/* PCB rendering code */

var emptyContext2d = document.createElement("canvas").getContext("2d");

function deg2rad(deg) {
  return deg * Math.PI / 180;
}

function calcFontPoint(linepoint, text, offsetx, offsety, tilt) {
  var point = [
    linepoint[0] * text.width + offsetx,
    linepoint[1] * text.height + offsety
  ];
  // This approximates pcbnew behavior with how text tilts depending on horizontal justification
  point[0] -= (linepoint[1] + 0.5 * (1 + text.justify[0])) * text.height * tilt;
  return point;
}

function drawText(ctx, text, color) {
  if ("ref" in text && !settings.renderReferences) return;
  if ("val" in text && !settings.renderValues) return;
  ctx.save();
  ctx.fillStyle = color;
  ctx.strokeStyle = color;
  ctx.lineCap = "round";
  ctx.lineJoin = "round";
  ctx.lineWidth = text.thickness;
  if ("svgpath" in text) {
    ctx.stroke(new Path2D(text.svgpath));
    ctx.restore();
    return;
  }
  if ("polygons" in text) {
    ctx.fill(getPolygonsPath(text));
    ctx.restore();
    return;
  }
  ctx.translate(...text.pos);
  ctx.translate(text.thickness * 0.5, 0);
  var angle = -text.angle;
  if (text.attr.includes("mirrored")) {
    ctx.scale(-1, 1);
    angle = -angle;
  }
  var tilt = 0;
  if (text.attr.includes("italic")) {
    tilt = 0.125;
  }
  var interline = text.height * 1.5 + text.thickness;
  var txt = text.text.split("\n");
  // KiCad ignores last empty line.
  if (txt[txt.length - 1] == '') txt.pop();
  ctx.rotate(deg2rad(angle));
  var offsety = (1 - text.justify[1]) / 2 * text.height; // One line offset
  offsety -= (txt.length - 1) * (text.justify[1] + 1) / 2 * interline; // Multiline offset
  for (var i in txt) {
    var lineWidth = text.thickness + interline / 2 * tilt;
    for (var j = 0; j < txt[i].length; j++) {
      if (txt[i][j] == '\t') {
        var fourSpaces = 4 * pcbdata.font_data[' '].w * text.width;
        lineWidth += fourSpaces - lineWidth % fourSpaces;
      } else {
        if (txt[i][j] == '~') {
          j++;
          if (j == txt[i].length)
            break;
        }
        lineWidth += pcbdata.font_data[txt[i][j]].w * text.width;
      }
    }
    var offsetx = -lineWidth * (text.justify[0] + 1) / 2;
    var inOverbar = false;
    for (var j = 0; j < txt[i].length; j++) {
      if (config.kicad_text_formatting) {
        if (txt[i][j] == '\t') {
          var fourSpaces = 4 * pcbdata.font_data[' '].w * text.width;
          offsetx += fourSpaces - offsetx % fourSpaces;
          continue;
        } else if (txt[i][j] == '~') {
          j++;
          if (j == txt[i].length)
            break;
          if (txt[i][j] != '~') {
            inOverbar = !inOverbar;
          }
        }
      }
      var glyph = pcbdata.font_data[txt[i][j]];
      if (inOverbar) {
        var overbarStart = [offsetx, -text.height * 1.4 + offsety];
        var overbarEnd = [offsetx + text.width * glyph.w, overbarStart[1]];

        if (!lastHadOverbar) {
          overbarStart[0] += text.height * 1.4 * tilt;
          lastHadOverbar = true;
        }
        ctx.beginPath();
        ctx.moveTo(...overbarStart);
        ctx.lineTo(...overbarEnd);
        ctx.stroke();
      } else {
        lastHadOverbar = false;
      }
      for (var line of glyph.l) {
        ctx.beginPath();
        ctx.moveTo(...calcFontPoint(line[0], text, offsetx, offsety, tilt));
        for (var k = 1; k < line.length; k++) {
          ctx.lineTo(...calcFontPoint(line[k], text, offsetx, offsety, tilt));
        }
        ctx.stroke();
      }
      offsetx += glyph.w * text.width;
    }
    offsety += interline;
  }
  ctx.restore();
}

