function Folders_AddNewFolder(p) { // folderId: string, ParentId: string, InsertAfterId: tabId or folderId, Name: string, Index: int, ExpandState: ("o","c"), AdditionalClass: string, SkipSetEvents: bool
    let newId = p.folderId ? p.folderId : Folders_GenerateNewFolderID();
    tt.folders[newId] = {id: newId, parent: (p.ParentId ? p.ParentId : ""), index: (p.Index ? p.Index : 0), name: (p.Name ? p.Name : labels.noname_group), expand: (p.ExpandState ? p.ExpandState : "")};
    Folders_AppendFolder({folderId: newId, Name: tt.folders[newId].name, InsertAfterId: p.InsertAfterId, ParentId: p.ParentId, ExpandState: p.ExpandState, SkipSetEvents: p.SkipSetEvents, AdditionalClass: p.AdditionalClass});
    Folders_SaveFolders();
    DOM_RefreshCounters();
    DOM_RefreshExpandStates();
    return newId;
}

function Folders_AppendFolder(p) { // folderId: string, ParentId: string, Name: string, ExpandState: ("o","c"), AdditionalClass: string, SetEvents: bool
    let ClassList = "folder";
    if (p.ExpandState) ClassList += " " + p.ExpandState;
    if (p.AdditionalClass != undefined) ClassList += " " + p.AdditionalClass;
    if (document.getElementById(p.folderId) == null) {
        let DIV_folder = DOM_New("div", undefined, {id: p.folderId, className: ClassList});
        let DIV_header = DOM_New("div", DIV_folder, {id: ("folder_header_" + p.folderId), className: ((opt.always_show_close && !opt.never_show_close) ? "folder_header close_show" : "folder_header"), draggable: (!p.SkipSetEvents ? true : false)});
        let DIV_expand = DOM_New("div", DIV_header, {id: ("folder_expand_" + p.folderId), className: "folder_icon"});
        let DIV_counter = DOM_New("div", DIV_header, {id: ("folder_counter_" + p.folderId), className: "folder_counter"});
        DOM_New("div", DIV_counter, {id: ("folder_counter_number_" + p.folderId), className: "counter_number"});
        DOM_New("div", DIV_header, {id: ("folder_title_" + p.folderId), className: "folder_title", textContent: p.Name});
        let DIV_children = DOM_New("div", DIV_folder, {id: ("°" + p.folderId), className: "children"});
        DOM_New("div", DIV_folder, {id: (p.folderId + "_drag_indicator"), className: "drag_indicator"});
        let DIV_close_button = DOM_New("div", DIV_header, {id: ("close" + p.folderId), className : (opt.never_show_close ? "close hidden" : "close")});
        DOM_New("div", DIV_close_button, {id: ("close_img" + p.folderId), className: (opt.never_show_close ? "close_img hidden" : "close_img")});
        if (!p.SkipSetEvents) {
            DIV_children.ondblclick = function(event) {
                if (event.target == this) Groups_ActionClickGroup(this.parentNode, opt.dbclick_group);
            }
            DIV_children.onclick = function(event) {
                if (event.target == this && event.which == 1) DOM_Deselect();
            }
            DIV_children.onmousedown = function(event) {
                event.stopImmediatePropagation();
                if (event.target == this) {
                    if (event.which == 2 && event.target == this) Groups_ActionClickGroup(this.parentNode, opt.midclick_group);
                    if (event.which == 3) Menu_ShowFGlobalMenu(event);
                }
            }
            if (!opt.never_show_close) {
                DIV_close_button.onmousedown = function(event) {
                    event.stopImmediatePropagation();
                    if (event.which != 3) Folders_RemoveFolder(this.parentNode.parentNode.id);
                }
                DIV_close_button.onmouseenter = function(event) {
                    this.classList.add("close_hover");
                }
                DIV_close_button.onmouseleave = function(event) {
                    this.classList.remove("close_hover");
                }
            }
            DIV_header.onclick = function(event) {
                if (event.which == 1 && !event.shiftKey && !event.ctrlKey && event.target.classList.contains("folder_header")) DOM_Deselect();
