// ---- Math and Utilities ----
// Vector Math
const vectorDot = (u, v) => u.map((x, i) => x * v[i]).reduce((x, y) => x + y);
const vectorMag = v => Math.sqrt(vectorDot(v, v));

// Angle Math
const rad2deg = 180 / Math.PI;

// Misc
const clamp = (min, value, max) => Math.min(Math.max(value, min), max);
const productLift =
  (...factors) =>
  (...args) =>
    factors
      .filter(fn => !!fn)
      .map(fn => fn(...args))
      .reduce((x, y) => x * y, 1);

// Pre-computation
const getVectorDataBuilder = (toHue, toLightness, toChroma, toHex) => vector => {
  const sqMag = vectorDot(vector, vector);
  const mag = Math.sqrt(sqMag);
  const unit = vector.map(c => c / mag);
  const hue = toHue(vector);
  const lightness = toLightness(vector);
  const chroma = toChroma(vector);
  const hex = toHex(vector);
  return { vector, sqMag, mag, unit, hue, lightness, chroma, hex };
};
const buildVectorDataJab = getVectorDataBuilder(
  jab => d3.jch(d3.jab(...jab)).h || 0, // Jab -> hue
  ([j]) => j / 100, // Jab -> lightness
  jab => d3.jch(d3.jab(...jab)).C / 100, // Jab -> chroma
  jab => d3.jab(...jab).formatHex() // Jab -> hex
);
const buildVectorDataRgb = getVectorDataBuilder(
  rgb => d3.hsl(d3.rgb(...rgb)).h || 0, // RGB -> hue
  rgb => d3.hsl(d3.rgb(...rgb)).l || 0, // RGB -> lightness
  rgb => d3.jch(d3.rgb(...rgb)).C / 100, // RGB -> chroma
  rgb => d3.rgb(...rgb).formatHex() // RGB -> hex
);

const buildClusterData = (
  size,
  inertia,
  mu1,
  mu2,
  mu3,
  nu1,
  nu2,
  nu3,
  totalSize,
  buildVectorDataForSpace
) => {
  const mu = buildVectorDataForSpace([mu1, mu2, mu3]);
  const nu = [nu1, nu2, nu3];
  const muNuAngle =
    rad2deg * Math.acos(clamp(-1, vectorDot(mu.unit, nu) / vectorMag(nu), 1));
  const proportion = size / totalSize;
  // "Visual Importance" - effectively a comparison where size is the
  // biggest factor, then lightness, then chroma
  const importance = 100 * proportion + 10 * mu.lightness + mu.chroma;
  return {
    size,
    inverseSize: 1 / size,
    inertia,
    mu,
    nu,
    muNuAngle,
    proportion,
    inverseProportion: 1 / proportion,
    importance,
  };
};

const pokemonData = databaseV3.map(([name, size, ...values]) => ({
  name,
  jab: {
    total: buildClusterData(size, ...values.slice(0, 7), size, buildVectorDataJab),
    clusters: [
      buildClusterData(...values.slice(7, 15), size, buildVectorDataJab),
      buildClusterData(...values.slice(15, 23), size, buildVectorDataJab),
      buildClusterData(...values.slice(23, 31), size, buildVectorDataJab),
      buildClusterData(...values.slice(31, 39), size, buildVectorDataJab),
    ].filter(c => c.size !== 0),
  },
  rgb: {
    total: buildClusterData(size, ...values.slice(39, 46), size, buildVectorDataRgb),
    clusters: [
      buildClusterData(...values.slice(46, 54), size, buildVectorDataRgb),
      buildClusterData(...values.slice(54, 62), size, buildVectorDataRgb),
      buildClusterData(...values.slice(62, 70), size, buildVectorDataRgb),
      buildClusterData(...values.slice(70, 78), size, buildVectorDataRgb),
    ].filter(c => c.size !== 0),
  },
}));

const pokemonLookup = new Fuse(pokemonData, { keys: ["name"] });

