/* JSONPath 0.8.0 - XPath for JSON

*
* Copyright (c) 2007 Stefan Goessner (goessner.net)
* Licensed under the MIT (MIT-LICENSE.txt) licence.
*/

function jsonPath(obj, expr, arg) {

var P = {
   resultType: arg && arg.resultType || "VALUE",
   result: [],
   normalize: function(expr) {
      var subx = [];
      return expr.replace(/[\['](\??\(.*?\))[\]']/g, function($0,$1){return "[#"+(subx.push($1)-1)+"]";})
                 .replace(/'?\.'?|\['?/g, ";")
                 .replace(/;;;|;;/g, ";..;")
                 .replace(/;$|'?\]|'$/g, "")
                 .replace(/#([0-9]+)/g, function($0,$1){return subx[$1];});
   },
   asPath: function(path) {
      var x = path.split(";"), p = "$";
      for (var i=1,n=x.length; i<n; i++)
         p += /^[0-9*]+$/.test(x[i]) ? ("["+x[i]+"]") : ("['"+x[i]+"']");
      return p;
   },
   store: function(p, v) {
      if (p) P.result[P.result.length] = P.resultType == "PATH" ? P.asPath(p) : v;
      return !!p;
   },
   trace: function(expr, val, path) {
      if (expr) {
         var x = expr.split(";"), loc = x.shift();
         x = x.join(";");
         if (val && val.hasOwnProperty(loc))
            P.trace(x, val[loc], path + ";" + loc);
         else if (loc === "*")
            P.walk(loc, x, val, path, function(m,l,x,v,p) { P.trace(m+";"+x,v,p); });
         else if (loc === "..") {
            P.trace(x, val, path);
            P.walk(loc, x, val, path, function(m,l,x,v,p) { typeof v[m] === "object" && P.trace("..;"+x,v[m],p+";"+m); });
         }
         else if (/,/.test(loc)) { // [name1,name2,...]
            for (var s=loc.split(/'?,'?/),i=0,n=s.length; i<n; i++)
               P.trace(s[i]+";"+x, val, path);
         }
         else if (/^\(.*?\)$/.test(loc)) // [(expr)]
            P.trace(P.eval(loc, val, path.substr(path.lastIndexOf(";")+1))+";"+x, val, path);
         else if (/^\?\(.*?\)$/.test(loc)) // [?(expr)]
            P.walk(loc, x, val, path, function(m,l,x,v,p) { if (P.eval(l.replace(/^\?\((.*?)\)$/,"$1"),v[m],m)) P.trace(m+";"+x,v,p); });
         else if (/^(-?[0-9]*):(-?[0-9]*):?([0-9]*)$/.test(loc)) // [start:end:step]  phyton slice syntax
            P.slice(loc, x, val, path);
      }
      else
         P.store(path, val);
   },
   walk: function(loc, expr, val, path, f) {
      if (val instanceof Array) {
         for (var i=0,n=val.length; i<n; i++)
            if (i in val)
               f(i,loc,expr,val,path);
      }
      else if (typeof val === "object") {
         for (var m in val)
            if (val.hasOwnProperty(m))
               f(m,loc,expr,val,path);
      }
   },
   slice: function(loc, expr, val, path) {
      if (val instanceof Array) {
         var len=val.length, start=0, end=len, step=1;
         loc.replace(/^(-?[0-9]*):(-?[0-9]*):?(-?[0-9]*)$/g, function($0,$1,$2,$3){start=parseInt($1||start);end=parseInt($2||end);step=parseInt($3||step);});
         start = (start < 0) ? Math.max(0,start+len) : Math.min(len,start);
         end   = (end < 0)   ? Math.max(0,end+len)   : Math.min(len,end);
         for (var i=start; i<end; i+=step)
            P.trace(i+";"+expr, val, path);
      }
   },
   eval: function(x, _v, _vname) {
      try { return $ && _v && eval(x.replace(/@/g, "_v")); }
      catch(e) { throw new SyntaxError("jsonPath: " + e.message + ": " + x.replace(/@/g, "_v").replace(/\^/g, "_a")); }
   }
};

var $ = obj;
if (expr && obj && (P.resultType == "VALUE" || P.resultType == "PATH")) {
   P.trace(P.normalize(expr).replace(/^\$;/,""), obj, "$");
   return P.result.length ? P.result : false;
}

}