utils.js

// utils.js

function extractStyleBlocks($) {
  let css = "";
  $("style").each((i, el) => {
    css += $(el).html() + "\n";
  });
  return css;
}

function parseCssRules(cssText) {
  const rules = [];
  const blockRegex = /([^{}]+)\{([^{}]+)\}/g;
  let match;
  while ((match = blockRegex.exec(cssText)) !== null) {
    const selector = match[1].trim();
    const body = match[2].trim();
    const decls = body.split(";").filter(Boolean);
    for (const decl of decls) {
      const [prop, ...rest] = decl.split(":");
      if (!prop || rest.length === 0) continue;
      rules.push({
        selector,
        property: prop.trim().toLowerCase(),
        value: rest.join(":").trim().toLowerCase(),
      });
    }
  }
  return rules;
}

function parseInlineStyles($) {
  const rules = [];
  $("[style]").each((i, el) => {
    const styleAttr = $(el).attr("style") || "";
    const decls = styleAttr.split(";").filter(Boolean);
    for (const decl of decls) {
      const [prop, ...rest] = decl.split(":");
      if (!prop || rest.length === 0) continue;
      rules.push({
        selector: `<${el.tagName}> (inline)`,
        property: prop.trim().toLowerCase(),
        value: rest.join(":").trim().toLowerCase(),
        element: el,
      });
    }
  });
  return rules;
}

function hexToRgb(hex) {
  hex = hex.replace("#", "");
  if (hex.length === 3) {
    hex = hex.split("").map((c) => c + c).join("");
  }
  if (hex.length !== 6) return null;
  const num = parseInt(hex, 16);
  return {
    r: (num >> 16) & 255,
    g: (num >> 8) & 255,
    b: num & 255,
  };
}

function luminance({ r, g, b }) {
  const a = [r, g, b].map((v) => {
    v /= 255;
    return v <= 0.03928 ? v / 12.92 : Math.pow((v + 0.055) / 1.055, 2.4);
  });
  return a[0] * 0.2126 + a[1] * 0.7152 + a[2] * 0.0722;
}

function contrastRatio(hex1, hex2) {
  const c1 = hexToRgb(hex1);
  const c2 = hexToRgb(hex2);
  if (!c1 || !c2) return null;
  const l1 = luminance(c1);
  const l2 = luminance(c2);
  const lighter = Math.max(l1, l2);
  const darker = Math.min(l1, l2);
  return (lighter + 0.05) / (darker + 0.05);
}

module.exports = {
  extractStyleBlocks,
  parseCssRules,
  parseInlineStyles,
  hexToRgb,
  contrastRatio,
};