            }
            DIV_header.onmousedown = function(event) {
                event.stopImmediatePropagation();
                if (tt.DOMmenu.style.top != "-1000px") Menu_HideMenus();
                if (event.which == 1) DOM_Select(event, this.parentNode);
                if (event.which == 2) {
                    event.preventDefault();
                    Folders_ActionClickFolder(this.parentNode, opt.midclick_folder);
                }
                if (event.which == 3) Menu_ShowFolderMenu(this.parentNode, event); // SHOW FOLDER MENU
            }
            DIV_header.ondblclick = function(event) { // edit folder
                if (event.which == 1 && !event.shiftKey && !event.ctrlKey && event.target.classList.contains("folder_header")) Folders_ActionClickFolder(this.parentNode, opt.dbclick_folder);
            }
            DIV_header.ondragstart = function(event) { // DRAG START
                event.stopPropagation();
                event.dataTransfer.setDragImage(document.getElementById("DragImage"), 0, 0);
                event.dataTransfer.setData("text", "");
                event.dataTransfer.setData("SourceWindowId", tt.CurrentWindowId);
                DOM_CleanUpDragAndDrop();
                tt.Dragging = true;
                tt.DraggingGroup = false;
                tt.DragTreeDepth = -1;
                let Nodes = [];
                if (this.parentNode.classList.contains("selected")) {
                    DOM_FreezeSelection(false);
                } else {
                    DOM_FreezeSelection(true);
                    DOM_SetClasses(this.parentNode, ["selected_temporarly", "selected"], [], []);
                }
                DOM_RemoveHeadersHoverClass();
                let selected = document.querySelectorAll(".selected, .selected .tab, .selected .folder");
                for (let s of selected) {
                    s.classList.add("dragged_tree");
                    if (s.classList.contains("pin")) {
                        tt.DraggingPin = true;
                        Nodes.push({id: s.id, parent: s.parentNode.id, selected: s.classList.contains("selected"), temporary: s.classList.contains("selected_temporarly"), NodeClass: "pin"});
                    }
                    if (s.classList.contains("tab")) {
                        tt.DraggingTab = true;
                        Nodes.push({id: s.id, parent: s.parentNode.id, selected: s.classList.contains("selected"), temporary: s.classList.contains("selected_temporarly"), NodeClass: "tab"});
                    }
                    if (s.classList.contains("folder")) {
                        tt.DraggingFolder = true;
                        Nodes.push({id: s.id, parent: s.parentNode.id, selected: s.classList.contains("selected"), temporary: s.classList.contains("selected_temporarly"), NodeClass: "folder", index: (tt.folders[s.id] ? tt.folders[s.id].index : 0), name: (tt.folders[s.id] ? tt.folders[s.id].name : labels.noname_group), expand: (tt.folders[s.id] ? tt.folders[s.id].expand : "")});
                    }
                }
                let DraggedFolderParents = DOM_GetParentsByClass(this.parentNode, "folder");
                for (let s of DraggedFolderParents) {
                    s.classList.add("dragged_parents");
                }
                event.dataTransfer.setData("Nodes", JSON.stringify(Nodes));
                event.dataTransfer.setData("NodesTypes", JSON.stringify({DraggingGroup: tt.DraggingGroup, DraggingPin: tt.DraggingPin, DraggingTab: tt.DraggingTab, DraggingFolder: tt.DraggingFolder}));
                chrome.runtime.sendMessage({command: "drag_start", DragTreeDepth: tt.DragTreeDepth, DraggingGroup: tt.DraggingGroup, DraggingPin: tt.DraggingPin, DraggingTab: tt.DraggingTab, DraggingFolder: tt.DraggingFolder});
            }
            DIV_header.ondragenter = function(event) {
                this.classList.remove("folder_header_hover");
