// GLOBAL ICON array
ICON={}
ICON["Import"]="import"
ICON["Storage"]="db"
ICON["Bin"]="trash"

// grab all selected thumbnails and return a <div> containing the thumbnails
// with extra yr and date attached as attributes so we can set the default
// dir name for a move directory - not used in del, but no harm to include them
function GetSelnAsDiv()
{
    seln=''
    $('.highlight').each(function( index ) { 
        seln+='<div fname="' + $(this).attr('fname') + '" yr="' + $(this).attr('yr') +
            '" date="' + $(this).attr('date') +
            '" class="px-1 col col-auto">' + $(this).children().parent().html() + '</div>'
        seln+='<input type="hidden" name="eid-'+index+'" value="'+$(this).attr('id')+'">'
        } )
    return '<div class="row col-12">'+seln+'</div>'
}

// return a list of eid=<id> for each selected thumbnail
function GetSelnAsData()
{
    to_del=''
    $('.highlight').each(function( index ) { to_del+='&eid-'+index+'='+$(this).attr('id') } )
    return to_del
}

// use an ajax POST to force an AI scan on the selected image(s)
function RunAIOnSeln(person)
{
    post_data = GetSelnAsData()
    post_data += '&person='+person.replace('ai-','')
    $.ajax({ type: 'POST', data: post_data, url: '/run_ai_on', success: function(data){ CheckForJobs() } })
}

// code to change the associated image/icon when the move to selection box (import or storage paths) is changed
function change_rp_sel()
{
    icon_url = $('option:selected', '#rp_sel').attr('icon_url')
    $('#move_path_icon').html( '<svg id="move_path_icon" width="20" height="20" fill="currentColor"><use xlink:href="'
        + icon_url + '"></svg>' )
    seld_ptype=$('option:selected', '#rp_sel').attr('path_type')
    $('#move_path_type').val( seld_ptype )
    // clear all 'existing' buttons
    $('.move_Import').addClass('d-none')
    $('.move_Storage').addClass('d-none')
    // show just selected path's (relevant) buttons
    $('.move_'+seld_ptype).removeClass('d-none')
}

// POST to see if there are any other existing directories named around this date
// (if so display them as options for a move)
function GetExistingDirsAsDiv( dt, divname, ptype )
{
    $.ajax({
        type: 'POST', data: null, url: '/get_existing_paths/'+dt,
        success: function(data) {
            $('#'+divname).html(data)
            dirs = JSON.parse(data)
            s=''
            dirs.forEach( function(item, index) {
                if( item.ptype != ptype )
                    vis = 'd-none '
                else
                    vis = ''
                s+= '<button class="btn btn-outline-primary move_'+item.ptype+ ' ' + vis + '" '
                    s+= 'onClick="$(\'#prefix\').val(\''+item.prefix.replace("\'","\\\'")+'\'); '
                        s+='$(\'#suffix\').val(\''+item.suffix.replace("\'","\\\'")+'\');return false;">'
                    s+=item.prefix+item.suffix
                    s+='</button>'
            } )
            if( s == '' )
                $('#existing').html('')
            else
                $('#move_'+ptype).removeClass('invisible')
            $('#'+divname).html(s)
        }
    } )
}

// wrapper to do some clean up before POST to /move_files or /delete_files
// used to remove the highlighted item(s) && reset the numbering so highlighting continues to work
function MoveOrDelCleanUpUI()
{
    // remove the images being moved (so UI immediately 'sees' the move)
    $("[name^=eid-]").each( function() { $('#'+$(this).attr('value')).remove() } )
    // reorder the images via ecnt again, so future highlighting can work
    document.mf_id=0; $('.figure').each( function() { $(this).attr('ecnt', document.mf_id ); document.mf_id++ } )
    $('#dbox').modal('hide')
}


