// Lightweight multi-page handler for GD fedl
(function(){
  function qs(id){return document.getElementById(id)}

  const page = document.body.dataset.page;
  let cachedItems = null;
  let cachedLevelMeta = null;

  function read(key, fallback){
    try{const v = localStorage.getItem(key); return v?JSON.parse(v):fallback}
    catch(e){return fallback}
  }

  function write(key, val){localStorage.setItem(key,JSON.stringify(val))}

  function parseData(txt){
    return txt.split(/\r?\n/).map(l=>l.trim()).filter(Boolean).map((l, index)=>{
      const parts = l.split('|').map(p=>p.trim());
      return {
        id:`legacy-${index + 1}`,
        level:parts[0]||'Unknown',
        position:parts[1]||'',
        title:parts[2]||'Untitled',
        url:parts[3]||''
      };
    });
  }

  function parseLevelMeta(txt){
    const map = {};
    txt.split(/\r?\n/).map(l=>l.trim()).filter(Boolean).forEach(l=>{
      if(l.startsWith('//')) return;
      const parts = l.split('|').map(p=>p.trim());
      const title = parts[0] || '';
      if(!title) return;
      map[title] = {
        levelId: parts[1] || 'unknown',
        percent: parts[2] || '100'
      };
    });
    return map;
  }

  function invalidateItems(){cachedItems = null}

  function loadItems(){
    if(cachedItems) return Promise.resolve(cachedItems);
    return fetch('/api/levels', {cache:'no-store'}).then(r=>{
      if(!r.ok) throw new Error('API unavailable');
      return r.json();
    }).then(data=>{
      cachedItems = Array.isArray(data.items) ? data.items : [];
      return cachedItems;
    }).catch(()=>{
      return fetch('data.txt').then(r=>r.text()).then(txt=>{
        cachedItems = parseData(txt);
        return cachedItems;
      });
    });
  }

  function requestJson(url, options){
    return fetch(url, Object.assign({
      cache:'no-store',
      headers:{'Content-Type':'application/json'}
    }, options || {})).then(async r=>{
      const data = await r.json().catch(()=>({}));
      if(!r.ok) throw new Error(data.error || 'Request failed.');
      return data;
    });
  }

  function loadLevelMeta(){
    if(cachedLevelMeta) return Promise.resolve(cachedLevelMeta);
    return fetch('level-ids.txt').then(r=>r.text()).then(txt=>{
      cachedLevelMeta = parseLevelMeta(txt);
      return cachedLevelMeta;
    }).catch(()=>{
      cachedLevelMeta = {};
      return cachedLevelMeta;
    });
  }

  function fetchLevelIdFromApi(title){
    const url = `https://gdbrowser.com/api/search/${encodeURIComponent(title)}?diff=-2&demonFilter=5&count=10`;
    return fetch(url).then(r=>r.json()).then(results=>{
      if(!Array.isArray(results) || !results.length) return null;
      const exact = results.find(item=>String(item.name||'').toLowerCase() === String(title||'').toLowerCase());
      const match = exact || results[0];
      if(!match || !match.id) return null;
      return String(match.id);
    }).catch(()=>null);
  }

  function extractYouTubeID(url){
    const m = String(url || '').match(/(?:v=|\/embed\/|youtu\.be\/)([A-Za-z0-9_-]{6,})/);
    return m ? m[1] : '';
  }

  function openVideo(url){
    if(!url) return;
    const id = extractYouTubeID(url);
    if(!id){
      window.open(url,'_blank');
      return;
    }
    let modal = document.querySelector('.video-modal');
    if(!modal){
      modal = document.createElement('div');
      modal.className = 'video-modal';
      const inner = document.createElement('div');
      inner.className = 'inner';
      const close = document.createElement('button');
      close.textContent = 'Close';
      close.className = 'btn';
      close.style.float = 'right';
      close.onclick = ()=>modal.remove();
      inner.appendChild(close);
      const iframe = document.createElement('iframe');
      iframe.allow = 'accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture';
      iframe.allowFullscreen = true;
      inner.appendChild(iframe);
      modal.appendChild(inner);
      document.body.appendChild(modal);
    }
    modal.querySelector('iframe').src = `https://www.youtube.com/embed/${id}`;
    modal.style.display = 'flex';
  }