function drawedge(ctx, scalefactor, edge, color) {
  ctx.strokeStyle = color;
  ctx.fillStyle = color;
  ctx.lineWidth = Math.max(1 / scalefactor, edge.width);
  ctx.lineCap = "round";
  ctx.lineJoin = "round";
  if ("svgpath" in edge) {
    ctx.stroke(new Path2D(edge.svgpath));
  } else {
    ctx.beginPath();
    if (edge.type == "segment") {
      ctx.moveTo(...edge.start);
      ctx.lineTo(...edge.end);
    }
    if (edge.type == "rect") {
      ctx.moveTo(...edge.start);
      ctx.lineTo(edge.start[0], edge.end[1]);
      ctx.lineTo(...edge.end);
      ctx.lineTo(edge.end[0], edge.start[1]);
      ctx.lineTo(...edge.start);
    }
    if (edge.type == "arc") {
      ctx.arc(
        ...edge.start,
        edge.radius,
        deg2rad(edge.startangle),
        deg2rad(edge.endangle));
    }
    if (edge.type == "circle") {
      ctx.arc(
        ...edge.start,
        edge.radius,
        0, 2 * Math.PI);
      ctx.closePath();
    }
    if (edge.type == "curve") {
      ctx.moveTo(...edge.start);
      ctx.bezierCurveTo(...edge.cpa, ...edge.cpb, ...edge.end);
    }
    if("filled" in edge && edge.filled)
      ctx.fill();
    else
      ctx.stroke();
  }
}

function getChamferedRectPath(size, radius, chamfpos, chamfratio) {
  // chamfpos is a bitmask, left = 1, right = 2, bottom left = 4, bottom right = 8
  var path = new Path2D();
  var width = size[0];
  var height = size[1];
  var x = width * -0.5;
  var y = height * -0.5;
  var chamfOffset = Math.min(width, height) * chamfratio;
  path.moveTo(x, 0);
  if (chamfpos & 4) {
    path.lineTo(x, y + height - chamfOffset);
    path.lineTo(x + chamfOffset, y + height);
    path.lineTo(0, y + height);
  } else {
    path.arcTo(x, y + height, x + width, y + height, radius);
  }
  if (chamfpos & 8) {
    path.lineTo(x + width - chamfOffset, y + height);
    path.lineTo(x + width, y + height - chamfOffset);
    path.lineTo(x + width, 0);
  } else {
    path.arcTo(x + width, y + height, x + width, y, radius);
  }
  if (chamfpos & 2) {
    path.lineTo(x + width, y + chamfOffset);
    path.lineTo(x + width - chamfOffset, y);
    path.lineTo(0, y);
  } else {
    path.arcTo(x + width, y, x, y, radius);
  }
  if (chamfpos & 1) {
    path.lineTo(x + chamfOffset, y);
    path.lineTo(x, y + chamfOffset);
    path.lineTo(x, 0);
  } else {
    path.arcTo(x, y, x, y + height, radius);
  }
  path.closePath();
  return path;
}

function getOblongPath(size) {
  return getChamferedRectPath(size, Math.min(size[0], size[1]) / 2, 0, 0);
}

function getPolygonsPath(shape) {
  if (shape.path2d) {
    return shape.path2d;
  }
  if ("svgpath" in shape) {
    shape.path2d = new Path2D(shape.svgpath);
  } else {
    var path = new Path2D();
    for (var polygon of shape.polygons) {
      path.moveTo(...polygon[0]);
      for (var i = 1; i < polygon.length; i++) {
        path.lineTo(...polygon[i]);
      }
      path.closePath();
    }
    shape.path2d = path;
  }
  return shape.path2d;
}

function drawPolygonShape(ctx, scalefactor, shape, color) {
  ctx.save();
  if (!("svgpath" in shape)) {
    ctx.translate(...shape.pos);
    ctx.rotate(deg2rad(-shape.angle));
  }
  if("filled" in shape && !shape.filled) {
    ctx.strokeStyle = color;
    ctx.lineWidth = Math.max(1 / scalefactor, shape.width);
    ctx.lineCap = "round";
    ctx.lineJoin = "round";
    ctx.stroke(getPolygonsPath(shape));
  } else {
    ctx.fillStyle = color;
    ctx.fill(getPolygonsPath(shape));
  }
  ctx.restore();
}

function drawDrawing(ctx, scalefactor, drawing, color) {
  if (["segment", "arc", "circle", "curve", "rect"].includes(drawing.type)) {
    drawedge(ctx, scalefactor, drawing, color);
  } else if (drawing.type == "polygon") {
    drawPolygonShape(ctx, scalefactor, drawing, color);
  } else {
    drawText(ctx, drawing, color);
  }
}

function getCirclePath(radius) {
  var path = new Path2D();
  path.arc(0, 0, radius, 0, 2 * Math.PI);
  path.closePath();
  return path;
}

function getCachedPadPath(pad) {
  if (!pad.path2d) {
    // if path2d is not set, build one and cache it on pad object
    if (pad.shape == "rect") {
      pad.path2d = new Path2D();
      pad.path2d.rect(...pad.size.map(c => -c * 0.5), ...pad.size);
    } else if (pad.shape == "oval") {
      pad.path2d = getOblongPath(pad.size);
    } else if (pad.shape == "circle") {
      pad.path2d = getCirclePath(pad.size[0] / 2);
    } else if (pad.shape == "roundrect") {
      pad.path2d = getChamferedRectPath(pad.size, pad.radius, 0, 0);
    } else if (pad.shape == "chamfrect") {
      pad.path2d = getChamferedRectPath(pad.size, pad.radius, pad.chamfpos, pad.chamfratio)
    } else if (pad.shape == "custom") {
      pad.path2d = getPolygonsPath(pad);
    }
  }
  return pad.path2d;
}

