const selectors = {
  get sortControl() {
    return document.forms.sortControl.elements;
  },
  get clusterControl() {
    return document.forms.clusterControl.elements;
  },
  get resultsToDisplay() {
    return selectors.sortControl.resultsToDisplay.value;
  },
  get colorSpace() {
    return selectors.sortControl.colorSpace.value;
  },
  get sortMetric() {
    return selectors.sortControl.sortMetric.value;
  },
  get sortOrder() {
    return selectors.sortControl.sortOrder.checked ? "max" : "min";
  },
  get scaleFactor() {
    return selectors.sortControl.rescaleFactor.value;
  },
  get useClusters() {
    return selectors.sortControl.useClusters.value;
  },
  get clusterSortMetric() {
    return selectors.clusterControl.sortMetric.value;
  },
  get clusterSortOrder() {
    return selectors.clusterControl.sortOrder.checked ? "max" : "min";
  },
  get clusterScaleFactor() {
    return selectors.clusterControl.rescaleFactor.value;
  },
  get prevColors() {
    return document.getElementById("prev-colors");
  },
  set background(hex) {
    document.querySelector(":root").style.setProperty("--background", hex);
  },
  set highlight(hex) {
    document.querySelector(":root").style.setProperty("--highlight", hex);
  },
};

const onMetricChange = (elements, skipUpdates = false) => {
  elements.sortOrderLabel.value = elements.sortOrder.checked
    ? "Maximizing"
    : "Minimizing";
  const kind = elements.metricKind.value;
  elements.whole.disabled = kind !== "whole";
  elements.mean.disabled = kind !== "mean";
  elements.statistic.disabled = kind !== "statistic";
  elements.sortMetric.value = elements[kind].value;

  if (!skipUpdates) {
    updateSort();
  }
};

const onColorChange = (inputValue, skipUpdates = false) => {
  const colorInput = "#" + (inputValue?.replace("#", "") ?? "FFFFFF");

  if (colorInput.length !== 7) {
    return;
  }

  const rgb = d3.color(colorInput);
  if (!rgb) {
    return;
  }

  const hex = rgb.formatHex();
  selectors.sortControl.colorText.value = hex;
  selectors.sortControl.colorPicker.value = hex;

  const contrast = getContrastingTextColor(hex);

  const newColor = document.createElement("div");
  newColor.innerHTML = hex;
  newColor.style = `
    color: ${contrast}; 
    background-color: ${hex};
  `;
  selectors.prevColors.prepend(newColor);

  selectors.background = hex;
  selectors.highlight = contrast;

  if (!skipUpdates) {
    updateScores(rgb);
    updateSort();
  }
};

const randomColor = () =>
  d3.hsl(Math.random() * 360, Math.random(), Math.random()).formatHex();

const calcScores = (data, target) => {
  const sigma = Math.sqrt(
    data.inertia - 2 * vectorDot(data.mu.vector, target.vector) + target.sqMag
  );
  const bigTheta = 1 - vectorDot(data.nu, target.unit);
  const rawPhi = Math.abs(data.mu.hue - target.hue);
  return {
    sigma,
    bigTheta,
    alpha: sigma * Math.pow(bigTheta, target.chroma + target.lightness),

    theta: rad2deg * Math.acos(vectorDot(data.mu.unit, target.unit)),
    phi: Math.min(rawPhi, 360 - rawPhi),
    delta: vectorMag(data.mu.vector.map((x, i) => x - target.vector[i])),
    manhattan: data.mu.vector
      .map((x, i) => Math.abs(x - target.vector[i]))
      .reduce((x, y) => x + y),
    ch: Math.max(...data.mu.vector.map((x, i) => Math.abs(x - target.vector[i]))),
    lightnessDiff: Math.abs(data.mu.lightness - target.lightness),

    inertia: data.inertia,
    variance: data.inertia - data.mu.sqMag,
    muNuAngle: data.muNuAngle,
    size: data.size,
    lightness: data.mu.lightness,
    chroma: data.mu.chroma,
    importance: data.importance,

    inverseSize: data.inverseSize,
    proportion: data.proportion,
    inverseProportion: data.inverseProportion,
  };
};

const sortOrders = {
  max: (a, b) => b - a,
  min: (a, b) => a - b,
};

const scaleOptions = {
  none: () => [1, 1, 1],
  direct: (scores) => scores.clusters.map((c) => c.proportion),
  inverse: (scores) => scores.clusters.map((c) => c.inverseProportion),
  size: (scores) => [scores.total.size, scores.total.size, scores.total.size],
  inverseSize: (scores) => [
    scores.total.inverseSize,
    scores.total.inverseSize,
    scores.total.inverseSize,
  ],
};

