/*! Dust - Asynchronous Templating - v2.4.2
* http://linkedin.github.io/dustjs/
* Copyright (c) 2014 Aleksander Williams; Released under the MIT License */
(function(root) {
  var dust = {},
      NONE = 'NONE',
      ERROR = 'ERROR',
      WARN = 'WARN',
      INFO = 'INFO',
      DEBUG = 'DEBUG',
      loggingLevels = [DEBUG, INFO, WARN, ERROR, NONE],
      EMPTY_FUNC = function() {},
      logger = {},
      originalLog,
      loggerContext;

  dust.debugLevel = NONE;

  // Try to find the console in global scope
  if (root && root.console && root.console.log) {
    loggerContext = root.console;
    originalLog = root.console.log;
  }

  // robust logger for node.js, modern browsers, and IE <= 9.
  logger.log = loggerContext ? function() {
      // Do this for normal browsers
      if (typeof originalLog === 'function') {
        logger.log = function() {
          originalLog.apply(loggerContext, arguments);
        };
      } else {
        // Do this for IE <= 9
        logger.log = function() {
          var message = Array.prototype.slice.apply(arguments).join(' ');
          originalLog(message);
        };
      }
      logger.log.apply(this, arguments);
  } : function() { /* no op */ };

  /**
   * Log dust debug statements, info statements, warning statements, and errors.
   * Filters out the messages based on the dust.debuglevel.
   * This default implementation will print to the console if it exists.
   * @param {String|Error} message the message to print/throw
   * @param {String} type the severity of the message(ERROR, WARN, INFO, or DEBUG)
   * @public
   */
  dust.log = function(message, type) {
    type = type || INFO;
    if (dust.debugLevel !== NONE && dust.indexInArray(loggingLevels, type) >= dust.indexInArray(loggingLevels, dust.debugLevel)) {
      if(!dust.logQueue) {
        dust.logQueue = [];
      }
      dust.logQueue.push({message: message, type: type});
      logger.log('[DUST ' + type + ']: ' + message);
    }
  };

  dust.helpers = {};

  dust.cache = {};

  dust.register = function(name, tmpl) {
    if (!name) {
      return;
    }
    dust.cache[name] = tmpl;
  };

  dust.render = function(name, context, callback) {
    var chunk = new Stub(callback).head;
    try {
      dust.load(name, chunk, Context.wrap(context, name)).end();
    } catch (err) {
      chunk.setError(err);
    }
  };

  dust.stream = function(name, context) {
    var stream = new Stream(),
        chunk = stream.head;
    dust.nextTick(function() {
      try {
        dust.load(name, stream.head, Context.wrap(context, name)).end();
      } catch (err) {
        chunk.setError(err);
      }
    });
    return stream;
  };

  dust.renderSource = function(source, context, callback) {
    return dust.compileFn(source)(context, callback);
  };

  dust.compileFn = function(source, name) {
    // name is optional. When name is not provided the template can only be rendered using the callable returned by this function.
    // If a name is provided the compiled template can also be rendered by name.
    name = name || null;
    var tmpl = dust.loadSource(dust.compile(source, name));
    return function(context, callback) {
      var master = callback ? new Stub(callback) : new Stream();
      dust.nextTick(function() {
        if(typeof tmpl === 'function') {
          tmpl(master.head, Context.wrap(context, name)).end();
        }
        else {
          dust.log(new Error('Template [' + name + '] cannot be resolved to a Dust function'), ERROR);
        }
      });
      return master;
    };
  };

  dust.load = function(name, chunk, context) {
    var tmpl = dust.cache[name];
    if (tmpl) {
      return tmpl(chunk, context);
    } else {
      if (dust.onLoad) {
        return chunk.map(function(chunk) {
          dust.onLoad(name, function(err, src) {
            if (err) {
              return chunk.setError(err);
            }
            if (!dust.cache[name]) {
              dust.loadSource(dust.compile(src, name));
            }
            dust.cache[name](chunk, context).end();
          });
        });
      }
      return chunk.setError(new Error('Template Not Found: ' + name));
    }
  };

  dust.loadSource = function(source, path) {
    return eval(source);
  };

  if (Array.isArray) {
    dust.isArray = Array.isArray;
  } else {
    dust.isArray = function(arr) {
      return Object.prototype.toString.call(arr) === '[object Array]';
    };
  }

