// SPDX-FileCopyrightText: 2023 Devin Lin <devin@kde.org>
// SPDX-License-Identifier: LGPL-2.0-or-later

import QtQuick
import QtQuick.Window
import QtQuick.Layouts
import QtQuick.Effects
import QtQuick.Controls as QQC2

import org.kde.kirigami as Kirigami

import org.kde.plasma.plasmoid 2.0
import org.kde.plasma.components 3.0 as PC3
import org.kde.plasma.private.mobileshell as MobileShell
import org.kde.plasma.private.mobileshell.shellsettingsplugin as ShellSettings
import QtQuick.Templates as T
import plasma.applet.org.kde.plasma.mobile.homescreen.folio as Folio

import "./delegate"
import "./settings"

Item {
    id: root
    property Folio.HomeScreen folio
    property MobileShell.MaskManager maskManager
    property Folio.HomeScreenState homeScreenState: folio.HomeScreenState

    property real topMargin: 0
    property real bottomMargin: 0
    property real leftMargin: 0
    property real rightMargin: 0

    property bool interactive: true
    readonly property color favouritesBarScrimColor: Qt.rgba(Kirigami.Theme.highlightColor.r, Kirigami.Theme.highlightColor.g, Kirigami.Theme.highlightColor.b, 0.14)

    // non-widget drop animation
    readonly property bool dropAnimationRunning: delegateDragItem.dropAnimationRunning || widgetDragItem.dropAnimationRunning

    // widget that is currently being dragged (or dropped)
    readonly property Folio.FolioWidget currentlyDraggedWidget: widgetDragItem.widget

    // how much to scale out in the settings mode
    readonly property real settingsModeHomeScreenScale: 0.8

    onTopMarginChanged: folio.HomeScreenState.viewTopPadding = root.topMargin
    onBottomMarginChanged: folio.HomeScreenState.viewBottomPadding = root.bottomMargin
    onLeftMarginChanged: folio.HomeScreenState.viewLeftPadding = root.leftMargin
    onRightMarginChanged: folio.HomeScreenState.viewRightPadding = root.rightMargin
    onWidthChanged: folio.HomeScreenState.viewWidth = width
    onHeightChanged: folio.HomeScreenState.viewHeight = height

    signal wallpaperSelectorTriggered()

    // called by any delegates when starting drag
    // returns the mapped coordinates to be used in the home screen state
    function prepareStartDelegateDrag(delegate, item, skipSwipeThreshold) {

        // If the user is prompted with a context menu, they may want to let go, and so we keep the detect swipe threshold.
        // Otherwise, we want to skip detecting a swipe because we know we immediately go into delegate dragging.
        if (skipSwipeThreshold) {
            swipeArea.setSkipSwipeThreshold(true);
        }

        if (delegate) {
            delegateDragItem.delegate = delegate;
        }
        return root.mapFromItem(item, 0, 0);
    }

    function cancelDelegateDrag() {
        homeScreenState.cancelDelegateDrag();
    }

    // sets the coordinates for the folder opening/closing animation
    function prepareFolderOpen(item) {
        return root.mapFromItem(item, 0, 0);
    }

    function openConfigure() {
        Plasmoid.internalAction("configure").trigger();
    }

    function showDesktopContextMenu() {
        desktopContextMenu.popup();
    }

    PC3.Menu {
        id: desktopContextMenu
        popupType: T.Popup.Window

        PC3.MenuItem {
            text: i18n("Desktop and Wallpaper...")
            icon.name: "preferences-desktop-wallpaper"
            onTriggered: root.wallpaperSelectorTriggered()
        }
        PC3.MenuItem {
            text: i18n("Add Widgets...")
            icon.name: "widget-alternatives"
            onTriggered: {
                folio.HomeScreenState.openSettingsView();
                settings.openWidgetsBrowser();
            }
        }
        PC3.MenuSeparator {}
        PC3.MenuItem {
            text: i18n("Configure Desktop...")
            icon.name: "settings-configure"
            onTriggered: root.openConfigure()
        }
    }