function drawPad(ctx, pad, color, outline) {
  ctx.save();
  ctx.translate(...pad.pos);
  ctx.rotate(-deg2rad(pad.angle));
  if (pad.offset) {
    ctx.translate(...pad.offset);
  }
  ctx.fillStyle = color;
  ctx.strokeStyle = color;
  var path = getCachedPadPath(pad);
  if (outline) {
    ctx.stroke(path);
  } else {
    ctx.fill(path);
  }
  ctx.restore();
}

function drawPadHole(ctx, pad, padHoleColor) {
  if (pad.type != "th") return;
  ctx.save();
  ctx.translate(...pad.pos);
  ctx.rotate(-deg2rad(pad.angle));
  ctx.fillStyle = padHoleColor;
  if (pad.drillshape == "oblong") {
    ctx.fill(getOblongPath(pad.drillsize));
  } else {
    ctx.fill(getCirclePath(pad.drillsize[0] / 2));
  }
  ctx.restore();
}

function drawFootprint(ctx, layer, scalefactor, footprint, colors, highlight, outline) {
  if (highlight) {
    // draw bounding box
    if (footprint.layer == layer) {
      ctx.save();
      ctx.globalAlpha = 0.2;
      ctx.translate(...footprint.bbox.pos);
      ctx.rotate(deg2rad(-footprint.bbox.angle));
      ctx.translate(...footprint.bbox.relpos);
      ctx.fillStyle = colors.pad;
      ctx.fillRect(0, 0, ...footprint.bbox.size);
      ctx.globalAlpha = 1;
      ctx.strokeStyle = colors.pad;
      ctx.lineWidth = 3 / scalefactor;
      ctx.strokeRect(0, 0, ...footprint.bbox.size);
      ctx.restore();
    }
  }
  // draw drawings
  for (var drawing of footprint.drawings) {
    if (drawing.layer == layer) {
      drawDrawing(ctx, scalefactor, drawing.drawing, colors.pad);
    }
  }
  ctx.lineWidth = 3 / scalefactor;
  // draw pads
  if (settings.renderPads) {
    for (var pad of footprint.pads) {
      if (pad.layers.includes(layer)) {
        drawPad(ctx, pad, colors.pad, outline);
        if (pad.pin1 &&
          (settings.highlightpin1 == "all" ||
            settings.highlightpin1 == "selected" && highlight)) {
          drawPad(ctx, pad, colors.outline, true);
        }
      }
    }
    for (var pad of footprint.pads) {
      drawPadHole(ctx, pad, colors.padHole);
    }
  }
}

function drawEdgeCuts(canvas, scalefactor) {
  var ctx = canvas.getContext("2d");
  var edgecolor = getComputedStyle(topmostdiv).getPropertyValue('--pcb-edge-color');
  for (var edge of pcbdata.edges) {
    drawDrawing(ctx, scalefactor, edge, edgecolor);
  }
}

function drawFootprints(canvas, layer, scalefactor, highlight) {
  var ctx = canvas.getContext("2d");
  ctx.lineWidth = 3 / scalefactor;
  var style = getComputedStyle(topmostdiv);

  var colors = {
    pad: style.getPropertyValue('--pad-color'),
    padHole: style.getPropertyValue('--pad-hole-color'),
    outline: style.getPropertyValue('--pin1-outline-color'),
  }

  for (var i = 0; i < pcbdata.footprints.length; i++) {
    var mod = pcbdata.footprints[i];
    var outline = settings.renderDnpOutline && pcbdata.bom.skipped.includes(i);
    var h = highlightedFootprints.includes(i);
    var d = markedFootprints.has(i);
    if (highlight) {
      if(h && d) {
        colors.pad = style.getPropertyValue('--pad-color-highlight-both');
        colors.outline = style.getPropertyValue('--pin1-outline-color-highlight-both');
      } else if (h) {
        colors.pad = style.getPropertyValue('--pad-color-highlight');
        colors.outline = style.getPropertyValue('--pin1-outline-color-highlight');
      } else if (d) {
        colors.pad = style.getPropertyValue('--pad-color-highlight-marked');
        colors.outline = style.getPropertyValue('--pin1-outline-color-highlight-marked');
      }
    }
    if( h || d || !highlight) {
      drawFootprint(ctx, layer, scalefactor, mod, colors, highlight, outline);
    }
  }
}