  // indexOf shim for arrays for IE <= 8
  // source: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/indexOf
  dust.indexInArray = function(arr, item, fromIndex) {
    fromIndex = +fromIndex || 0;
    if (Array.prototype.indexOf) {
      return arr.indexOf(item, fromIndex);
    } else {
    if ( arr === undefined || arr === null ) {
      throw new TypeError( 'cannot call method "indexOf" of null' );
    }

    var length = arr.length; // Hack to convert object.length to a UInt32

    if (Math.abs(fromIndex) === Infinity) {
      fromIndex = 0;
    }

    if (fromIndex < 0) {
      fromIndex += length;
      if (fromIndex < 0) {
        fromIndex = 0;
      }
    }

    for (;fromIndex < length; fromIndex++) {
      if (arr[fromIndex] === item) {
        return fromIndex;
      }
    }

    return -1;
    }
  };

  dust.nextTick = (function() {
    return function(callback) {
      setTimeout(callback,0);
    };
  } )();

  dust.isEmpty = function(value) {
    if (dust.isArray(value) && !value.length) {
      return true;
    }
    if (value === 0) {
      return false;
    }
    return (!value);
  };

  // apply the filter chain and return the output string
  dust.filter = function(string, auto, filters) {
    if (filters) {
      for (var i=0, len=filters.length; i<len; i++) {
        var name = filters[i];
        if (name === 's') {
          auto = null;
        }
        else if (typeof dust.filters[name] === 'function') {
          string = dust.filters[name](string);
        }
        else {
          dust.log('Invalid filter [' + name + ']', WARN);
        }
      }
    }
    // by default always apply the h filter, unless asked to unescape with |s
    if (auto) {
      string = dust.filters[auto](string);
    }
    return string;
  };

  dust.filters = {
    h: function(value) { return dust.escapeHtml(value); },
    j: function(value) { return dust.escapeJs(value); },
    u: encodeURI,
    uc: encodeURIComponent,
    js: function(value) {
      if (!JSON) {
        dust.log('JSON is undefined.  JSON stringify has not been used on [' + value + ']', WARN);
        return value;
      } else {
        return JSON.stringify(value);
      }
    },
    jp: function(value) {
      if (!JSON) {dust.log('JSON is undefined.  JSON parse has not been used on [' + value + ']', WARN);
        return value;
      } else {
        return JSON.parse(value);
      }
    }
  };

  function Context(stack, global, blocks, templateName) {
    this.stack  = stack;
    this.global = global;
    this.blocks = blocks;
    this.templateName = templateName;
  }

  dust.makeBase = function(global) {
    return new Context(new Stack(), global);
  };

  Context.wrap = function(context, name) {
    if (context instanceof Context) {
      return context;
    }
    return new Context(new Stack(context), {}, null, name);
  };

  /**
   * Public API for getting a value from the context.
   * @method get
   * @param {string|array} path The path to the value. Supported formats are:
   * 'key'
   * 'path.to.key'
   * '.path.to.key'
   * ['path', 'to', 'key']
   * ['key']
   * @param {boolean} [cur=false] Boolean which determines if the search should be limited to the
   * current context (true), or if get should search in parent contexts as well (false).
   * @public
   * @returns {string|object}
   */
  Context.prototype.get = function(path, cur) {
    if (typeof path === 'string') {
      if (path[0] === '.') {
        cur = true;
        path = path.substr(1);
      }
      path = path.split('.');
    }
    return this._get(cur, path);
  };

  /**
   * Get a value from the context
   * @method _get
   * @param {boolean} cur Get only from the current context
   * @param {array} down An array of each step in the path
   * @private
   * @return {string | object}
   */
  Context.prototype._get = function(cur, down) {
    var ctx = this.stack,
        i = 1,
        value, first, len, ctxThis;
    first = down[0];
    len = down.length;

    if (cur && len === 0) {
      ctxThis = ctx;
      ctx = ctx.head;
    } else {
      if (!cur) {
        // Search up the stack for the first value
        while (ctx) {
          if (ctx.isObject) {
            ctxThis = ctx.head;
            value = ctx.head[first];
            if (value !== undefined) {
              break;
            }
          }
          ctx = ctx.tail;
        }

        if (value !== undefined) {
          ctx = value;
        } else {
          ctx = this.global ? this.global[first] : undefined;
        }
      } else if (ctx) {
        // if scope is limited by a leading dot, don't search up the tree
        if(ctx.head) {
          ctx = ctx.head[first];
        } else {
          //context's head is empty, value we are searching for is not defined
          ctx = undefined;
        }
      }

      while (ctx && i < len) {
        ctxThis = ctx;
        ctx = ctx[down[i]];
        i++;
      }
    }