  if(page==='roulette'){
    const spinBtn = qs('roulette-spin');
    const statusEl = qs('roulette-status');
    const titleEl = qs('roulette-title');
    const rankEl = qs('roulette-rank');
    const idEl = qs('roulette-level-id');
    const noteEl = qs('roulette-note');
    const openEl = qs('roulette-open');

    function showPick(item, meta){
      statusEl.textContent = 'Your demon is:';
      titleEl.textContent = item.title;
      rankEl.textContent = `Rank: #${item.position}`;
      idEl.textContent = `Level ID: ${meta.levelId || 'unknown'}`;
      noteEl.textContent = meta.source === 'api'
        ? 'Level ID was looked up from the Geometry Dash community API.'
        : 'Level ID came from your local level-ids.txt file.';
      if(item.url){
        openEl.hidden = false;
        openEl.href = item.url;
      }else{
        openEl.hidden = true;
      }
    }

    spinBtn.addEventListener('click', ()=>{
      statusEl.textContent = 'Spinning...';
      titleEl.textContent = 'Choosing a demon';
      rankEl.textContent = 'Rank: -';
      idEl.textContent = 'Level ID: -';
      noteEl.textContent = 'Checking your local file and API if needed.';
      openEl.hidden = true;
      Promise.all([loadItems(), loadLevelMeta()]).then(([items, metaMap])=>{
        if(!items.length){
          statusEl.textContent = 'No demons found.';
          titleEl.textContent = 'Add demons from the manage page';
          idEl.textContent = 'Level ID: -';
          noteEl.textContent = 'No list data was found.';
          return;
        }
        const item = items[Math.floor(Math.random()*items.length)];
        const localMeta = metaMap[item.title] || {levelId:'unknown', percent:'100'};
        if(localMeta.levelId && localMeta.levelId !== 'unknown'){
          window.setTimeout(()=>showPick(item, {levelId: localMeta.levelId, percent: localMeta.percent, source: 'file'}), 350);
          return;
        }
        fetchLevelIdFromApi(item.title).then(levelId=>{
          const meta = {
            levelId: levelId || 'unknown',
            percent: localMeta.percent || '100',
            source: levelId ? 'api' : 'file'
          };
          window.setTimeout(()=>showPick(item, meta), 350);
        });
      }).catch(err=>{
        statusEl.textContent = 'Could not load the list.';
        titleEl.textContent = 'Run the Node server';
        rankEl.textContent = 'Rank: -';
        idEl.textContent = 'Level ID: -';
        noteEl.textContent = 'The local file or API lookup failed.';
        console.error(err);
      });
    });
  }

  if(page==='players'){
    const form = qs('player-form');
    const nameIn = qs('player-name');
    const list = qs('players');
    let players = read('gd_players',[]);

    function render(){
      list.innerHTML='';
      players.forEach((p,idx)=>{
        const li=document.createElement('li');
        li.innerHTML=`<span><span class="name">${escapeHtml(p.name)}</span> <span class="muted">(${p.id})</span></span>`;
        const actions=document.createElement('div');
        actions.className='actions';
        const edit=document.createElement('button');
        edit.textContent='Edit';
        edit.onclick=()=>{const nv=prompt('Edit name',p.name); if(nv){players[idx].name=nv; write('gd_players',players); render()}};
        const del=document.createElement('button');
        del.textContent='Delete';
        del.onclick=()=>{if(confirm('Delete player?')){players.splice(idx,1); write('gd_players',players); render()}};
        actions.appendChild(edit);
        actions.appendChild(del);
        li.appendChild(actions);
        list.appendChild(li);
      });
    }

    form.addEventListener('submit',e=>{
      e.preventDefault();
      const name=nameIn.value.trim();
      if(!name) return;
      players.push({id:Date.now().toString(36),name});
      write('gd_players',players);
      nameIn.value='';
      render();
    });

    render();
  }

  if(page==='lists'){
    const levelsEl = qs('levels');
    const listArea = qs('list-area');

    function loadData(){
      loadItems().then(items=>{
        setupLevels(items);
      }).catch(err=>{
        listArea.innerHTML='<tr><td colspan="3" class="muted">Failed to load list data. Start the Node server and try again.</td></tr>';
        console.error(err);
      });
    }

