var compilerbase = require("./base");

exports.attach = function(Handlebars) {

compilerbase.attach(Handlebars);

// BEGIN(BROWSER)

/*jshint eqnull:true*/
var Compiler = Handlebars.Compiler = function() {};
var JavaScriptCompiler = Handlebars.JavaScriptCompiler = function() {};

// the foundHelper register will disambiguate helper lookup from finding a
// function in a context. This is necessary for mustache compatibility, which
// requires that context functions in blocks are evaluated by blockHelperMissing,
// and then proceed as if the resulting value was provided to blockHelperMissing.

Compiler.prototype = {
  compiler: Compiler,

  disassemble: function() {
    var opcodes = this.opcodes, opcode, out = [], params, param;

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

      if (opcode.opcode === 'DECLARE') {
        out.push("DECLARE " + opcode.name + "=" + opcode.value);
      } else {
        params = [];
        for (var j=0; j<opcode.args.length; j++) {
          param = opcode.args[j];
          if (typeof param === "string") {
            param = "\"" + param.replace("\n", "\\n") + "\"";
          }
          params.push(param);
        }
        out.push(opcode.opcode + " " + params.join(" "));
      }
    }

    return out.join("\n");
  },
  equals: function(other) {
    var len = this.opcodes.length;
    if (other.opcodes.length !== len) {
      return false;
    }

    for (var i = 0; i < len; i++) {
      var opcode = this.opcodes[i],
          otherOpcode = other.opcodes[i];
      if (opcode.opcode !== otherOpcode.opcode || opcode.args.length !== otherOpcode.args.length) {
        return false;
      }
      for (var j = 0; j < opcode.args.length; j++) {
        if (opcode.args[j] !== otherOpcode.args[j]) {
          return false;
        }
      }
    }

    len = this.children.length;
    if (other.children.length !== len) {
      return false;
    }
    for (i = 0; i < len; i++) {
      if (!this.children[i].equals(other.children[i])) {
        return false;
      }
    }

    return true;
  },

  guid: 0,

  compile: function(program, options) {
    this.children = [];
    this.depths = {list: []};
    this.options = options;

    // These changes will propagate to the other compiler components
    var knownHelpers = this.options.knownHelpers;
    this.options.knownHelpers = {
      'helperMissing': true,
      'blockHelperMissing': true,
      'each': true,
      'if': true,
      'unless': true,
      'with': true,
      'log': true
    };
    if (knownHelpers) {
      for (var name in knownHelpers) {
        this.options.knownHelpers[name] = knownHelpers[name];
      }
    }

    return this.program(program);
  },

  accept: function(node) {
    return this[node.type](node);
  },

  program: function(program) {
    var statements = program.statements, statement;
    this.opcodes = [];

    for(var i=0, l=statements.length; i<l; i++) {
      statement = statements[i];
      this[statement.type](statement);
    }
    this.isSimple = l === 1;

    this.depths.list = this.depths.list.sort(function(a, b) {
      return a - b;
    });

    return this;
  },

  compileProgram: function(program) {
    var result = new this.compiler().compile(program, this.options);
    var guid = this.guid++, depth;

    this.usePartial = this.usePartial || result.usePartial;

    this.children[guid] = result;

    for(var i=0, l=result.depths.list.length; i<l; i++) {
      depth = result.depths.list[i];

      if(depth < 2) { continue; }
      else { this.addDepth(depth - 1); }
    }

    return guid;
  },

  block: function(block) {
    var mustache = block.mustache,
        program = block.program,
        inverse = block.inverse;

    if (program) {
      program = this.compileProgram(program);
    }

    if (inverse) {
      inverse = this.compileProgram(inverse);
    }

    var type = this.classifyMustache(mustache);

    if (type === "helper") {
      this.helperMustache(mustache, program, inverse);
    } else if (type === "simple") {
      this.simpleMustache(mustache);

      // now that the simple mustache is resolved, we need to
      // evaluate it by executing `blockHelperMissing`
      this.opcode('pushProgram', program);
      this.opcode('pushProgram', inverse);
      this.opcode('emptyHash');
      this.opcode('blockValue');
    } else {
      this.ambiguousMustache(mustache, program, inverse);