function drawBgLayer(layername, canvas, layer, scalefactor, edgeColor, polygonColor, textColor) {
  var ctx = canvas.getContext("2d");
  for (var d of pcbdata.drawings[layername][layer]) {
    if (["segment", "arc", "circle", "curve", "rect"].includes(d.type)) {
      drawedge(ctx, scalefactor, d, edgeColor);
    } else if (d.type == "polygon") {
      drawPolygonShape(ctx, scalefactor, d, polygonColor);
    } else {
      drawText(ctx, d, textColor);
    }
  }
}

function drawTracks(canvas, layer, defaultColor, highlight) {
  ctx = canvas.getContext("2d");
  ctx.lineCap = "round";

  var hasHole = (track) => (
    'drillsize' in track &&
    track.start[0] == track.end[0] &&
    track.start[1] == track.end[1]);

  // First draw tracks and tented vias
  for (var track of pcbdata.tracks[layer]) {
    if (highlight && highlightedNet != track.net) continue;
    if (!hasHole(track)) {
      ctx.strokeStyle = highlight ? defaultColor : settings.netColors[track.net] || defaultColor;
      ctx.lineWidth = track.width;
      ctx.beginPath();
      if ('radius' in track) {
        ctx.arc(
          ...track.center,
          track.radius,
          deg2rad(track.startangle),
          deg2rad(track.endangle));
      } else {
        ctx.moveTo(...track.start);
        ctx.lineTo(...track.end);
      }
      ctx.stroke();
    }
  }
  // Second pass to draw untented vias
  var style = getComputedStyle(topmostdiv);
  var holeColor = style.getPropertyValue('--pad-hole-color')

  for (var track of pcbdata.tracks[layer]) {
    if (highlight && highlightedNet != track.net) continue;
    if (hasHole(track)) {
      ctx.strokeStyle = highlight ? defaultColor : settings.netColors[track.net] || defaultColor;
      ctx.lineWidth = track.width;
      ctx.beginPath();
      ctx.moveTo(...track.start);
      ctx.lineTo(...track.end);
      ctx.stroke();
      ctx.strokeStyle = holeColor;
      ctx.lineWidth = track.drillsize;
      ctx.lineTo(...track.end);
      ctx.stroke();
    }
  }
}

function drawZones(canvas, layer, defaultColor, highlight) {
  ctx = canvas.getContext("2d");
  ctx.lineJoin = "round";
  for (var zone of pcbdata.zones[layer]) {
    if (highlight && highlightedNet != zone.net) continue;
    ctx.strokeStyle = highlight ? defaultColor : settings.netColors[zone.net] || defaultColor;
    ctx.fillStyle = highlight ? defaultColor : settings.netColors[zone.net] || defaultColor;
    if (!zone.path2d) {
      zone.path2d = getPolygonsPath(zone);
    }
    ctx.fill(zone.path2d, zone.fillrule || "nonzero");
    if (zone.width > 0) {
      ctx.lineWidth = zone.width;
      ctx.stroke(zone.path2d);
    }
  }
}

function clearCanvas(canvas, color = null) {
  var ctx = canvas.getContext("2d");
  ctx.save();
  ctx.setTransform(1, 0, 0, 1, 0, 0);
  if (color) {
    ctx.fillStyle = color;
    ctx.fillRect(0, 0, canvas.width, canvas.height);
  } else {
    if (!window.matchMedia("print").matches)
      ctx.clearRect(0, 0, canvas.width, canvas.height);
  }
  ctx.restore();
}

function drawNets(canvas, layer, highlight) {
  var style = getComputedStyle(topmostdiv);
  if (settings.renderZones) {
    var zoneColor = style.getPropertyValue(highlight ? '--zone-color-highlight' : '--zone-color');
    drawZones(canvas, layer, zoneColor, highlight);
  }
  if (settings.renderTracks) {
    var trackColor = style.getPropertyValue(highlight ? '--track-color-highlight' : '--track-color');
    drawTracks(canvas, layer, trackColor, highlight);
  }
  if (highlight && settings.renderPads) {
    var padColor = style.getPropertyValue('--pad-color-highlight');
    var padHoleColor = style.getPropertyValue('--pad-hole-color');
    var ctx = canvas.getContext("2d");
    for (var footprint of pcbdata.footprints) {
      // draw pads
      var padDrawn = false;
      for (var pad of footprint.pads) {
        if (highlightedNet != pad.net) continue;
        if (pad.layers.includes(layer)) {
          drawPad(ctx, pad, padColor, false);
          padDrawn = true;
        }
      }
      if (padDrawn) {
        // redraw all pad holes because some pads may overlap
        for (var pad of footprint.pads) {
          drawPadHole(ctx, pad, padHoleColor);
        }
      }
    }
  }
}