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(clamp(-1, vectorDot(data.mu.unit, target.unit), 1)),
    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,

    muHex: data.mu.hex,
  };
};

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

// who needs a framework?
const makeTemplate = (id, definition = () => ({})) => {
  const content = document.getElementById(id).content;
  return (...args) => {
    const fragment = content.cloneNode(true);
    const binds = Object.fromEntries(
      Array.from(fragment.querySelectorAll("[bind-to]")).map(element => {
        const name = element.getAttribute("bind-to");
        element.removeAttribute("bind-to");
        return [name, element];
      })
    );
    Object.entries(definition(...args))
      .map(([name, settings]) => [binds[name], settings])
      .filter(([bind]) => !!bind)
      .forEach(([bind, settings]) =>
        Object.entries(settings).forEach(([setting, value]) => {
          if (setting.startsWith("@")) {
            bind.addEventListener(setting.slice(1), value);
          } else if (setting.startsWith("--")) {
            bind.style.setProperty(setting, value);
          } else if (setting === "dataset") {
            Object.entries(value).forEach(([key, data]) => (bind.dataset[key] = data));
          } else if (setting === "append") {
            if (Array.isArray(value)) {
              bind.append(...value);
            } else {
              bind.append(value);
            }
          } else {
            bind[setting] = value;
          }
        })
      );
    return [fragment, binds];
  };
};

// ---- Selectors ----

const rootStyle = document.querySelector(":root").style;
const colorSearchResultsTarget = document.getElementById("color-results");
const nameSearchResultsTarget = document.getElementById("name-results");
const prevColorsSidebar = document.getElementById("prevColors");
const clusterRankingTitle = document.getElementById("cls-title");
const clusterMetricSection = document.getElementById("cls-metric-mount");
const clusterFunctionSection = document.getElementById("cls-fn");

const colorCalculateForm = document.forms.colorCalculateForm;
const colorSortForm = document.forms.colorSortForm;
const targetColorElements = document.forms.targetColorForm.elements;
const colorDisplayElements = document.forms.colorDisplayForm.elements;
const nameSearchFormElements = document.forms.nameSearchForm.elements;

// ---- Add Metric Selects ----

const createMetricSelect = makeTemplate("metric-select-template");
const [{ firstElementChild: sortMetricForm }] = createMetricSelect();
const [{ firstElementChild: clusterMetricForm }] = createMetricSelect();

document.getElementById("sort-metric-mount").append(sortMetricForm);
sortMetricForm.elements.metricKind.value = "whole";

document.getElementById("cls-metric-mount").append(clusterMetricForm);
clusterMetricForm.elements.metricKind.value = "stat";

const updateMetricSelects = form => {
  const kind = form.elements.metricKind.value;
  form.elements.whole.disabled = kind !== "whole";
  form.elements.mean.disabled = kind !== "mean";
  form.elements.stat.disabled = kind !== "stat";
  form.elements.metric.value = form.elements[kind].value;
};

// bit of a hack, but lets us control this all from the template
const metricSymbols = Object.fromEntries(
  Array.from(document.querySelectorAll("option")).map(el => [
    el.value,
    el.textContent.at(-2),
  ])
);

const updateMetricDisplays = () => {
  updateMetricSelects(sortMetricForm);
  updateMetricSelects(clusterMetricForm);

  colorCalculateForm.elements.sortMetricSymbolP.value =
    colorCalculateForm.elements.sortMetricSymbolB.value =
      metricSymbols[
        sortMetricForm.elements[sortMetricForm.elements.metricKind.value].value
      ];

  colorCalculateForm.elements.clusterMetricSymbol.value =
    metricSymbols[
      clusterMetricForm.elements[clusterMetricForm.elements.metricKind.value].value
    ];
};