      // now that the simple mustache is resolved, we need to
      // evaluate it by executing `blockHelperMissing`
      this.opcode('pushProgram', program);
      this.opcode('pushProgram', inverse);
      this.opcode('emptyHash');
      this.opcode('ambiguousBlockValue');
    }

    this.opcode('append');
  },

  hash: function(hash) {
    var pairs = hash.pairs, pair, val;

    this.opcode('pushHash');

    for(var i=0, l=pairs.length; i<l; i++) {
      pair = pairs[i];
      val  = pair[1];

      if (this.options.stringParams) {
        this.opcode('pushStringParam', val.stringModeValue, val.type);
      } else {
        this.accept(val);
      }

      this.opcode('assignToHash', pair[0]);
    }
    this.opcode('popHash');
  },

  partial: function(partial) {
    var partialName = partial.partialName;
    this.usePartial = true;

    if(partial.context) {
      this.ID(partial.context);
    } else {
      this.opcode('push', 'depth0');
    }

    this.opcode('invokePartial', partialName.name);
    this.opcode('append');
  },

  content: function(content) {
    this.opcode('appendContent', content.string);
  },

  mustache: function(mustache) {
    var options = this.options;
    var type = this.classifyMustache(mustache);

    if (type === "simple") {
      this.simpleMustache(mustache);
    } else if (type === "helper") {
      this.helperMustache(mustache);
    } else {
      this.ambiguousMustache(mustache);
    }

    if(mustache.escaped && !options.noEscape) {
      this.opcode('appendEscaped');
    } else {
      this.opcode('append');
    }
  },

  ambiguousMustache: function(mustache, program, inverse) {
    var id = mustache.id,
        name = id.parts[0],
        isBlock = program != null || inverse != null;

    this.opcode('getContext', id.depth);

    this.opcode('pushProgram', program);
    this.opcode('pushProgram', inverse);

    this.opcode('invokeAmbiguous', name, isBlock);
  },

  simpleMustache: function(mustache) {
    var id = mustache.id;

    if (id.type === 'DATA') {
      this.DATA(id);
    } else if (id.parts.length) {
      this.ID(id);
    } else {
      // Simplified ID for `this`
      this.addDepth(id.depth);
      this.opcode('getContext', id.depth);
      this.opcode('pushContext');
    }

    this.opcode('resolvePossibleLambda');
  },

  helperMustache: function(mustache, program, inverse) {
    var params = this.setupFullMustacheParams(mustache, program, inverse),
        name = mustache.id.parts[0];

    if (this.options.knownHelpers[name]) {
      this.opcode('invokeKnownHelper', params.length, name);
    } else if (this.knownHelpersOnly) {
      throw new Error("You specified knownHelpersOnly, but used the unknown helper " + name);
    } else {
      this.opcode('invokeHelper', params.length, name);
    }
  },

  ID: function(id) {
    this.addDepth(id.depth);
    this.opcode('getContext', id.depth);

    var name = id.parts[0];
    if (!name) {
      this.opcode('pushContext');
    } else {
      this.opcode('lookupOnContext', id.parts[0]);
    }

    for(var i=1, l=id.parts.length; i<l; i++) {
      this.opcode('lookup', id.parts[i]);
    }
  },

  DATA: function(data) {
    this.options.data = true;
    this.opcode('lookupData', data.id);
  },

  STRING: function(string) {
    this.opcode('pushString', string.string);
  },

  INTEGER: function(integer) {
    this.opcode('pushLiteral', integer.integer);
  },

  BOOLEAN: function(bool) {
    this.opcode('pushLiteral', bool.bool);
  },

  comment: function() {},

  // HELPERS
  opcode: function(name) {
    this.opcodes.push({ opcode: name, args: [].slice.call(arguments, 1) });
  },

  declare: function(name, value) {
    this.opcodes.push({ opcode: 'DECLARE', name: name, value: value });
  },

  addDepth: function(depth) {
    if(isNaN(depth)) { throw new Error("EWOT"); }
    if(depth === 0) { return; }

    if(!this.depths[depth]) {
      this.depths[depth] = true;
      this.depths.list.push(depth);
    }
  },

  classifyMustache: function(mustache) {
    var isHelper   = mustache.isHelper;
    var isEligible = mustache.eligibleHelper;
    var options    = this.options;

