/**
 * @OnlyCurrentDoc
 * Student Data Merger — single-file installation.
 * If your project already defines onOpen, remove ONLY the wrapper below
 * and add sdmOnOpen(); inside your existing onOpen function.
 */
function onOpen(e) { sdmOnOpen(); }

/** Student Data Merger 1.5.0. Only the current spreadsheet is accessed. */
function sdmOnOpen() {
  SpreadsheetApp.getUi().createMenu('Student Data').addItem('Merge Data', 'sdmShowMerger').addSeparator().addItem('Manage Backups', 'sdmShowBackupManager').addToUi();
}
function sdmShowMerger() {
  SpreadsheetApp.getUi().showModalDialog(sdmMergerDialog_('Merger',sdmGetMergerSheets).setWidth(1000).setHeight(730), 'Student Data Merger · 1.5.0');
}
function sdmGetMergerSheets() {
  return SpreadsheetApp.getActive().getSheets().filter(function(s) {
    return !s.isSheetHidden();
  }).map(function(s) {
    var lastColumn=s.getLastColumn();
    // Only row 1 is fetched at launch, regardless of the number of students.
    return {id:s.getSheetId(), name:s.getName(), headers:lastColumn ? s.getRange(1,1,1,lastColumn).getDisplayValues()[0] : []};
  });
}
function sdmReadMergeSource_(id) {
  var s=SpreadsheetApp.getActive().getSheetById(Number(id));
  if(!s) throw new Error('A selected tab no longer exists. Reopen the tool.');
  var rows=s.getDataRange().getDisplayValues();
  if(rows.length<2) throw new Error(s.getName()+': add headers in row 1 and at least one student row.');
  var headers=rows[0].map(function(h){return h.trim();});
  if(headers.some(function(h){return !h;}) || new Set(headers).size!==headers.length) throw new Error(s.getName()+': every column needs a unique, nonblank header.');
  return {name:s.getName(), headers:headers, rows:rows.slice(1).map(function(r,i){return {values:r, row:i+2};}).filter(function(r){return r.values.some(function(v){return v!=='';});})};
}
function sdmNormalizeStudentId_(v) { return String(v).trim(); }
function sdmBuildMergePlan_(main, incoming, config) {
  var mi=Number(config.mainKey), ii=Number(config.incomingKey);
  if(!Number.isInteger(mi)||mi<0||mi>=main.headers.length||!Number.isInteger(ii)||ii<0||ii>=incoming.headers.length) throw new Error('Choose valid Student ID columns.');
  var cols=config.columns;
  if(!Array.isArray(cols)||!cols.length) throw new Error('Select at least one incoming column.');
  if(new Set(cols).size!==cols.length || cols.some(function(c){return !Number.isInteger(c)||c<0||c>=incoming.headers.length||c===ii;})) throw new Error('Invalid incoming column selection.');
  function index(source,key) {
    var map=new Map(), errors=[];
    source.rows.forEach(function(r){
      var id=sdmNormalizeStudentId_(r.values[key]);
      if(!id) errors.push('blank ID at row '+r.row);
      else if(map.has(id)) errors.push('duplicate ID '+id+' at rows '+map.get(id).row+' and '+r.row);
      else map.set(id,r);
    });
    if(errors.length) throw new Error(source.name+': '+errors.slice(0,15).join('; ')+(errors.length>15 ? '; additional issues exist.' : ''));
    return map;
  }
  var master=index(main,mi), extra=index(incoming,ii), headers=main.headers.slice();
  var mappings=cols.map(function(c){
    var target=headers.indexOf(incoming.headers[c]);
    // Never let an incoming field overwrite the master ID column.
    if(target===mi) throw new Error('Incoming column '+incoming.headers[c]+' collides with the roster ID header. Rename that incoming header first.');
    if(target<0){target=headers.length;headers.push(incoming.headers[c]);}
    return {source:c,target:target};
  });
  var conflicts=[], newcomers=[], missing=[], matched=0;
  extra.forEach(function(r,id){
    if(!master.has(id)) newcomers.push({id:id,values:r.values,row:r.row});
    else {
      matched++;
      mappings.forEach(function(m){var old=master.get(id).values[m.target]||'', next=r.values[m.source];
        if(old!=='' && next!=='' && old!==next) conflicts.push({key:r.row+':'+m.source,id:id,column:headers[m.target],original:old,incoming:next});
      });
    }
  });
  master.forEach(function(r,id){if(!extra.has(id)) missing.push(id);});
  return {headers:headers,mappings:mappings,conflicts:conflicts,newcomers:newcomers,missing:missing,matched:matched,mainKey:mi,incomingKey:ii};
}
function sdmLoadMerge_(config) {
  // Hash only known settings in a fixed order. RPC object key order is not stable.