// show the DBox for a move file, includes all thumbnails of selected files to move
// and a pre-populated folder to move them into, with text field to add a suffix
function MoveDBox(path_details, db_url)
{
    $('#dbox-title').html('Move Selected File(s) to new directory in Storage Path')  
    div =`
        <div class="form-row col-12">
        <p class="col">Moving the following files?</p>
        </div>
        <form id="mv_fm" class="form form-control-inline col-12">
        <input id="move_path_type" name="move_path_type" type="hidden"
        `
    div += ' value="' + path_details[0].type + '"></input>'
    div+=GetSelnAsDiv()
    yr=$('.highlight').first().attr('yr')
    dt=$('.highlight').first().attr('date')
    div+='<div class="row">Use Existing Directory (in the chosen path):</div><div id="existing"></div>'
    GetExistingDirsAsDiv( dt, "existing", path_details[0].type )
    div+=`
        <div class="input-group my-3">
        <alert class="alert alert-primary my-auto py-1">
        `
    // NB: alert-primary here is a hack to get the bg the same color as the alert primary by
    div+= '<svg id="move_path_icon" width="20" height="20" fill="currentColor"><use xlink:href="' + path_details[0].icon_url + '"></svg>'
    div+= '<select id="rp_sel" name="rel_path" class="text-primary alert-primary py-1 border border-primary rounded" onChange="change_rp_sel()">'
    for(p of path_details) {
        div+= '<option path_type="'+p.type+'" icon_url="'+p.icon_url+'">'+p.path+'</option>'
    }
    div+= '</select>'
    div+=`
        </alert>
        <input id="prefix" type="text" name="prefix" class="text-primary text-right form-control"
        `
    div+="value="+yr+'/'+dt+"-"
    div+=`
        "></input>
        <input id="suffix" type="text" name="suffix" class="form-control" placeholder="name"> </input>
        </div>
        <div class="form-row col-12 mt-2">
            <button onClick="$('#dbox').modal('hide'); return false;" class="btn btn-outline-secondary offset-1 col-2">Cancel</button>
            <button id="move_submit" onClick="MoveOrDelCleanUpUI(); $.ajax({ type: 'POST', data: $('#mv_fm').serialize(), url: '/move_files', success: function(data) { 
                if( $(location).attr('pathname').match('search') !== null ) { window.location='/' }; CheckForJobs() } }); return false" class="btn btn-outline-primary col-2">Ok</button>
        </div>
        </form>
    `

    $('#dbox-content').html(div)
    $('#dbox').modal('show')
    $("#prefix").keypress(function (e) { if (e.which == 13) { $("#move_submit").click(); return false; } } )
    $("#suffix").keypress(function (e) { if (e.which == 13) { $("#move_submit").click(); return false; } } )
}

// show the DBox for a delete/restore file, includes all thumbnails of selected files 
// with appropriate coloured button to Delete or Restore files`
function DelDBox(del_or_undel)
{
    to_del = GetSelnAsData()
    $('#dbox-title').html(del_or_undel+' Selected File(s)')
    div ='<div class="row col-12"><p class="col">' + del_or_undel + ' the following files?</p></div>'
    div+=GetSelnAsDiv()
    div+=`<div class="row col-12 mt-3">
            <button onClick="$('#dbox').modal('hide')" class="btn btn-outline-secondary col-2">Cancel</button>
    `
    div+=`
    <button onClick="MoveOrDelCleanUpUI(); $.ajax({ type: 'POST', data: to_del, url:
    `
    if( del_or_undel == "Delete" )
        div+=`
        '/delete_files',
        success: function(data){ 
            if( $(location).attr('pathname').match('search') !== null ) { window.location='/' }; CheckForJobs() } }); return false" class="btn btn-outline-danger col-2">Ok</button>
        </div>
        `
    else
        // just force page reload to / for now if restoring files from a search path -- a search (by name) 
        // would match the deleted/restored file, so it would be complex to clean up the UI (and can't reload, as DB won't be changed yet)
        div+=`
        '/restore_files',
        success: function(data){ 
            if( $(location).attr('pathname').match('search') !== null ) { window.location='/' }; CheckForJobs() } }); return false" class="btn btn-outline-success col-2">Ok</button>
        </div>
        `
    $('#dbox-content').html(div)
    $('#dbox').modal('show')
}

