import { toUTF8String } from "./utils.js";
const svgReg = /<svg\s([^>"']|"[^"]*"|'[^']*')*>/;
const extractorRegExps = {
  height: /\sheight=(['"])([^%]+?)\1/,
  root: svgReg,
  viewbox: /\sviewBox=(['"])(.+?)\1/i,
  width: /\swidth=(['"])([^%]+?)\1/
};
const INCH_CM = 2.54;
const units = {
  in: 96,
  cm: 96 / INCH_CM,
  em: 16,
  ex: 8,
  m: 96 / INCH_CM * 100,
  mm: 96 / INCH_CM / 10,
  pc: 96 / 72 / 12,
  pt: 96 / 72,
  px: 1
};
const unitsReg = new RegExp(
  `^([0-9.]+(?:e\\d+)?)(${Object.keys(units).join("|")})?$`
);
function parseLength(len) {
  const m = unitsReg.exec(len);
  if (!m) {
    return void 0;
  }
  return Math.round(Number(m[1]) * (units[m[2]] || 1));
}
function parseViewbox(viewbox) {
  const bounds = viewbox.split(" ");
  return {
    height: parseLength(bounds[3]),
    width: parseLength(bounds[2])
  };
}
function parseAttributes(root) {
  const width = extractorRegExps.width.exec(root);
  const height = extractorRegExps.height.exec(root);
  const viewbox = extractorRegExps.viewbox.exec(root);
  return {
    height: height && parseLength(height[2]),
    viewbox: viewbox && parseViewbox(viewbox[2]),
    width: width && parseLength(width[2])
  };
}
function calculateByDimensions(attrs) {
  return {
    height: attrs.height,
    width: attrs.width
  };
}
function calculateByViewbox(attrs, viewbox) {
  const ratio = viewbox.width / viewbox.height;
  if (attrs.width) {
    return {
      height: Math.floor(attrs.width / ratio),
      width: attrs.width
    };
  }
  if (attrs.height) {
    return {
      height: attrs.height,
      width: Math.floor(attrs.height * ratio)
    };
  }
  return {
    height: viewbox.height,
    width: viewbox.width
  };
}
const SVG = {
  // Scan only the first kilo-byte to speed up the check on larger files
  validate: (input) => svgReg.test(toUTF8String(input, 0, 1e3)),
  calculate(input) {
    const root = extractorRegExps.root.exec(toUTF8String(input));
    if (root) {
      const attrs = parseAttributes(root[0]);
      if (attrs.width && attrs.height) {
        return calculateByDimensions(attrs);
      }
      if (attrs.viewbox) {
        return calculateByViewbox(attrs, attrs.viewbox);
      }
    }
    throw new TypeError("Invalid SVG");
  }
};
export {
  SVG
};