    // if ambiguous, we can possibly resolve the ambiguity now
    if (isEligible && !isHelper) {
      var name = mustache.id.parts[0];

      if (options.knownHelpers[name]) {
        isHelper = true;
      } else if (options.knownHelpersOnly) {
        isEligible = false;
      }
    }

    if (isHelper) { return "helper"; }
    else if (isEligible) { return "ambiguous"; }
    else { return "simple"; }
  },

  pushParams: function(params) {
    var i = params.length, param;

    while(i--) {
      param = params[i];

      if(this.options.stringParams) {
        if(param.depth) {
          this.addDepth(param.depth);
        }

        this.opcode('getContext', param.depth || 0);
        this.opcode('pushStringParam', param.stringModeValue, param.type);
      } else {
        this[param.type](param);
      }
    }
  },

  setupMustacheParams: function(mustache) {
    var params = mustache.params;
    this.pushParams(params);

    if(mustache.hash) {
      this.hash(mustache.hash);
    } else {
      this.opcode('emptyHash');
    }

    return params;
  },

  // this will replace setupMustacheParams when we're done
  setupFullMustacheParams: function(mustache, program, inverse) {
    var params = mustache.params;
    this.pushParams(params);

    this.opcode('pushProgram', program);
    this.opcode('pushProgram', inverse);

    if(mustache.hash) {
      this.hash(mustache.hash);
    } else {
      this.opcode('emptyHash');
    }

    return params;
  }
};

var Literal = function(value) {
  this.value = value;
};

JavaScriptCompiler.prototype = {
  // PUBLIC API: You can override these methods in a subclass to provide
  // alternative compiled forms for name lookup and buffering semantics
  nameLookup: function(parent, name /* , type*/) {
    if (/^[0-9]+$/.test(name)) {
      return parent + "[" + name + "]";
    } else if (JavaScriptCompiler.isValidJavaScriptVariableName(name)) {
      return parent + "." + name;
    }
    else {
      return parent + "['" + name + "']";
    }
  },

  appendToBuffer: function(string) {
    if (this.environment.isSimple) {
      return "return " + string + ";";
    } else {
      return {
        appendToBuffer: true,
        content: string,
        toString: function() { return "buffer += " + string + ";"; }
      };
    }
  },

  initializeBuffer: function() {
    return this.quotedString("");
  },

  namespace: "Handlebars",
  // END PUBLIC API

  compile: function(environment, options, context, asObject) {
    this.environment = environment;
    this.options = options || {};

    Handlebars.log(Handlebars.logger.DEBUG, this.environment.disassemble() + "\n\n");

    this.name = this.environment.name;
    this.isChild = !!context;
    this.context = context || {
      programs: [],
      environments: [],
      aliases: { }
    };

    this.preamble();

    this.stackSlot = 0;
    this.stackVars = [];
    this.registers = { list: [] };
    this.compileStack = [];
    this.inlineStack = [];

    this.compileChildren(environment, options);

    var opcodes = environment.opcodes, opcode;

    this.i = 0;

    for(l=opcodes.length; this.i<l; this.i++) {
      opcode = opcodes[this.i];

      if(opcode.opcode === 'DECLARE') {
        this[opcode.name] = opcode.value;
      } else {
        this[opcode.opcode].apply(this, opcode.args);
      }
    }

    return this.createFunctionContext(asObject);
  },

  nextOpcode: function() {
    var opcodes = this.environment.opcodes;
    return opcodes[this.i + 1];
  },

  eat: function() {
    this.i = this.i + 1;
  },

  preamble: function() {
    var out = [];

    if (!this.isChild) {
      var namespace = this.namespace;
      var copies = "helpers = helpers || " + namespace + ".helpers;";
      if (this.environment.usePartial) { copies = copies + " partials = partials || " + namespace + ".partials;"; }
      if (this.options.data) { copies = copies + " data = data || {};"; }
      out.push(copies);
    } else {
      out.push('');
    }

    if (!this.environment.isSimple) {
      out.push(", buffer = " + this.initializeBuffer());
    } else {
      out.push("");
    }

    // track the last context pushed into place to allow skipping the
    // getContext opcode when it would be a noop
    this.lastContext = 0;
    this.source = out;
  },

  createFunctionContext: function(asObject) {
    var locals = this.stackVars.concat(this.registers.list);

    if(locals.length > 0) {
      this.source[1] = this.source[1] + ", " + locals.join(", ");
    }