    Keys.onPressed: (event) => {
        // The root is focused when we aren't in key navigation mode
        // Begin key navigation when arrow keys are pressed
        if (event.key === Qt.Key_Up || event.key === Qt.Key_Down
            || event.key === Qt.Key_Left || event.key === Qt.Key_Right) {
            homeScreenPages.forceActiveFocus();
            event.accepted = true;
        }
    }

    // determine how tall an app label is, for delegate measurements
    DelegateLabel {
        id: appLabelMetrics
        text: "M\nM"
        visible: false

        onHeightChanged: folio.HomeScreenState.pageDelegateLabelHeight = appLabelMetrics.height

        Component.onCompleted: {
            folio.HomeScreenState.pageDelegateLabelWidth = Kirigami.Units.smallSpacing;
        }
    }

    // a way of stopping focus
    FocusScope {
        id: noFocus
    }

    // Listen to view changes
    Connections {
        target: folio.HomeScreenState

        function onViewStateChanged() {
            if (folio.HomeScreenState.viewState === Folio.HomeScreenState.PageView) {
                // Focus root when on page view
                root.forceActiveFocus();
            }
        }
    }

    // Drag and drop area
    DelegateDropArea {
        id: dropArea
        folio: root.folio
        anchors.fill: parent

        // Area that can be swiped
        MobileShell.SwipeArea {
            id: swipeArea
            anchors.fill: parent

            interactive: root.interactive &&
                settings.homeScreenInteractive &&
                !dropArea.containsDrag &&
                (appDrawer.flickable.atYBeginning || // there are cases where contentY > 0 but atYBeginning is true
                appDrawer.flickable.contentY <= 10 ||
                // disable the swipe area when we are swiping in the app drawer, and not in drag-and-drop
                folio.HomeScreenState.swipeState === Folio.HomeScreenState.AwaitingDraggingDelegate ||
                folio.HomeScreenState.swipeState === Folio.HomeScreenState.DraggingDelegate ||
                folio.HomeScreenState.swipeState === Folio.HomeScreenState.SwipingAppDrawerGrid ||
                folio.HomeScreenState.viewState !== Folio.HomeScreenState.AppDrawerView)

            onSwipeStarted: (currentPos, startPos) => {
                const deltaX = currentPos.x - startPos.x;
                const deltaY = currentPos.y - startPos.y;
                homeScreenState.swipeStarted(deltaX, deltaY);
            }
            onSwipeEnded: {
                homeScreenState.swipeEnded();
            }
            onSwipeMove: (totalDeltaX, totalDeltaY, deltaX, deltaY) => {
                // cancel swipe when settings component is opening to prevent conflicts
                if (folio.HomeScreenState.settingsOpenProgress && folio.HomeScreenState.viewState !== Folio.HomeScreenState.SettingsView) {
                    homeScreenState.swipeCancelled();
                    return;
                }
                homeScreenState.swipeMoved(totalDeltaX, totalDeltaY, deltaX, deltaY);
            }

            onTouchpadScrollStarted: {
                if (!ShellSettings.Settings.convergenceModeEnabled) {
                    root.homeScreenState.swipeStarted(0, 0);
                }
            }
            onTouchpadScrollEnded: {
                if (!ShellSettings.Settings.convergenceModeEnabled) {
                    root.homeScreenState.swipeEnded();
                }
            }
            onTouchpadScrollMove: (totalDeltaX, totalDeltaY, deltaX, deltaY) => {
                if (!ShellSettings.Settings.convergenceModeEnabled) {
                    root.homeScreenState.swipeMoved(totalDeltaX, totalDeltaY, deltaX, deltaY);
                }
            }

            onPressedChanged: {
                if (pressed) {
                    // ensures that components like the widget settings overlay close when swiping
                    noFocus.forceActiveFocus();
                }
            }

