var __defProp = Object.defineProperty;
var __getOwnPropDesc = Object.getOwnPropertyDescriptor;
var __getOwnPropNames = Object.getOwnPropertyNames;
var __hasOwnProp = Object.prototype.hasOwnProperty;
var __export = (target, all) => {
  for (var name in all)
    __defProp(target, name, { get: all[name], enumerable: true });
};
var __copyProps = (to, from, except, desc) => {
  if (from && typeof from === "object" || typeof from === "function") {
    for (let key of __getOwnPropNames(from))
      if (!__hasOwnProp.call(to, key) && key !== except)
        __defProp(to, key, { get: () => from[key], enumerable: !(desc = __getOwnPropDesc(from, key)) || desc.enumerable });
  }
  return to;
};
var __toCommonJS = (mod) => __copyProps(__defProp({}, "__esModule", { value: true }), mod);

// dist/index.js
var dist_exports = {};
__export(dist_exports, {
  Geoid: () => Geoid,
  parsePGM: () => parsePGM
});
module.exports = __toCommonJS(dist_exports);

// dist/geoid.js
var c0_ = 240;
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var stencilsize_ = 12;
var nterms_ = (3 + 1) * (3 + 2) / 2;
var PIXEL_SIZE = 2;
var Geoid = class {
  /**
   * @constructs
   * Create a Geoid instance.
   * @param options - object which includes parameters parsed from *.pgm header
   * @param options.data - binary buffer of *.pgm file
   */
  constructor(options) {
    this._v00 = 0;
    this._v01 = 0;
    this._v10 = 0;
    this._v11 = 0;
    this._t = [];
    this.options = options;
    this._ix = this.options._width;
    this._iy = this.options._height;
  }
  /**
   * Calculates difference between mean see level height and WGS84 ellipsoid height
   * Code is ported from /GeographicLib-1.50.1/src/Geoid.cpp
   * @param lat - latitude
   * @param lon - longitude
   * @returns height in meters
   */
  // eslint-disable-next-line max-statements, complexity
  getHeight(lat, lon) {
    lat = Math.abs(lat) > 90 ? NaN : lat;
    if (isNaN(lat) || isNaN(lon)) {
      return NaN;
    }
    const rem = remainder(lon, 360);
    lon = rem !== -180 ? rem : 180;
    let fx = lon * this.options._rlonres;
    let fy = -lat * this.options._rlatres;
    let ix = Math.floor(fx);
    let iy = Math.min(Math.round((this.options._height - 1) / 2 - 1), Math.floor(fy));
    fx -= ix;
    fy -= iy;
    iy += (this.options._height - 1) / 2;
    ix += ix < 0 ? this.options._width : ix >= this.options._width ? -this.options._width : 0;
    let v00 = 0;
    let v01 = 0;
    let v10 = 0;
    let v11 = 0;
    let t = new Array(nterms_);
    if (!(ix === this._ix && iy === this._iy)) {
      if (!this.options.cubic) {
        v00 = this._rawval(ix, iy);
        v01 = this._rawval(ix + 1, iy);
        v10 = this._rawval(ix, iy + 1);
        v11 = this._rawval(ix + 1, iy + 1);
      } else {
        const v = [
          this._rawval(ix, iy - 1),
          this._rawval(ix + 1, iy - 1),
          this._rawval(ix - 1, iy),
          this._rawval(ix, iy),
          this._rawval(ix + 1, iy),
          this._rawval(ix + 2, iy),
          this._rawval(ix - 1, iy + 1),
          this._rawval(ix, iy + 1),
          this._rawval(ix + 1, iy + 1),
          this._rawval(ix + 2, iy + 1),
          this._rawval(ix, iy + 2),
          this._rawval(ix + 1, iy + 2)
        ];
        let c3x = c3n_;
        if (iy !== 0) {
          c3x = iy === this.options._height - 2 ? c3s_ : c3_;
        }
        let c0x = c0n_;
        if (iy !== 0) {
          c0x = iy === this.options._height - 2 ? c0s_ : c0_;
        }
        for (let i = 0; i < nterms_; ++i) {
          t[i] = 0;
          for (let j = 0; j < stencilsize_; ++j) {
            t[i] += v[j] * c3x[nterms_ * j + i];
          }
          t[i] /= c0x;
        }
      }
    } else if (!this.options.cubic) {
      v00 = this._v00;
      v01 = this._v01;
      v10 = this._v10;
      v11 = this._v11;
    } else {
      t = this._t;
    }
    if (!this.options.cubic) {
      const a = (1 - fx) * v00 + fx * v01;
      const b = (1 - fx) * v10 + fx * v11;
      const c = (1 - fy) * a + fy * b;
      const h2 = this.options._offset + this.options._scale * c;
      this._ix = ix;
      this._iy = iy;
      this._v00 = v00;
      this._v01 = v01;
      this._v10 = v10;
      this._v11 = v11;
      return h2;
    }
    let h = t[0] + fx * (t[1] + fx * (t[3] + fx * t[6])) + fy * (t[2] + fx * (t[4] + fx * t[7]) + fy * (t[5] + fx * t[8] + fy * t[9]));
    h = this.options._offset + this.options._scale * h;
    this._ix = ix;
    this._iy = iy;
    this._t = t;
    return h;
  }
  // PRIVATE
  /**
   * Method seeks for particular data in th pgm buffer
   * Code is ported from corresponding method
   * in /GeographicLib-1.50.1/include/GeographicLib/Geoid.hpp
   * @param {number} ix - longituge parameter
   * @param {number} iy - latitude parameter
   * @returns {number} data from pgm binary buffer
   */
  _rawval(ix, iy) {
    if (ix < 0) {
      ix += this.options._width;
    } else if (ix >= this.options._width) {
      ix -= this.options._width;
    }
    if (iy < 0 || iy >= this.options._height) {
      iy = iy < 0 ? -iy : 2 * (this.options._height - 1) - iy;
      ix += (ix < this.options._width / 2 ? 1 : -1) * this.options._width / 2;
    }
    const bufferPosition = this.options._datastart + PIXEL_SIZE * (iy * this.options._swidth + ix);
    const a = this.options.data[bufferPosition];
    const b = this.options.data[bufferPosition + 1];
    const r = a << 8 | b;
    return r;
  }
};
function remainder(x, y) {
  y = Math.abs(y);
  let z = fmod(x, y);
  if (2 * Math.abs(z) === y)
    z -= fmod(x, 2 * y) - z;
  else if (2 * Math.abs(z) > y)
    z += z < 0 ? y : -y;
  return z;
}
function fmod(x, y) {
  return x - Math.floor(x / y) * y;
}

