'use strict';

var NEUTRAL = 1;
var KEYWORD = 2;
var NUMBER = 3;
var QUOTED = 4;
var AFTERQUOTE = 5;
var ENDED = -1;
var whitespace = /\s/;
var latin = /[A-Za-z]/;
var keyword = /[A-Za-z84]/;
var endThings = /[,\]]/;
var digets = /[\d\.E\-\+]/;
// const ignoredChar = /[\s_\-\/\(\)]/g;
function Parser(text) {
  if (typeof text !== 'string') {
    throw new Error('not a string');
  }
  this.text = text.trim();
  this.level = 0;
  this.place = 0;
  this.root = null;
  this.stack = [];
  this.currentObject = null;
  this.state = NEUTRAL;
}
Parser.prototype.readCharicter = function() {
  var char = this.text[this.place++];
  if (this.state !== QUOTED) {
    while (whitespace.test(char)) {
      if (this.place >= this.text.length) {
        return;
      }
      char = this.text[this.place++];
    }
  }
  switch (this.state) {
    case NEUTRAL:
      return this.neutral(char);
    case KEYWORD:
      return this.keyword(char)
    case QUOTED:
      return this.quoted(char);
    case AFTERQUOTE:
      return this.afterquote(char);
    case NUMBER:
      return this.number(char);
    case ENDED:
      return;
  }
};
Parser.prototype.afterquote = function(char) {
  if (char === '"') {
    this.word += '"';
    this.state = QUOTED;
    return;
  }
  if (endThings.test(char)) {
    this.word = this.word.trim();
    this.afterItem(char);
    return;
  }
  throw new Error('havn\'t handled "' +char + '" in afterquote yet, index ' + this.place);
};
Parser.prototype.afterItem = function(char) {
  if (char === ',') {
    if (this.word !== null) {
      this.currentObject.push(this.word);
    }
    this.word = null;
    this.state = NEUTRAL;
    return;
  }
  if (char === ']') {
    this.level--;
    if (this.word !== null) {
      this.currentObject.push(this.word);
      this.word = null;
    }
    this.state = NEUTRAL;
    this.currentObject = this.stack.pop();
    if (!this.currentObject) {
      this.state = ENDED;
    }

    return;
  }
};
Parser.prototype.number = function(char) {
  if (digets.test(char)) {
    this.word += char;
    return;
  }
  if (endThings.test(char)) {
    this.word = parseFloat(this.word);
    this.afterItem(char);
    return;
  }
  throw new Error('havn\'t handled "' +char + '" in number yet, index ' + this.place);
};
Parser.prototype.quoted = function(char) {
  if (char === '"') {
    this.state = AFTERQUOTE;
    return;
  }
  this.word += char;
  return;
};
Parser.prototype.keyword = function(char) {
  if (keyword.test(char)) {
    this.word += char;
    return;
  }
  if (char === '[') {
    var newObjects = [];
    newObjects.push(this.word);
    this.level++;
    if (this.root === null) {
      this.root = newObjects;
    } else {
      this.currentObject.push(newObjects);
    }
    this.stack.push(this.currentObject);
    this.currentObject = newObjects;
    this.state = NEUTRAL;
    return;
  }
  if (endThings.test(char)) {
    this.afterItem(char);
    return;
  }
  throw new Error('havn\'t handled "' +char + '" in keyword yet, index ' + this.place);
};
Parser.prototype.neutral = function(char) {
  if (latin.test(char)) {
    this.word = char;
    this.state = KEYWORD;
    return;
  }
  if (char === '"') {
    this.word = '';
    this.state = QUOTED;
    return;
  }
  if (digets.test(char)) {
    this.word = char;
    this.state = NUMBER;
    return;
  }
  if (endThings.test(char)) {
    this.afterItem(char);
    return;
  }
  throw new Error('havn\'t handled "' +char + '" in neutral yet, index ' + this.place);
};
Parser.prototype.output = function() {
  while (this.place < this.text.length) {
    this.readCharicter();
  }
  if (this.state === ENDED) {
    return this.root;
  }
  throw new Error('unable to parse string "' +this.text + '". State is ' + this.state);
};

function parseString(txt) {
  var parser = new Parser(txt);
  return parser.output();
}

function mapit(obj, key, value) {
  if (Array.isArray(key)) {
    value.unshift(key);
    key = null;
  }
  var thing = key ? {} : obj;