    function computeCategories(items){
      const max = items.reduce((m,it)=>Math.max(m, Number(it.position)||0), 0);
      const cats = ['Full List'];
      for(let i=1;i<=max;i+=10){
        const start = i;
        const end = Math.min(i+9, max);
        cats.push(`Top ${start}-${end}`);
      }
      return cats;
    }

    function setupLevels(items){
      const categories = computeCategories(items);
      levelsEl.innerHTML='';
      const filterSelect = qs('level-filter');
      filterSelect.innerHTML = '<option value="all">Full List</option>';
      categories.forEach(cat=>{
        const li = document.createElement('li');
        const btn = document.createElement('button');
        btn.type = 'button';
        btn.textContent = cat;
        btn.className = 'level-link';
        btn.addEventListener('click', ()=> {
          selectLevel(cat, items, btn);
          filterSelect.value = cat;
        });
        li.appendChild(btn);
        levelsEl.appendChild(li);

        const opt = document.createElement('option');
        opt.value = cat;
        opt.textContent = cat;
        filterSelect.appendChild(opt);
      });
      qs('search').addEventListener('input', ()=> renderTable(items));
      filterSelect.addEventListener('change', ()=> renderTable(items));
      selectLevel('Full List', items, levelsEl.querySelector('.level-link'));
    }

    function selectLevel(level, items, linkEl){
      levelsEl.querySelectorAll('.level-link').forEach(a=>a.classList.remove('active'));
      if(linkEl) linkEl.classList.add('active');
      qs('level-filter').value = level;
      renderTable(items);
    }

    function renderTable(items){
      const q = (qs('search') && qs('search').value || '').toLowerCase();
      const levelFilter = (qs('level-filter') && qs('level-filter').value) || 'all';
      const filtered = items.filter(it=>{
        if(levelFilter && levelFilter!=='all' && levelFilter!=='Full List'){
          const m = levelFilter.match(/Top\s*(\d+)-(\d+)/i);
          if(m){
            const s = Number(m[1]);
            const e = Number(m[2]);
            const pos = Number(it.position)||0;
            if(pos < s || pos > e) return false;
          }
        }
        if(!q) return true;
        return (it.title||'').toLowerCase().includes(q) || (it.level||'').toLowerCase().includes(q);
      }).sort((a,b)=> (Number(a.position)||0)-(Number(b.position)||0));

      const tbody = qs('list-area');
      tbody.innerHTML='';
      filtered.forEach(it=>{
        const tr = document.createElement('tr');
        const tdNum = document.createElement('td');
        tdNum.textContent = it.position;
        const tdTitle = document.createElement('td');
        tdTitle.textContent = it.title;
        const tdAct = document.createElement('td');
        const a = document.createElement('a');
        a.textContent='Open';
        a.href='#';
        a.className='btn';
        a.addEventListener('click', (e)=>{e.preventDefault(); openVideo(it.url)});
        tdAct.appendChild(a);
        tr.appendChild(tdNum);
        tr.appendChild(tdTitle);
        tr.appendChild(tdAct);
        tbody.appendChild(tr);
      });
    }

    loadData();
  }

  if(page==='manage'){
    const form = qs('level-form');
    const statusEl = qs('manage-status');
    const listEl = qs('manage-list');
    const searchEl = qs('manage-search');
    const formTitleEl = qs('manage-form-title');
    const submitEl = qs('level-submit');
    const resetEl = qs('level-reset');
    const idEl = qs('level-id');
    const categoryEl = qs('level-category');
    const positionEl = qs('level-position');
    const titleEl = qs('level-title');
    const urlEl = qs('level-url');
    let items = [];

    function setStatus(message, isError){
      statusEl.textContent = message;
      statusEl.style.color = isError ? '#ffb4b4' : '';
    }

    function resetForm(){
      form.reset();
      idEl.value = '';
      categoryEl.value = 'new';
      formTitleEl.textContent = 'Add Entry';
      submitEl.textContent = 'Save Entry';
      setStatus(`Loaded ${items.length} entr${items.length===1?'y':'ies'} from the server.`, false);
    }

    function fillForm(item){
      idEl.value = item.id || '';
      categoryEl.value = item.level || 'new';
      positionEl.value = item.position || '';
      titleEl.value = item.title || '';
      urlEl.value = item.url || '';
      formTitleEl.textContent = `Edit #${item.position}`;
      submitEl.textContent = 'Update Entry';
      window.scrollTo({top:0, behavior:'smooth'});
    }