    // Generate minimizer alias mappings
    if (!this.isChild) {
      for (var alias in this.context.aliases) {
        this.source[1] = this.source[1] + ', ' + alias + '=' + this.context.aliases[alias];
      }
    }

    if (this.source[1]) {
      this.source[1] = "var " + this.source[1].substring(2) + ";";
    }

    // Merge children
    if (!this.isChild) {
      this.source[1] += '\n' + this.context.programs.join('\n') + '\n';
    }

    if (!this.environment.isSimple) {
      this.source.push("return buffer;");
    }

    var params = this.isChild ? ["depth0", "data"] : ["Handlebars", "depth0", "helpers", "partials", "data"];

    for(var i=0, l=this.environment.depths.list.length; i<l; i++) {
      params.push("depth" + this.environment.depths.list[i]);
    }

    // Perform a second pass over the output to merge content when possible
    var source = this.mergeSource();

    if (!this.isChild) {
      var revision = Handlebars.COMPILER_REVISION,
          versions = Handlebars.REVISION_CHANGES[revision];
      source = "this.compilerInfo = ["+revision+",'"+versions+"'];\n"+source;
    }

    if (asObject) {
      params.push(source);

      return Function.apply(this, params);
    } else {
      var functionSource = 'function ' + (this.name || '') + '(' + params.join(',') + ') {\n  ' + source + '}';
      Handlebars.log(Handlebars.logger.DEBUG, functionSource + "\n\n");
      return functionSource;
    }
  },
  mergeSource: function() {
    // WARN: We are not handling the case where buffer is still populated as the source should
    // not have buffer append operations as their final action.
    var source = '',
        buffer;
    for (var i = 0, len = this.source.length; i < len; i++) {
      var line = this.source[i];
      if (line.appendToBuffer) {
        if (buffer) {
          buffer = buffer + '\n    + ' + line.content;
        } else {
          buffer = line.content;
        }
      } else {
        if (buffer) {
          source += 'buffer += ' + buffer + ';\n  ';
          buffer = undefined;
        }
        source += line + '\n  ';
      }
    }
    return source;
  },

  // [blockValue]
  //
  // On stack, before: hash, inverse, program, value
  // On stack, after: return value of blockHelperMissing
  //
  // The purpose of this opcode is to take a block of the form
  // `{{#foo}}...{{/foo}}`, resolve the value of `foo`, and
  // replace it on the stack with the result of properly
  // invoking blockHelperMissing.
  blockValue: function() {
    this.context.aliases.blockHelperMissing = 'helpers.blockHelperMissing';

    var params = ["depth0"];
    this.setupParams(0, params);

    this.replaceStack(function(current) {
      params.splice(1, 0, current);
      return "blockHelperMissing.call(" + params.join(", ") + ")";
    });
  },

  // [ambiguousBlockValue]
  //
  // On stack, before: hash, inverse, program, value
  // Compiler value, before: lastHelper=value of last found helper, if any
  // On stack, after, if no lastHelper: same as [blockValue]
  // On stack, after, if lastHelper: value
  ambiguousBlockValue: function() {
    this.context.aliases.blockHelperMissing = 'helpers.blockHelperMissing';

    var params = ["depth0"];
    this.setupParams(0, params);

    var current = this.topStack();
    params.splice(1, 0, current);

    // Use the options value generated from the invocation
    params[params.length-1] = 'options';

    this.source.push("if (!" + this.lastHelper + ") { " + current + " = blockHelperMissing.call(" + params.join(", ") + "); }");
  },

  // [appendContent]
  //
  // On stack, before: ...
  // On stack, after: ...
  //
  // Appends the string value of `content` to the current buffer
  appendContent: function(content) {
    this.source.push(this.appendToBuffer(this.quotedString(content)));
  },

  // [append]
  //
  // On stack, before: value, ...
  // On stack, after: ...
  //
  // Coerces `value` to a String and appends it to the current buffer.
  //
  // If `value` is truthy, or 0, it is coerced into a string and appended
  // Otherwise, the empty string is appended
  append: function() {
    // Force anything that is inlined onto the stack so we don't have duplication
    // when we examine local
    this.flushInline();
    var local = this.popStack();
    this.source.push("if(" + local + " || " + local + " === 0) { " + this.appendToBuffer(local) + " }");
    if (this.environment.isSimple) {
      this.source.push("else { " + this.appendToBuffer("''") + " }");
    }
  },

