var Handlebars = require("handlebars");

// BEGIN(BROWSER)
Handlebars.Compiler = function() {};
Handlebars.JavaScriptCompiler = function() {};

(function(Compiler, JavaScriptCompiler) {
  Compiler.OPCODE_MAP = {
    appendContent: 1,
    getContext: 2,
    lookupWithHelpers: 3,
    lookup: 4,
    append: 5,
    invokeMustache: 6,
    appendEscaped: 7,
    pushString: 8,
    truthyOrFallback: 9,
    functionOrFallback: 10,
    invokeProgram: 11,
    invokePartial: 12,
    push: 13,
    assignToHash: 15,
    pushStringParam: 16
  };

  Compiler.MULTI_PARAM_OPCODES = {
    appendContent: 1,
    getContext: 1,
    lookupWithHelpers: 1,
    lookup: 1,
    invokeMustache: 2,
    pushString: 1,
    truthyOrFallback: 1,
    functionOrFallback: 1,
    invokeProgram: 2,
    invokePartial: 1,
    push: 1,
    assignToHash: 1,
    pushStringParam: 1
  };

  Compiler.DISASSEMBLE_MAP = {};

  for(var prop in Compiler.OPCODE_MAP) {
    var value = Compiler.OPCODE_MAP[prop];
    Compiler.DISASSEMBLE_MAP[value] = prop;
  }

  Compiler.multiParamSize = function(code) {
    return Compiler.MULTI_PARAM_OPCODES[Compiler.DISASSEMBLE_MAP[code]];
  };

  Compiler.prototype = {
    compiler: Compiler,

    disassemble: function() {
      var opcodes = this.opcodes, opcode, nextCode;
      var out = [], str, name, value;

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

        if(opcode === 'DECLARE') {
          name = opcodes[++i];
          value = opcodes[++i];
          out.push("DECLARE " + name + " = " + value);
        } else {
          str = Compiler.DISASSEMBLE_MAP[opcode];

          var extraParams = Compiler.multiParamSize(opcode);
          var codes = [];

          for(var j=0; j<extraParams; j++) {
            nextCode = opcodes[++i];

            if(typeof nextCode === "string") {
              nextCode = "\"" + nextCode.replace("\n", "\\n") + "\"";
            }

            codes.push(nextCode);
          }

          str = str + " " + codes.join(" ");

          out.push(str);
        }
      }

      return out.join("\n");
    },

    guid: 0,

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

      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;
      var depth, child, inverse, inverseGuid;

      var params = this.setupStackForMustache(mustache);

      var programGuid = this.compileProgram(block.program);

      if(block.program.inverse) {
        inverseGuid = this.compileProgram(block.program.inverse);
        this.declare('inverse', inverseGuid);
      }

      this.opcode('invokeProgram', programGuid, params.length);
      this.declare('inverse', null);
      this.opcode('append');
    },

    inverse: function(block) {
      var params = this.setupStackForMustache(block.mustache);

      var programGuid = this.compileProgram(block.program);

      this.declare('inverse', programGuid);

      this.opcode('invokeProgram', null, params.length);
      this.opcode('append');
    },

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

      this.opcode('push', '{}');

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

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

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

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

      this.opcode('invokePartial', id.original);
      this.opcode('append');
    },

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

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

      this.opcode('invokeMustache', params.length, mustache.id.original);

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

    ID: function(id) {
      this.addDepth(id.depth);

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

      this.opcode('lookupWithHelpers', id.parts[0] || null);

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

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

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

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

    comment: function() {},

    // HELPERS
    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.string);
        } else {
          this[param.type](param);
        }
      }
    },

    opcode: function(name, val1, val2) {
      this.opcodes.push(Compiler.OPCODE_MAP[name]);
      if(val1 !== undefined) { this.opcodes.push(val1); }
      if(val2 !== undefined) { this.opcodes.push(val2); }
    },

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

    addDepth: function(depth) {
      if(depth === 0) { return; }

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

    setupStackForMustache: function(mustache) {
      var params = mustache.params;

      this.pushParams(params);

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

      this.ID(mustache.id);

      return params;
    }
  };

  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(JavaScriptCompiler.RESERVED_WORDS[name] || name.indexOf('-') !== -1 || !isNaN(name)) {
        return parent + "['" + name + "']";
      } else if (/^[0-9]+$/.test(name)) {
        return parent + "[" + name + "]";
      } else {
        return parent + "." + name;
      }
    },

    appendToBuffer: function(string) {
      return "buffer = buffer + " + string + ";";
    },

    initializeBuffer: function() {
      return this.quotedString("");
    },
    // END PUBLIC API

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

      this.preamble();

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

      this.compileChildren(environment, options);

