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

// BEGIN(BROWSER)

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

(function(Compiler, JavaScriptCompiler) {
  // 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");
    },

    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]);
      }
    },

    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];

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

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

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

    simpleMustache: function(mustache, program, inverse) {
      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 "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: [],
        aliases: { }
      };

      this.preamble();

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

      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, opcode = opcodes[this.i + 1];
      return opcodes[this.i + 1];
    },

    eat: function(opcode) {
      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) {
        var aliases = [];
        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]);
      }

      if (asObject) {
        params.push(this.source.join("\n  "));

        return Function.apply(this, params);
      } else {
        var functionSource = 'function ' + (this.name || '') + '(' + params.join(',') + ') {\n  ' + this.source.join("\n  ") + '}';
        Handlebars.log(Handlebars.logger.DEBUG, functionSource + "\n\n");
        return functionSource;
      }
    },

    // [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);

      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() {
      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() {
      var opcode = this.nextOpcode(), extra = "";
      this.context.aliases.escapeExpression = 'this.escapeExpression';

      if(opcode && opcode.opcode === 'appendContent') {
        extra = " + " + this.quotedString(opcode.args[0]);
        this.eat(opcode);
      }

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

    // [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.pushStack(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.pushStack(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.push('{}');

      if (this.options.stringParams) {
        this.register('hashTypes', '{}');
      }
    },

    // [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.pushStack(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.useRegister('foundHelper');

      this.pushStack("(foundHelper = " + helper.name + ") ? foundHelper.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.pushStack(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) {
      this.context.aliases.functionType = '"function"';

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

      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.pushStack("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();

      if (this.options.stringParams) {
        var type = this.popStack();
        this.popStack();
        this.source.push("hashTypes['" + key + "'] = " + type + ";");
      }

      var hash = this.topStack();

      this.source.push(hash + "['" + 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();

        this.context.programs.push('');     // Placeholder to prevent name conflicts for nested children
        var index = this.context.programs.length;
        child.index = index;
        child.name = 'program' + index;
        this.context.programs[index] = compiler.compile(child, options, this.context);
      }
    },

    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) {
      this.compileStack.push(new Literal(item));
      return item;
    },

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

    replaceStack: function(callback) {
      var stack = this.topStack(),
          item = callback.call(this, stack);

      // Prevent modification of the context depth variable. Through replaceStack
      if (/^depth/.test(stack)) {
        stack = this.nextStack();
      }

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

    nextStack: function(skipCompileStack) {
      var name = this.incrStack();
      this.compileStack.push(name);
      return name;
    },

    incrStack: function() {
      this.stackSlot++;
      if(this.stackSlot > this.stackVars.length) { this.stackVars.push("stack" + this.stackSlot); }
      return "stack" + this.stackSlot;
    },

    popStack: function() {
      var item = this.compileStack.pop();

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

    topStack: function() {
      var item = this.compileStack[this.compileStack.length - 1];

      if (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.Compiler, Handlebars.JavaScriptCompiler);

Handlebars.precompile = function(string, options) {
  if (typeof string !== 'string') {
    throw new Handlebars.Exception("You must pass a string to Handlebars.compile. You passed " + string);
  }

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

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

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