/*
 * Copyright (C) 2013 Canonical, Ltd.
 *
 * 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; version 3.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */

import QtQuick 2.0
import Ubuntu.Components 0.1
import Utils 0.1
import Unity 0.1
import "../Components"
import "../Components/ListItems" as ListItems

FocusScope {
    id: scopeView

    property Scope scope
    property SortFilterProxyModel categories: categoryFilter
    property bool isCurrent
    property alias moving: categoryView.moving
    property int tabBarHeight: 0
    property PageHeader pageHeader: null
    property OpenEffect openEffect: null
    property Item previewListView: null

    signal endReached
    signal movementStarted
    signal positionedAtBeginning
    signal headerPositionChanged(int position)
    signal headerHeightChanged(int height)

    property bool enableHeightBehaviorOnNextCreation: false
    property var categoryView: categoryView

    // FIXME delay the search so that daemons have time to settle, note that
    // removing this will break ScopeView::test_changeScope
    onScopeChanged: {
        if (scope) {
            timer.restart();
            scope.activateApplication.connect(activateApp);
        }
    }

    function activateApp(appId) {
        shell.activateApplication(appId);
    }

    Binding {
        target: scope
        property: "isActive"
        value: isCurrent
    }

    Timer {
        id: timer
        interval: 2000
        onTriggered: scope.searchQuery = ""
    }

    SortFilterProxyModel {
        id: categoryFilter
        model: scope ? scope.categories : null
        dynamicSortFilter: true
        filterRole: Categories.RoleCount
        filterRegExp: /^0$/
        invertMatch: true
    }

    onIsCurrentChanged: {
        pageHeader.resetSearch();
        previewListView.open = false;
    }

    onMovementStarted: categoryView.showHeader()

    onPositionedAtBeginning: categoryView.positionAtBeginning()

    Binding {
        target: scopeView.scope
        property: "searchQuery"
        value: pageHeader.searchQuery
        when: isCurrent
    }

    Binding {
        target: pageHeader
        property: "searchQuery"
        value: scopeView.scope.searchQuery
        when: isCurrent
    }

    Connections {
        target: panel
        onSearchClicked: if (isCurrent) {
            pageHeader.triggerSearch()
            categoryView.showHeader()
        }
    }

    Connections {
        target: scopeView.scope
        onShowDash: previewListView.open = false;
        onHideDash: previewListView.open = false;
    }

    ScopeListView {
        id: categoryView
        objectName: "categoryListView"
        anchors.fill: parent
        model: scopeView.categories
        forceNoClip: previewListView.onScreen

        onAtYEndChanged: if (atYEnd) endReached()
        onMovingChanged: if (moving && atYEnd) endReached()

        property string expandedCategoryId: ""
        signal correctExpandedCategory();

        onContentYChanged: pageHeader.positionRealHeader();
        onOriginYChanged: pageHeader.positionRealHeader();
        onContentHeightChanged: pageHeader.positionRealHeader();

        Behavior on contentY {
            enabled: previewListView.open
            UbuntuNumberAnimation {}
        }

        delegate: ListItems.Base {
            id: baseItem
            objectName: "dashCategory" + category
            highlightWhenPressed: false

            readonly property bool expandable: rendererLoader.item ? rendererLoader.item.expandable : false
            readonly property bool filtered: rendererLoader.item ? rendererLoader.item.filter : true
            readonly property string category: categoryId

            Loader {
                id: rendererLoader
                anchors {
                    top: parent.top
                    left: parent.left
                    right: parent.right
                }

                source: getRenderer(model.renderer, model.contentType, model.rendererHint, results)