  config={mainSheet:Number(config.mainSheet),incomingSheet:Number(config.incomingSheet),mainKey:Number(config.mainKey),incomingKey:Number(config.incomingKey),columns:config.columns};
  if(Number(config.mainSheet)===Number(config.incomingSheet)) throw new Error('Choose two different tabs.');
  var main=sdmReadMergeSource_(config.mainSheet), incoming=sdmReadMergeSource_(config.incomingSheet);
  var plan=sdmBuildMergePlan_(main,incoming,config);
  var digest=Utilities.base64Encode(Utilities.computeDigest(Utilities.DigestAlgorithm.SHA_256,JSON.stringify({main:main,incoming:incoming,config:config})));
  return {main:main,incoming:incoming,plan:plan,digest:digest};
}
function sdmPreviewMerge(config) {
  var data=sdmLoadMerge_(config), p=data.plan;
  return {digest:data.digest,matched:p.matched,mainCount:data.main.rows.length,missing:p.missing,conflicts:p.conflicts,newcomers:p.newcomers,incomingHeaders:data.incoming.headers};
}
function sdmMergedRows_(data, choices) {
  var p=data.plan, byId=new Map(data.incoming.rows.map(function(r){return [sdmNormalizeStudentId_(r.values[p.incomingKey]),r];}));
  if(['keep','incoming','review'].indexOf(choices.conflictMode)<0 || ['add','exclude','review'].indexOf(choices.newMode)<0) throw new Error('Choose how to handle new students and conflicts.');
  var validNew=new Set(p.newcomers.map(function(r){return r.id;})), selected=new Set(choices.includeIds||[]);
  selected.forEach(function(id){if(!validNew.has(id)) throw new Error('Invalid new student selection.');});
  if(choices.conflictMode==='review') p.conflicts.forEach(function(c){if(!choices.conflicts || ['keep','incoming'].indexOf(choices.conflicts[c.key])<0) throw new Error('Resolve every conflict.');});
  var result=data.main.rows.map(function(r){
    var row=r.values.slice(); while(row.length<p.headers.length) row.push('');
    var next=byId.get(sdmNormalizeStudentId_(r.values[p.mainKey]));
    if(next) p.mappings.forEach(function(m){
      var v=next.values[m.source], old=row[m.target];
      if(v==='') return; // Incoming blanks never erase existing information.
      var decision=choices.conflictMode==='review' ? choices.conflicts[next.row+':'+m.source] : choices.conflictMode;
      if(old===''||old===v||decision==='incoming') row[m.target]=v;
    });
    return row;
  });
  var excluded=[];
  p.newcomers.forEach(function(r){
    if(choices.newMode==='add'||(choices.newMode==='review'&&selected.has(r.id))){
      var row=p.headers.map(function(){return '';}); row[p.mainKey]=r.values[p.incomingKey];
      p.mappings.forEach(function(m){row[m.target]=r.values[m.source];});result.push(row);
    } else excluded.push(r.values);
  });
  return {rows:result,excluded:excluded};
}
function sdmExecuteMerge(config,digest,choices) {
  var lock=LockService.getDocumentLock(); lock.waitLock(30000);
  var created=[], committed=false, original=null, replacement=null, originalName=null, originalRenamed=false;
  try {
    var data=sdmLoadMerge_(config);
    if(data.digest!==digest) throw new Error('Source data changed. Preview again before merging.');
    var result=sdmMergedRows_(data,choices), ss=SpreadsheetApp.getActive();
    var stamp=Utilities.formatDate(new Date(),ss.getSpreadsheetTimeZone(),'yyyy-MM-dd HHmmss');
    function write(label,headers,rows) {
      var name=label+' '+stamp, n=2; while(ss.getSheetByName(name)) name=label+' '+stamp+' '+n++;
      var sheet=ss.insertSheet(name);created.push(sheet);
      var values=[headers].concat(rows).map(function(row){return row.map(function(v){v=String(v);return /^[=']/.test(v) ? "'"+v : v;});});
      if(sheet.getMaxRows()<values.length) sheet.insertRowsAfter(sheet.getMaxRows(),values.length-sheet.getMaxRows());
      if(sheet.getMaxColumns()<headers.length) sheet.insertColumnsAfter(sheet.getMaxColumns(),headers.length-sheet.getMaxColumns());
      sheet.getRange(1,1,values.length,headers.length).setNumberFormat('@').setValues(values);
      sheet.setFrozenRows(1);sheet.getRange(1,1,1,headers.length).setFontWeight('bold').setBackground('#dcece8');
      return name;
    }
    original=ss.getSheetById(Number(config.mainSheet));
    if(!original) throw new Error('The roster tab no longer exists.');
    // Copy the complete master, retaining styles, dimensions, rules and unchanged cells.