    // Return the ctx or a function wrapping the application of the context.
    if (typeof ctx === 'function') {
      return function() {
        try {
          return ctx.apply(ctxThis, arguments);
        } catch (err) {
          dust.log(err, ERROR);
          throw err;
        }
      };
    } else {
      if (ctx === undefined) {
        dust.log('Cannot find the value for reference [{' + down.join('.') + '}] in template [' + this.getTemplateName() + ']');
      }
      return ctx;
    }
  };

  Context.prototype.getPath = function(cur, down) {
    return this._get(cur, down);
  };

  Context.prototype.push = function(head, idx, len) {
    return new Context(new Stack(head, this.stack, idx, len), this.global, this.blocks, this.getTemplateName());
  };

  Context.prototype.rebase = function(head) {
    return new Context(new Stack(head), this.global, this.blocks, this.getTemplateName());
  };

  Context.prototype.current = function() {
    return this.stack.head;
  };

  Context.prototype.getBlock = function(key, chk, ctx) {
    if (typeof key === 'function') {
      var tempChk = new Chunk();
      key = key(tempChk, this).data.join('');
    }

    var blocks = this.blocks;

    if (!blocks) {
      dust.log('No blocks for context[{' + key + '}] in template [' + this.getTemplateName() + ']', DEBUG);
      return;
    }
    var len = blocks.length, fn;
    while (len--) {
      fn = blocks[len][key];
      if (fn) {
        return fn;
      }
    }
  };

  Context.prototype.shiftBlocks = function(locals) {
    var blocks = this.blocks,
        newBlocks;

    if (locals) {
      if (!blocks) {
        newBlocks = [locals];
      } else {
        newBlocks = blocks.concat([locals]);
      }
      return new Context(this.stack, this.global, newBlocks, this.getTemplateName());
    }
    return this;
  };

  Context.prototype.getTemplateName = function() {
    return this.templateName;
  };

  function Stack(head, tail, idx, len) {
    this.tail = tail;
    this.isObject = head && typeof head === 'object';
    this.head = head;
    this.index = idx;
    this.of = len;
  }

  function Stub(callback) {
    this.head = new Chunk(this);
    this.callback = callback;
    this.out = '';
  }

  Stub.prototype.flush = function() {
    var chunk = this.head;

    while (chunk) {
      if (chunk.flushable) {
        this.out += chunk.data.join(''); //ie7 perf
      } else if (chunk.error) {
        this.callback(chunk.error);
        dust.log('Chunk error [' + chunk.error + '] thrown. Ceasing to render this template.', WARN);
        this.flush = EMPTY_FUNC;
        return;
      } else {
        return;
      }
      chunk = chunk.next;
      this.head = chunk;
    }
    this.callback(null, this.out);
  };

  function Stream() {
    this.head = new Chunk(this);
  }

  Stream.prototype.flush = function() {
    var chunk = this.head;

    while(chunk) {
      if (chunk.flushable) {
        this.emit('data', chunk.data.join('')); //ie7 perf
      } else if (chunk.error) {
        this.emit('error', chunk.error);
        dust.log('Chunk error [' + chunk.error + '] thrown. Ceasing to render this template.', WARN);
        this.flush = EMPTY_FUNC;
        return;
      } else {
        return;
      }
      chunk = chunk.next;
      this.head = chunk;
    }
    this.emit('end');
  };

  Stream.prototype.emit = function(type, data) {
    if (!this.events) {
      dust.log('No events to emit', INFO);
      return false;
    }
    var handler = this.events[type];
    if (!handler) {
      dust.log('Event type [' + type + '] does not exist', WARN);
      return false;
    }
    if (typeof handler === 'function') {
      handler(data);
    } else if (dust.isArray(handler)) {
      var listeners = handler.slice(0);
      for (var i = 0, l = listeners.length; i < l; i++) {
        listeners[i](data);
      }
    } else {
      dust.log('Event Handler [' + handler + '] is not of a type that is handled by emit', WARN);
    }
  };

  Stream.prototype.on = function(type, callback) {
    if (!this.events) {
      this.events = {};
    }
    if (!this.events[type]) {
      dust.log('Event type [' + type + '] does not exist. Using just the specified callback.', WARN);
      if(callback) {
        this.events[type] = callback;
      } else {
        dust.log('Callback for type [' + type + '] does not exist. Listener not registered.', WARN);
      }
    } else if(typeof this.events[type] === 'function') {
      this.events[type] = [this.events[type], callback];
    } else {
      this.events[type].push(callback);
    }
    return this;
  };