// ---- Styling ----

const getColorStyles = hex => {
  const { r, g, b } = d3.color(hex);
  const highlight =
    vectorDot([r, g, b], [0.3, 0.6, 0.1]) >= 128
      ? "var(--color-dark)"
      : "var(--color-light)";
  return {
    "--highlight": highlight,
    "--background": hex,
    "--shadow-component": highlight.includes("light") ? "255" : "0",
  };
};

const setColorStyles = (style, hex) =>
  Object.entries(getColorStyles(hex)).forEach(([prop, value]) =>
    style.setProperty(prop, value)
  );

// ---- Pokemon Display ----

// pulled out bc the render uses them
const metricScores = {};
const bestClusterIndices = {};
const objectiveValues = {};

const createPokemonTooltip = makeTemplate("pkmn-data-template", data =>
  Object.fromEntries(
    Object.entries(data).map(([metric, value]) => [
      metric,
      { innerText: value.toFixed?.(2)?.replace(".00", "") },
    ])
  )
);

const createPokemonTile = makeTemplate(
  "pkmn-tile-template",
  (pkmnName, colorSpace, enableTotalFlags, enableClusterFlags) => {
    const formattedName = pkmnName
      .split("-")
      .map(part => part.charAt(0).toUpperCase() + part.substr(1))
      .join(" ");
    const name = {
      innerText: formattedName,
      title: formattedName,
    };

    let spriteName = pkmnName
      .replace("-alola", "-alolan")
      .replace("-galar", "-galarian")
      .replace("-hisui", "-hisuian")
      .replace("-paldea", "-paldean")
      .replace("-paldeanfire", "-paldean-fire") // tauros
      .replace("-paldeanwater", "-paldean-water") // tauros
      .replace("-phony", "") // sinistea and polteageist
      .replace("darmanitan-galarian", "darmanitan-galarian-standard")
      .replace("chienpao", "chien-pao")
      .replace("tinglu", "ting-lu")
      .replace("wochien", "wo-chien")
      .replace("chiyu", "chi-yu");
    if (
      [
        "flabebe",
        "floette",
        "florges",
        "vivillon",
        "basculin",
        "furfrou",
        "magearna",
        "alcremie",
      ].find(s => spriteName.includes(s))
    ) {
      spriteName = spriteName.replace(/-.*$/, "");
    }
    const imageErrorHandler = ({ target }) => {
      target.removeEventListener("error", imageErrorHandler);
      target.src = `https://img.pokemondb.net/sprites/scarlet-violet/icon/${spriteName}.png`;
    };
    const image = {
      alt: formattedName,
      src: `https://img.pokemondb.net/sprites/sword-shield/icon/${spriteName}.png`,
      "@error": imageErrorHandler,
    };

    const score = {
      innerText: objectiveValues[pkmnName][colorSpace].toFixed(2),
    };

    const { total, clusters } = metricScores[pkmnName][colorSpace];
    const buttonBinds = [
      [clusters[0], "cls1Btn", "cls1Data"],
      [clusters[1], "cls2Btn", "cls2Data"],
      [clusters[2], "cls3Btn", "cls3Data"],
      [clusters[3], "cls4Btn", "cls4Data"],
      [total, "totalBtn", "totalData"],
    ]
      .filter(([data]) => !!data)
      .map(([data, button, tooltip], index) => {
        return {
          [button]: {
            dataset: {
              included:
                enableClusterFlags && index === bestClusterIndices[pkmnName][colorSpace],
            },
            hidden: false,
            innerText: data.muHex,
            "@click"() {
              model.setTargetColor(data.muHex);
            },
            ...getColorStyles(data.muHex),
          },
          [tooltip]: {
            append: createPokemonTooltip(data)[0],
          },
        };
      })
      .reduce((a, b) => ({ ...a, ...b }), {});
    buttonBinds.totalBtn.dataset.included = enableTotalFlags;

    return { name, image, score, ...buttonBinds };
  }
);