    replacement=original.copyTo(ss);created.push(replacement);
    var merged=replacement.getName(), unmatched=null;
    sdmApplyMergeToCopy_(replacement,data,result);

    if(result.excluded.length) unmatched=write('Unmatched Students',data.incoming.headers,result.excluded);
    SpreadsheetApp.flush();
    if(sdmLoadMerge_(config).digest!==digest) throw new Error('Source data changed during the merge. Preview again.');
    original=ss.getSheetById(Number(config.mainSheet));
    if(!original) throw new Error('The roster tab no longer exists.');
    originalName=original.getName();
    var backupSuffix=' Backup '+stamp, counter=1;
    var backupName=originalName.slice(0,100-backupSuffix.length)+backupSuffix;
    while(ss.getSheetByName(backupName)) {
      backupSuffix=' Backup '+stamp+' '+(++counter);
      backupName=originalName.slice(0,100-backupSuffix.length)+backupSuffix;
    }
    replacement=created[0];
    original.setName(backupName); originalRenamed=true;
    replacement.setName(originalName);
    original.hideSheet();
    SpreadsheetApp.flush();
    committed=true;
    merged=originalName;
    var incomingDeleted=false, cleanupWarning=null;
    if(choices.deleteIncoming===true) {
      // Output is complete before optional cleanup. Cleanup failures never roll it back.
      try {
        // The source snapshot was checked immediately before archiving the roster.
        var incomingSheet=ss.getSheetById(Number(config.incomingSheet));
        if(!incomingSheet || Number(config.mainSheet)===incomingSheet.getSheetId()) throw new Error('Incoming tab could not be safely identified.');
        ss.deleteSheet(incomingSheet);
        incomingDeleted=true;
      } catch(cleanupError) {
        cleanupWarning='The merged result was created, but the incoming tab was kept. '+cleanupError.message;
      }
    }
    return {merged:merged,unmatched:unmatched,rows:result.rows.length,backup:backupName,incomingDeleted:incomingDeleted,cleanupWarning:cleanupWarning};
  } catch(e) {
    if(!committed) {
      if(originalRenamed) {
        try {
          original.showSheet();
          if(replacement && replacement.getName()===originalName) replacement.setName('Merge recovery '+Utilities.getUuid().slice(0,8));
          original.setName(originalName);
        } catch(restoreError) {
          throw new Error('Merge interrupted. All source and result tabs were retained for recovery. '+e.message+' Restore issue: '+restoreError.message);
        }
      }
      created.forEach(function(s){try{SpreadsheetApp.getActive().deleteSheet(s);}catch(ignore){}});
    }
    throw e;
  } finally {lock.releaseLock();}
}

/** Update only changed cells in the master copy; preserve original row positions. */
function sdmApplyMergeToCopy_(sheet,data,result) {
  var width=data.plan.headers.length, existingWidth=data.main.headers.length;
  var lastRosterRow=data.main.rows.reduce(function(n,r){return Math.max(n,r.row);},1);
  var newCount=result.rows.length-data.main.rows.length;
  var endRow=lastRosterRow+newCount;
  if(sheet.getMaxRows()<endRow) sheet.insertRowsAfter(sheet.getMaxRows(),endRow-sheet.getMaxRows());
  if(sheet.getMaxColumns()<width) sheet.insertColumnsAfter(sheet.getMaxColumns(),width-sheet.getMaxColumns());
  if(newCount && data.main.rows.length) {
    // Only new students inherit the last roster row's format; existing rows are untouched.
    sheet.getRange(lastRosterRow,1,1,existingWidth).copyFormatToRange(sheet,1,existingWidth,lastRosterRow+1,endRow);
  }
  var changes=[];
  function add(row,col,value) {
    if(!changes[col]) changes[col]=[];
    // Explicit literal text prevents automatic date/ID conversion without changing formats.