function drawHighlightsOnLayer(canvasdict, clear = true) {
  if (clear) {
    clearCanvas(canvasdict.highlight);
  }
  if (markedFootprints.size > 0 || highlightedFootprints.length > 0) {
    drawFootprints(canvasdict.highlight, canvasdict.layer,
      canvasdict.transform.s * canvasdict.transform.zoom, true);
  }
  if (highlightedNet !== null) {
    drawNets(canvasdict.highlight, canvasdict.layer, true);
  }
}

function drawHighlights() {
  drawHighlightsOnLayer(allcanvas.front);
  drawHighlightsOnLayer(allcanvas.back);
}

function drawBackground(canvasdict, clear = true) {
  if (clear) {
    clearCanvas(canvasdict.bg);
    clearCanvas(canvasdict.fab);
    clearCanvas(canvasdict.silk);
  }

  drawNets(canvasdict.bg, canvasdict.layer, false);
  drawFootprints(canvasdict.bg, canvasdict.layer,
    canvasdict.transform.s * canvasdict.transform.zoom, false);

  drawEdgeCuts(canvasdict.bg, canvasdict.transform.s * canvasdict.transform.zoom);

  var style = getComputedStyle(topmostdiv);
  var edgeColor = style.getPropertyValue('--silkscreen-edge-color');
  var polygonColor = style.getPropertyValue('--silkscreen-polygon-color');
  var textColor = style.getPropertyValue('--silkscreen-text-color');
  if (settings.renderSilkscreen) {
    drawBgLayer(
      "silkscreen", canvasdict.silk, canvasdict.layer,
      canvasdict.transform.s * canvasdict.transform.zoom,
      edgeColor, polygonColor, textColor);
  }
  edgeColor = style.getPropertyValue('--fabrication-edge-color');
  polygonColor = style.getPropertyValue('--fabrication-polygon-color');
  textColor = style.getPropertyValue('--fabrication-text-color');
  if (settings.renderFabrication) {
    drawBgLayer(
      "fabrication", canvasdict.fab, canvasdict.layer,
      canvasdict.transform.s * canvasdict.transform.zoom,
      edgeColor, polygonColor, textColor);
  }
}

function prepareCanvas(canvas, flip, transform) {
  var ctx = canvas.getContext("2d");
  ctx.setTransform(1, 0, 0, 1, 0, 0);
  ctx.scale(transform.zoom, transform.zoom);
  ctx.translate(transform.panx, transform.pany);
  if (flip) {
    ctx.scale(-1, 1);
  }
  ctx.translate(transform.x, transform.y);
  ctx.rotate(deg2rad(settings.boardRotation + (flip && settings.offsetBackRotation ? - 180 : 0)));
  ctx.scale(transform.s, transform.s);
}

function prepareLayer(canvasdict) {
  var flip = (canvasdict.layer === "B");
  for (var c of ["bg", "fab", "silk", "highlight"]) {
    prepareCanvas(canvasdict[c], flip, canvasdict.transform);
  }
}

function rotateVector(v, angle) {
  angle = deg2rad(angle);
  return [
    v[0] * Math.cos(angle) - v[1] * Math.sin(angle),
    v[0] * Math.sin(angle) + v[1] * Math.cos(angle)
  ];
}

function applyRotation(bbox, flip) {
  var corners = [
    [bbox.minx, bbox.miny],
    [bbox.minx, bbox.maxy],
    [bbox.maxx, bbox.miny],
    [bbox.maxx, bbox.maxy],
  ];
  corners = corners.map((v) => rotateVector(v, settings.boardRotation + (flip && settings.offsetBackRotation ? - 180 : 0)));
  return {
    minx: corners.reduce((a, v) => Math.min(a, v[0]), Infinity),
    miny: corners.reduce((a, v) => Math.min(a, v[1]), Infinity),
    maxx: corners.reduce((a, v) => Math.max(a, v[0]), -Infinity),
    maxy: corners.reduce((a, v) => Math.max(a, v[1]), -Infinity),
  }
}

function recalcLayerScale(layerdict, width, height) {
  var flip = (layerdict.layer === "B");
  var bbox = applyRotation(pcbdata.edges_bbox, flip);
  var scalefactor = 0.98 * Math.min(
    width / (bbox.maxx - bbox.minx),
    height / (bbox.maxy - bbox.miny)
  );
  if (scalefactor < 0.1) {
    scalefactor = 1;
  }
  layerdict.transform.s = scalefactor;
  if (flip) {
    layerdict.transform.x = -((bbox.maxx + bbox.minx) * scalefactor + width) * 0.5;
  } else {
    layerdict.transform.x = -((bbox.maxx + bbox.minx) * scalefactor - width) * 0.5;
  }
  layerdict.transform.y = -((bbox.maxy + bbox.miny) * scalefactor - height) * 0.5;
  for (var c of ["bg", "fab", "silk", "highlight"]) {
    canvas = layerdict[c];
    canvas.width = width;
    canvas.height = height;
    canvas.style.width = (width / devicePixelRatio) + "px";
    canvas.style.height = (height / devicePixelRatio) + "px";
  }
}

