/*
    Copyright (C) 2011  Martin Gräßlin <mgraesslin@kde.org>
    Copyright (C) 2012  Gregor Taetzner <gregor@freenet.de>
    Copyright (C) 2012  Marco Martin <mart@kde.org>
    Copyright (C) 2013 2014 David Edmundson <davidedmundson@kde.org>
    Copyright 2014 Sebastian Kügler <sebas@kde.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
import QtQuick 2.3
import org.kde.plasma.plasmoid 2.0
import QtQuick.Layouts 1.1
import org.kde.plasma.core as PlasmaCore
import org.kde.plasma.components as PlasmaComponents
import org.kde.plasma.extras as PlasmaExtras
import org.kde.kquickcontrolsaddons 2.0

import org.kde.plasma.private.kicker 0.1 as Kicker

Item {
    id: root
    Layout.minimumWidth: PlasmaCore.Units.gridUnit * 26
    Layout.maximumWidth: Layout.minimumWidth

    Layout.minimumHeight: PlasmaCore.Units.gridUnit * 34
    Layout.maximumHeight: Layout.minimumHeight

    property string previousState
    property bool switchTabsOnHover: plasmoid.configuration.switchTabsOnHover
    property Item currentView: mainTabGroup.currentTab.decrementCurrentIndex ? mainTabGroup.currentTab : mainTabGroup.currentTab.item
    property KickoffButton firstButton: null
    property var configMenuItems

    property QtObject globalFavorites: rootModelFavorites

    state: "Normal"

    onFocusChanged: {
        header.input.forceActiveFocus();
    }

    function switchToInitial() {
        if (firstButton != null) {
            root.state = "Normal";
            mainTabGroup.currentTab = firstButton.tab;
            tabBar.currentTab = firstButton;
            header.query = ""
        }
    }

    Kicker.DragHelper {
        id: dragHelper

        dragIconSize: PlasmaCore.Units.iconSizes.medium
        onDropped: kickoff.dragSource = null
    }

    Kicker.AppsModel {
        id: rootModel

        autoPopulate: false

        appletInterface: plasmoid

        appNameFormat: plasmoid.configuration.showAppsByName ? 0 : 1
        flat: false
        sorted: plasmoid.configuration.alphaSort
        showSeparators: false
        showTopLevelItems: true

        favoritesModel: Kicker.KAStatsFavoritesModel {
            id: rootModelFavorites
            favorites: plasmoid.configuration.favorites

            onFavoritesChanged: {
                plasmoid.configuration.favorites = favorites;
            }
        }

        Component.onCompleted: {
            favoritesModel.initForClient("org.kde.plasma.kickoff.favorites.instance-" + plasmoid.id)

            if (!plasmoid.configuration.favoritesPortedToKAstats) {
                favoritesModel.portOldFavorites(plasmoid.configuration.favorites);
                plasmoid.configuration.favoritesPortedToKAstats = true;
            }

            rootModel.refresh();
        }
    }

    PlasmaCore.DataSource {
        id: pmSource
        engine: "powermanagement"
        connectedSources: ["PowerDevil"]
    }

    PlasmaCore.Svg {
        id: arrowsSvg

        imagePath: "widgets/arrows"
        size: "16x16"
    }

    Header {
        id: header
    }

    Item {
        id: mainArea
        anchors.topMargin: mainTabGroup.state == "top" ? PlasmaCore.Units.smallSpacing : 0

        PlasmaComponents.TabGroup {
            id: mainTabGroup
            currentTab: favoritesPage

            anchors {
                fill: parent
            }

            //pages
            FavoritesView {
                id: favoritesPage
            }
            PlasmaExtras.ConditionalLoader {
                id: applicationsPage
                when: mainTabGroup.currentTab == applicationsPage
                source: Qt.resolvedUrl("ApplicationsView.qml")
            }
            PlasmaExtras.ConditionalLoader {
                id: systemPage
                when: mainTabGroup.currentTab == systemPage
                source: Qt.resolvedUrl("ComputerView.qml")
            }
            PlasmaExtras.ConditionalLoader {
                id: recentlyUsedPage
                when: mainTabGroup.currentTab == recentlyUsedPage
                source: Qt.resolvedUrl("RecentlyUsedView.qml")
            }
            PlasmaExtras.ConditionalLoader {
                id: oftenUsedPage
                when: mainTabGroup.currentTab == oftenUsedPage
                source: Qt.resolvedUrl("OftenUsedView.qml")
            }
            PlasmaExtras.ConditionalLoader {
                id: leavePage
                when: mainTabGroup.currentTab == leavePage
                source: Qt.resolvedUrl("LeaveView.qml")
            }
            PlasmaExtras.ConditionalLoader {
                id: searchPage
                when: root.state == "Search"
                //when: mainTabGroup.currentTab == searchPage || root.state == "Search"
                source: Qt.resolvedUrl("SearchView.qml")
            }