  // [appendEscaped]
  //
  // On stack, before: value, ...
  // On stack, after: ...
  //
  // Escape `value` and append it to the buffer
  appendEscaped: function() {
    this.context.aliases.escapeExpression = 'this.escapeExpression';

    this.source.push(this.appendToBuffer("escapeExpression(" + this.popStack() + ")"));
  },

  // [getContext]
  //
  // On stack, before: ...
  // On stack, after: ...
  // Compiler value, after: lastContext=depth
  //
  // Set the value of the `lastContext` compiler value to the depth
  getContext: function(depth) {
    if(this.lastContext !== depth) {
      this.lastContext = depth;
    }
  },

  // [lookupOnContext]
  //
  // On stack, before: ...
  // On stack, after: currentContext[name], ...
  //
  // Looks up the value of `name` on the current context and pushes
  // it onto the stack.
  lookupOnContext: function(name) {
    this.push(this.nameLookup('depth' + this.lastContext, name, 'context'));
  },

  // [pushContext]
  //
  // On stack, before: ...
  // On stack, after: currentContext, ...
  //
  // Pushes the value of the current context onto the stack.
  pushContext: function() {
    this.pushStackLiteral('depth' + this.lastContext);
  },

  // [resolvePossibleLambda]
  //
  // On stack, before: value, ...
  // On stack, after: resolved value, ...
  //
  // If the `value` is a lambda, replace it on the stack by
  // the return value of the lambda
  resolvePossibleLambda: function() {
    this.context.aliases.functionType = '"function"';

    this.replaceStack(function(current) {
      return "typeof " + current + " === functionType ? " + current + ".apply(depth0) : " + current;
    });
  },

  // [lookup]
  //
  // On stack, before: value, ...
  // On stack, after: value[name], ...
  //
  // Replace the value on the stack with the result of looking
  // up `name` on `value`
  lookup: function(name) {
    this.replaceStack(function(current) {
      return current + " == null || " + current + " === false ? " + current + " : " + this.nameLookup(current, name, 'context');
    });
  },

  // [lookupData]
  //
  // On stack, before: ...
  // On stack, after: data[id], ...
  //
  // Push the result of looking up `id` on the current data
  lookupData: function(id) {
    this.push(this.nameLookup('data', id, 'data'));
  },

  // [pushStringParam]
  //
  // On stack, before: ...
  // On stack, after: string, currentContext, ...
  //
  // This opcode is designed for use in string mode, which
  // provides the string value of a parameter along with its
  // depth rather than resolving it immediately.
  pushStringParam: function(string, type) {
    this.pushStackLiteral('depth' + this.lastContext);

    this.pushString(type);

    if (typeof string === 'string') {
      this.pushString(string);
    } else {
      this.pushStackLiteral(string);
    }
  },

  emptyHash: function() {
    this.pushStackLiteral('{}');

    if (this.options.stringParams) {
      this.register('hashTypes', '{}');
    }
  },
  pushHash: function() {
    this.hash = {values: [], types: []};
  },
  popHash: function() {
    var hash = this.hash;
    this.hash = undefined;

    if (this.options.stringParams) {
      this.register('hashTypes', '{' + hash.types.join(',') + '}');
    }
    this.push('{\n    ' + hash.values.join(',\n    ') + '\n  }');
  },

  // [pushString]
  //
  // On stack, before: ...
  // On stack, after: quotedString(string), ...
  //
  // Push a quoted version of `string` onto the stack
  pushString: function(string) {
    this.pushStackLiteral(this.quotedString(string));
  },

  // [push]
  //
  // On stack, before: ...
  // On stack, after: expr, ...
  //
  // Push an expression onto the stack
  push: function(expr) {
    this.inlineStack.push(expr);
    return expr;
  },

  // [pushLiteral]
  //
  // On stack, before: ...
  // On stack, after: value, ...
  //
  // Pushes a value onto the stack. This operation prevents
  // the compiler from creating a temporary variable to hold
  // it.
  pushLiteral: function(value) {
    this.pushStackLiteral(value);
  },