function redrawCanvas(layerdict) {
  prepareLayer(layerdict);
  drawBackground(layerdict);
  drawHighlightsOnLayer(layerdict);
}

function resizeCanvas(layerdict) {
  var canvasdivid = {
    "F": "frontcanvas",
    "B": "backcanvas"
  } [layerdict.layer];
  var width = document.getElementById(canvasdivid).clientWidth * devicePixelRatio;
  var height = document.getElementById(canvasdivid).clientHeight * devicePixelRatio;
  recalcLayerScale(layerdict, width, height);
  redrawCanvas(layerdict);
}

function resizeAll() {
  resizeCanvas(allcanvas.front);
  resizeCanvas(allcanvas.back);
}

function pointWithinDistanceToSegment(x, y, x1, y1, x2, y2, d) {
  var A = x - x1;
  var B = y - y1;
  var C = x2 - x1;
  var D = y2 - y1;

  var dot = A * C + B * D;
  var len_sq = C * C + D * D;
  var dx, dy;
  if (len_sq == 0) {
    // start and end of the segment coincide
    dx = x - x1;
    dy = y - y1;
  } else {
    var param = dot / len_sq;
    var xx, yy;
    if (param < 0) {
      xx = x1;
      yy = y1;
    } else if (param > 1) {
      xx = x2;
      yy = y2;
    } else {
      xx = x1 + param * C;
      yy = y1 + param * D;
    }
    dx = x - xx;
    dy = y - yy;
  }
  return dx * dx + dy * dy <= d * d;
}

function modulo(n, mod) {
  return ((n % mod) + mod) % mod;
}

function pointWithinDistanceToArc(x, y, xc, yc, radius, startangle, endangle, d) {
  var dx = x - xc;
  var dy = y - yc;
  var r_sq = dx * dx + dy * dy;
  var rmin = Math.max(0, radius - d);
  var rmax = radius + d;

  if (r_sq < rmin * rmin || r_sq > rmax * rmax)
    return false;

  var angle1 = modulo(deg2rad(startangle), 2 * Math.PI);
  var dx1 = xc + radius * Math.cos(angle1) - x;
  var dy1 = yc + radius * Math.sin(angle1) - y;
  if (dx1 * dx1 + dy1 * dy1 <= d * d)
    return true;

  var angle2 = modulo(deg2rad(endangle), 2 * Math.PI);
  var dx2 = xc + radius * Math.cos(angle2) - x;
  var dy2 = yc + radius * Math.sin(angle2) - y;
  if (dx2 * dx2 + dy2 * dy2 <= d * d)
    return true;

  var angle = modulo(Math.atan2(dy, dx), 2 * Math.PI);
  if (angle1 > angle2)
    return (angle >= angle2 || angle <= angle1);
  else
    return (angle >= angle1 && angle <= angle2);
}

function pointWithinPad(x, y, pad) {
  var v = [x - pad.pos[0], y - pad.pos[1]];
  v = rotateVector(v, pad.angle);
  if (pad.offset) {
    v[0] -= pad.offset[0];
    v[1] -= pad.offset[1];
  }
  return emptyContext2d.isPointInPath(getCachedPadPath(pad), ...v);
}

function netHitScan(layer, x, y) {
  // Check track segments
  if (settings.renderTracks && pcbdata.tracks) {
    for (var track of pcbdata.tracks[layer]) {
      if ('radius' in track) {
        if (pointWithinDistanceToArc(x, y, ...track.center, track.radius, track.startangle, track.endangle, track.width / 2)) {
          return track.net;
        }
      } else {
        if (pointWithinDistanceToSegment(x, y, ...track.start, ...track.end, track.width / 2)) {
          return track.net;
        }
      }
    }
  }
  // Check pads
  if (settings.renderPads) {
    for (var footprint of pcbdata.footprints) {
      for (var pad of footprint.pads) {
        if (pad.layers.includes(layer) && pointWithinPad(x, y, pad)) {
          return pad.net;
        }
      }
    }
  }
  return null;
}

function pointWithinFootprintBbox(x, y, bbox) {
  var v = [x - bbox.pos[0], y - bbox.pos[1]];
  v = rotateVector(v, bbox.angle);
  return bbox.relpos[0] <= v[0] && v[0] <= bbox.relpos[0] + bbox.size[0] &&
    bbox.relpos[1] <= v[1] && v[1] <= bbox.relpos[1] + bbox.size[1];
}

function bboxHitScan(layer, x, y) {
  var result = [];
  for (var i = 0; i < pcbdata.footprints.length; i++) {
    var footprint = pcbdata.footprints[i];
    if (footprint.layer == layer) {
      if (pointWithinFootprintBbox(x, y, footprint.bbox)) {
        result.push(i);
      }
    }
  }
  return result;
}