    changes[col].push({row:row,value:"'"+String(value)});
  }
  for(var c=existingWidth;c<width;c++) add(1,c,data.plan.headers[c]);
  result.rows.forEach(function(values,i){
    var old=i<data.main.rows.length ? data.main.rows[i] : null;
    var row=old ? old.row : lastRosterRow+1+i-data.main.rows.length;
    values.forEach(function(value,c){
      var before=old && c<existingWidth ? old.values[c] : '';
      if(value!==before) add(row,c,value);
    });
  });
  // Batch adjacent changed cells in each column, leaving unchanged formulas intact.
  changes.forEach(function(cells,c){
    if(!cells) return;
    var start=0;
    while(start<cells.length) {
      var end=start+1;
      while(end<cells.length && cells[end].row===cells[end-1].row+1) end++;
      sheet.getRange(cells[start].row,c+1,end-start,1).setValues(cells.slice(start,end).map(function(cell){return [cell.value];}));
      start=end;
    }
  });
}

function sdmShowBackupManager() {
  SpreadsheetApp.getUi().showModalDialog(sdmMergerDialog_('Backups',sdmListMergerBackups).setWidth(760).setHeight(650), 'Manage Backups · 1.5.0');
}
/** Recognize hidden backups made by released versions, without reading student cells. */
function sdmBackupInfo_(sheet) {
  if(!sheet.isSheetHidden()) return null;
  var name=sheet.getName();
  var match=/^(.+) Backup (\d{4}-\d{2}-\d{2}) (\d{2})(\d{2})(\d{2})(?: (\d+))?$/.exec(name);
  if(!match) return null;
  return {id:sheet.getSheetId(),name:name,date:match[2]+' '+match[3]+':'+match[4]+':'+match[5],order:match[2]+match[3]+match[4]+match[5],sequence:Number(match[6]||1)};
}
function sdmListMergerBackups() {
  return SpreadsheetApp.getActive().getSheets().map(sdmBackupInfo_).filter(function(b){return b!==null;}).sort(function(a,b){
    return a.order.localeCompare(b.order)||a.sequence-b.sequence||a.name.localeCompare(b.name);
  });
}
function sdmDeleteMergerBackups(selected) {
  if(!Array.isArray(selected)||!selected.length) throw new Error('Select at least one backup.');
  var lock=LockService.getDocumentLock();lock.waitLock(30000);
  try {
    var ss=SpreadsheetApp.getActive(),seen=new Set();
    // Validate every selection before starting. Never trust client-supplied tab IDs alone.
    var targets=selected.map(function(item){
      if(!item || !Number.isInteger(item.id) || seen.has(item.id)) throw new Error('Invalid or duplicate backup selection. Refresh the list.');
      seen.add(item.id);
      var sheet=ss.getSheetById(item.id), info=sheet ? sdmBackupInfo_(sheet) : null;
      if(!info || info.name!==item.name) throw new Error('A selected backup changed or is no longer hidden. Refresh the list before deleting.');
      return {sheet:sheet,info:info};
    });
    var deleted=[],failures=[];
    targets.forEach(function(target){
      try {
        var current=sdmBackupInfo_(target.sheet);
        if(!current || current.name!==target.info.name) throw new Error('Backup changed; kept for safety.');
        ss.deleteSheet(target.sheet);deleted.push(target.info.name);
      } catch(e) {failures.push({name:target.info.name,message:e.message||String(e)});}
    });
    return {deleted:deleted,failures:failures};
  } finally {lock.releaseLock();}
}

/** Include fresh startup data in the menu request, avoiding a second RPC. */
function sdmMergerDialog_(file,loader) {
  var template=HtmlService.createTemplate(sdmScreenHtml_(file)), initial;
  try {initial={items:loader()};}
  catch(e) {initial={error:e.message||String(e)};}
  template.initialJson=JSON.stringify(initial).replace(/</g,'\\u003c').replace(/\u2028/g,'\\u2028').replace(/\u2029/g,'\\u2029');
  return template.evaluate();
}

function sdmScreenHtml_(file) {