// show the DBox for a lame quick version of file details 
function DetailsDBox()
{
    $('#dbox-title').html('Details of Selected File(s)')  
    var div ='<div class="row col-12">'
    $('.highlight').each(function( index ) { 
            div += "<div class='col-3' style='background-color:lightgray'>Name:</div><div class='col-9' style='background-color:lightgray'>" + $(this).attr('fname') + "</div>"
            div += "<div class='col-3'>Date:</div><div class='col-9'>" + $(this).attr('pretty_date') + "</div>"
            dir = $(this).attr('in_dir')
            if( dir.slice(-1) != "/" )
                dir=dir.concat('/')
            div += "<div class='col-3'>Dir:</div><div class='col-9'>" + dir + "</div>"
            div += "<div class='col-3'>Size:</div><div class='col-9'>" + $(this).attr('size') + " MB</div>"
            div += "<div class='col-3'>Hash:</div><div class='col-9'>" + $(this).attr('hash') + "</div>"
            div += "<div class='col-3'>Path Type:</div><div class='col-9'>" + $(this).attr('path_type') + "</div>"
        } )
        div += `
            </div>
            <br>
            <div class="form-row col-12">
                <button onClick="$('#dbox').modal('hide'); return false;" class="btn btn-outline-secondary offset-1 col-2">Cancel</button>
            </div>
        `
    $('#dbox-content').html(div)
    $('#dbox').modal('show')
}


// function to change the size of thumbnails (and resets button bar to newly
// selected size)
function ChangeSize(clicked_button,sz)
{
	$('.sz-but.btn-info').removeClass('btn-info text-white').addClass('btn-outline-info')
	$(clicked_button).addClass('btn-info text-white').removeClass('btn-outline-info')
	$('.thumb').attr( {height: sz, style: 'font-size:'+sz+'px' } )
	$('#size').val(sz)
    sz=sz-22
    $('.svg').height(sz);
    $('.svg').width(sz);
    $('.svg_cap').width(sz);
}

// DoSel is called when a click event occurs, and sets the selection via adding
// 'highlight' to the class of the appropriate thumbnails
// e == event (can see if shift/ctrl held down while left-clicking
// el == element the click is on
// this allows single-click to select, ctrl-click to (de)select 1 item, and
// shift-click to add all elements between highlighted area and clicked area,
// whether you click after highlight or before
function DoSel(e, el)
{
    if( e.ctrlKey || document.fake_ctrl === 1 )
    {
        $(el).toggleClass('highlight')
        if( document.fake_ctrl === 1 )
            document.fake_ctrl=0
        return
    }
    if( e.shiftKey || document.fake_shift === 1 )
    {
        st=Number($('.highlight').first().attr('ecnt'))
        end=Number($('.highlight').last().attr('ecnt'))
        clicked=Number($(el).attr('ecnt'))
        // if we shift-click first element, then st/end are NaN, so just highlightthe one clicked
        if( isNaN(st) )
        {
            $('.entry').slice( clicked, clicked+1 ).addClass('highlight')
            return
        }
        if( clicked > end )
            $('.entry').slice( end, clicked+1 ).addClass('highlight')
        else
            $('.entry').slice( clicked, st ).addClass('highlight')

        if( document.fake_shift === 1 )
            document.fake_shift=0
        return
    }
    $('.highlight').removeClass('highlight')
    $(el).addClass('highlight')
}

// if a selection exists, enable move & del/restore buttons otherwise disable them
function SetButtonState() {
    var sel=false
    $('.highlight').each(function( index ) { sel=true } )
    if( sel ) {
        $('#move').attr('disabled', false )
        $('#del').attr('disabled', false )
    } else {
        $('#move').attr('disabled', true )
        $('#del').attr('disabled', true )
    }
}