// dist/parse-pgm.js
var ENDL = 10;
var PIXEL_MAX = 65535;
function parsePGM(data, options) {
  const getline = _getLineGenerator(data);
  let currentLine = getline.next();
  if (currentLine.done || currentLine.value.line !== "P5") {
    throw new Error("Geoid model file: File not in PGM format");
  }
  let _offset = Number.MAX_VALUE;
  let _scale = 0;
  let _maxerror = -1;
  let _rmserror = -1;
  let _description = "NONE";
  let _datetime = "UNKNOWN";
  let _width = 0;
  let _height = 0;
  let _datastart = null;
  let _swidth = null;
  do {
    currentLine = getline.next();
    const s = currentLine.value.line;
    if (!s.length) {
      continue;
    }
    if (s[0] === "#") {
      const sArr = s.split(" ");
      const commentId = sArr[0];
      const key = sArr[1];
      if (commentId !== "#" || !key) {
        continue;
      }
      const infoArr = sArr.length > 2 ? sArr.slice(2) : [];
      if (key === "Description") {
        _description = infoArr.join(" ");
      } else if (key === "DateTime") {
        _datetime = infoArr.join(" ");
      } else if (key === "Offset") {
        if (!sArr[2]) {
          throw new Error("Geoid model file: Error reading offset");
        }
        _offset = parseInt(sArr[2], 10);
      } else if (key === "Scale") {
        if (!sArr[2]) {
          throw new Error("Geoid model file: Error reading scale");
        }
        _scale = parseFloat(sArr[2]);
      } else if (key === (options.cubic ? "MaxCubicError" : "MaxBilinearError")) {
        if (isFinite(parseFloat(sArr[2]))) {
          _maxerror = parseFloat(sArr[2]);
        }
      } else if (key === (options.cubic ? "RMSCubicError" : "RMSBilinearError")) {
        if (isFinite(parseFloat(sArr[2]))) {
          _rmserror = parseFloat(sArr[2]);
        }
      }
    } else {
      let sArr = s.split(" ");
      sArr = sArr.filter((testString) => testString !== "");
      _width = parseInt(sArr[0], 10);
      _height = parseInt(sArr[1], 10);
      if (!(_width && _height)) {
        throw new Error("Geoid model file: Error reading raster size");
      }
      break;
    }
  } while (!currentLine.done);
  currentLine = getline.next();
  const maxval = parseInt(currentLine.value.line, 10);
  if (currentLine.done) {
    throw new Error("Geoid model file: Error reading maxval");
  }
  if (maxval !== PIXEL_MAX) {
    throw new Error("Geoid model file: Incorrect value of maxval");
  }
  _datastart = currentLine.value.offset;
  _swidth = _width;
  if (_offset === Number.MAX_VALUE) {
    throw new Error("Geoid model file: Offset not set");
  }
  if (_scale === 0) {
    throw new Error("Geoid model file: Scale not set");
  }
  if (_scale < 0) {
    throw new Error("Geoid model file: Scale must be positive");
  }
  if (_height < 2 || _width < 2) {
    throw new Error("Geoid model file: Raster size too small");
  }
  if (_width & 1) {
    throw new Error("Geoid model file: Raster width is odd");
  }
  if (!(_height & 1)) {
    throw new Error("Geoid model file: Raster height is even");
  }
  const _rlonres = _width / 360;
  const _rlatres = (_height - 1) / 180;
  return new Geoid({
    cubic: options.cubic,
    _width,
    _height,
    _rlonres,
    _rlatres,
    _offset,
    _scale,
    _swidth,
    _datastart,
    _maxerror,
    _rmserror,
    _description,
    _datetime,
    data
  });
}
function* _getLineGenerator(data) {
  let offset = 0;
  do {
    const endLineIndex = data.indexOf(ENDL, offset);
    if (endLineIndex !== -1) {
      const line = data.subarray(offset, endLineIndex);
      offset = endLineIndex + 1;
      yield { offset, line: _getStringFromCharArray(line) };
    } else {
      const line = data.subarray(offset, data.length);
      offset = data.length;
      yield { offset, line: _getStringFromCharArray(line) };
    }
  } while (offset < data.length);
  return { offset, line: "" };
}
function _getStringFromCharArray(array) {
  let s = "";
  for (const char of array) {
    s += String.fromCharCode(char);
  }
  return s;
}
//# sourceMappingURL=index.cjs.map