  var screens={"Merger": "<!DOCTYPE html>\n<html><head><base target=\"_top\"><style>\nbody{font:15px Arial,sans-serif;color:#203631;margin:24px}h2{margin-bottom:8px}label{display:block;margin:14px 0 6px}select,button{padding:9px;font:inherit}button{cursor:pointer;margin:16px 8px 0 0}button.primary{background:#176c59;color:white;border:0;border-radius:5px}input{margin-right:8px}.grid{display:grid;grid-template-columns:1fr 1fr;gap:24px}.box{background:#f2f7f5;padding:16px;border-radius:8px;margin:16px 0}#status{white-space:pre-wrap;margin:15px 0}table{border-collapse:collapse;width:100%;font-size:14px}td,th{padding:8px;border-bottom:1px solid #ddd;text-align:left;overflow-wrap:anywhere} .scroll{max-height:260px;overflow:auto} .error{color:#a12626}small{color:#52645e} [hidden]{display:none!important}\n.complete{max-width:760px;margin:24px auto}.complete h2{font-size:28px;margin:12px 0}.successMark{display:inline-flex;align-items:center;justify-content:center;width:46px;height:46px;background:#e2f2e9;color:#176c59;border-radius:50%;font-size:28px}.complete>p{color:#52645e;line-height:1.5}.resultDetails{margin:24px 0;border:1px solid #dce6e2;border-radius:12px;padding:6px 20px}.resultRow{padding:15px 0;border-bottom:1px solid #e5ece9}.resultRow:last-child{border-bottom:0}.resultRow dt{font-size:13px;color:#52645e;margin-bottom:6px}.resultRow dd{margin:0;font-size:16px;overflow-wrap:anywhere;line-height:1.5}.warning{background:#fff5dd;border:1px solid #e8ce8b;padding:16px;border-radius:8px;line-height:1.5;white-space:pre-wrap}.complete button{padding:12px 20px}\n</style></head><body>\n<div id=\"intro\"><h2>Merge student data</h2><p>Use student IDs to combine two tabs. Row 1 must contain unique column headers. The merged result takes your roster\u2019s name. The original roster becomes a hidden, dated backup. You can choose whether to keep the incoming tab.</p></div>\n<div id=\"setup\"><div class=\"grid\"><div><label for=\"main\">Main roster tab</label><select id=\"main\" disabled><option>Loading tabs\u2026</option></select><label for=\"mk\">Roster Student ID column</label><select id=\"mk\" disabled><option>Loading tabs\u2026</option></select></div><div><label for=\"incoming\">Incoming data tab</label><select id=\"incoming\" disabled><option>Loading tabs\u2026</option></select><label for=\"ik\">Incoming Student ID column</label><select id=\"ik\" disabled><option>Loading tabs\u2026</option></select></div></div>\n<label>Incoming columns to include</label><small>Identical header names update the existing roster column. Other headers create new columns. Rename headers in your source tab if needed.</small><div><button type=\"button\" id=\"selectAll\" disabled>Select all</button><button type=\"button\" id=\"deselectAll\" disabled>Deselect all</button></div><div id=\"columns\" class=\"box\"></div>\n<button class=\"primary\" id=\"preview\" disabled>Preview merge</button></div>\n<div id=\"review\" hidden><div id=\"summary\" class=\"box\"></div>\n<div id=\"newSection\" hidden><label for=\"newMode\">Students found only in incoming data</label><select id=\"newMode\"><option value=\"\">Choose an action\u2026</option><option value=\"add\">Add all to merged roster</option><option value=\"exclude\">Leave all out; put them in Unmatched Students</option><option value=\"review\">Choose students individually</option></select><div id=\"newList\" class=\"scroll\" hidden></div></div>\n<div id=\"conflictSection\" hidden><label for=\"conflictMode\">Different nonblank values for the same student and column</label><select id=\"conflictMode\"><option value=\"\">Choose an action\u2026</option><option value=\"keep\">Keep all original values</option><option value=\"incoming\">Use all incoming values</option><option value=\"review\">Review each difference</option></select><div id=\"conflictList\" class=\"scroll\" hidden></div></div>\n<p><small>Blank incoming values never erase existing values. The master\u2019s formatting and unchanged cells are preserved. Incoming values are added as text. Students only in the main roster remain in the result.</small></p>\n<label id=\"cleanupLabel\" for=\"deleteIncoming\"></label><select id=\"deleteIncoming\"><option value=\"keep\">Keep the incoming tab (default)</option><option value=\"delete\">Delete the incoming tab after a successful merge</option></select><p><small>Deletion removes the entire selected incoming tab, including columns you did not merge. The original roster is kept as a hidden backup.