  // [pushProgram]
  //
  // On stack, before: ...
  // On stack, after: program(guid), ...
  //
  // Push a program expression onto the stack. This takes
  // a compile-time guid and converts it into a runtime-accessible
  // expression.
  pushProgram: function(guid) {
    if (guid != null) {
      this.pushStackLiteral(this.programExpression(guid));
    } else {
      this.pushStackLiteral(null);
    }
  },

  // [invokeHelper]
  //
  // On stack, before: hash, inverse, program, params..., ...
  // On stack, after: result of helper invocation
  //
  // Pops off the helper's parameters, invokes the helper,
  // and pushes the helper's return value onto the stack.
  //
  // If the helper is not found, `helperMissing` is called.
  invokeHelper: function(paramSize, name) {
    this.context.aliases.helperMissing = 'helpers.helperMissing';

    var helper = this.lastHelper = this.setupHelper(paramSize, name, true);

    this.push(helper.name);
    this.replaceStack(function(name) {
      return name + ' ? ' + name + '.call(' +
          helper.callParams + ") " + ": helperMissing.call(" +
          helper.helperMissingParams + ")";
    });
  },

  // [invokeKnownHelper]
  //
  // On stack, before: hash, inverse, program, params..., ...
  // On stack, after: result of helper invocation
  //
  // This operation is used when the helper is known to exist,
  // so a `helperMissing` fallback is not required.
  invokeKnownHelper: function(paramSize, name) {
    var helper = this.setupHelper(paramSize, name);
    this.push(helper.name + ".call(" + helper.callParams + ")");
  },

  // [invokeAmbiguous]
  //
  // On stack, before: hash, inverse, program, params..., ...
  // On stack, after: result of disambiguation
  //
  // This operation is used when an expression like `{{foo}}`
  // is provided, but we don't know at compile-time whether it
  // is a helper or a path.
  //
  // This operation emits more code than the other options,
  // and can be avoided by passing the `knownHelpers` and
  // `knownHelpersOnly` flags at compile-time.
  invokeAmbiguous: function(name, helperCall) {
    this.context.aliases.functionType = '"function"';

    this.pushStackLiteral('{}');    // Hash value
    var helper = this.setupHelper(0, name, helperCall);

    var helperName = this.lastHelper = this.nameLookup('helpers', name, 'helper');

    var nonHelper = this.nameLookup('depth' + this.lastContext, name, 'context');
    var nextStack = this.nextStack();

    this.source.push('if (' + nextStack + ' = ' + helperName + ') { ' + nextStack + ' = ' + nextStack + '.call(' + helper.callParams + '); }');
    this.source.push('else { ' + nextStack + ' = ' + nonHelper + '; ' + nextStack + ' = typeof ' + nextStack + ' === functionType ? ' + nextStack + '.apply(depth0) : ' + nextStack + '; }');
  },

  // [invokePartial]
  //
  // On stack, before: context, ...
  // On stack after: result of partial invocation
  //
  // This operation pops off a context, invokes a partial with that context,
  // and pushes the result of the invocation back.
  invokePartial: function(name) {
    var params = [this.nameLookup('partials', name, 'partial'), "'" + name + "'", this.popStack(), "helpers", "partials"];

    if (this.options.data) {
      params.push("data");
    }

    this.context.aliases.self = "this";
    this.push("self.invokePartial(" + params.join(", ") + ")");
  },

  // [assignToHash]
  //
  // On stack, before: value, hash, ...
  // On stack, after: hash, ...
  //
  // Pops a value and hash off the stack, assigns `hash[key] = value`
  // and pushes the hash back onto the stack.
  assignToHash: function(key) {
    var value = this.popStack(),
        type;

    if (this.options.stringParams) {
      type = this.popStack();
      this.popStack();
    }

    var hash = this.hash;
    if (type) {
      hash.types.push("'" + key + "': " + type);
    }
    hash.values.push("'" + key + "': (" + value + ")");
  },