            state: {
                switch (plasmoid.location) {
                case PlasmaCore.Types.LeftEdge:
                    return LayoutMirroring.enabled ? "right" : "left";
                case PlasmaCore.Types.TopEdge:
                    return "top";
                case PlasmaCore.Types.RightEdge:
                    return LayoutMirroring.enabled ? "left" : "right";
                case PlasmaCore.Types.BottomEdge:
                default:
                    return "bottom";
                }
            }
            states: [
                State {
                    name: "left"
                    AnchorChanges {
                        target: header
                        anchors {
                            left: root.left
                            top: undefined
                            right: root.right
                            bottom: root.bottom
                        }
                    }
                    PropertyChanges {
                        target: header
                        width: header.implicitWidth
                        location: PlasmaExtras.PlasmoidHeading.Location.Footer
                    }
                    AnchorChanges {
                        target: mainArea
                        anchors {
                            left: tabBar.right
                            top: root.top
                            right: root.right
                            bottom: header.top
                        }
                    }
                    PropertyChanges {
                        target: tabBar
                        width: (tabBar.opacity == 0) ? 0 : PlasmaCore.Units.gridUnit * 5
                    }
                    AnchorChanges {
                        target: tabBar
                        anchors {
                            left: root.left
                            top: root.top
                            right: undefined
                            bottom: header.top
                        }
                    }
                    PropertyChanges {
                        target:tabBarSeparator
                        width: tabBarSeparatorLine.elementSize("vertical-line").width
                        elementId: "vertical-line"
                    }
                    AnchorChanges {
                        target: tabBarSeparator
                        anchors {
                            left: tabBar.right
                            top: tabBar.top
                            bottom:tabBar.bottom
                        }
                    }
                },
                State {
                    name: "top"
                    AnchorChanges {
                        target: header
                        anchors {
                            left: root.left
                            top: undefined
                            right: root.right
                            bottom: root.bottom
                        }
                    }
                    PropertyChanges {
                        target: header
                        height: header.implicitHeight
                        location: PlasmaExtras.PlasmoidHeading.Location.Footer
                    }
                    AnchorChanges {
                        target: mainArea
                        anchors {
                            left: root.left
                            top: tabBar.bottom
                            right: root.right
                            bottom: header.top
                        }
                    }
                    PropertyChanges {
                        target: tabBar
                        height: (tabBar.opacity == 0) ? 0 : PlasmaCore.Units.gridUnit * 5
                    }
                    AnchorChanges {
                        target: tabBar
                        anchors {
                            left: root.left
                            top: root.top
                            right: root.right
                            bottom: undefined
                        }
                    }
                    PropertyChanges {
                        target:tabBarSeparator
                        height: tabBarSeparatorLine.elementSize("horizontal-line").height
                        elementId: "horizontal-line"
                    }
                    AnchorChanges {
                        target: tabBarSeparator
                        anchors {
                            left: tabBar.left
                            right: tabBar.right
                            top: tabBar.bottom
                        }
                    }
                },
                State {
                    name: "right"
                    AnchorChanges {
                        target: header
                        anchors {
                            left: root.left
                            top: undefined
                            right: root.right
                            bottom: root.bottom
                        }
                    }
                    PropertyChanges {
                        target: header
                        width: header.implicitWidth
                        location: PlasmaExtras.PlasmoidHeading.Location.Footer
                    }
                    AnchorChanges {
                        target: mainArea
                        anchors {
                            left: root.left
                            top: root.top
                            right: tabBar.left
                            bottom: header.top
                        }
                    }
                    PropertyChanges {
                        target: tabBar
                        width: (tabBar.opacity == 0) ? 0 : PlasmaCore.Units.gridUnit * 5
                    }
                    AnchorChanges {
                        target: tabBar
                        anchors {
                            left: undefined
                            top: root.top
                            right: root.right
                            bottom: header.top
                        }
                    }
                    PropertyChanges {
                        target:tabBarSeparator
                        width: tabBarSeparatorLine.elementSize("vertical-line").width
                        elementId: "vertical-line"
                    }
                    AnchorChanges {
                        target: tabBarSeparator
                        anchors {
                            right: tabBar.left
                            top: tabBar.top
                            bottom: tabBar.bottom
                        }
                    }
                },
                State {
                    name: "bottom"
                    AnchorChanges {
                        target: header
                        anchors {
                            left: root.left
                            top: root.top
                            right: root.right
                            bottom: undefined
                        }
                    }
                    PropertyChanges {
                        target: header
                        height: header.implicitHeight
                        location: PlasmaExtras.PlasmoidHeading.Location.Header
                    }
                    AnchorChanges {
                        target: mainArea
                        anchors {
                            left: root.left
                            top: header.bottom
                            right: root.right
                            bottom: tabBar.top
                        }
                    }
                    PropertyChanges {
                        target: tabBar
                        height: (tabBar.opacity == 0) ? 0 : PlasmaCore.Units.gridUnit * 5
                    }
                    AnchorChanges {
                        target: tabBar
                        anchors {
                            left: root.left
                            top: undefined
                            right: root.right
                            bottom: root.bottom
                        }
                    }
                    PropertyChanges {
                        target:tabBarSeparator
                        height: tabBarSeparatorLine.elementSize("horizontal-line").height
                        elementId: "horizontal-line"
                    }
                    AnchorChanges {
                        target: tabBarSeparator
                        anchors {
                            bottom: tabBar.top
                            left: tabBar.left
                            right: tabBar.right
                        }
                    }
                }
            ]
        } // mainTabGroup
    }