</small></p>\n<button id=\"back\">Back to setup</button><button class=\"primary\" id=\"merge\">Merge and back up roster</button></div>\n<section id=\"complete\" class=\"complete\" hidden aria-labelledby=\"completeTitle\" tabindex=\"-1\"><span class=\"successMark\" aria-hidden=\"true\">\u2713</span><h2 id=\"completeTitle\">Merge complete</h2><p>Your updated roster is ready.</p><dl id=\"resultDetails\" class=\"resultDetails\"></dl><div id=\"completionWarning\" class=\"warning\" hidden role=\"alert\"></div><button type=\"button\" id=\"done\" class=\"primary\">Done \u2014 return to spreadsheet</button><p><small>To view a backup later, choose View \u2192 Hidden sheets.</small></p></section>\n<div id=\"status\" role=\"status\" aria-live=\"polite\">Loading tabs\u2026</div>\n<script id=\"initialData\" type=\"application/json\"><?!= initialJson ?></script>\n<script>\nconst $=id=>document.getElementById(id);let sheets=[],config,plan,busy=false;\nfunction el(tag,text){const n=document.createElement(tag);if(text!==undefined)n.textContent=text;return n;}\nfunction option(select,value,label){const o=el('option',label);o.value=value;select.append(o);}\nfunction status(text,error=false){$('status').textContent=text;$('status').className=error?'error':'';}\nfunction working(value){busy=value;document.querySelectorAll('button').forEach(b=>b.disabled=value);}\nfunction failed(e){working(false);status(e.message||String(e),true);}\nfunction populate(side,key){const s=sheets.find(s=>String(s.id)===$(side).value);$(key).replaceChildren();s.headers.forEach((h,i)=>option($(key),i,(i+1)+': '+(h||'(blank header)')));const candidate=s.headers.findIndex(h=>/student.*(id|number)|^id$/i.test(h));if(candidate>=0)$(key).value=candidate;if(side==='incoming')columns();}\nfunction columns(){const s=sheets.find(s=>String(s.id)===$('incoming').value);$('columns').replaceChildren();s.headers.forEach((h,i)=>{if(i===Number($('ik').value))return;const l=el('label');const c=el('input');c.type='checkbox';c.value=i;c.checked=true;l.append(c,document.createTextNode(h||'(blank header)'));$('columns').append(l);});}\n$('selectAll').onclick=()=>{$('columns').querySelectorAll('input[type=checkbox]').forEach(c=>c.checked=true);};\n$('deselectAll').onclick=()=>{$('columns').querySelectorAll('input[type=checkbox]').forEach(c=>c.checked=false);};\n$('main').onchange=()=>populate('main','mk');$('incoming').onchange=()=>populate('incoming','ik');$('ik').onchange=columns;\n$('newMode').onchange=()=>{$('newList').hidden=$('newMode').value!=='review';};$('conflictMode').onchange=()=>{$('conflictList').hidden=$('conflictMode').value!=='review';};\n$('back').onclick=()=>{$('review').hidden=true;$('setup').hidden=false;status('');};\n$('preview').onclick=()=>{if(busy)return;config={mainSheet:Number($('main').value),incomingSheet:Number($('incoming').value),mainKey:Number($('mk').value),incomingKey:Number($('ik').value),columns:[...$('columns').querySelectorAll('input:checked')].map(n=>Number(n.value))};working(true);status('Checking student IDs and comparing values\u2026');google.script.run.withFailureHandler(failed).withSuccessHandler(p=>{working(false);plan=p;$('deleteIncoming').value='keep';$('cleanupLabel').textContent='After merging, what should happen to \u201c'+sheets.find(s=>s.id===config.incomingSheet).name+'\u201d?';$('setup').hidden=true;$('review').hidden=false;const summary=[`${p.mainCount} roster students`,`${p.matched} matched`];\nif(p.newcomers.length)summary.push(`${p.newcomers.length} incoming-only student(s)`);\nif(p.missing.length)summary.push(`${p.missing.length} roster student(s) without incoming data (kept in result)`);\nif(p.conflicts.length)summary.push(`${p.conflicts.length} conflicting value(s)`);\nif(!p.newcomers.length&&!p.missing.length&&!p.conflicts.length)summary.push('All students matched; no discrepancies to review');\n$('summary').textContent=summary.join(' \u00b7 ')+'.';\n$('newSection').hidden=p.newcomers.length===0;\n$('conflictSection').hidden=p.conflicts.length===0;\n$('newMode').value=p.newcomers.length?'':'exclude';$('conflictMode').value=p.conflicts.length?'':'keep';$('newList').replaceChildren();$('conflictList').replaceChildren();$('newList').hidden=true;$('conflictList').hidden=true;\nconst