            SettingsComponent {
                id: settings
                folio: root.folio
                homeScreen: root
                settingsModeHomeScreenScale: root.settingsModeHomeScreenScale

                // Don't anchor, since we set y
                width: parent.width
                height: parent.height
                opacity: folio.HomeScreenState.settingsOpenProgress
                visible: opacity > 0

                z: 1

                bottomMargin: root.bottomMargin
                leftMargin: root.leftMargin
                rightMargin: root.rightMargin
            }

            Item {
                id: mainHomeScreen
                anchors.fill: parent

                // we stop showing halfway through the animation (skip in convergence — desktop stays visible)
                opacity: ShellSettings.Settings.convergenceModeEnabled
                    ? 1
                    : 1 - Math.max(homeScreenState.appDrawerOpenProgress, homeScreenState.searchWidgetOpenProgress, homeScreenState.folderOpenProgress) * 2
                visible: opacity > 0 // prevent handlers from picking up events

                transform: [
                    Scale {
                        property real scaleFactor: ShellSettings.Settings.convergenceModeEnabled
                            ? 0
                            : Math.max(homeScreenState.appDrawerOpenProgress, homeScreenState.searchWidgetOpenProgress)
                        origin.x: mainHomeScreen.width / 2
                        origin.y: mainHomeScreen.height / 2
                        yScale: 1 - (scaleFactor * 2) * 0.1
                        xScale: 1 - (scaleFactor * 2) * 0.1
                    }
                ]

                HomeScreenPages {
                    id: homeScreenPages
                    folio: root.folio
                    maskManager: root.maskManager
                    homeScreen: root

                    anchors.topMargin: root.topMargin
                    anchors.leftMargin: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Left ? 0 : root.leftMargin
                    anchors.rightMargin: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Right ? 0 : root.rightMargin
                    anchors.bottomMargin: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom ? 0 : root.bottomMargin

                    // update the model with page dimensions
                    onWidthChanged: {
                        homeScreenState.pageWidth = homeScreenPages.width;
                    }
                    onHeightChanged: {
                        homeScreenState.pageHeight = homeScreenPages.height;
                    }

                    // Keyboard navigation from pages
                    Keys.onPressed: (event) => {
                        switch (event.key) {
                        case Qt.Key_Up:
                            // Open search widget when going up
                            folio.HomeScreenState.openSearchWidget();
                            event.accepted = true;
                            break;
                        case Qt.Key_Down:
                            // Focus on favorites bar or app drawer, depending on its physical location
                            if (folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom) {
                                favouritesBar.forceActiveFocus();
                            } else {
                                folio.HomeScreenState.openAppDrawer();
                            }
                            event.accepted = true;
                            break;
                        case Qt.Key_Left:
                            if (folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Left) {
                                // If favorites bar is on the left, navigate to it
                                favouritesBar.forceActiveFocus();
                            } else {
                                // Otherwise go to page on the left
                                folio.HomeScreenState.goToPage(folio.HomeScreenState.currentPage - 1, false);
                                homeScreenPages.focusCurrentPageForKeyboardNav();
                            }
                            event.accepted = true;
                            break;
                        case Qt.Key_Right:
                            if (folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Right) {
                                // If favorites bar is on the right, navigate to it
                                favouritesBar.forceActiveFocus();
                            } else {
                                // Otherwise go to page on the right
                                folio.HomeScreenState.goToPage(folio.HomeScreenState.currentPage + 1, false);
                                homeScreenPages.focusCurrentPageForKeyboardNav();
                            }
                            event.accepted = true;
                            break;
                        default:
                            break;
                        }
                    }

                    transform: [
                        Scale {
                            // animation when settings opens
                            property real scaleFactor: 1 - folio.HomeScreenState.settingsOpenProgress * (1 - settingsModeHomeScreenScale)
                            origin.x: root.leftMargin + (root.width - root.rightMargin - root.leftMargin) / 2
                            origin.y: root.height * settingsModeHomeScreenScale / 2
                            xScale: scaleFactor
                            yScale: scaleFactor
                        }
                    ]