  // HELPERS

  compiler: JavaScriptCompiler,

  compileChildren: function(environment, options) {
    var children = environment.children, child, compiler;

    for(var i=0, l=children.length; i<l; i++) {
      child = children[i];
      compiler = new this.compiler();

      var index = this.matchExistingProgram(child);

      if (index == null) {
        this.context.programs.push('');     // Placeholder to prevent name conflicts for nested children
        index = this.context.programs.length;
        child.index = index;
        child.name = 'program' + index;
        this.context.programs[index] = compiler.compile(child, options, this.context);
        this.context.environments[index] = child;
      } else {
        child.index = index;
        child.name = 'program' + index;
      }
    }
  },
  matchExistingProgram: function(child) {
    for (var i = 0, len = this.context.environments.length; i < len; i++) {
      var environment = this.context.environments[i];
      if (environment && environment.equals(child)) {
        return i;
      }
    }
  },

  programExpression: function(guid) {
    this.context.aliases.self = "this";

    if(guid == null) {
      return "self.noop";
    }

    var child = this.environment.children[guid],
        depths = child.depths.list, depth;

    var programParams = [child.index, child.name, "data"];

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

      if(depth === 1) { programParams.push("depth0"); }
      else { programParams.push("depth" + (depth - 1)); }
    }

    if(depths.length === 0) {
      return "self.program(" + programParams.join(", ") + ")";
    } else {
      programParams.shift();
      return "self.programWithDepth(" + programParams.join(", ") + ")";
    }
  },

  register: function(name, val) {
    this.useRegister(name);
    this.source.push(name + " = " + val + ";");
  },

  useRegister: function(name) {
    if(!this.registers[name]) {
      this.registers[name] = true;
      this.registers.list.push(name);
    }
  },

  pushStackLiteral: function(item) {
    return this.push(new Literal(item));
  },

  pushStack: function(item) {
    this.flushInline();

    var stack = this.incrStack();
    if (item) {
      this.source.push(stack + " = " + item + ";");
    }
    this.compileStack.push(stack);
    return stack;
  },

  replaceStack: function(callback) {
    var prefix = '',
        inline = this.isInline(),
        stack;

    // If we are currently inline then we want to merge the inline statement into the
    // replacement statement via ','
    if (inline) {
      var top = this.popStack(true);

      if (top instanceof Literal) {
        // Literals do not need to be inlined
        stack = top.value;
      } else {
        // Get or create the current stack name for use by the inline
        var name = this.stackSlot ? this.topStackName() : this.incrStack();

        prefix = '(' + this.push(name) + ' = ' + top + '),';
        stack = this.topStack();
      }
    } else {
      stack = this.topStack();
    }

    var item = callback.call(this, stack);

    if (inline) {
      if (this.inlineStack.length || this.compileStack.length) {
        this.popStack();
      }
      this.push('(' + prefix + item + ')');
    } else {
      // Prevent modification of the context depth variable. Through replaceStack
      if (!/^stack/.test(stack)) {
        stack = this.nextStack();
      }

      this.source.push(stack + " = (" + prefix + item + ");");
    }
    return stack;
  },

  nextStack: function() {
    return this.pushStack();
  },

  incrStack: function() {
    this.stackSlot++;
    if(this.stackSlot > this.stackVars.length) { this.stackVars.push("stack" + this.stackSlot); }
    return this.topStackName();
  },
  topStackName: function() {
    return "stack" + this.stackSlot;
  },
  flushInline: function() {
    var inlineStack = this.inlineStack;
    if (inlineStack.length) {
      this.inlineStack = [];
      for (var i = 0, len = inlineStack.length; i < len; i++) {
        var entry = inlineStack[i];
        if (entry instanceof Literal) {
          this.compileStack.push(entry);
        } else {
          this.pushStack(entry);
        }
      }
    }
  },
  isInline: function() {
    return this.inlineStack.length;
  },

  popStack: function(wrapped) {
    var inline = this.isInline(),
        item = (inline ? this.inlineStack : this.compileStack).pop();

    if (!wrapped && (item instanceof Literal)) {
      return item.value;
    } else {
      if (!inline) {
        this.stackSlot--;
      }
      return item;
    }
  },

  topStack: function(wrapped) {
    var stack = (this.isInline() ? this.inlineStack : this.compileStack),
        item = stack[stack.length - 1];

    if (!wrapped && (item instanceof Literal)) {
      return item.value;
    } else {
      return item;
    }
  },

  quotedString: function(str) {
    return '"' + str
      .replace(/\\/g, '\\\\')
      .replace(/"/g, '\\"')
      .replace(/\n/g, '\\n')
      .replace(/\r/g, '\\r') + '"';
  },

  setupHelper: function(paramSize, name, missingParams) {
    var params = [];
    this.setupParams(paramSize, params, missingParams);
    var foundHelper = this.nameLookup('helpers', name, 'helper');

    return {
      params: params,
      name: foundHelper,
      callParams: ["depth0"].concat(params).join(", "),
      helperMissingParams: missingParams && ["depth0", this.quotedString(name)].concat(params).join(", ")
    };
  },