                onLoaded: {
                    if (item.enableHeightBehavior !== undefined && item.enableHeightBehaviorOnNextCreation !== undefined) {
                        item.enableHeightBehavior = scopeView.enableHeightBehaviorOnNextCreation;
                        scopeView.enableHeightBehaviorOnNextCreation = false;
                    }
                    if (source.toString().indexOf("Apps/RunningApplicationsGrid.qml") != -1) {
                        // TODO: the running apps grid doesn't support standard scope results model yet
                        item.firstModel = Qt.binding(function() { return results.firstModel })
                        item.secondModel = Qt.binding(function() { return results.secondModel })
                        item.canEnableTerminationMode = Qt.binding(function() { return scopeView.isCurrent })
                    } else {
                        item.model = Qt.binding(function() { return results })
                    }
                    item.objectName = Qt.binding(function() { return categoryId })
                    if (item.expandable) {
                        var shouldFilter = categoryId != categoryView.expandedCategoryId;
                        if (shouldFilter != item.filter) {
                            item.filter = shouldFilter;
                        }
                    }
                    updateDelegateCreationRange();
                }

                Component.onDestruction: {
                    if (item.enableHeightBehavior !== undefined && item.enableHeightBehaviorOnNextCreation !== undefined) {
                        scopeView.enableHeightBehaviorOnNextCreation = item.enableHeightBehaviorOnNextCreation;
                    }
                }

                Connections {
                    target: rendererLoader.item
                    onClicked: {
                        // Prepare the preview in case activate() triggers a preview only
                        openEffect.positionPx = Math.max(mapToItem(categoryView, 0, itemY).y, pageHeader.height + categoryView.stickyHeaderHeight);
                        previewListView.categoryId = categoryId
                        previewListView.categoryDelegate = rendererLoader.item
                        previewListView.model = target.model;
                        previewListView.init = true;
                        previewListView.currentIndex = index;

                        var item = target.model.get(index);

                        if ((scopeView.scope.id == "applications.scope" && categoryId == "installed")
                                || (scopeView.scope.id == "home.scope" && categoryId == "applications.scope")) {
                            scopeView.scope.activate(item.uri, item.icon, item.category, 0, item.mimetype, item.title,
                                                     item.comment, item.dndUri, item.metadata)
                        } else {
                            previewListView.open = true

                            scopeView.scope.preview(item.uri, item.icon, item.category, 0, item.mimetype, item.title,
                                                    item.comment, item.dndUri, item.metadata)
                        }
                    }
                    onPressAndHold: {
                        openEffect.positionPx = Math.max(mapToItem(categoryView, 0, itemY).y, pageHeader.height + categoryView.stickyHeaderHeight);
                        previewListView.categoryId = categoryId
                        previewListView.categoryDelegate = rendererLoader.item
                        previewListView.model = target.model;
                        previewListView.init = true;
                        previewListView.currentIndex = index;
                        previewListView.open = true

                        var item = target.model.get(index)
                        scopeView.scope.preview(item.uri, item.icon, item.category, 0, item.mimetype, item.title,
                                                item.comment, item.dndUri, item.metadata)
                    }
                }
                Connections {
                    target: categoryView
                    onExpandedCategoryIdChanged: {
                        collapseAllButExpandedCategory();
                    }
                    onCorrectExpandedCategory: {
                        collapseAllButExpandedCategory();
                    }
                    function collapseAllButExpandedCategory() {
                        var item = rendererLoader.item;
                        if (item.expandable) {
                            var shouldFilter = categoryId != categoryView.expandedCategoryId;
                            if (shouldFilter != item.filter) {
                                // If the filter animation will be seen start it, otherwise, just flip the switch
                                var shrinkingVisible = shouldFilter && y + item.collapsedHeight < categoryView.height;
                                var growingVisible = !shouldFilter && y + height < categoryView.height;
                                if (!previewListView.open || !shouldFilter) {
                                    if (shrinkingVisible || growingVisible) {
                                        item.startFilterAnimation(shouldFilter)
                                    } else {
                                        item.filter = shouldFilter;
                                    }
                                    if (!shouldFilter && !previewListView.open) {
                                        categoryView.maximizeVisibleArea(index, item.uncollapsedHeight);
                                    }
                                }
                            }
                        }
                    }
                    onContentYChanged: rendererLoader.updateDelegateCreationRange();
                    onHeightChanged: rendererLoader.updateDelegateCreationRange();
                }