const currentScores = {};
const currentBestClusterIndices = {};
let sortedData = [];

const updateScores = (rgb) => {
  const { J, a, b } = d3.jab(rgb);
  const targetJab = buildVectorData([J, a, b], jab2hue, jab2lit, jab2chroma, jab2hex);
  const targetRgb = buildVectorData(
    [rgb.r, rgb.g, rgb.b],
    rgb2hue,
    rgb2lit,
    rgb2chroma,
    rgb2hex
  );
  pokemonData.forEach(({ name, jab, rgb }) => {
    currentScores[name] = {
      jab: {
        total: calcScores(jab.total, targetJab),
        clusters: jab.clusters.map((c) => calcScores(c, targetJab)),
      },
      rgb: {
        total: calcScores(rgb.total, targetRgb),
        clusters: rgb.clusters.map((c) => calcScores(c, targetRgb)),
      },
    };
  });
};

const updateSort = () => {
  // update cluster rankings
  const clusterSortOrder = sortOrders[selectors.clusterSortOrder];
  const clusterScaleOption = scaleOptions[selectors.clusterScaleFactor];
  pokemonData.forEach(({ name }) => {
    const { jab, rgb } = currentScores[name];
    // multiply scale with the intended metric, and find the index of the best value
    const forSpace = (clusters, scales) =>
      clusters
        .map((c, i) => [c[selectors.clusterSortMetric] * scales[i], i])
        .reduce((a, b) => (clusterSortOrder(a[0], b[0]) > 0 ? b : a))[1];
    currentBestClusterIndices[name] = {
      jab: forSpace(jab.clusters, clusterScaleOption(jab)),
      rgb: forSpace(rgb.clusters, clusterScaleOption(rgb)),
    };
  });

  // set up for actual sort
  const scaleOption = scaleOptions[selectors.scaleFactor];
  let valueExtractor;
  switch (selectors.useClusters) {
    case "off":
      valueExtractor = (name) =>
        currentScores[name][selectors.colorSpace].total[selectors.sortMetric];
      break;
    case "on":
      valueExtractor = (name) => {
        const index = currentBestClusterIndices[name][selectors.colorSpace];
        return (
          scaleOption(currentScores[name][selectors.colorSpace])[index] *
          currentScores[name][selectors.colorSpace].clusters[index][selectors.sortMetric]
        );
      };
      break;
    case "mult":
      valueExtractor = (name) => {
        const index = currentBestClusterIndices[name][selectors.colorSpace];
        return (
          currentScores[name][selectors.colorSpace].total[selectors.sortMetric] *
          scaleOption(currentScores[name][selectors.colorSpace])[index] *
          currentScores[name][selectors.colorSpace].clusters[index][selectors.sortMetric]
        );
      };
      break;
  }

  // update actual sorted data
  const sortOrder = sortOrders[selectors.sortOrder];
  sortedData = pokemonData
    .map(({ name }) => name)
    .sort((a, b) => sortOrder(valueExtractor(a), valueExtractor(b)));

  // and desplay results
  showResults();
};

const showResults = () => {
  // TODO
  console.log(sortedData.slice(0, selectors.resultsToDisplay));
};

window.addEventListener("load", () => {
  const metricTemplate = document.getElementById("metric-form-template").content;

  selectors.sortControl.metric.appendChild(metricTemplate.cloneNode(true));
  selectors.sortControl.metricKind.value = "whole";
  selectors.sortControl.whole.value = "alpha";
  onMetricChange(selectors.sortControl, true);

  selectors.clusterControl.metric.appendChild(metricTemplate.cloneNode(true));
  selectors.clusterControl.sortOrder.checked = true;
  selectors.clusterControl.metricKind.value = "statistic";
  selectors.clusterControl.statistic.value = "importance";
  onMetricChange(selectors.clusterControl, true);

  const scaleTemplate = document.getElementById("scale-form-template").content;
  selectors.sortControl.rescaleSection.appendChild(scaleTemplate.cloneNode(true));
  selectors.sortControl.rescaleFactor.value = "inverse";

  selectors.clusterControl.rescaleSection.appendChild(scaleTemplate.cloneNode(true));
  selectors.clusterControl.rescaleFactor.value = "none";

  document.body.addEventListener("click", ({ target: { innerText }, detail }) => {
    if (detail === 2 && innerText?.includes("#")) {
      const clickedHex = innerText?.match(/.*(#[0-9a-fA-F]{6}).*/)?.[1] ?? "";
      if (clickedHex) {
        onColorChange(clickedHex);
      }
    }
  });

  onColorChange(randomColor());
});