var Handlebars = {};
Handlebars.Exception = require("handlebars/utils").Exception;

// BEGIN(BROWSER)
(function() {

  Handlebars.AST = {};

  Handlebars.AST.ProgramNode = function(statements, inverse) {
    this.type = "program";
    this.statements = statements;
    if(inverse) { this.inverse = new Handlebars.AST.ProgramNode(inverse); }
  };

  Handlebars.AST.MustacheNode = function(params, unescaped) {
    this.type = "mustache";
    this.id = params[0];
    this.params = params.slice(1);
    this.escaped = !unescaped;
  };

  Handlebars.AST.PartialNode = function(id, context) {
    this.type    = "partial";

    // TODO: disallow complex IDs

    this.id      = id;
    this.context = context;
  };

  var verifyMatch = function(open, close) {
    if(open.original !== close.original) {
      throw new Handlebars.Exception(open.original + " doesn't match " + close.original);
    }
  };

  Handlebars.AST.BlockNode = function(mustache, program, close) {
    verifyMatch(mustache.id, close);
    this.type = "block";
    this.mustache = mustache;
    this.program  = program;
  };

  Handlebars.AST.InverseNode = function(mustache, program, close) {
    verifyMatch(mustache.id, close);
    this.type = "inverse";
    this.mustache = mustache;
    this.program  = program;
  };

  Handlebars.AST.ContentNode = function(string) {
    this.type = "content";
    this.string = string;
  };

  Handlebars.AST.IdNode = function(parts) {
    this.type = "ID";
    this.original = parts.join("/");

    var dig = [], depth = 0;

    for(var i=0,l=parts.length; i<l; i++) {
      var part = parts[i];

      if(part === "..") { depth++; }
      else if(part === "." || part === "this") { continue; }
      else { dig.push(part); }
    }

    this.parts    = dig;
    this.depth    = depth;
    this.isSimple = (dig.length === 1) && (depth === 0)
  };

  Handlebars.AST.StringNode = function(string) {
    this.type = "STRING";
    this.string = string;
  };

  Handlebars.AST.CommentNode = function(comment) {
    this.type = "comment";
    this.comment = comment;
  };

})();
// END(BROWSER)

exports.AST = Handlebars.AST;