: headingIcon.valid ? Kirigami.Units.smallSpacing * 2 : Kirigami.Units.largeSpacing
    property int topPadding: headingIcon.valid ? Kirigami.Units.smallSpacing * 2 : Kirigami.Units.largeSpacing
    property int rightPadding: headingIcon.valid ? Kirigami.Units.smallSpacing * 2 : Kirigami.Units.largeSpacing
    property int bottomPadding: headingIcon.valid ? Kirigami.Units.smallSpacing * 2 : Kirigami.Units.largeSpacing

    property int implicitWidth: Layout.preferredWidth

    readonly property bool empty: title.length === 0 &&             // string
                                  source.toString().length === 0 && // QUrl
                                  !titleIcon                        // QVariant handled by Kirigami.Icon
//END properties

    signal toggled(bool checked)

    Layout.fillWidth: true

    Layout.preferredWidth: titleLayout.implicitWidth || sourceSize.width
    Layout.preferredHeight: titleLayout.completed && source.toString().length > 0 ? width/(sourceSize.width / sourceSize.height) : Layout.minimumHeight
    Layout.minimumHeight: titleLayout.implicitHeight > 0 ? titleLayout.implicitHeight + Kirigami.Units.smallSpacing * 2 : 0

    onTitleAlignmentChanged: {
        // VERTICAL ALIGNMENT
        titleLayout.anchors.top = undefined
        titleLayout.anchors.verticalCenter = undefined
        titleLayout.anchors.bottom = undefined
        shadowedRectangle.anchors.top = undefined
        shadowedRectangle.anchors.verticalCenter = undefined
        shadowedRectangle.anchors.bottom = undefined

        if (root.titleAlignment & Qt.AlignTop) {
            titleLayout.anchors.top = root.top
            shadowedRectangle.anchors.top = root.top
        }
        else if (root.titleAlignment & Qt.AlignVCenter) {
            titleLayout.anchors.verticalCenter = root.verticalCenter
            shadowedRectangle.anchors.verticalCenter = root.verticalCenter
        }
        else if (root.titleAlignment & Qt.AlignBottom) {
            titleLayout.anchors.bottom = root.bottom
            shadowedRectangle.anchors.bottom = root.bottom
        }

        // HORIZONTAL ALIGNMENT
        titleLayout.anchors.left = undefined
        titleLayout.anchors.horizontalCenter = undefined
        titleLayout.anchors.right = undefined
        if (root.titleAlignment & Qt.AlignRight) {
            titleLayout.anchors.right = root.right
        }
        else if (root.titleAlignment & Qt.AlignHCenter) {
            titleLayout.anchors.horizontalCenter = root.horizontalCenter
        }
        else if (root.titleAlignment & Qt.AlignLeft) {
            titleLayout.anchors.left = root.left
        }
    }
    fillMode: Image.PreserveAspectCrop
    asynchronous: true

    color: "transparent"

    Component.onCompleted: {
        titleLayout.completed = true;
    }

    Kirigami.ShadowedRectangle {
        id: shadowedRectangle
        anchors {
            left: parent.left
            right: parent.right
        }
        height: Math.min(parent.height, titleLayout.height * 1.5)

        opacity: 0.5
        color: "black"

        corners.topLeftRadius: root.titleAlignment & Qt.AlignTop ? root.corners.topLeftRadius : 0
        corners.topRightRadius: root.titleAlignment & Qt.AlignTop ? root.corners.topRightRadius : 0
        corners.bottomLeftRadius: root.titleAlignment & Qt.AlignBottom ? root.corners.bottomLeftRadius : 0
        corners.bottomRightRadius: root.titleAlignment & Qt.AlignBottom ? root.corners.bottomRightRadius : 0

        visible: root.source.toString().length !== 0 && root.title.length !== 0 && ((root.titleAlignment & Qt.AlignTop) || (root.titleAlignment & Qt.AlignVCenter) || (root.titleAlignment & Qt.AlignBottom))
    }

    RowLayout {
        id: titleLayout
        property bool completed: false
        anchors {
            leftMargin: root.leftPadding
            topMargin: root.topPadding
            rightMargin: root.rightPadding
            bottomMargin: root.bottomPadding
        }
        width: Math.min(implicitWidth, parent.width -root.leftPadding -root.rightPadding - (checkboxLoader.active ? Kirigami.Units.largeSpacing : 0))
        height: Math.min(implicitHeight, parent.height -root.topPadding -root.bottomPadding)
        Kirigami.Icon {
            id: headingIcon
            Layout.minimumWidth: Kirigami.Units.iconSizes.large
            Layout.minimumHeight: width
            visible: valid
            isMask: false
        }
        Kirigami.Heading {
            id: heading
            Layout.fillWidth: true
            Layout.fillHeight: true
            verticalAlignment: Text.AlignVCenter
            visible: text.length > 0
            level: 1
            color: root.source.toString().length > 0 ? "white" : Kirigami.Theme.textColor
            wrapMode: Text.NoWrap
            elide: Text.ElideRight
        }
    }

    Loader {
        id: checkboxLoader
        anchors {
            top: parent.top
            right: parent.right
            topMargin: root.topPadding
        }
        active: root.checkable
        sourceComponent: QQC2.CheckBox {
            checked: root.checked
            onToggled: root.toggled(checked);
        }
    }
}