  var out = value.reduce(function(newObj, item) {
    sExpr(item, newObj);
    return newObj
  }, thing);
  if (key) {
    obj[key] = out;
  }
}

function sExpr(v, obj) {
  if (!Array.isArray(v)) {
    obj[v] = true;
    return;
  }
  var key = v.shift();
  if (key === 'PARAMETER') {
    key = v.shift();
  }
  if (v.length === 1) {
    if (Array.isArray(v[0])) {
      obj[key] = {};
      sExpr(v[0], obj[key]);
      return;
    }
    obj[key] = v[0];
    return;
  }
  if (!v.length) {
    obj[key] = true;
    return;
  }
  if (key === 'TOWGS84') {
    obj[key] = v;
    return;
  }
  if (!Array.isArray(key)) {
    obj[key] = {};
  }

  var i;
  switch (key) {
    case 'UNIT':
    case 'PRIMEM':
    case 'VERT_DATUM':
      obj[key] = {
        name: v[0].toLowerCase(),
        convert: v[1]
      };
      if (v.length === 3) {
        sExpr(v[2], obj[key]);
      }
      return;
    case 'SPHEROID':
    case 'ELLIPSOID':
      obj[key] = {
        name: v[0],
        a: v[1],
        rf: v[2]
      };
      if (v.length === 4) {
        sExpr(v[3], obj[key]);
      }
      return;
    case 'PROJECTEDCRS':
    case 'PROJCRS':
    case 'GEOGCS':
    case 'GEOCCS':
    case 'PROJCS':
    case 'LOCAL_CS':
    case 'GEODCRS':
    case 'GEODETICCRS':
    case 'GEODETICDATUM':
    case 'EDATUM':
    case 'ENGINEERINGDATUM':
    case 'VERT_CS':
    case 'VERTCRS':
    case 'VERTICALCRS':
    case 'COMPD_CS':
    case 'COMPOUNDCRS':
    case 'ENGINEERINGCRS':
    case 'ENGCRS':
    case 'FITTED_CS':
    case 'LOCAL_DATUM':
    case 'DATUM':
      v[0] = ['name', v[0]];
      mapit(obj, key, v);
      return;
    default:
      i = -1;
      while (++i < v.length) {
        if (!Array.isArray(v[i])) {
          return sExpr(v, obj[key]);
        }
      }
      return mapit(obj, key, v);
  }
}

var D2R = 0.01745329251994329577;
function rename(obj, params) {
  var outName = params[0];
  var inName = params[1];
  if (!(outName in obj) && (inName in obj)) {
    obj[outName] = obj[inName];
    if (params.length === 3) {
      obj[outName] = params[2](obj[outName]);
    }
  }
}

function d2r(input) {
  return input * D2R;
}

function cleanWKT(wkt) {
  if (wkt.type === 'GEOGCS') {
    wkt.projName = 'longlat';
  } else if (wkt.type === 'LOCAL_CS') {
    wkt.projName = 'identity';
    wkt.local = true;
  } else {
    if (typeof wkt.PROJECTION === 'object') {
      wkt.projName = Object.keys(wkt.PROJECTION)[0];
    } else {
      wkt.projName = wkt.PROJECTION;
    }
  }
  if (wkt.UNIT) {
    wkt.units = wkt.UNIT.name.toLowerCase();
    if (wkt.units === 'metre') {
      wkt.units = 'meter';
    }
    if (wkt.UNIT.convert) {
      if (wkt.type === 'GEOGCS') {
        if (wkt.DATUM && wkt.DATUM.SPHEROID) {
          wkt.to_meter = wkt.UNIT.convert*wkt.DATUM.SPHEROID.a;
        }
      } else {
        wkt.to_meter = wkt.UNIT.convert, 10;
      }
    }
  }
  var geogcs = wkt.GEOGCS;
  if (wkt.type === 'GEOGCS') {
    geogcs = wkt;
  }
  if (geogcs) {
    //if(wkt.GEOGCS.PRIMEM&&wkt.GEOGCS.PRIMEM.convert){
    //  wkt.from_greenwich=wkt.GEOGCS.PRIMEM.convert*D2R;
    //}
    if (geogcs.DATUM) {
      wkt.datumCode = geogcs.DATUM.name.toLowerCase();
    } else {
      wkt.datumCode = geogcs.name.toLowerCase();
    }
    if (wkt.datumCode.slice(0, 2) === 'd_') {
      wkt.datumCode = wkt.datumCode.slice(2);
    }
    if (wkt.datumCode === 'new_zealand_geodetic_datum_1949' || wkt.datumCode === 'new_zealand_1949') {
      wkt.datumCode = 'nzgd49';
    }
    if (wkt.datumCode === 'wgs_1984') {
      if (wkt.PROJECTION === 'Mercator_Auxiliary_Sphere') {
        wkt.sphere = true;
      }
      wkt.datumCode = 'wgs84';
    }
    if (wkt.datumCode.slice(-6) === '_ferro') {
      wkt.datumCode = wkt.datumCode.slice(0, - 6);
    }
    if (wkt.datumCode.slice(-8) === '_jakarta') {
      wkt.datumCode = wkt.datumCode.slice(0, - 8);
    }
    if (~wkt.datumCode.indexOf('belge')) {
      wkt.datumCode = 'rnb72';
    }
    if (geogcs.DATUM && geogcs.DATUM.SPHEROID) {
      wkt.ellps = geogcs.DATUM.SPHEROID.name.replace('_19', '').replace(/[Cc]larke\_18/, 'clrk');
      if (wkt.ellps.toLowerCase().slice(0, 13) === 'international') {
        wkt.ellps = 'intl';
      }