    PlasmaComponents.TabBar {
        id: tabBar

        property int count: 5 // updated in createButtons()

        Behavior on width {
            NumberAnimation { duration: PlasmaCore.Units.longDuration; easing.type: Easing.InQuad; }
            enabled: plasmoid.expanded
        }
        Behavior on height {
            NumberAnimation { duration: PlasmaCore.Units.longDuration; easing.type: Easing.InQuad; }
            enabled: plasmoid.expanded
        }

        tabPosition: {
            switch (plasmoid.location) {
            case PlasmaCore.Types.TopEdge:
                return Qt.TopEdge;
            case PlasmaCore.Types.LeftEdge:
                return Qt.LeftEdge;
            case PlasmaCore.Types.RightEdge:
                return Qt.RightEdge;
            default:
                return Qt.BottomEdge;
            }
        }

        onCurrentTabChanged: header.input.forceActiveFocus();

        Connections {
            target: plasmoid
            function onExpandedChanged() {
                if(menuItemsChanged()) {
                    createButtons();
                }
                if (!plasmoid.expanded) {
                    switchToInitial();
                }
            }
        }
    } // tabBar

    PlasmaCore.SvgItem {
        id: tabBarSeparator
        svg: PlasmaCore.Svg {
            id: tabBarSeparatorLine
            imagePath: "widgets/line"
        }
    }

    MouseArea {
        anchors.fill: tabBar

        property var oldPos: null

        enabled: root.state !== "Search"
        hoverEnabled: root.switchTabsOnHover

        onExited: {
            // Reset so we switch immediately when MouseArea is entered
            // freshly, e.g. from the panel.
            oldPos = null;

            clickTimer.stop();
        }

        onPositionChanged: {
            // Reject multiple events with the same coordinates that QQuickWindow
            // synthesizes.
            if (oldPos === Qt.point(mouse.x, mouse.y)) {
                return;
            }

            var button = tabBar.layout.childAt(mouse.x, mouse.y);

            if (!button || button.objectName !== "KickoffButton") {
                clickTimer.stop();

                return;
            }

            // Switch immediately when MouseArea was freshly entered, e.g.
            // from the panel.
            if (oldPos === null) {
                oldPos = Qt.point(mouse.x, mouse.y);

                clickTimer.stop();
                button.clicked();

                return;
            }

            var dx  = (mouse.x - oldPos.x);
            var dy  = (mouse.y - oldPos.y);