table=el('table'),head=el('tr');head.append(el('th','Include'));p.incomingHeaders.forEach(h=>head.append(el('th',h)));table.append(head);p.newcomers.forEach(r=>{const tr=el('tr'),td=el('td'),c=el('input');c.type='checkbox';c.value=r.id;td.append(c);tr.append(td);r.values.forEach(v=>tr.append(el('td',v)));table.append(tr);});$('newList').append(table);\np.conflicts.forEach(c=>{const box=el('div');box.className='box';box.append(el('p',`Student ID ${c.id} \u00b7 ${c.column}`),el('p','Original: '+c.original),el('p','Incoming: '+c.incoming));const s=el('select');s.dataset.key=c.key;s.setAttribute('aria-label','Decision for '+c.id+' '+c.column);option(s,'','Choose\u2026');option(s,'keep','Keep original');option(s,'incoming','Use incoming');box.append(s);$('conflictList').append(box);});status(p.newcomers.length||p.conflicts.length?'Review your choices before creating the result.':'Ready to merge. Choose whether to keep the incoming tab, then merge and back up your roster.');}).sdmPreviewMerge(config);};\n$('merge').onclick=()=>{if(busy)return;const conflicts={};$('conflictList').querySelectorAll('select').forEach(s=>conflicts[s.dataset.key]=s.value);const choices={deleteIncoming:$('deleteIncoming').value==='delete',newMode:$('newMode').value,conflictMode:$('conflictMode').value,includeIds:[...$('newList').querySelectorAll('input:checked')].map(c=>c.value),conflicts};if(!choices.newMode||!choices.conflictMode)return status('Choose an action for new students and conflicting values.',true);if(choices.conflictMode==='review'&&Object.values(conflicts).some(v=>!v))return status('Resolve every conflict before continuing.',true);working(true);status('Creating result tabs\u2026');google.script.run.withFailureHandler(failed).withSuccessHandler(showMergeComplete).sdmExecuteMerge(config,plan.digest,choices);};\nfunction showMergeComplete(r){\n working(false);$('intro').hidden=true;$('setup').hidden=true;$('review').hidden=true;status('');\n $('resultDetails').replaceChildren();\n function detail(label,value){const row=el('div');row.className='resultRow';row.append(el('dt',label),el('dd',value));$('resultDetails').append(row);}\n detail('Updated roster',r.merged);\n detail('Students in roster',String(r.rows));\n detail('Original roster backup',r.backup+' (hidden)');\n detail('Incoming data tab',r.incomingDeleted?'Deleted after the merge':'Kept in your spreadsheet');\n if(r.unmatched)detail('Excluded incoming students',r.unmatched);\n $('completionWarning').hidden=!r.cleanupWarning;$('completionWarning').textContent=r.cleanupWarning||'';\n $('complete').hidden=false;$('complete').focus();\n}\n$('done').onclick=()=>google.script.host.close();\nfunction initializeMerger(s){sheets=s.filter(x=>x.headers.length);if(sheets.length<2){status('Add or unhide two tabs with column headers, then reopen this tool.',true);$('preview').disabled=true;return;}['main','incoming','mk','ik'].forEach(id=>{$(id).replaceChildren();$(id).disabled=false;});sheets.forEach(s=>{option($('main'),s.id,s.name);option($('incoming'),s.id,s.name);});$('incoming').selectedIndex=1;populate('main','mk');populate('incoming','ik');$('preview').disabled=false;$('selectAll').disabled=false;$('deselectAll').disabled=false;status('');}\nconst initial=JSON.parse($('initialData').textContent);\nif(initial.error)status('Could not load tabs. Close and reopen the tool to retry. '+initial.error,true);else initializeMerger(initial.items);\n</script></body></html>\n", "Backups": "<!DOCTYPE html>\n<html><head><base target=\"_top\"><style>\nbody{font:15px Arial,sans-serif;color:#203631;margin:24px}button{font:inherit;padding:9px;margin:8px 8px 8px 0;cursor:pointer}table{border-collapse:collapse;width:100%}td,th{text-align:left;padding:10px;border-bottom:1px solid #ddd;overflow-wrap:anywhere}.scroll{max-height:330px;overflow:auto}#status{white-space:pre-wrap;margin:15px 0}.error{color:#a12626}.danger{background:#a12626;color:white;border:0;border-radius:5px}[hidden]{display:none!important}\n</style></head><body>\n<h2>Manage hidden backups</h2>\n<p>Oldest first. Only hidden tabs named using the merger\u2019s dated backup pattern appear here. Deleting removes the entire backup tab.