            }
            DIV_header.ondragend = function(event) {
                if (opt.open_tree_on_hover) {
                    clearTimeout(tt.DragOverTimer);
                    tt.DragOverId = "";
                }
                setTimeout(function() {DOM_CleanUpDragAndDrop();}, 300);
                setTimeout(function() {chrome.runtime.sendMessage({command: "drag_end"});}, 500);
            }
            DIV_header.onmouseover = function(event) {
                this.classList.add("folder_header_hover");
                if (opt.never_show_close == false && opt.always_show_close == false) this.classList.add("close_show");
            }
            DIV_header.onmouseleave = function(event) {
                this.classList.remove("folder_header_hover");
                if (opt.never_show_close == false && opt.always_show_close == false) this.classList.remove("close_show");
            }
            DIV_header.ondragleave = function(event) {
                DOM_RemoveHighlight();
            }
            DIV_header.ondragover = function(event) {
                if (tt.DraggingGroup == false && (tt.DraggingPin || tt.DraggingTab || tt.DraggingFolder) && this.parentNode.classList.contains("dragged_tree") == false) {
                    if (this.parentNode.classList.contains("before") == false && event.layerY < this.clientHeight / 3) {
                        DOM_RemoveHighlight();
                        DOM_SetClasses(this.parentNode, ["before", "highlighted_drop_target"], ["inside", "after"], []);
                    }
                    if (this.parentNode.classList.contains("inside") == false && event.layerY > this.clientHeight / 3 && event.layerY <= 2 * (this.clientHeight / 3)) {
                        DOM_RemoveHighlight();
                        DOM_SetClasses(this.parentNode, ["inside", "highlighted_drop_target"], ["before", "after"], []);
                    }
                    if (this.parentNode.classList.contains("after") == false && this.parentNode.classList.contains("o") == false && event.layerY > 2 * (this.clientHeight / 3)) {
                        DOM_RemoveHighlight();
                        DOM_SetClasses(this.parentNode, ["after", "highlighted_drop_target"], ["inside", "before"], []);
                    }
                }
                if (opt.open_tree_on_hover && tt.DragOverId != this.id) {
                    if (this.parentNode.classList.contains("c") && this.parentNode.classList.contains("dragged_tree") == false) {
                        clearTimeout(tt.DragOverTimer);
                        tt.DragOverId = this.id;
                        let This = this;
                        tt.DragOverTimer = setTimeout(function() {
                            if (tt.DragOverId == This.id) DOM_SetClasses(This.parentNode, ["o"], ["c"], []);
                        }, 1500);
                    }
                }
            }
            DIV_expand.onmousedown = function(event) {
                event.stopPropagation();
                if (tt.DOMmenu.style.top != "-1000px") Menu_HideMenus();
                if (event.which == 1 && !event.shiftKey && !event.ctrlKey && event.target == this) { // EXPAND/COLLAPSE FOLDER
                    event.stopPropagation();
                    DOM_EventExpandBox(this.parentNode.parentNode);
                    DOM_RefreshExpandStates();
                    DOM_RefreshCounters();
                }
            }
        }
        if (p.ParentId == "pin_list" || p.ParentId == "" || p.ParentId == undefined || document.getElementById("°" + p.ParentId) == null) {
            document.getElementById("°" + tt.active_group).appendChild(DIV_folder);
        } else {
            document.getElementById("°" + p.ParentId).appendChild(DIV_folder);
        }
        if (p.InsertAfterId) {
            let After = document.getElementById(p.InsertAfterId);
            if (After != null) DOM_InsterAfterNode(DIV_folder, After);
        }
    }
}