            // Check Manhattan length against drag distance to get a decent
            // pointer motion vector.
            if ((Math.abs(dx) + Math.abs(dy)) > Qt.styleHints.startDragDistance) {
                if (tabBar.currentTab !== button) {
                    var tabBarPos = mapToItem(tabBar, oldPos.x, oldPos.y);
                    oldPos = Qt.point(mouse.x, mouse.y);

                    var angleMouseMove = Math.atan2(dy, dx) * 180 / Math.PI;
                    var angleToCornerA = 0;
                    var angleToCornerB = 0;

                    switch (plasmoid.location) {
                        case PlasmaCore.Types.TopEdge: {
                            angleToCornerA = Math.atan2(tabBar.height - tabBarPos.y, 0 - tabBarPos.x);
                            angleToCornerB = Math.atan2(tabBar.height - tabBarPos.y, tabBar.width - tabBarPos.x);

                            break;
                        }
                        case PlasmaCore.Types.LeftEdge: {
                            angleToCornerA = Math.atan2(0 - tabBarPos.y, tabBar.width - tabBarPos.x);
                            angleToCornerB = Math.atan2(tabBar.height - tabBarPos.y, tabBar.width - tabBarPos.x);

                            break;
                        }
                        case PlasmaCore.Types.RightEdge: {
                            angleToCornerA = Math.atan2(0 - tabBarPos.y, 0 - tabBarPos.x);
                            angleToCornerB = Math.atan2(tabBar.height - tabBarPos.y, 0 - tabBarPos.x);

                            break;
                        }
                        // PlasmaCore.Types.BottomEdge
                        default: {
                            angleToCornerA = Math.atan2(0 - tabBarPos.y, 0 - tabBarPos.x);
                            angleToCornerB = Math.atan2(0 - tabBarPos.y, tabBar.width - tabBarPos.x);
                        }
                    }

                    // Degrees are nicer to debug than radians.
                    angleToCornerA = angleToCornerA * 180 / Math.PI;
                    angleToCornerB = angleToCornerB * 180 / Math.PI;

                    var lower = Math.min(angleToCornerA, angleToCornerB);
                    var upper = Math.max(angleToCornerA, angleToCornerB);

                    // If the motion vector is outside the angle range from oldPos to the
                    // relevant tab bar corners, switch immediately. Otherwise start the
                    // timer, which gets aborted should the pointer exit the tab bar
                    // early.
                    var inRange = (lower < angleMouseMove == angleMouseMove < upper);

                    // Mirror-flip.
                    if (plasmoid.location === PlasmaCore.Types.RightEdge ? inRange : !inRange) {
                        clickTimer.stop();
                        button.clicked();

                        return;
                    } else {
                        clickTimer.pendingButton = button;
                        clickTimer.start();
                    }
                } else {
                    oldPos = Qt.point(mouse.x, mouse.y);
                }
            }
        }

        onClicked: {
            clickTimer.stop();

            var button = tabBar.layout.childAt(mouse.x, mouse.y);

            if (!button || button.objectName !== "KickoffButton") {
                return;
            }

            button.clicked();
        }

        Timer {
            id: clickTimer

            property Item pendingButton: null

            interval: 250

            onTriggered: {
                if (pendingButton) {
                    pendingButton.clicked();
                }
            }
        }
    }

    Keys.forwardTo: [tabBar.layout]

    Keys.onPressed: {

        if (mainTabGroup.currentTab == applicationsPage) {
            if (event.key !== Qt.Key_Tab) {
                root.state = "Applications";
            }
        }

        switch(event.key) {
            case Qt.Key_Up: {
                currentView.decrementCurrentIndex();
                event.accepted = true;
                break;
            }
            case Qt.Key_Down: {
                currentView.incrementCurrentIndex();
                event.accepted = true;
                break;
            }
            case Qt.Key_Left: {
                if (header.input.focus && header.state == "query") {
                    break;
                }
                if (!currentView.deactivateCurrentIndex()) {
                    if (root.state == "Applications") {
                        mainTabGroup.currentTab = firstButton.tab;
                        tabBar.currentTab = firstButton;
                    }
                    root.state = "Normal"
                }
                event.accepted = true;
                break;
            }
            case Qt.Key_Right: {
                if (header.input.focus && header.state == "query") {
                    break;
                }
                currentView.activateCurrentIndex();
                event.accepted = true;
                break;
            }
            case Qt.Key_Tab: {
                root.state == "Applications" ? root.state = "Normal" : root.state = "Applications";
                event.accepted = true;
                break;
            }
            case Qt.Key_Enter:
            case Qt.Key_Return: {
                currentView.activateCurrentIndex(1);
                event.accepted = true;
                break;
            }
            case Qt.Key_Escape: {
                if (header.state != "query") {
                    plasmoid.expanded = false;
                } else {
                    header.query = "";
                }
                event.accepted = true;
                break;
            }
            case Qt.Key_Menu: {
                currentView.openContextMenu();
                event.accepted = true;
                break;
            }
            default:
                if (!header.input.focus) {
                    header.input.forceActiveFocus();
                }
        }
    }