</p>\n<div id=\"listView\"><button id=\"all\" disabled>Select all</button><button id=\"none\" disabled>Deselect all</button><button id=\"refresh\" disabled>Refresh</button>\n<div class=\"scroll\"><table><thead><tr><th>Select</th><th>Backup tab</th><th>Merge date/time</th></tr></thead><tbody id=\"rows\"></tbody></table></div>\n<p id=\"count\"></p><button id=\"review\" disabled>Review selected backups</button></div>\n<div id=\"confirmation\" hidden><h3>Confirm deletion</h3><p>These backup tabs will be deleted. Your current roster tabs will be kept.</p><div class=\"scroll\"><ul id=\"selectedNames\"></ul></div><button id=\"cancel\">Back to list</button><button class=\"danger\" id=\"delete\">Delete selected backups</button></div>\n<div id=\"status\" role=\"status\" aria-live=\"polite\">Loading backups\u2026</div>\n<script id=\"initialData\" type=\"application/json\"><?!= initialJson ?></script>\n<script>\nconst $=id=>document.getElementById(id);let backups=[],selected=[],busy=false;\nfunction message(text,error=false){$('status').textContent=text;$('status').className=error?'error':'';}\nfunction checked(){return [...$('rows').querySelectorAll('input:checked')].map(c=>backups[Number(c.value)]);}\nfunction count(){const n=checked().length;$('count').textContent=n+' of '+backups.length+' backups selected.';$('review').disabled=busy||n===0;}\nfunction working(value){busy=value;document.querySelectorAll('button,input').forEach(n=>n.disabled=value);if(!value){$('all').disabled=!backups.length;$('none').disabled=!backups.length;count();}}\nfunction renderBackups(items,report){backups=items;$('rows').replaceChildren();items.forEach((b,i)=>{const row=document.createElement('tr'),cell=document.createElement('td'),checkbox=document.createElement('input');checkbox.type='checkbox';checkbox.value=i;checkbox.setAttribute('aria-label','Select '+b.name);checkbox.onchange=count;cell.append(checkbox);row.append(cell);[b.name,b.date].forEach(text=>{const td=document.createElement('td');td.textContent=text;row.append(td);});$('rows').append(row);});working(false);message(report||(!items.length?'No hidden merger backups found.':'Choose backups to delete. Dates use the spreadsheet\u2019s timezone.'));}\nfunction load(report){working(true);message('Loading backups\u2026');google.script.run.withFailureHandler(e=>{working(false);$('review').disabled=true;message('Could not load backups. Use Refresh to retry. '+(e.message||String(e)),true);}).withSuccessHandler(items=>renderBackups(items,report)).sdmListMergerBackups();}\n$('all').onclick=()=>{$('rows').querySelectorAll('input').forEach(c=>c.checked=true);count();};\n$('none').onclick=()=>{$('rows').querySelectorAll('input').forEach(c=>c.checked=false);count();};\n$('refresh').onclick=()=>load();\n$('review').onclick=()=>{selected=checked().map(b=>({id:b.id,name:b.name}));if(!selected.length)return;$('selectedNames').replaceChildren();selected.forEach(b=>{const li=document.createElement('li');li.textContent=b.name;$('selectedNames').append(li);});$('listView').hidden=true;$('confirmation').hidden=false;message('Check the names before confirming deletion.');};\n$('cancel').onclick=()=>{$('confirmation').hidden=true;$('listView').hidden=false;message('');};\n$('delete').onclick=()=>{if(busy)return;working(true);message('Deleting selected backups\u2026');google.script.run.withFailureHandler(e=>{working(false);$('confirmation').hidden=true;$('listView').hidden=false;$('review').disabled=true;message((e.message||String(e))+' Use Refresh before trying again.',true);}).withSuccessHandler(r=>{$('confirmation').hidden=true;$('listView').hidden=false;const report=r.deleted.length+' backup(s) deleted.'+(r.failures.length?' Kept: '+r.failures.map(f=>f.name+' \u2014 '+f.message).join('; '):'');load(report);}).sdmDeleteMergerBackups(selected);};\nconst initial=JSON.parse($('initialData').textContent);\nif(initial.error){working(false);message('Could not load backups. Use Refresh to retry. '+initial.error,true);}else renderBackups(initial.items);\n</script></body></html>\n"};
  if(!Object.prototype.hasOwnProperty.call(screens,file)) throw new Error("Unknown merger screen.");
  return screens[file];
}