    function renderItems(){
      const q = (searchEl.value || '').trim().toLowerCase();
      const visible = items.filter(item=>{
        if(!q) return true;
        return String(item.title||'').toLowerCase().includes(q) || String(item.level||'').toLowerCase().includes(q);
      }).sort((a,b)=>Number(a.position)-Number(b.position));

      listEl.innerHTML = '';
      if(!visible.length){
        const tr = document.createElement('tr');
        const td = document.createElement('td');
        td.colSpan = 5;
        td.className = 'muted';
        td.textContent = 'No entries match the current search.';
        tr.appendChild(td);
        listEl.appendChild(tr);
        return;
      }

      visible.forEach(item=>{
        const tr = document.createElement('tr');

        const posTd = document.createElement('td');
        posTd.textContent = item.position;

        const catTd = document.createElement('td');
        catTd.textContent = item.level;

        const titleTd = document.createElement('td');
        titleTd.textContent = item.title;

        const linkTd = document.createElement('td');
        if(item.url){
          const link = document.createElement('a');
          link.href = item.url;
          link.target = '_blank';
          link.rel = 'noopener noreferrer';
          link.className = 'table-link';
          link.textContent = 'Open video';
          linkTd.appendChild(link);
        }else{
          linkTd.textContent = '-';
        }

        const actionsTd = document.createElement('td');
        const actions = document.createElement('div');
        actions.className = 'table-actions';

        const editBtn = document.createElement('button');
        editBtn.type = 'button';
        editBtn.className = 'btn';
        editBtn.textContent = 'Edit';
        editBtn.addEventListener('click', ()=>fillForm(item));

        const deleteBtn = document.createElement('button');
        deleteBtn.type = 'button';
        deleteBtn.className = 'btn ghost-btn';
        deleteBtn.textContent = 'Delete';
        deleteBtn.addEventListener('click', ()=>{
          if(!confirm(`Delete "${item.title}"?`)) return;
          setStatus(`Deleting "${item.title}"...`, false);
          requestJson(`/api/levels/${encodeURIComponent(item.id)}`, {method:'DELETE'})
            .then(data=>{
              items = Array.isArray(data.items) ? data.items : [];
              invalidateItems();
              renderItems();
              resetForm();
            })
            .catch(error=>setStatus(error.message, true));
        });

        actions.appendChild(editBtn);
        actions.appendChild(deleteBtn);
        actionsTd.appendChild(actions);

        tr.appendChild(posTd);
        tr.appendChild(catTd);
        tr.appendChild(titleTd);
        tr.appendChild(linkTd);
        tr.appendChild(actionsTd);
        listEl.appendChild(tr);
      });
    }

    function loadManageItems(){
      setStatus('Loading current entries from the server.', false);
      loadItems().then(data=>{
        items = Array.isArray(data) ? [...data] : [];
        renderItems();
        resetForm();
      }).catch(error=>setStatus(error.message || 'Could not load entries.', true));
    }

    form.addEventListener('submit', e=>{
      e.preventDefault();
      const payload = {
        level: categoryEl.value.trim() || 'new',
        position: positionEl.value.trim(),
        title: titleEl.value.trim(),
        url: urlEl.value.trim()
      };
      const id = idEl.value.trim();
      const isEdit = Boolean(id);
      setStatus(isEdit ? `Updating "${payload.title}"...` : `Creating "${payload.title}"...`, false);
      requestJson(isEdit ? `/api/levels/${encodeURIComponent(id)}` : '/api/levels', {
        method: isEdit ? 'PUT' : 'POST',
        body: JSON.stringify(payload)
      }).then(data=>{
        items = Array.isArray(data.items) ? data.items : items;
        invalidateItems();
        renderItems();
        resetForm();
      }).catch(error=>setStatus(error.message, true));
    });

    resetEl.addEventListener('click', resetForm);
    searchEl.addEventListener('input', renderItems);
    loadManageItems();
  }

  function escapeHtml(s){return String(s).replace(/[&<>"']/g, c=>({"&":"&amp;","<":"&lt;",">":"&gt;","\"":"&quot;","'":"&#39;"})[c])}
})();