// Check if the set of highlights are either only figures, dirs or both
// used to work out what options are shown in the file context menu
function FiguresOrDirsOrBoth() {
    var figure=false
    var dir=false
    $('.highlight').each(function( index ) { 
        if( $(this).hasClass('figure') ) {
            figure=true
        } 
        if( $(this).hasClass('dir') ) {
            dir=true
        } 
    } )
    if( figure & ! dir )
        return "figure"
    if( ! figure & dir )
        return "dir"
    return "both"
}

// Check if the set of highlights contain Bin and Not Bin...
// if its both, then no del/restore is possible in context menu
// otherwise can either set del or restore appropriately
function SelContainsBinAndNotBin() {
    var bin=false
    var not_bin=false
    $('.highlight').each(function( index ) { 
        if( $(this).attr('path_type') == "Bin" ) {
            bin=true
        } else {
            not_bin=true
        }
    } )
    if( bin && not_bin )
        return true
    else
        return false
}

// checks to see if there is no selection active
function NoSel() {
    var sel=false
    $('.highlight').each(function( index ) { sel=true } )
    // func looks for No Selection, so if sel is true and we have a sel, return false (i.e. NOT No Sel -> Sel )
    if( sel )
        return false
    else
        return true
}

/**
 * Renders a group header or entry based on the object and options.
 * @param {Object} obj - The object containing file/directory details.
 * @param {Object} last - Tracks the last printed group (e.g., { printed: null }).
 * @param {Object} ecnt - Entry counter (e.g., { val: 0 }).
 * @returns {string} - Generated HTML string.
 */
function addFigure( obj, last, ecnt) 
{
  let html = "";

  // Grouping logic
  if (OPT.grouping === "Day") {
    if (last.printed !== obj.file_details.day) {
      html += `<div class="row ps-3"><h6>Day: ${obj.file_details.day} of ${obj.file_details.month}/${obj.file_details.year}</h6></div>`;
      last.printed = obj.file_details.day;
    }
  } else if (OPT.grouping === "Week") {
    if (last.printed !== obj.file_details.woy) {
      html += `<div class="row ps-3"><h6>Week #: ${obj.file_details.woy} of ${obj.file_details.year}</h6></div>`;
      last.printed = obj.file_details.woy;
    }
  } else if (OPT.grouping === "Month") {
    if (last.printed !== obj.file_details.month) {
      html += `<div class="row ps-3"><h6>Month: ${obj.file_details.month} of ${obj.file_details.year}</h6></div>`;
      last.printed = obj.file_details.month;
    }
  }

  // Image/Video/Unknown entry
  if (obj.type.name === "Image" || obj.type.name === "Video" || obj.type.name === "Unknown") {
    if (!OPT.folders || isTopLevelFolder(obj.in_dir.in_path.path_prefix + '/' + obj.in_dir.rel_path + '/' + obj.name, OPT.cwd)) {
      const pathType = obj.in_dir.in_path.type.name;
      const size = obj.file_details.size_mb;
      const hash = obj.file_details.hash;
      const inDir = `${obj.in_dir.in_path.path_prefix}/${obj.in_dir.rel_path}`;
      const fname = obj.name;
      const yr = obj.file_details.year;
      const date = `${yr}${String(obj.file_details.month).padStart(2, '0')}${String(obj.file_details.day).padStart(2, '0')}`;
      const prettyDate = `${obj.file_details.day}/${obj.file_details.month}/${obj.file_details.year}`;
      const type = obj.type.name;

      html += `
        <figure id="${obj.id}" ecnt="${ecnt}" class="col col-auto g-0 figure entry m-1"
                path_type="${pathType}" size="${size}" hash="${hash}" in_dir="${inDir}"
                fname="${fname}" yr="${yr}" date="${date}" pretty_date="${prettyDate}" type="${type}">
          ${renderMedia(obj)}
        </figure>
      `;
    }
  }
  // Directory entry
  else if (obj.type.name === "Directory" && OPT.folders) {
    const dirname = obj.dir_details.rel_path.length
      ? `${obj.dir_details.in_path.path_prefix}/${obj.dir_details.rel_path}`
      : obj.dir_details.in_path.path_prefix;