  Stream.prototype.pipe = function(stream) {
    this.on('data', function(data) {
      try {
        stream.write(data, 'utf8');
      } catch (err) {
        dust.log(err, ERROR);
      }
    }).on('end', function() {
      try {
        return stream.end();
      } catch (err) {
        dust.log(err, ERROR);
      }
    }).on('error', function(err) {
      stream.error(err);
    });
    return this;
  };

  function Chunk(root, next, taps) {
    this.root = root;
    this.next = next;
    this.data = []; //ie7 perf
    this.flushable = false;
    this.taps = taps;
  }

  Chunk.prototype.write = function(data) {
    var taps  = this.taps;

    if (taps) {
      data = taps.go(data);
    }
    this.data.push(data);
    return this;
  };

  Chunk.prototype.end = function(data) {
    if (data) {
      this.write(data);
    }
    this.flushable = true;
    this.root.flush();
    return this;
  };

  Chunk.prototype.map = function(callback) {
    var cursor = new Chunk(this.root, this.next, this.taps),
        branch = new Chunk(this.root, cursor, this.taps);

    this.next = branch;
    this.flushable = true;
    try {
      callback(branch);
    } catch(e) {
      dust.log(e, ERROR);
      branch.setError(e);
    }
    return cursor;
  };

  Chunk.prototype.tap = function(tap) {
    var taps = this.taps;

    if (taps) {
      this.taps = taps.push(tap);
    } else {
      this.taps = new Tap(tap);
    }
    return this;
  };

  Chunk.prototype.untap = function() {
    this.taps = this.taps.tail;
    return this;
  };

  Chunk.prototype.render = function(body, context) {
    return body(this, context);
  };

  Chunk.prototype.reference = function(elem, context, auto, filters) {
    if (typeof elem === 'function') {
      // Changed the function calling to use apply with the current context to make sure
      // that "this" is wat we expect it to be inside the function
      elem = elem.apply(context.current(), [this, context, null, {auto: auto, filters: filters}]);
      if (elem instanceof Chunk) {
        return elem;
      }
    }
    if (!dust.isEmpty(elem)) {
      return this.write(dust.filter(elem, auto, filters));
    } else {
      return this;
    }
  };

  Chunk.prototype.section = function(elem, context, bodies, params) {
    // anonymous functions
    if (typeof elem === 'function') {
      try {
        elem = elem.apply(context.current(), [this, context, bodies, params]);
      } catch(e) {
        dust.log(e, ERROR);
        return this.setError(e);
      }
      // functions that return chunks are assumed to have handled the body and/or have modified the chunk
      // use that return value as the current chunk and go to the next method in the chain
      if (elem instanceof Chunk) {
        return elem;
      }
    }
    var body = bodies.block,
        skip = bodies['else'];

    // a.k.a Inline parameters in the Dust documentations
    if (params) {
      context = context.push(params);
    }

    /*
    Dust's default behavior is to enumerate over the array elem, passing each object in the array to the block.
    When elem resolves to a value or object instead of an array, Dust sets the current context to the value
    and renders the block one time.
    */
    //non empty array is truthy, empty array is falsy
    if (dust.isArray(elem)) {
      if (body) {
        var len = elem.length, chunk = this;
        if (len > 0) {
          // any custom helper can blow up the stack
          // and store a flattened context, guard defensively
          if(context.stack.head) {
            context.stack.head['$len'] = len;
          }
          for (var i=0; i<len; i++) {
            if(context.stack.head) {
              context.stack.head['$idx'] = i;
            }
            chunk = body(chunk, context.push(elem[i], i, len));
          }
          if(context.stack.head) {
            context.stack.head['$idx'] = undefined;
            context.stack.head['$len'] = undefined;
          }
          return chunk;
        }
        else if (skip) {
          return skip(this, context);
        }
      }
    } else if (elem  === true) {
     // true is truthy but does not change context
      if (body) {
        return body(this, context);
      }
    } else if (elem || elem === 0) {
       // everything that evaluates to true are truthy ( e.g. Non-empty strings and Empty objects are truthy. )
       // zero is truthy
       // for anonymous functions that did not returns a chunk, truthiness is evaluated based on the return value
      if (body) {
        return body(this, context.push(elem));
      }
     // nonexistent, scalar false value, scalar empty string, null,
     // undefined are all falsy
    } else if (skip) {
      return skip(this, context);
    }
    dust.log('Not rendering section (#) block in template [' + context.getTemplateName() + '], because above key was not found', DEBUG);
    return this;
  };