  // the params and contexts arguments are passed in arrays
  // to fill in
  setupParams: function(paramSize, params, useRegister) {
    var options = [], contexts = [], types = [], param, inverse, program;

    options.push("hash:" + this.popStack());

    inverse = this.popStack();
    program = this.popStack();

    // Avoid setting fn and inverse if neither are set. This allows
    // helpers to do a check for `if (options.fn)`
    if (program || inverse) {
      if (!program) {
        this.context.aliases.self = "this";
        program = "self.noop";
      }

      if (!inverse) {
       this.context.aliases.self = "this";
        inverse = "self.noop";
      }

      options.push("inverse:" + inverse);
      options.push("fn:" + program);
    }

    for(var i=0; i<paramSize; i++) {
      param = this.popStack();
      params.push(param);

      if(this.options.stringParams) {
        types.push(this.popStack());
        contexts.push(this.popStack());
      }
    }

    if (this.options.stringParams) {
      options.push("contexts:[" + contexts.join(",") + "]");
      options.push("types:[" + types.join(",") + "]");
      options.push("hashTypes:hashTypes");
    }

    if(this.options.data) {
      options.push("data:data");
    }

    options = "{" + options.join(",") + "}";
    if (useRegister) {
      this.register('options', options);
      params.push('options');
    } else {
      params.push(options);
    }
    return params.join(", ");
  }
};

var reservedWords = (
  "break else new var" +
  " case finally return void" +
  " catch for switch while" +
  " continue function this with" +
  " default if throw" +
  " delete in try" +
  " do instanceof typeof" +
  " abstract enum int short" +
  " boolean export interface static" +
  " byte extends long super" +
  " char final native synchronized" +
  " class float package throws" +
  " const goto private transient" +
  " debugger implements protected volatile" +
  " double import public let yield"
).split(" ");

var compilerWords = JavaScriptCompiler.RESERVED_WORDS = {};

for(var i=0, l=reservedWords.length; i<l; i++) {
  compilerWords[reservedWords[i]] = true;
}

JavaScriptCompiler.isValidJavaScriptVariableName = function(name) {
  if(!JavaScriptCompiler.RESERVED_WORDS[name] && /^[a-zA-Z_$][0-9a-zA-Z_$]+$/.test(name)) {
    return true;
  }
  return false;
};

Handlebars.precompile = function(input, options) {
  if (!input || (typeof input !== 'string' && input.constructor !== Handlebars.AST.ProgramNode)) {
    throw new Handlebars.Exception("You must pass a string or Handlebars AST to Handlebars.precompile. You passed " + input);
  }

  options = options || {};
  if (!('data' in options)) {
    options.data = true;
  }
  var ast = Handlebars.parse(input);
  var environment = new Compiler().compile(ast, options);
  return new JavaScriptCompiler().compile(environment, options);
};

Handlebars.compile = function(input, options) {
  if (!input || (typeof input !== 'string' && input.constructor !== Handlebars.AST.ProgramNode)) {
    throw new Handlebars.Exception("You must pass a string or Handlebars AST to Handlebars.compile. You passed " + input);
  }

  options = options || {};
  if (!('data' in options)) {
    options.data = true;
  }
  var compiled;
  function compile() {
    var ast = Handlebars.parse(input);
    var environment = new Compiler().compile(ast, options);
    var templateSpec = new JavaScriptCompiler().compile(environment, options, undefined, true);
    return Handlebars.template(templateSpec);
  }

  // Template is only compiled on first use and cached after that point.
  return function(context, options) {
    if (!compiled) {
      compiled = compile();
    }
    return compiled.call(this, context, options);
  };
};


// END(BROWSER)

return Handlebars;

};