function handlePointerDown(e, layerdict) {
  if (e.button != 0 && e.button != 1) {
    return;
  }
  e.preventDefault();
  e.stopPropagation();

  if (!e.hasOwnProperty("offsetX")) {
    // The polyfill doesn't set this properly
    e.offsetX = e.pageX - e.currentTarget.offsetLeft;
    e.offsetY = e.pageY - e.currentTarget.offsetTop;
  }

  layerdict.pointerStates[e.pointerId] = {
    distanceTravelled: 0,
    lastX: e.offsetX,
    lastY: e.offsetY,
    downTime: Date.now(),
  };
}

function handleMouseClick(e, layerdict) {
  if (!e.hasOwnProperty("offsetX")) {
    // The polyfill doesn't set this properly
    e.offsetX = e.pageX - e.currentTarget.offsetLeft;
    e.offsetY = e.pageY - e.currentTarget.offsetTop;
  }

  var x = e.offsetX;
  var y = e.offsetY;
  var t = layerdict.transform;
  var flip = layerdict.layer === "B";
  if (flip) {
    x = (devicePixelRatio * x / t.zoom - t.panx + t.x) / -t.s;
  } else {
    x = (devicePixelRatio * x / t.zoom - t.panx - t.x) / t.s;
  }
  y = (devicePixelRatio * y / t.zoom - t.y - t.pany) / t.s;
  var v = rotateVector([x, y], -settings.boardRotation + (flip && settings.offsetBackRotation ? - 180 : 0));
  if ("nets" in pcbdata) {
    var net = netHitScan(layerdict.layer, ...v);
    if (net !== highlightedNet) {
      netClicked(net);
    }
  }
  if (highlightedNet === null) {
    var footprints = bboxHitScan(layerdict.layer, ...v);
    if (footprints.length > 0) {
      footprintsClicked(footprints);
    }
  }
}

function handlePointerLeave(e, layerdict) {
  e.preventDefault();
  e.stopPropagation();

  if (!settings.redrawOnDrag) {
    redrawCanvas(layerdict);
  }

  delete layerdict.pointerStates[e.pointerId];
}

function resetTransform(layerdict) {
  layerdict.transform.panx = 0;
  layerdict.transform.pany = 0;
  layerdict.transform.zoom = 1;
  redrawCanvas(layerdict);
}

function handlePointerUp(e, layerdict) {
  if (!e.hasOwnProperty("offsetX")) {
    // The polyfill doesn't set this properly
    e.offsetX = e.pageX - e.currentTarget.offsetLeft;
    e.offsetY = e.pageY - e.currentTarget.offsetTop;
  }

  e.preventDefault();
  e.stopPropagation();

  if (e.button == 2) {
    // Reset pan and zoom on right click.
    resetTransform(layerdict);
    layerdict.anotherPointerTapped = false;
    return;
  }

  // We haven't necessarily had a pointermove event since the interaction started, so make sure we update this now
  var ptr = layerdict.pointerStates[e.pointerId];
  ptr.distanceTravelled += Math.abs(e.offsetX - ptr.lastX) + Math.abs(e.offsetY - ptr.lastY);

  if (e.button == 0 && ptr.distanceTravelled < 10 && Date.now() - ptr.downTime <= 500) {
    if (Object.keys(layerdict.pointerStates).length == 1) {
      if (layerdict.anotherPointerTapped) {
        // This is the second pointer coming off of a two-finger tap
        resetTransform(layerdict);
      } else {
        // This is just a regular tap
        handleMouseClick(e, layerdict);
      }
      layerdict.anotherPointerTapped = false;
    } else {
      // This is the first finger coming off of what could become a two-finger tap
      layerdict.anotherPointerTapped = true;
    }
  } else {
    if (!settings.redrawOnDrag) {
      redrawCanvas(layerdict);
    }
    layerdict.anotherPointerTapped = false;
  }

  delete layerdict.pointerStates[e.pointerId];
}

function handlePointerMove(e, layerdict) {
  if (!layerdict.pointerStates.hasOwnProperty(e.pointerId)) {
    return;
  }
  e.preventDefault();
  e.stopPropagation();

  if (!e.hasOwnProperty("offsetX")) {
    // The polyfill doesn't set this properly
    e.offsetX = e.pageX - e.currentTarget.offsetLeft;
    e.offsetY = e.pageY - e.currentTarget.offsetTop;
  }

  var thisPtr = layerdict.pointerStates[e.pointerId];

  var dx = e.offsetX - thisPtr.lastX;
  var dy = e.offsetY - thisPtr.lastY;