                    states: [
                        State {
                            name: "bottom"
                            when: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom
                            AnchorChanges {
                                target: homeScreenPages
                                anchors.top: parent.top
                                anchors.bottom: favouritesBar.top
                                anchors.left: parent.left
                                anchors.right: parent.right
                            }
                        }, State {
                            name: "left"
                            when: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Left
                            AnchorChanges {
                                target: homeScreenPages
                                anchors.top: parent.top
                                anchors.bottom: parent.bottom
                                anchors.left: favouritesBar.right
                                anchors.right: parent.right
                            }
                        }, State {
                            name: "right"
                            when: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Right
                            AnchorChanges {
                                target: homeScreenPages
                                anchors.top: parent.top
                                anchors.bottom: parent.bottom
                                anchors.left: parent.left
                                anchors.right: favouritesBar.left
                            }
                        }
                    ]
                }

                Rectangle {
                    id: favouritesBarScrim
                    color: root.favouritesBarScrimColor

                    Component.onCompleted: maskManager.assignToMask(this)

                    // don't show in settings mode
                    opacity: 1 - folio.HomeScreenState.settingsOpenProgress
                    visible: folio.FolioSettings.showFavouritesBarBackground
                             && !ShellSettings.Settings.convergenceModeEnabled

                    anchors.top: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom ? favouritesBar.top : parent.top
                    anchors.bottom: parent.bottom
                    anchors.left: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Right ? favouritesBar.left : parent.left
                    anchors.right: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Left ? favouritesBar.right : parent.right

                    // because of the scale animation, we need to extend the panel out a bit
                    anchors.topMargin: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom ? 0 : -Kirigami.Units.gridUnit * 5
                    anchors.bottomMargin: -Kirigami.Units.gridUnit * 5
                    anchors.leftMargin: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Right ? 0 : -Kirigami.Units.gridUnit * 5
                    anchors.rightMargin: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Left ? 0 : -Kirigami.Units.gridUnit * 5
                }

                FavouritesBar {
                    id: favouritesBar
                    folio: root.folio
                    maskManager: root.maskManager
                    homeScreen: root

                    // don't show in settings mode
                    opacity: 1 - folio.HomeScreenState.settingsOpenProgress
                    // Hidden in convergence mode — the dock overlay window renders it instead
                    visible: opacity > 0 && !ShellSettings.Settings.convergenceModeEnabled

                    // one is ignored as anchors are set
                    height: ShellSettings.Settings.convergenceModeEnabled ? MobileShell.Constants.convergenceDockHeight : Kirigami.Units.gridUnit * 6
                    width: ShellSettings.Settings.convergenceModeEnabled ? MobileShell.Constants.convergenceDockHeight : Kirigami.Units.gridUnit * 6

                    anchors.topMargin: root.topMargin
                    anchors.bottomMargin: ShellSettings.Settings.convergenceModeEnabled ? 0 : root.bottomMargin
                    anchors.leftMargin: root.leftMargin
                    anchors.rightMargin: root.rightMargin

                    // Keyboard navigation on favorites bar
                    Keys.onPressed: (event) => {
                        switch (event.key) {
                        case Qt.Key_Up:
                            // Focus on homescreen pages or search widget depending on physical position
                            if (folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom) {
                                homeScreenPages.forceActiveFocus();
                            } else {
                                folio.HomeScreenState.openSearchWidget();
                            }
                            event.accepted = true;
                            break;
                        case Qt.Key_Down:
                            // Open app drawer
                            folio.HomeScreenState.openAppDrawer();
                            event.accepted = true;
                            break;
                        case Qt.Key_Left:
                            if (folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Left) {
                                // Go to left page if mounted on the left
                                folio.HomeScreenState.goToPage(folio.HomeScreenState.currentPage - 1, false);
                                event.accepted = true;
                            }
                            break;
                        case Qt.Key_Right:
                            if (folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Right) {
                                // Go to right page if mounted on the right
                                folio.HomeScreenState.goToPage(folio.HomeScreenState.currentPage + 1, false);
                                event.accepted = true;
                            }
                            break;
                        default:
                            break;
                        }
                    }

