(() => {
  const container = document.getElementById('chord-container');
  const rootFilters = document.getElementById('root-filters');
  const qualityFilters = document.getElementById('quality-filters');

  const roots = ['C','C#','D','D#','E','F','F#','G','G#','A','A#','B'];
  let activeRoots = new Set();
  let activeQualities = new Set();
  let allChords = [];
  let maxFret = 4;
  let numStrings = 6;

  function initFilters() {
    roots.forEach(r => {
      const pill = document.createElement('button');
      pill.className = 'filter-pill';
      pill.textContent = r;
      pill.addEventListener('click', () => {
        if (activeRoots.has(r)) {
          activeRoots.delete(r);
          pill.classList.remove('active');
        } else {
          activeRoots.add(r);
          pill.classList.add('active');
        }
        applyFilters();
      });
      rootFilters.appendChild(pill);
    });

    if (window.go && window.go.main && window.go.main.App) {
      window.go.main.App.GetChordDefinitions().then(defs => {
        const qualities = new Set();
        for (const cat of Object.keys(defs)) {
          for (const q of Object.keys(defs[cat])) {
            qualities.add(q);
          }
        }
        Array.from(qualities).sort().forEach(q => {
          const pill = document.createElement('button');
          pill.className = 'filter-pill';
          pill.textContent = q;
          pill.addEventListener('click', () => {
            if (activeQualities.has(q)) {
              activeQualities.delete(q);
              pill.classList.remove('active');
            } else {
              activeQualities.add(q);
              pill.classList.add('active');
            }
            applyFilters();
          });
          qualityFilters.appendChild(pill);
        });
      });
    }
  }

  function applyFilters() {
    const cards = container.querySelectorAll('.chord-card');
    cards.forEach((card, i) => {
      const chord = allChords[i];
      if (!chord) return;

      let show = true;
      if (activeRoots.size > 0 && !activeRoots.has(chord.root)) {
        show = false;
      }
      if (activeQualities.size > 0 && !activeQualities.has(chord.quality)) {
        show = false;
      }
      card.style.display = show ? '' : 'none';
    });
  }

  function buildChordCards(chords, mf, ns) {
    allChords = chords;
    maxFret = mf || maxFret;
    numStrings = ns || numStrings;
    container.innerHTML = '';

    chords.forEach(match => {
      const card = document.createElement('div');
      card.className = 'chord-card';

      const h2 = document.createElement('h2');
      h2.textContent = match.chord;
      card.appendChild(h2);

      const fb = document.createElement('div');
      fb.className = 'fretboard';
      fb.dataset.fingering = JSON.stringify(match.fingering);
      card.appendChild(fb);

      if (match.alternatives && match.alternatives.length > 0) {
        const altSection = document.createElement('div');
        altSection.className = 'alternatives';
        const h3 = document.createElement('h3');
        h3.textContent = 'Alternatives:';
        altSection.appendChild(h3);

        const altContainer = document.createElement('div');
        altContainer.className = 'alternatives-container';
        match.alternatives.forEach(alt => {
          const altFb = document.createElement('div');
          altFb.className = 'fretboard alternative-fretboard';
          altFb.dataset.fingering = JSON.stringify(alt);
          altContainer.appendChild(altFb);
        });
        altSection.appendChild(altContainer);
        card.appendChild(altSection);
      }

      container.appendChild(card);
    });

    renderFretboards();
    applyFilters();
  }

  function renderFretboards() {
    const fretboards = document.querySelectorAll('.fretboard');
    fretboards.forEach(fb => {
      const fingering = JSON.parse(fb.dataset.fingering);
      const wrapper = document.createElement('div');
      wrapper.className = 'fretboard';

      fb.innerHTML = '';
      fb.style.display = 'inline-block';
      fb.style.marginBottom = '1rem';

      const fretCounts = {};
      fingering.forEach(f => {
        if (!isNaN(f)) fretCounts[f] = (fretCounts[f] || 0) + 1;
      });

      const entries = Object.entries(fretCounts)
        .filter(([, count]) => count >= 2)
        .map(([f]) => parseInt(f));

      let barreFretNum = null;
      for (const f of entries.sort((a, b) => a - b)) {
        if (fingering.every(x => x === 'x' || isNaN(x) || parseInt(x) >= f)) {
          barreFretNum = f;
          break;
        }
      }

      const fretMatrix = [];
      for (let s = 0; s < numStrings; s++) {
        const stringRow = [];
        for (let f = 1; f <= maxFret; f++) {
          const fret = document.createElement('div');
          fret.className = 'fret';
          fret.dataset.row = s;
          fret.dataset.col = f;

          const fretValue = fingering[s];
          const numericFret = parseInt(fretValue, 10);
          if (fretValue === 'x' && f === 1) {
            fret.setAttribute('muted', '');
            fret.textContent = 'x';
          } else if (fretValue !== 'x' && numericFret === f) {
            fret.dataset.dot = 'true';
            if (barreFretNum !== null && numericFret === barreFretNum) {
              fret.classList.add('barre');
            }
          }
          stringRow.push(fret);
        }
        fretMatrix.push(stringRow);
      }

      const barreCols = [];
      if (barreFretNum !== null) {
        for (let s = 0; s < numStrings; s++) {
          if (parseInt(fingering[s]) === barreFretNum) barreCols.push(s);
        }
      }

      for (let s = numStrings - 1; s >= 0; s--) {
        const stringRow = document.createElement('div');
        stringRow.className = 'fret-row';
        for (let f = 1; f <= maxFret; f++) {
          stringRow.appendChild(fretMatrix[s][f - 1]);
        }
        wrapper.appendChild(stringRow);
      }

      fb.appendChild(wrapper);

      if (barreFretNum !== null && barreCols.length >= 2) {
        const start = Math.min(...barreCols);
        const end = Math.max(...barreCols);
        const line = document.createElement('div');
        line.className = 'barre-line';

        requestAnimationFrame(() => {
          let totalDotCenter = 0;
          let dotCount = 0;

          for (let s = start; s <= end; s++) {
            const dotFret = fretMatrix[s][barreFretNum - 1];
            if (dotFret) {
              const rect = dotFret.getBoundingClientRect();
              totalDotCenter += (rect.left + rect.right) / 2;
              dotCount++;
            }
          }
          const avgDotCenter = totalDotCenter / dotCount;
          const parentRect = wrapper.getBoundingClientRect();
          const dotCenter = avgDotCenter - parentRect.left;

          const firstDot = fretMatrix[start][barreFretNum - 1];
          const lastDot = fretMatrix[end][barreFretNum - 1];
          const rect1 = firstDot.getBoundingClientRect();
          const rect2 = lastDot.getBoundingClientRect();

          const top = Math.min(rect1.top, rect2.top) - parentRect.top;
          const bottom = Math.max(rect1.bottom, rect2.bottom) - parentRect.top;
          const height = bottom - top;

          line.style.top = Math.round(top) + 'px';
          line.style.height = Math.round(height) + 'px';
          line.style.left = Math.round(dotCenter) + 'px';
          line.textContent = '|';

          wrapper.appendChild(line);
        });
      }
    });
  }

  container.addEventListener('click', (e) => {
    const fb = e.target.closest('[data-fingering]');
    if (!fb || !window.playChord || !window.currentTuningMIDI) return;
    const fing = JSON.parse(fb.dataset.fingering);
    const midi = [];
    fing.forEach((f, i) => {
      if (f === 'x') return;
      midi.push(window.currentTuningMIDI[i] + parseInt(f));
    });
    if (midi.length) window.playChord(midi);
  });

  window.buildChordCards = buildChordCards;
  initFilters();
})();