  // If this number is low on pointer up, we count the action as a click
  thisPtr.distanceTravelled += Math.abs(dx) + Math.abs(dy);

  if (Object.keys(layerdict.pointerStates).length == 1) {
    // This is a simple drag
    layerdict.transform.panx += devicePixelRatio * dx / layerdict.transform.zoom;
    layerdict.transform.pany += devicePixelRatio * dy / layerdict.transform.zoom;
  } else if (Object.keys(layerdict.pointerStates).length == 2) {
    var otherPtr = Object.values(layerdict.pointerStates).filter((ptr) => ptr != thisPtr)[0];

    var oldDist = Math.sqrt(Math.pow(thisPtr.lastX - otherPtr.lastX, 2) + Math.pow(thisPtr.lastY - otherPtr.lastY, 2));
    var newDist = Math.sqrt(Math.pow(e.offsetX - otherPtr.lastX, 2) + Math.pow(e.offsetY - otherPtr.lastY, 2));

    var scaleFactor = newDist / oldDist;

    if (scaleFactor != NaN) {
      layerdict.transform.zoom *= scaleFactor;

      var zoomd = (1 - scaleFactor) / layerdict.transform.zoom;
      layerdict.transform.panx += devicePixelRatio * otherPtr.lastX * zoomd;
      layerdict.transform.pany += devicePixelRatio * otherPtr.lastY * zoomd;
    }
  }

  thisPtr.lastX = e.offsetX;
  thisPtr.lastY = e.offsetY;

  if (settings.redrawOnDrag) {
    redrawCanvas(layerdict);
  }
}

function handleMouseWheel(e, layerdict) {
  e.preventDefault();
  e.stopPropagation();
  var t = layerdict.transform;
  var wheeldelta = e.deltaY;
  if (e.deltaMode == 1) {
    // FF only, scroll by lines
    wheeldelta *= 30;
  } else if (e.deltaMode == 2) {
    wheeldelta *= 300;
  }
  var m = Math.pow(1.1, -wheeldelta / 40);
  // Limit amount of zoom per tick.
  if (m > 2) {
    m = 2;
  } else if (m < 0.5) {
    m = 0.5;
  }
  t.zoom *= m;
  var zoomd = (1 - m) / t.zoom;
  t.panx += devicePixelRatio * e.offsetX * zoomd;
  t.pany += devicePixelRatio * e.offsetY * zoomd;
  redrawCanvas(layerdict);
}

function addMouseHandlers(div, layerdict) {
  div.addEventListener("pointerdown", function(e) {
    handlePointerDown(e, layerdict);
  });
  div.addEventListener("pointermove", function(e) {
    handlePointerMove(e, layerdict);
  });
  div.addEventListener("pointerup", function(e) {
    handlePointerUp(e, layerdict);
  });
  var pointerleave = function(e) {
    handlePointerLeave(e, layerdict);
  }
  div.addEventListener("pointercancel", pointerleave);
  div.addEventListener("pointerleave", pointerleave);
  div.addEventListener("pointerout", pointerleave);

  div.onwheel = function(e) {
    handleMouseWheel(e, layerdict);
  }
  for (var element of [div, layerdict.bg, layerdict.fab, layerdict.silk, layerdict.highlight]) {
    element.addEventListener("contextmenu", function(e) {
      e.preventDefault();
    }, false);
  }
}

function setRedrawOnDrag(value) {
  settings.redrawOnDrag = value;
  writeStorage("redrawOnDrag", value);
}

function setBoardRotation(value) {
  settings.boardRotation = value * 5;
  writeStorage("boardRotation", settings.boardRotation);
  document.getElementById("rotationDegree").textContent = settings.boardRotation;
  resizeAll();
}

function setOffsetBackRotation(value) {
  settings.offsetBackRotation = value;
  writeStorage("offsetBackRotation", value);
  resizeAll();
}

function initRender() {
  allcanvas = {
    front: {
      transform: {
        x: 0,
        y: 0,
        s: 1,
        panx: 0,
        pany: 0,
        zoom: 1,
      },
      pointerStates: {},
      anotherPointerTapped: false,
      bg: document.getElementById("F_bg"),
      fab: document.getElementById("F_fab"),
      silk: document.getElementById("F_slk"),
      highlight: document.getElementById("F_hl"),
      layer: "F",
    },
    back: {
      transform: {
        x: 0,
        y: 0,
        s: 1,
        panx: 0,
        pany: 0,
        zoom: 1,
      },
      pointerStates: {},
      anotherPointerTapped: false,
      bg: document.getElementById("B_bg"),
      fab: document.getElementById("B_fab"),
      silk: document.getElementById("B_slk"),
      highlight: document.getElementById("B_hl"),
      layer: "B",
    }
  };
  addMouseHandlers(document.getElementById("frontcanvas"), allcanvas.front);
  addMouseHandlers(document.getElementById("backcanvas"), allcanvas.back);
}