                    states: [
                        State {
                            name: "bottom"
                            when: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom
                            AnchorChanges {
                                target: favouritesBar
                                anchors.top: undefined
                                anchors.bottom: parent.bottom
                                anchors.left: parent.left
                                anchors.right: parent.right
                            }
                            PropertyChanges {
                                target: favouritesBar
                                height: ShellSettings.Settings.convergenceModeEnabled ? MobileShell.Constants.convergenceDockHeight : Kirigami.Units.gridUnit * 6
                            }
                        }, State {
                            name: "left"
                            when: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Left
                            AnchorChanges {
                                target: favouritesBar
                                anchors.top: parent.top
                                anchors.bottom: parent.bottom
                                anchors.left: parent.left
                                anchors.right: undefined
                            }
                            PropertyChanges {
                                target: favouritesBar
                                width: Kirigami.Units.gridUnit * 6
                            }
                        }, State {
                            name: "right"
                            when: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Right
                            AnchorChanges {
                                target: favouritesBar
                                anchors.top: parent.top
                                anchors.bottom: parent.bottom
                                anchors.left: undefined
                                anchors.right: parent.right
                            }
                            PropertyChanges {
                                target: favouritesBar
                                width: Kirigami.Units.gridUnit * 6
                            }
                        }
                    ]
                }

                Item {
                    id: pageIndicatorWrapper
                    property bool favouritesBarAtBottom: folio.HomeScreenState.favouritesBarLocation === Folio.HomeScreenState.Bottom

                    // don't show in settings mode
                    opacity: 1 - folio.HomeScreenState.settingsOpenProgress
                    visible: opacity > 0 && !ShellSettings.Settings.convergenceModeEnabled

                    anchors.top: parent.top
                    anchors.left: parent.left
                    anchors.right: parent.right
                    anchors.bottom: favouritesBarAtBottom ? favouritesBar.top : parent.bottom

                    anchors.topMargin: root.topMargin
                    anchors.leftMargin: root.leftMargin
                    anchors.rightMargin: root.rightMargin
                    anchors.bottomMargin: favouritesBarAtBottom ? 0 : (root.bottomMargin + Kirigami.Units.largeSpacing)

                    // show page indicator if there are multiple pages
                    QQC2.PageIndicator {
                        visible: count > 1
                        Kirigami.Theme.inherit: false
                        Kirigami.Theme.colorSet: Kirigami.Theme.Complementary

                        anchors.horizontalCenter: parent.horizontalCenter
                        anchors.bottom: parent.bottom

                        currentIndex: folio.HomeScreenState.currentPage
                        count: folio.PageListModel.length

                        TapHandler {
                            enabled: !ShellSettings.Settings.convergenceModeEnabled
                            onTapped: folio.HomeScreenState.openAppDrawer()
                        }
                    }

                    // show arrow to open app drawer when there is 1 page (hidden in convergence mode)
                    Kirigami.Icon {
                        source: 'arrow-up'
                        Kirigami.Theme.inherit: false
                        Kirigami.Theme.colorSet: Kirigami.Theme.Complementary
                        isMask: true
                        color: Kirigami.Theme.textColor

                        implicitHeight: Kirigami.Units.iconSizes.small
                        implicitWidth: Kirigami.Units.iconSizes.small

                        visible: folio.PageListModel.length <= 1 && !ShellSettings.Settings.convergenceModeEnabled

                        anchors.horizontalCenter: parent.horizontalCenter
                        anchors.bottom: parent.bottom
                        anchors.bottomMargin: Kirigami.Units.smallSpacing