    if (isTopLevelFolder(dirname, OPT.cwd)) {
      html += `
        <figure class="col col-auto g-0 dir entry m-1" id="${obj.id}" ecnt="${ecnt}" dir="${dirname}" type="Directory">
          <svg class="svg" width="${OPT.size - 22}" height="${OPT.size - 22}" fill="currentColor">
            <use xlink:href="/internal/icons.svg#Directory"></use>
          </svg>
          <figcaption class="svg_cap figure-caption text-center text-wrap text-break">${obj.name}</figcaption>
        </figure>
      `;
      html += `<script>f=$('#${obj.id}'); w=f.find('svg').width(); f.find('figcaption').width(w);</script>`;
    }
  }

  $('#figures').append( html )
  return
}

// Helper function to render media (image/video/unknown)
function renderMedia(obj) {
  const isImageOrUnknown = obj.type.name === "Image" || obj.type.name === "Unknown";
  const isVideo = obj.type.name === "Video";
  const path = `${obj.in_dir.in_path.path_prefix}/${obj.in_dir.rel_path}/${obj.name}`;
  const thumb = obj.file_details.thumbnail
    ? `<a href="${path}"><img alt="${obj.name}" class="thumb" height="${OPT.size}" src="data:image/jpeg;base64,${obj.file_details.thumbnail}"></a>`
    : `<a href="${path}"><svg width="${OPT.size}" height="${OPT.size}" fill="white"><use xlink:href="/internal/icons.svg#unknown_ftype"/></svg></a>`;

  let mediaHtml = `<div style="position:relative; width:100%">${thumb}`;

  if (isImageOrUnknown) {
    if (OPT.search_term) {
      mediaHtml += `
        <div style="position:absolute; bottom: 0px; left: 2px;">
          <svg width="16" height="16" fill="white"><use xlink:href="/internal/icons.svg#${getLocationIcon(obj)}"/></svg>
        </div>
      `;
    }
    mediaHtml += `
      <div id="s${obj.id}" style="display:none; position:absolute; top: 50%; left:50%; transform:translate(-50%, -50%);">
        <img height="64px" src="/internal/throbber.gif">
      </div>
    `;
  } else if (isVideo) {
    mediaHtml += `
      <div style="position:absolute; top: 0px; left: 2px;">
        <svg width="16" height="16" fill="white"><use xlink:href="/internal/icons.svg#film"/></svg>
      </div>
    `;
    if (OPT.search_term) {
      mediaHtml += `
        <div style="position:absolute; bottom: 0px; left: 2px;">
          <svg width="16" height="16" fill="white"><use xlink:href="/internal/icons.svg#${getLocationIcon(obj)}"/></svg>
        </div>
      `;
    }
  }

  mediaHtml += `</div>`;
  return mediaHtml;
}

// Helper: Check if path is a top-level folder of cwd
function isTopLevelFolder(path, cwd) {
  // Implement your logic here
  return true; // Placeholder
}

// Helper: Get location icon (placeholder)
function getLocationIcon(obj) {
    return ICON[obj.in_dir.in_path.type.name]
}

// POST to get entry ids, and then getPage for a specified directory
function getDirEntries(dir_id, back)
{
    data={}
    data.dir_id=dir_id
    data.back=back

    $.ajax({
        type: 'POST',
        url: '/get_dir_entries',
        data: JSON.stringify(data),
        contentType: 'application/json',
        dataType: 'json',
        success: function(res) {
            document.entries=res
            // rebuild entryList/pageList as each dir comes with new entries
            entryList=res.map(obj => obj.id);
            pageList=entryList.slice(0, OPT.how_many)
            if( back )
                document.back_id = res[0].in_dir.eid
            drawPageOfFigures()
        },
        error: function(xhr, status, error) {
            console.error("Error:", error);
        }
    });
}