const renderPokemon = (list, target) => {
  target.innerText = "";

  const colorSpace = colorSortForm.elements.colorSpace.value;

  const {
    sortUseWholeImage,
    sortUseBestCluster,
    sortUseClusterSize,
    sortUseInvClusterSize,
    sortUseTotalSize,
    sortUseInvTotalSize,
  } = Object.fromEntries(new FormData(colorCalculateForm).entries());

  const enableTotalFlags = !!(
    sortUseWholeImage ||
    sortUseTotalSize ||
    sortUseInvTotalSize
  );

  const enableClusterFlags = !!(
    sortUseBestCluster ||
    sortUseClusterSize ||
    sortUseInvClusterSize
  );

  target.append(
    ...list.map(
      name => createPokemonTile(name, colorSpace, enableTotalFlags, enableClusterFlags)[0]
    )
  );
};

// ---- Calculation Logic ----

const model = {
  setTargetColor(newColor) {
    const hex = `#${newColor?.replace("#", "")}`;
    if (hex.length !== 7) {
      return;
    }

    setColorStyles(rootStyle, hex);

    const oldColor = this.targetColor;
    this.targetColor = hex;

    targetColorElements.colorText.value = hex;
    targetColorElements.colorText.dataset.lastValid = hex;
    targetColorElements.colorPicker.value = hex;

    if (oldColor) {
      const prevButton = document.createElement("button");
      prevButton.innerText = oldColor;
      prevButton.classList = "color-select";
      setColorStyles(prevButton.style, oldColor);
      prevButton.addEventListener("click", () => this.setTargetColor(oldColor));
      prevColorsSidebar.prepend(prevButton);
    }

    const rgb = d3.rgb(hex);
    const { J, a, b } = d3.jab(rgb);
    const targetJab = buildVectorDataJab([J, a, b]);
    const targetRgb = buildVectorDataRgb([rgb.r, rgb.g, rgb.b]);

    pokemonData.forEach(({ name, jab, rgb }) => {
      metricScores[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)),
        },
      };
    });

    this.calculateObjective();
  },

  calculateObjective() {
    const {
      clusterUseClusterSize,
      clusterUseInvClusterSize,
      clusterUseTotalSize,
      clusterUseInvTotalSize,
      clusterSortOrder,
      sortUseWholeImage,
      sortUseBestCluster,
      sortUseClusterSize,
      sortUseInvClusterSize,
      sortUseTotalSize,
      sortUseInvTotalSize,
    } = Object.fromEntries(new FormData(colorCalculateForm).entries());

    const clsMetric = clusterMetricForm.elements.metric.value;
    const getClusterScore = productLift(
      cluster => cluster[clsMetric],
      clusterUseClusterSize && (cluster => cluster.size),
      clusterUseInvClusterSize && (cluster => cluster.inverseSize),
      clusterUseTotalSize && ((_, total) => total.size),
      clusterUseInvTotalSize && ((_, total) => total.inverseSize)
    );

    const clsSort = sortOrders[clusterSortOrder];
    const getBestClusterIndex = ({ total, clusters }) =>
      clusters
        .map((c, i) => [getClusterScore(c, total), i])
        .reduce((a, b) => (clsSort(a[0], b[0]) > 0 ? b : a))[1];

    Object.entries(metricScores).forEach(([name, { jab, rgb }]) => {
      bestClusterIndices[name] = {
        jab: getBestClusterIndex(jab),
        rgb: getBestClusterIndex(rgb),
      };
    });

    const metric = sortMetricForm.elements.metric.value;
    const getSortScore = productLift(
      sortUseWholeImage && (({ total }) => total[metric]),
      sortUseBestCluster && (({ clusters }, i) => clusters[i][metric]),
      sortUseClusterSize && (({ clusters }, i) => clusters[i].size),
      sortUseInvClusterSize && (({ clusters }, i) => clusters[i].inverseSize),
      sortUseTotalSize && (({ total }) => total.size),
      sortUseInvTotalSize && (({ total }) => total.inverseSize)
    );