                        TapHandler {
                            onTapped: folio.HomeScreenState.openAppDrawer()
                        }
                    }
                }
            }

            // folder view
            FolderView {
                id: folderView
                folio: root.folio
                anchors.fill: parent
                anchors.topMargin: root.topMargin
                anchors.leftMargin: root.leftMargin
                anchors.rightMargin: root.rightMargin
                anchors.bottomMargin: root.bottomMargin

                homeScreen: root
                opacity: homeScreenState.folderOpenProgress
                transform: Translate { y: folderView.opacity > 0 ? 0 : folderView.height }
            }

            // Click-to-dismiss overlay (mobile only; convergence uses layer-shell overlay)
            MouseArea {
                anchors.fill: parent
                visible: !ShellSettings.Settings.convergenceModeEnabled
                         && homeScreenState.appDrawerOpenProgress > 0
                onClicked: folio.HomeScreenState.closeAppDrawer()
            }

            // bottom app drawer (mobile only; convergence uses layer-shell overlay)
            AppDrawer {
                id: appDrawer
                folio: root.folio
                visible: !ShellSettings.Settings.convergenceModeEnabled

                width: parent.width
                height: parent.height

                homeScreen: root

                // we only start showing it halfway through
                opacity: homeScreenState.appDrawerOpenProgress < 0.5 ? 0 : (homeScreenState.appDrawerOpenProgress - 0.5) * 2

                // position for animation
                property real animationY: (1 - homeScreenState.appDrawerOpenProgress) * (Kirigami.Units.gridUnit * 2)

                // Full-screen position
                x: 0
                y: (opacity > 0) ? animationY : parent.height

                headerHeight: Math.round(Kirigami.Units.gridUnit * 4)
                headerItem: AppDrawerHeader {
                    id: appDrawerHeader
                    folio: root.folio

                    onReleaseFocusRequested: appDrawer.forceActiveFocus()
                }

                // Account for panels
                topPadding: root.topMargin
                bottomPadding: root.bottomMargin
                leftPadding: root.leftMargin
                rightPadding: root.rightMargin

                // Forward keyboard text to the search bar
                Keys.onPressed: (event) => {
                    if (event.text.trim().length > 0) {
                        appDrawerHeader.addSearchText(event.text);
                        appDrawerHeader.forceActiveFocus();
                        event.accepted = true;
                    } else if (event.key === Qt.Key_Left || event.key === Qt.Key_Right || event.key === Qt.Key_Up || event.key === Qt.Key_Down) {
                        appDrawerHeader.forceActiveFocus();
                        event.accepted = true;
                    }
                }

                Connections {
                    target: folio.HomeScreenState

                    function onAppDrawerOpened() {
                        appDrawer.forceActiveFocus();
                    }

                    function onAppDrawerClosed() {
                        // reset app drawer position when closed
                        appDrawer.flickable.contentY = 0;
                    }
                }
            }

            // search component
            MobileShell.KRunnerScreen {
                id: searchWidget
                anchors.fill: parent

                opacity: homeScreenState.searchWidgetOpenProgress
                visible: opacity > 0
                transform: Translate { y: (1 - homeScreenState.searchWidgetOpenProgress) * (-Kirigami.Units.gridUnit * 2) }

                onVisibleChanged: {
                    if (!visible) {
                        // clear search bar when closed
                        searchWidget.clearField();
                    }
                }

                // focus the search bar if it opens
                Connections {
                    target: folio.HomeScreenState

                    function onSearchWidgetOpenProgressChanged() {
                        if (homeScreenState.searchWidgetOpenProgress === 1.0) {
                            searchWidget.requestFocus();
                        }
                    }
                }

                onRequestedClose: (triggeredByKeyEvent) => {
                    homeScreenState.closeSearchWidget();
                }

                anchors.topMargin: root.topMargin
                anchors.bottomMargin: root.bottomMargin
                anchors.leftMargin: root.leftMargin
                anchors.rightMargin: root.rightMargin
            }
        }
    }
}