      wkt.a = geogcs.DATUM.SPHEROID.a;
      wkt.rf = parseFloat(geogcs.DATUM.SPHEROID.rf, 10);
    }
    if (~wkt.datumCode.indexOf('osgb_1936')) {
      wkt.datumCode = 'osgb36';
    }
    if (~wkt.datumCode.indexOf('osni_1952')) {
      wkt.datumCode = 'osni52';
    }
    if (~wkt.datumCode.indexOf('tm65')
      || ~wkt.datumCode.indexOf('geodetic_datum_of_1965')) {
      wkt.datumCode = 'ire65';
    }
    if (wkt.datumCode === 'ch1903+') {
      wkt.datumCode = 'ch1903';
    }
  }
  if (wkt.b && !isFinite(wkt.b)) {
    wkt.b = wkt.a;
  }

  function toMeter(input) {
    var ratio = wkt.to_meter || 1;
    return input * ratio;
  }
  var renamer = function(a) {
    return rename(wkt, a);
  };
  var list = [
    ['standard_parallel_1', 'Standard_Parallel_1'],
    ['standard_parallel_2', 'Standard_Parallel_2'],
    ['false_easting', 'False_Easting'],
    ['false_northing', 'False_Northing'],
    ['central_meridian', 'Central_Meridian'],
    ['latitude_of_origin', 'Latitude_Of_Origin'],
    ['latitude_of_origin', 'Central_Parallel'],
    ['scale_factor', 'Scale_Factor'],
    ['k0', 'scale_factor'],
    ['latitude_of_center', 'Latitude_Of_Center'],
    ['latitude_of_center', 'Latitude_of_center'],
    ['lat0', 'latitude_of_center', d2r],
    ['longitude_of_center', 'Longitude_Of_Center'],
    ['longitude_of_center', 'Longitude_of_center'],
    ['longc', 'longitude_of_center', d2r],
    ['x0', 'false_easting', toMeter],
    ['y0', 'false_northing', toMeter],
    ['long0', 'central_meridian', d2r],
    ['lat0', 'latitude_of_origin', d2r],
    ['lat0', 'standard_parallel_1', d2r],
    ['lat1', 'standard_parallel_1', d2r],
    ['lat2', 'standard_parallel_2', d2r],
    ['azimuth', 'Azimuth'],
    ['alpha', 'azimuth', d2r],
    ['srsCode', 'name']
  ];
  list.forEach(renamer);
  if (!wkt.long0 && wkt.longc && (wkt.projName === 'Albers_Conic_Equal_Area' || wkt.projName === 'Lambert_Azimuthal_Equal_Area')) {
    wkt.long0 = wkt.longc;
  }
  if (!wkt.lat_ts && wkt.lat1 && (wkt.projName === 'Stereographic_South_Pole' || wkt.projName === 'Polar Stereographic (variant B)')) {
    wkt.lat0 = d2r(wkt.lat1 > 0 ? 90 : -90);
    wkt.lat_ts = wkt.lat1;
  }
}
var index = function(wkt) {
  var lisp = parseString(wkt);
  var type = lisp.shift();
  var name = lisp.shift();
  lisp.unshift(['name', name]);
  lisp.unshift(['type', type]);
  var obj = {};
  sExpr(lisp, obj);
  cleanWKT(obj);
  return obj;
};

module.exports = index;