function Folders_GenerateNewFolderID() {
    let newID = "";
    while (newID == "") {
        newID = "f_" + GenerateRandomID();
        if (document.getElementById(newID) != null) newID = "";
    }
    return newID;
}

function Folders_PreAppendFolders(folders) {
    for (let folderId in folders) {Folders_AppendFolder({folderId: folderId, Name: folders[folderId].name, ParentId: "tab_list", ExpandState: folders[folderId].expand});}
}

function Folders_AppendFolders(folders) {
    for (let folderId in folders) {
        let f = document.getElementById(folderId);
        let parent = document.getElementById("°" + folders[folderId].parent);
        if (f != null && parent != null && folders[folderId].parent != f.parentNode.parentNode.id && parent.parentNode.classList.contains("pin") == false) parent.appendChild(f);
    }
}

function Folders_SaveFolders() {
    let query = document.querySelectorAll(".folder");
    for (let s of query) {
        tt.folders[s.id].parent = s.parentNode.parentNode.id;
        tt.folders[s.id].index = Array.from(s.parentNode.children).indexOf(s);
        tt.folders[s.id].expand = (s.classList.contains("c") ? "c" : (s.classList.contains("o") ? "o" : ""));
    }
    chrome.runtime.sendMessage({command: "save_folders", folders: tt.folders, windowId: tt.CurrentWindowId});
}

function Folders_RemoveFolder(FolderId) {
    if (opt.debug) Utils_log("f: RemoveFolder, folderId " + FolderId);
    let folder = document.getElementById(FolderId);
    if (folder != null) {
        if (opt.promote_children == true) {
            if (opt.promote_children_in_first_child == true && folder.childNodes[1].childNodes.length > 1) {
                DOM_PromoteChildrenToFirstChild(folder);
            } else {
                let Children = folder.childNodes[1];
                while (Children.lastChild) {
                    DOM_InsterAfterNode(Children.lastChild, folder);
                }
            }
        } else {
            let query = document.querySelectorAll("#" + FolderId + " .tab");
            for (let s of query) {
                chrome.tabs.remove(parseInt(s.id), null);
            }
            query = document.querySelectorAll("#" + FolderId + " .folder");
            for (let s of query) {
                delete tt.folders[s.id];
            }
        }
        folder.parentNode.removeChild(folder);
        delete tt.folders[FolderId];
        DOM_RefreshExpandStates();
        chrome.runtime.sendMessage({command: "save_folders", folders: tt.folders, windowId: tt.CurrentWindowId});
    }
}

function Folders_ShowRenameFolderDialog(FolderId) { // Rename folder popup
    if (opt.debug) Utils_log("f: ShowRenameFolderDialog, folderId " + FolderId);
    DOM_HideRenameDialogs();
    if (tt.folders[FolderId]) {
        let name = document.getElementById("folder_edit_name");
        name.value = tt.folders[FolderId].name;
        let folderEditDialog = document.getElementById("folder_edit");
        folderEditDialog.setAttribute("FolderId", FolderId);
        DOM_SetStyle(folderEditDialog, {display: "block", left: "", top: document.getElementById("toolbar").getBoundingClientRect().height + document.getElementById("pin_list").getBoundingClientRect().height + 8 + "px"});
        setTimeout(function() {document.getElementById("folder_edit_name").select();}, 5);
    }
}

function Folders_FolderRenameConfirm() { // when pressed OK in folder popup
    let name = document.getElementById("folder_edit_name");
    let FolderId = document.getElementById("folder_edit").getAttribute("FolderId");
    tt.folders[FolderId].name = name.value;
    document.getElementById("folder_title_"+FolderId).textContent = name.value;
    DOM_HideRenameDialogs();
    if (opt.debug) Utils_log("f: FolderRenameConfirm, folderId " + FolderId + ", name: " + name.value);
    chrome.runtime.sendMessage({command: "save_folders", folders: tt.folders, windowId: tt.CurrentWindowId});
    DOM_RefreshCounters();
}

function Folders_ActionClickFolder(FolderNode, bgOption) {
    if (opt.debug) Utils_log("f: ActionClickFolder, folderId " + FolderNode.id + ", bgOption: " + bgOption);
    if (bgOption == "rename_folder") Folders_ShowRenameFolderDialog(FolderNode.id);
    if (bgOption == "new_folder") {
        let FolderId = Folders_AddNewFolder({ParentId: FolderNode.id});
        Folders_ShowRenameFolderDialog(FolderId);
    }
    if (bgOption == "new_tab") Tabs_OpenNewTab(false, undefined, FolderNode.id,  (opt.append_child_tab === "bottom" ? true : false));
    if (bgOption == "expand_collapse") DOM_EventExpandBox(FolderNode);
    if (bgOption == "close_folder") Folders_RemoveFolder(FolderNode.id);
    if (bgOption == "unload_folder") {
        let tabsArr = [];
        let query = document.querySelectorAll("#" + FolderNode.id + " .tab");
        for (let s of query) {
            tabsArr.push(parseInt(s.id));
        }
        Tabs_DiscardTabs(tabsArr);
    }
}