    Object.entries(metricScores).forEach(([name, { jab, rgb }]) => {
      objectiveValues[name] = {
        jab: getSortScore(jab, bestClusterIndices[name].jab),
        rgb: getSortScore(rgb, bestClusterIndices[name].rgb),
      };
    });

    this.renderNameSearchResults();
    this.rank();
  },

  rank() {
    const { colorSpace, sortOrder } = Object.fromEntries(
      new FormData(colorSortForm).entries()
    );
    const compare = sortOrders[sortOrder];
    const sortFn = (a, b) =>
      compare(objectiveValues[a][colorSpace], objectiveValues[b][colorSpace]);

    this.ranked = pokemonData
      .map(({ name }) => name)
      .sort((a, b) => sortFn(a, b) || a.localeCompare(b));

    this.renderColorSearchResults();
  },

  setNameSearchResults(newNameResults) {
    this.nameSearchResults = newNameResults;
    this.renderNameSearchResults();
  },

  renderNameSearchResults() {
    renderPokemon(this.nameSearchResults ?? [], nameSearchResultsTarget);
  },

  renderColorSearchResults() {
    renderPokemon(
      this.ranked.slice(0, parseInt(colorDisplayElements.resultsToDisplay.value)),
      colorSearchResultsTarget
    );
  },
};

// ---- Form Controls ----

nameSearchFormElements.input.addEventListener("input", ({ target: { value } }) => {
  model.setNameSearchResults(
    pokemonLookup.search(value, { limit: 24 }).map(({ item: { name } }) => name)
  );
});

nameSearchFormElements.clear.addEventListener("click", () => {
  nameSearchFormElements.input.value = "";
  model.setNameSearchResults([]);
});

nameSearchFormElements.random.addEventListener("click", () => {
  model.setNameSearchResults(
    Array.from(
      { length: 24 },
      () => pokemonData[Math.floor(Math.random() * pokemonData.length)].name
    )
  );
});

targetColorElements.colorText.addEventListener("input", ({ target }) => {
  if (target.willValidate && !target.validity.valid) {
    target.value = target.dataset.lastValid || "";
  } else {
    model.setTargetColor(target.value);
  }
});

targetColorElements.colorPicker.addEventListener("change", ({ target }) =>
  model.setTargetColor(target.value)
);

const randomizeTargetColor = () =>
  model.setTargetColor(
    d3.hsl(Math.random() * 360, Math.random(), Math.random()).formatHex()
  );

targetColorElements.randomColor.addEventListener("click", randomizeTargetColor);

colorDisplayElements.resultsToDisplay.addEventListener(
  "input",
  ({ target: { value } }) => {
    colorDisplayElements.output.value = value;
  }
);

colorDisplayElements.resultsToDisplay.addEventListener("change", () =>
  model.renderColorSearchResults()
);

Array.from(colorSortForm.elements).forEach(el =>
  el.addEventListener("change", () => model.rank())
);

Array.from(colorCalculateForm.elements).forEach(el =>
  el.addEventListener("change", () => {
    const { sortUseBestCluster, sortUseClusterSize, sortUseInvClusterSize } =
      Object.fromEntries(new FormData(colorCalculateForm).entries());
    clusterRankingTitle.dataset.faded =
      clusterMetricSection.dataset.faded =
      clusterFunctionSection.dataset.faded =
        !(sortUseBestCluster || sortUseClusterSize || sortUseInvClusterSize);
    model.calculateObjective();
  })
);

sortMetricForm.addEventListener("change", () => {
  updateMetricDisplays();
  model.calculateObjective();
});

clusterMetricForm.addEventListener("change", () => {
  updateMetricDisplays();
  model.calculateObjective();
});

// ---- Initial Setup ----

updateMetricDisplays();
randomizeTargetColor();