(function () {
    "use strict";

    var groupDescription = "グループ説明";
    var itemDescription = "アイテム説明";
    var itemContent = "<p>内容";

    // これらの 3 つの文字列は、プレースホルダー イメージをエンコードします。
    // 実際のデータで backgroundImage プロパティをイメージの URL に設定できます。
    var lightGray = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXY7h4+cp/AAhpA3h+ANDKAAAAAElFTkSuQmCC";
    var mediumGray = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXY5g8dcZ/AAY/AsAlWFQ+AAAAAElFTkSuQmCC";
    var darkGray = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXY3B0cPoPAANMAcOba1BlAAAAAElFTkSuQmCC";

    // これらの各サンプル グループには、個別に表示する一意のキーが
    // 必要です。
    var sampleGroups = [
        { key: "group1", title: "Group Title: 1", subtitle: "Group Subtitle: 1", backgroundImage: darkGray, description: groupDescription },
        { key: "group2", title: "Group Title: 2", subtitle: "Group Subtitle: 2", backgroundImage: lightGray, description: groupDescription },
        { key: "group3", title: "Group Title: 3", subtitle: "Group Subtitle: 3", backgroundImage: mediumGray, description: groupDescription },
        { key: "group4", title: "Group Title: 4", subtitle: "Group Subtitle: 4", backgroundImage: lightGray, description: groupDescription },
        { key: "group5", title: "Group Title: 5", subtitle: "Group Subtitle: 5", backgroundImage: mediumGray, description: groupDescription },
        { key: "group6", title: "Group Title: 6", subtitle: "Group Subtitle: 6", backgroundImage: darkGray, description: groupDescription }
    ];

    // これらの各サンプル項目には、特定のグループへの参照が
    // 必要です。
    var sampleItems = [
        { group: sampleGroups[0], title: "Item Title: 1", subtitle: "Item Subtitle: 1", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[0], title: "Item Title: 2", subtitle: "Item Subtitle: 2", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[0], title: "Item Title: 3", subtitle: "Item Subtitle: 3", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
        { group: sampleGroups[0], title: "Item Title: 4", subtitle: "Item Subtitle: 4", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[0], title: "Item Title: 5", subtitle: "Item Subtitle: 5", description: itemDescription, content: itemContent, backgroundImage: mediumGray },

        { group: sampleGroups[1], title: "Item Title: 1", subtitle: "Item Subtitle: 1", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[1], title: "Item Title: 2", subtitle: "Item Subtitle: 2", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
        { group: sampleGroups[1], title: "Item Title: 3", subtitle: "Item Subtitle: 3", description: itemDescription, content: itemContent, backgroundImage: lightGray },

        { group: sampleGroups[2], title: "Item Title: 1", subtitle: "Item Subtitle: 1", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
        { group: sampleGroups[2], title: "Item Title: 2", subtitle: "Item Subtitle: 2", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[2], title: "Item Title: 3", subtitle: "Item Subtitle: 3", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[2], title: "Item Title: 4", subtitle: "Item Subtitle: 4", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[2], title: "Item Title: 5", subtitle: "Item Subtitle: 5", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
        { group: sampleGroups[2], title: "Item Title: 6", subtitle: "Item Subtitle: 6", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[2], title: "Item Title: 7", subtitle: "Item Subtitle: 7", description: itemDescription, content: itemContent, backgroundImage: mediumGray },

        { group: sampleGroups[3], title: "Item Title: 1", subtitle: "Item Subtitle: 1", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[3], title: "Item Title: 2", subtitle: "Item Subtitle: 2", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[3], title: "Item Title: 3", subtitle: "Item Subtitle: 3", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[3], title: "Item Title: 4", subtitle: "Item Subtitle: 4", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[3], title: "Item Title: 5", subtitle: "Item Subtitle: 5", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
        { group: sampleGroups[3], title: "Item Title: 6", subtitle: "Item Subtitle: 6", description: itemDescription, content: itemContent, backgroundImage: lightGray },

        { group: sampleGroups[4], title: "Item Title: 1", subtitle: "Item Subtitle: 1", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[4], title: "Item Title: 2", subtitle: "Item Subtitle: 2", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[4], title: "Item Title: 3", subtitle: "Item Subtitle: 3", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[4], title: "Item Title: 4", subtitle: "Item Subtitle: 4", description: itemDescription, content: itemContent, backgroundImage: mediumGray },

        { group: sampleGroups[5], title: "Item Title: 1", subtitle: "Item Subtitle: 1", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[5], title: "Item Title: 2", subtitle: "Item Subtitle: 2", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[5], title: "Item Title: 3", subtitle: "Item Subtitle: 3", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
        { group: sampleGroups[5], title: "Item Title: 4", subtitle: "Item Subtitle: 4", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[5], title: "Item Title: 5", subtitle: "Item Subtitle: 5", description: itemDescription, content: itemContent, backgroundImage: lightGray },
        { group: sampleGroups[5], title: "Item Title: 6", subtitle: "Item Subtitle: 6", description: itemDescription, content: itemContent, backgroundImage: mediumGray },
        { group: sampleGroups[5], title: "Item Title: 7", subtitle: "Item Subtitle: 7", description: itemDescription, content: itemContent, backgroundImage: darkGray },
        { group: sampleGroups[5], title: "Item Title: 8", subtitle: "Item Subtitle: 8", description: itemDescription, content: itemContent, backgroundImage: lightGray }
    ];

    // Get a reference for an item, using the group key and item title as a
    // unique reference to the item that can be easily serialized.
    function getItemReference(item) {
        return [item.group.key, item.title];
    }

    function resolveGroupReference(key) {
        for (var i = 0; i < groupedItems.groups.length; i++) {
            if (groupedItems.groups.getAt(i).key === key) {
                return groupedItems.groups.getAt(i);
            }
        }
    }

    function resolveItemReference(reference) {
        for (var i = 0; i < groupedItems.length; i++) {
            var item = groupedItems.getAt(i);
            if (item.group.key === reference[0] && item.title === reference[1]) {
                return item;
            }
        }
    }

    // この関数は、指定されたグループに属する項目のみが格納された
    // WinJS.Binding.List を返します。
    function getItemsFromGroup(group) {
        return list.createFiltered(function (item) { return item.group.key === group.key; });
    }

    var list = new WinJS.Binding.List();
    var groupedItems = list.createGrouped(
        function groupKeySelector(item) { return item.group.key; },
        function groupDataSelector(item) { return item.group; }
    );

    // TODO: データを実際のデータに置き換えます。
    // 非同期ソースのデータは使用可能になるたびに追加できます。
    sampleItems.forEach(function (item) {
        list.push(item);
    });

    WinJS.Namespace.define("Data", {
        items: groupedItems,
        groups: groupedItems.groups,
        getItemsFromGroup: getItemsFromGroup,
        getItemReference: getItemReference,
        resolveGroupReference: resolveGroupReference,
        resolveItemReference: resolveItemReference
    });
})();