    states: [
        State {
            name: "Normal"
            PropertyChanges {
                target: root
                Keys.forwardTo: [tabBar.layout]
            }
            PropertyChanges {
                target: tabBar
                //Set the opacity and NOT the visibility, as visibility is recursive
                //and this binding would be executed also on popup show/hide
                //as recommended by the docs: https://doc.qt.io/qt-5/qml-qtquick-item.html#visible-prop
                //plus, it triggers https://bugreports.qt.io/browse/QTBUG-66907
                //in which a mousearea may think it's under the mouse while it isn't
                opacity: tabBar.count > 1 ? 1 : 0
            }
        },
        State {
            name: "Applications"
            PropertyChanges {
                target: root
                Keys.forwardTo: [root]
            }
            PropertyChanges {
                target: tabBar
                opacity: tabBar.count > 1 ? 1 : 0
            }
        },
        State {
            name: "Search"
            PropertyChanges {
                target: tabBar
                opacity: 0
            }
            PropertyChanges {
                target: mainTabGroup
                currentTab: searchPage
            }
            PropertyChanges {
                target: root
                Keys.forwardTo: [root]
            }
        }
    ] // states

    function getButtonDefinition(name) {
        switch(name) {
        case "bookmark":
            return {id: "bookmarkButton", tab: favoritesPage, iconSource: "bookmarks", text: i18n("Favorites")};
        case "application":
            return {id: "applicationButton", tab: applicationsPage, iconSource: "applications-other", text: i18n("Applications")};
        case "computer":
            return {id: "computerButton", tab: systemPage, iconSource: pmSource.data["PowerDevil"] && pmSource.data["PowerDevil"]["Is Lid Present"] ? "computer-laptop" : "computer", text: i18n("Computer")};
        case "used":
            return {id: "usedButton", tab: recentlyUsedPage, iconSource: "view-history", text: i18n("History")};
        case "oftenUsed":
            return {id: "usedButton", tab: oftenUsedPage, iconSource: "office-chart-pie", text: i18n("Often Used")};
        case "leave":
            return {id: "leaveButton", tab: leavePage, iconSource: "system-log-out", text: i18n("Leave")};
        }
    }

    Component {
        id: kickoffButton
        KickoffButton {}
    }


    Component.onCompleted: {
        createButtons();
    }

    function getEnabled(configuration) {
        var res = [];
        for(var i = 0; i < configuration.length; i++) {
            var confItemName = configuration[i].substring(0, configuration[i].indexOf(":"));
            var confItemEnabled = configuration[i].substring(configuration[i].length-1) === "t";
            if(confItemEnabled) {
                res.push(confItemName);
            }
        }

        return res;
    }

    function createButtons() {
        configMenuItems = plasmoid.configuration.menuItems;
        var menuItems = getEnabled(plasmoid.configuration.menuItems);
        tabBar.count = menuItems.length

        // remove old menu items
        for(var i = tabBar.layout.children.length -1; i >= 0; i--)  {
            if(tabBar.layout.children[i].objectName === "KickoffButton") {
                tabBar.layout.children[i].destroy();
            }
        }

        for (var i = 0; i < menuItems.length; i++) {
             var props = getButtonDefinition(menuItems[i]);
             var button = kickoffButton.createObject(tabBar.layout, props);
             if(i === 0) {
                 firstButton = button;
                 switchToInitial();
             }
        }

    }

    function menuItemsChanged() {
        if(configMenuItems.length !== plasmoid.configuration.menuItems.length) {
            return true;
        }

        for(var i = 0; i < configMenuItems.length; i++) {
            if(configMenuItems[i] !== plasmoid.configuration.menuItems[i]) {
                return true;
            }
        }
        return false;
    }
}