  Chunk.prototype.exists = function(elem, context, bodies) {
    var body = bodies.block,
        skip = bodies['else'];

    if (!dust.isEmpty(elem)) {
      if (body) {
        return body(this, context);
      }
    } else if (skip) {
      return skip(this, context);
    }
    dust.log('Not rendering exists (?) block in template [' + context.getTemplateName() + '], because above key was not found', DEBUG);
    return this;
  };

  Chunk.prototype.notexists = function(elem, context, bodies) {
    var body = bodies.block,
        skip = bodies['else'];

    if (dust.isEmpty(elem)) {
      if (body) {
        return body(this, context);
      }
    } else if (skip) {
      return skip(this, context);
    }
    dust.log('Not rendering not exists (^) block check in template [' + context.getTemplateName() + '], because above key was found', DEBUG);
    return this;
  };

  Chunk.prototype.block = function(elem, context, bodies) {
    var body = bodies.block;

    if (elem) {
      body = elem;
    }

    if (body) {
      return body(this, context);
    }
    return this;
  };

  Chunk.prototype.partial = function(elem, context, params) {
    var partialContext;
    //put the params context second to match what section does. {.} matches the current context without parameters
    // start with an empty context
    partialContext = dust.makeBase(context.global);
    partialContext.blocks = context.blocks;
    if (context.stack && context.stack.tail){
      // grab the stack(tail) off of the previous context if we have it
      partialContext.stack = context.stack.tail;
    }
    if (params){
      //put params on
      partialContext = partialContext.push(params);
    }

    if(typeof elem === 'string') {
      partialContext.templateName = elem;
    }

    //reattach the head
    partialContext = partialContext.push(context.stack.head);

    var partialChunk;
    if (typeof elem === 'function') {
      partialChunk = this.capture(elem, partialContext, function(name, chunk) {
        partialContext.templateName = partialContext.templateName || name;
        dust.load(name, chunk, partialContext).end();
      });
    } else {
      partialChunk = dust.load(elem, this, partialContext);
    }
    return partialChunk;
  };

  Chunk.prototype.helper = function(name, context, bodies, params) {
    var chunk = this;
    // handle invalid helpers, similar to invalid filters
    if(dust.helpers[name]) {
      try {
        return dust.helpers[name](chunk, context, bodies, params);
      } catch(e) {
        dust.log('Error in ' + name + ' helper: ' + e, ERROR);
        return chunk.setError(e);
      }
    } else {
      dust.log('Invalid helper [' + name + ']', WARN);
      return chunk;
    }
  };

  Chunk.prototype.capture = function(body, context, callback) {
    return this.map(function(chunk) {
      var stub = new Stub(function(err, out) {
        if (err) {
          chunk.setError(err);
        } else {
          callback(out, chunk);
        }
      });
      body(stub.head, context).end();
    });
  };

  Chunk.prototype.setError = function(err) {
    this.error = err;
    this.root.flush();
    return this;
  };

  function Tap(head, tail) {
    this.head = head;
    this.tail = tail;
  }

  Tap.prototype.push = function(tap) {
    return new Tap(tap, this);
  };

  Tap.prototype.go = function(value) {
    var tap = this;

    while(tap) {
      value = tap.head(value);
      tap = tap.tail;
    }
    return value;
  };

  var HCHARS = new RegExp(/[&<>\"\']/),
      AMP    = /&/g,
      LT     = /</g,
      GT     = />/g,
      QUOT   = /\"/g,
      SQUOT  = /\'/g;

  dust.escapeHtml = function(s) {
    if (typeof s === 'string') {
      if (!HCHARS.test(s)) {
        return s;
      }
      return s.replace(AMP,'&amp;').replace(LT,'&lt;').replace(GT,'&gt;').replace(QUOT,'&quot;').replace(SQUOT, '&#39;');
    }
    return s;
  };

  var BS = /\\/g,
      FS = /\//g,
      CR = /\r/g,
      LS = /\u2028/g,
      PS = /\u2029/g,
      NL = /\n/g,
      LF = /\f/g,
      SQ = /'/g,
      DQ = /"/g,
      TB = /\t/g;

  dust.escapeJs = function(s) {
    if (typeof s === 'string') {
      return s
        .replace(BS, '\\\\')
        .replace(FS, '\\/')
        .replace(DQ, '\\"')
        .replace(SQ, '\\\'')
        .replace(CR, '\\r')
        .replace(LS, '\\u2028')
        .replace(PS, '\\u2029')
        .replace(NL, '\\n')
        .replace(LF, '\\f')
        .replace(TB, '\\t');
    }
    return s;
  };


  if (typeof exports === 'object') {
    module.exports = dust;
  } else {
    root.dust = dust;
  }

})((function(){return this;})());