/** RX quality vs distance chart for TX/RX track compare. */
(function (global) {
  'use strict';

  function drawQualityDistChart(canvas, samples, qualityColor, highlightDist) {
    if (!canvas) return;
    const ctx = canvas.getContext('2d');
    const w = canvas.clientWidth || 280;
    const h = canvas.clientHeight || 140;
    if (canvas.width !== w) canvas.width = w;
    if (canvas.height !== h) canvas.height = h;
    ctx.fillStyle = '#0a0a14';
    ctx.fillRect(0, 0, w, h);

    if (!samples?.length) {
      ctx.fillStyle = '#888';
      ctx.font = '11px system-ui';
      ctx.fillText('нет данных качества', 12, h / 2);
      return;
    }

    const dists = samples.map(s => s.distM);
    const minD = Math.min(...dists);
    const maxD = Math.max(...dists);
    const span = Math.max(maxD - minD, 1);
    const binCount = Math.min(20, Math.max(5, Math.ceil(span / 10)));
    const binW = span / binCount;
    const bins = Array.from({ length: binCount }, (_, i) => ({
      min: minD + i * binW,
      max: minD + (i + 1) * binW,
      qualities: [],
    }));
    for (const s of samples) {
      let idx = Math.floor((s.distM - minD) / binW);
      if (idx >= binCount) idx = binCount - 1;
      if (idx < 0) idx = 0;
      bins[idx].qualities.push(s.quality);
    }

    const margin = { l: 36, r: 8, t: 16, b: 22 };
    const plotW = w - margin.l - margin.r;
    const plotH = h - margin.t - margin.b;

    ctx.strokeStyle = '#333';
    ctx.beginPath();
    ctx.moveTo(margin.l, margin.t);
    ctx.lineTo(margin.l, margin.t + plotH);
    ctx.lineTo(margin.l + plotW, margin.t + plotH);
    ctx.stroke();

    ctx.fillStyle = '#888';
    ctx.font = '9px system-ui';
    ctx.fillText('0%', 2, margin.t + plotH);
    ctx.fillText('100%', 2, margin.t + 8);
    ctx.fillText(`${Math.round(minD)}m`, margin.l, h - 2);
    ctx.fillText(`${Math.round(maxD)}m`, margin.l + plotW - 24, h - 2);
    ctx.fillStyle = '#ccc';
    ctx.font = '10px system-ui';
    ctx.fillText('RX Quality vs расстояние', margin.l, margin.t - 4);

    const barW = plotW / binCount * 0.75;
    bins.forEach((b, i) => {
      if (!b.qualities.length) return;
      const avg = b.qualities.reduce((a, v) => a + v, 0) / b.qualities.length;
      const cx = margin.l + (i + 0.5) / binCount * plotW;
      const barH = (avg / 100) * plotH;
      const x = cx - barW / 2;
      const y = margin.t + plotH - barH;
      const col = qualityColor ? qualityColor(avg) : '#888';
      const highlight = highlightDist != null
        && highlightDist >= b.min && highlightDist < b.max;
      ctx.fillStyle = col;
      ctx.globalAlpha = highlight ? 1 : 0.75;
      ctx.fillRect(x, y, barW, barH);
      ctx.globalAlpha = 1;
      if (highlight) {
        ctx.strokeStyle = '#fff';
        ctx.lineWidth = 1.5;
        ctx.strokeRect(x, y, barW, barH);
      }
    });

    ctx.fillStyle = 'rgba(255,255,255,0.25)';
    samples.forEach(s => {
      const x = margin.l + ((s.distM - minD) / span) * plotW;
      const y = margin.t + plotH - (s.quality / 100) * plotH;
      ctx.beginPath();
      ctx.arc(x, y, 1.5, 0, Math.PI * 2);
      ctx.fill();
    });
  }

  global.QualityViz = {
    drawQualityDistChart,
  };
})(typeof window !== 'undefined' ? window : globalThis);