                function updateDelegateCreationRange() {
                    // Do not update the range if we are overshooting up or down, since we'll come back
                    // to the stable position and delete/create items without any reason
                    if (categoryView.contentY < categoryView.originY) {
                        return;
                    } else if (categoryView.contentY + categoryView.height > categoryView.contentHeight) {
                        return;
                    }

                    if (item.hasOwnProperty("delegateCreationBegin")) {
                        if (baseItem.y + baseItem.height <= 0) {
                            // Not visible (item at top of the list)
                            item.delegateCreationBegin = baseItem.height
                            item.delegateCreationEnd = baseItem.height
                        } else if (baseItem.y >= categoryView.height) {
                            // Not visible (item at bottom of the list)
                            item.delegateCreationBegin = 0
                            item.delegateCreationEnd = 0
                        } else {
                            item.delegateCreationBegin = Math.max(-baseItem.y, 0)
                            item.delegateCreationEnd = Math.min(categoryView.height + item.delegateCreationBegin, baseItem.height)
                        }
                    }
                }
            }
        }

        sectionProperty: "name"
        sectionDelegate: ListItems.Header {
            objectName: "dashSectionHeader" + delegate.category
            property var delegate: categoryView.item(delegateIndex)
            width: categoryView.width
            text: section
            image: {
                if (delegate && delegate.expandable)
                    return delegate.filtered ? "graphics/header_handlearrow.png" : "graphics/header_handlearrow2.png"
                return "";
            }
            onClicked: {
                if (categoryView.expandedCategoryId != delegate.category)
                    categoryView.expandedCategoryId = delegate.category;
                else
                    categoryView.expandedCategoryId = "";
            }
        }
        pageHeader: Item {
            implicitHeight: scopeView.tabBarHeight
            onHeightChanged: scopeView.headerHeightChanged(height)
            onYChanged: positionRealHeader();

            function positionRealHeader() {
                scopeView.headerPositionChanged(y + parent.y)
            }
        }
    }

    function getDefaultRendererId(contentType) {
        switch (contentType) {
            default: return "grid";
        }
    }

    function getRenderer(rendererId, contentType, rendererHint, results) {
        if (rendererId == "default") {
            rendererId = getDefaultRendererId(contentType);
        }
        if (rendererId == "carousel") {
            // Selectively disable carousel, 6 is fixed for now, should change on the form factor
            if (results.count <= 6)
                rendererId = "grid"
        }
        switch (rendererId) {
            case "carousel": {
                switch (contentType) {
                    case "music": return "Music/MusicCarousel.qml";
                    case "video": return "Video/VideoCarousel.qml";
                    default: return "Generic/GenericCarousel.qml";
                }
            }
            case "grid": {
                switch (contentType) {
                    case "apps": {
                        if (rendererHint == "toggled")
                            return "Apps/DashPluginFilterGrid.qml";
                        else
                            return "Generic/GenericFilterGrid.qml";
                    }
                    case "music": return "Music/MusicFilterGrid.qml";
                    case "video": return "Video/VideoFilterGrid.qml";
                    case "weather": return "Generic/WeatherFilterGrid.qml";
                    default: return "Generic/GenericFilterGrid.qml";
                }
            }
            case "special": {
                switch (contentType) {
                    case "apps": return "Apps/RunningApplicationsGrid.qml";
                    default: return "Generic/GenericFilterGrid.qml";
                }
            }
            default: return "Generic/GenericFilterGrid.qml";
        }
    }

    Connections {
        target: scopeView.scope
        onPreviewReady: {
            if (previewListView.init) {
                // Preview was triggered because of a click on the item. Need to expand now.
                if (!previewListView.open) {
                    previewListView.open = true
                }

                var index = previewListView.currentIndex
                previewListView.currentIndex = -1
                previewListView.currentIndex = index
                previewListView.init = false
            }
            previewListView.currentItem.previewData = preview
        }
    }

    // TODO: Move as InverseMouseArea to DashPreview
    MouseArea {
        objectName: "closePreviewMouseArea"
        enabled: previewListView.onScreen
        anchors {
            fill: parent
            topMargin: openEffect.bottomGapPx
        }
        onClicked: {
            previewListView.open = false;
        }
    }
}