text: import {D2R} from './constants/values';
  import PrimeMeridian from './constants/PrimeMeridian';
  import units from './constants/units';
  import match from './match';
  
  export default function(defData) {
    var self = {};
    var paramObj = defData.split('+').map(function(v) {
      return v.trim();
    }).filter(function(a) {
      return a;
    }).reduce(function(p, a) {
      var split = a.split('=');
      split.push(true);
      p[split[0].toLowerCase()] = split[1];
      return p;
    }, {});
    var paramName, paramVal, paramOutname;
    var params = {
      proj: 'projName',
      datum: 'datumCode',
      rf: function(v) {
        self.rf = parseFloat(v);
      },
      lat_0: function(v) {
        self.lat0 = v * D2R;
      },
      lat_1: function(v) {
        self.lat1 = v * D2R;
      },
      lat_2: function(v) {
        self.lat2 = v * D2R;
      },
      lat_ts: function(v) {
        self.lat_ts = v * D2R;
      },
      lon_0: function(v) {
        self.long0 = v * D2R;
      },
      lon_1: function(v) {
        self.long1 = v * D2R;
      },
      lon_2: function(v) {
        self.long2 = v * D2R;
      },
      alpha: function(v) {
        self.alpha = parseFloat(v) * D2R;
      },
      lonc: function(v) {
        self.longc = v * D2R;
      },
      x_0: function(v) {
        self.x0 = parseFloat(v);
      },
      y_0: function(v) {
        self.y0 = parseFloat(v);
      },
      k_0: function(v) {
        self.k0 = parseFloat(v);
      },
      k: function(v) {
        self.k0 = parseFloat(v);
      },
      a: function(v) {
        self.a = parseFloat(v);
      },
      b: function(v) {
        self.b = parseFloat(v);
      },
      r_a: function() {
        self.R_A = true;
      },
      zone: function(v) {
        self.zone = parseInt(v, 10);
      },
      south: function() {
        self.utmSouth = true;
      },
      towgs84: function(v) {
        self.datum_params = v.split(",").map(function(a) {
          return parseFloat(a);
        });
      },
      to_meter: function(v) {
        self.to_meter = parseFloat(v);
      },
      units: function(v) {
        self.units = v;
        var unit = match(units, v);
        if (unit) {
          self.to_meter = unit.to_meter;
        }
      },
      from_greenwich: function(v) {
        self.from_greenwich = v * D2R;
      },
      pm: function(v) {
        var pm = match(PrimeMeridian, v);
        self.from_greenwich = (pm ? pm : parseFloat(v)) * D2R;
      },
      nadgrids: function(v) {
        if (v === '@null') {
          self.datumCode = 'none';
        }
        else {
          self.nadgrids = v;
        }
      },
      axis: function(v) {
        var legalAxis = "ewnsud";
        if (v.length === 3 && legalAxis.indexOf(v.substr(0, 1)) !== -1 && legalAxis.indexOf(v.substr(1, 1)) !== -1 && legalAxis.indexOf(v.substr(2, 1)) !== -1) {
          self.axis = v;
        }
      },
      approx: function() {
        self.approx = true;
      }
    };
    for (paramName in paramObj) {
      paramVal = paramObj[paramName];
      if (paramName in params) {
        paramOutname = params[paramName];
        if (typeof paramOutname === 'function') {
          paramOutname(paramVal);
        }
        else {
          self[paramOutname] = paramVal;
        }
      }
      else {
        self[paramName] = paramVal;
      }
    }
    if(typeof self.datumCode === 'string' && self.datumCode !== "WGS84"){
      self.datumCode = self.datumCode.toLowerCase();
    }
    return self;
  }
  