// this function draws all the figures from document.entries - called when we
// change pages, but also when we change say grouping/other OPTs
function drawPageOfFigures()
{
    $('#figures').empty()
    var last = { printed: null }
    var ecnt=0

    if( OPT.folders )
    {
        if( document.entries.length && document.entries[0].in_dir.rel_path == '' )
        {
            gray="_gray"
            back=""
            cl=""
        }
        else
        {
            gray=""
            back="Back"
            cl="back"
        }
        // back button, if gray/back decide if we see grayed out folder and/or the name of the folder we go back to
        html=`<div class="col col-auto g-0 m-1">
                <figure id="${document.back_id}" ecnt="0" class="${cl} entry m-1" type="Directory">
                    <svg class="svg" width="${OPT.size-22}" height="${OPT.size-22}">
                        <use xlink:href="internal/icons.svg#folder_back${gray}"/>
                    </svg>
                    <figcaption class="figure-caption text-center">${back}</figcaption>
                </figure>
             </div>`
        ecnt++
        /*
            <script>f=$('#_back'); w=f.find('svg').width(); f.find('figcaption').width(w);</script>
        */
        $('#figures').append(html)
    }
    for (const obj of document.entries) {
        addFigure( obj, last, ecnt )
        ecnt++
    }
    if( document.entries.length == 0 && OPT.search_term != '' )
        $('#figures').append( `<span class="alert alert-danger p-2 col-auto"> No matches for: '${OPT.search_term}'</span>` )
    $('.figure').click( function(e) { DoSel(e, this ); SetButtonState(); return false; });
    $('.figure').dblclick( function(e) { dblClickToViewEntry( $(this).attr('id') ) } )
    // for dir, getDirEntries 2nd param is back (or "up" a dir)
    $(".dir").click( function(e) { document.back_id=this.id; getDirEntries(this.id,false) } )
    $(".back").click( function(e) { getDirEntries(this.id,true) } )
}

function getPageFileList(res, viewingIdx)
{
    $('#file_list_div').empty()
    html='<table class="table table-striped table-sm col-12">'
    html+='<thead><tr class="table-primary"><th>Name</th><th>Size (MB)</th><th>Path Prefix</th><th>Hash</th></tr></thead><tbody>'
    for (const obj of res) {
        html+=`<tr>
                <td>
                <div class="d-flex align-items-center">
                  <a href="${obj.in_dir.in_path.path_prefix}/${obj.in_dir.rel_path}/${obj.name}">
                    <img class="img-fluid me-2" style="max-width: 100px;"
                      src="data:image/jpeg;base64,${obj.file_details.thumbnail}"></img>
                  </a>
                  <span>${obj.name}</span>
                </div>
                <td>${obj.file_details.size_mb}</td>
                <td>${obj.in_dir.in_path.path_prefix.replace("static/","")}/${obj.in_dir.rel_path}</td>
                <td>${obj.file_details.hash}</td>
             </tr>`
    }
    html+='</tbody></table>'
    $('#file_list_div').append(html)
}

// function called when we get another page from inside the files view
function getPageFigures(res, viewingIdx)
{
    // add all the figures to files_div
    drawPageOfFigures()
}

// function called when we get another page from inside the viewer
function getPageViewer(res, viewingIdx)
{
    document.viewing=document.entries[viewingIdx]
    // update viewing, arrows and image/video too
    ViewImageOrVideo()
}

// Function to get the 'page' of entry ids out of entryList
function getPage(pageNumber, successCallback, viewingIdx=0)
{
    // before we do anything, disabled left/right arrows on viewer to stop
    // getting another event before we have the data for the page back
    $('#la').prop('disabled', true)
    $('#ra').prop('disabled', true)
    const startIndex = (pageNumber - 1) * OPT.how_many;
    const endIndex = startIndex + OPT.how_many;
    pageList = entryList.slice(startIndex, endIndex);

    // set up data to send to server to get the entry data for entries in pageList
    data={}
    data.ids = pageList

    $.ajax({
        type: 'POST', url: '/get_entries_by_ids',
        data: JSON.stringify(data), contentType: 'application/json',
        dataType: 'json',
        success: function(res) { document.entries=res; successCallback(res,viewingIdx); },
        error: function(xhr, status, error) { console.error("Error:", error); } });
    resetNextPrevButtons()
    return
}

// Quick Function to check if we are on the first page
function isFirstPage(pageNumber) 
{
    return pageNumber <= 1;
}

// Function to check if we are on the last page
function isLastPage(pageNumber) 
{
    const totalPages = Math.ceil(entryList.length / OPT.how_many);
    return pageNumber >= totalPages;
}

// given an id in the list, return which page we are on (page 1 is first page)
function getPageNumberForId(id) {
    const idx = entryList.indexOf(id);
    // should be impossible but jic
    if (idx === -1) {
        return -1; // or null, if you prefer
    }
    return Math.floor(idx / OPT.how_many) + 1;
}

// if we are on first page, disable prev, it not ensure next is enabled
// if we are on last page, disable next, it not ensure prev is enabled
function resetNextPrevButtons()
{
    if ( isFirstPage( getPageNumberForId(pageList[0]) ) )
        $('.prev').prop('disabled', true).addClass('disabled');
    else
        $('.prev').prop('disabled', false).removeClass('disabled');

    if ( isLastPage( getPageNumberForId(pageList[0]) ) )
        $('.next').prop('disabled', true).addClass('disabled');
    else
        $('.next').prop('disabled', false).removeClass('disabled');
}

// get list of eids for the next page, also make sure next/prev buttons make sense for page we are on
function nextPage(successCallback)
{
    // pageList[0] is the first entry on this page
    const currentPage=getPageNumberForId( pageList[0] )
    // should never happen / just return pageList unchanged
    if ( currentPage === -1 || isLastPage( currentPage ) )
    {
        console.error( "WARNING: seems first on pg=" + firstEntryOnPage + " of how many=" + OPT.how_many + " gives currentPage=" + currentPage + " and we cant go next page?" )
        return
    }
    getPage( currentPage+1, successCallback )
    return
}

// get list of eids for the prev page, also make sure next/prev buttons make sense for page we are on
function prevPage(successCallback)
{
    // pageList[0] is the first entry on this page
    const currentPage=getPageNumberForId( pageList[0] )
    // should never happen / just return pageList unchanged
    if (currentPage === 1 || currentPage === -1 )
    {
        console.error( "WARNING: seems first on pg=" + firstEntryOnPage + " of how many=" + OPT.how_many + " gives currentPage=" + currentPage + " and we cant go prev page?" )
        return
    }
    getPage( currentPage-1, successCallback )
    return
}

function isMobile() {
    try{ document.createEvent("TouchEvent"); return true; }
    catch(e){ return false; }
}


function changeOPT(successCallback) {
    OPT.how_many=$('#how_many').val()
    new_f=$('#folders').val()
    new_f=( new_f == 'True' )
    // if change to/from folders, also fix the noo menu
    if( new_f != OPT.folders )
    {
        if( new_f )
        {
            $('#noo option:lt(2)').prop('disabled', true);
            $('#noo').val(OPT.default_folder_noo)
        }
        else
        {
            $('#noo option:lt(2)').prop('disabled', false);
            $('#noo').val(OPT.default_flat_noo)
        }
    }
    OPT.noo=$('#noo').val()
    OPT.folders=new_f
    OPT.folders=$('#folders').val()
    OPT.grouping=$('#grouping').val()
    OPT.size=$('#size').val()
    $.ajax({
        type: 'POST',
        url: '/change_file_opts',
        data: JSON.stringify(OPT),
        contentType: 'application/json',
        success: function(resp) {
            entryList=resp.query_data.entry_list
            // put data back into booleans, ints, etc
            OPT.folders=( OPT.folders == 'True' )
            OPT.how_many=parseInt(OPT.how_many)
            $('.how_many_text').html( `&nbsp;${OPT.how_many} files&nbsp;` )
            OPT.root_eid=parseInt(OPT.root_eid)
            OPT.size=parseInt(OPT.size)
            getPage(1,successCallback)
        }
    })
}