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

      var opcodes = environment.opcodes, opcode, name, declareName, declareVal;

      this.i = 0;

      for(l=opcodes.length; this.i<l; this.i++) {
        opcode = this.nextOpcode(0);

        if(opcode[0] === 'DECLARE') {
          this.i = this.i + 2;
          this[opcode[1]] = opcode[2];
        } else {
          this.i = this.i + opcode[1].length;
          this[opcode[0]].apply(this, opcode[1]);
        }
      }

      return this.createFunction();
    },

    nextOpcode: function(n) {
      var opcodes = this.environment.opcodes, opcode = opcodes[this.i + n], name, val;
      var extraParams, codes;

      if(opcode === 'DECLARE') {
        name = opcodes[this.i + 1];
        val  = opcodes[this.i + 2];
        return ['DECLARE', name, val];
      } else {
        name = Compiler.DISASSEMBLE_MAP[opcode];

        extraParams = Compiler.multiParamSize(opcode);
        codes = [];

        for(var j=0; j<extraParams; j++) {
          codes.push(opcodes[this.i + j + 1 + n]);
        }

        return [name, codes];
      }
    },

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

    preamble: function() {
      var out = [];
      out.push("var buffer = " + this.initializeBuffer() + ", currentContext = context");

      var copies = "helpers = helpers || Handlebars.helpers;";
      if(this.environment.usePartial) { copies = copies + " partials = partials || Handlebars.partials;"; }
      out.push(copies);

      // 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;
    },

    createFunction: function() {
      var container = {
        escapeExpression: Handlebars.Utils.escapeExpression,
        invokePartial: Handlebars.VM.invokePartial,
        programs: [],
        program: function(i, helpers, partials, data) {
          var programWrapper = this.programs[i];
          if(data) {
            return Handlebars.VM.program(this.children[i], helpers, partials, data);
          } else if(programWrapper) {
            return programWrapper;
          } else {
            programWrapper = this.programs[i] = Handlebars.VM.program(this.children[i], helpers, partials);
            return programWrapper;
          }
        },
        programWithDepth: Handlebars.VM.programWithDepth,
        noop: Handlebars.VM.noop
      };
      var locals = this.stackVars.concat(this.registers.list);

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

      this.source[0] = this.source[0] + ";";

      this.source.push("return buffer;");

      var params = ["Handlebars", "context", "helpers", "partials"];

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

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

      if(params.length === 4 && !this.environment.usePartial) { params.pop(); }

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

      var fn = Function.apply(this, params);
      fn.displayName = "Handlebars.js";

      Handlebars.log(Handlebars.logger.DEBUG, fn.toString() + "\n\n");

      container.render = fn;

      container.children = this.environment.children;

      return function(context, options, $depth) {
        options = options || {};
        var args = [Handlebars, context, options.helpers, options.partials, options.data];
        var depth = Array.prototype.slice.call(arguments, 2);
        args = args.concat(depth);
        return container.render.apply(container, args);
      };
    },

    appendContent: function(content) {
      this.source.push(this.appendToBuffer(this.quotedString(content)));
    },

    append: function() {
      var local = this.popStack();
      this.source.push("if(" + local + " || " + local + " === 0) { " + this.appendToBuffer(local) + " }");
    },

    appendEscaped: function() {
      var opcode = this.nextOpcode(1), extra = "";

      if(opcode[0] === 'appendContent') {
        extra = " + " + this.quotedString(opcode[1][0]);
        this.eat(opcode);
      }

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

    getContext: function(depth) {
      if(this.lastContext !== depth) {
        this.lastContext = depth;

        if(depth === 0) {
          this.source.push("currentContext = context;");
        } else {
          this.source.push("currentContext = depth" + depth + ";");
        }
      }
    },

    lookupWithHelpers: function(name) {
      if(name) {
        var topStack = this.nextStack();

        var toPush =  "if('" + name + "' in helpers) { " + topStack +
                      " = " + this.nameLookup('helpers', name, 'helper') +
                      "; } else { " + topStack + " = " +
                      this.nameLookup('currentContext', name, 'context') +
                      "; }";

        this.source.push(toPush);
      } else {
        this.pushStack("currentContext");
      }
    },

    lookup: function(name) {
      var topStack = this.topStack();
      this.source.push(topStack + " = " + this.nameLookup(topStack, name, 'context') + ";");
    },

    pushStringParam: function(string) {
      this.pushStack("currentContext");
      this.pushString(string);
    },

    pushString: function(string) {
      this.pushStack(this.quotedString(string));
    },

    push: function(name) {
      this.pushStack(name);
    },

    invokeMustache: function(paramSize, original) {
      this.populateParams(paramSize, this.quotedString(original), "{}", null, function(nextStack, helperMissingString, id) {
        this.source.push("else if(" + id + "=== undefined) { " + nextStack + " = helpers.helperMissing.call(" + helperMissingString + "); }");
        this.source.push("else { " + nextStack + " = " + id + "; }");
      });
    },

    invokeProgram: function(guid, paramSize) {
      var inverse = this.programExpression(this.inverse);
      var mainProgram = this.programExpression(guid);

      this.populateParams(paramSize, null, mainProgram, inverse, function(nextStack, helperMissingString, id) {
        this.source.push("else { " + nextStack + " = helpers.blockHelperMissing.call(" + helperMissingString + "); }");
      });
    },

    populateParams: function(paramSize, helperId, program, inverse, fn) {
      var id = this.popStack(), nextStack;
      var params = [], param, stringParam;

      var hash = this.popStack();

      this.register('tmp1', program);
      this.source.push('tmp1.hash = ' + hash + ';');

      if(this.options.stringParams) {
        this.source.push('tmp1.contexts = [];');
      }

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

        if(this.options.stringParams) {
          this.source.push('tmp1.contexts.push(' + this.popStack() + ');');
        }
      }

      if(inverse) {
        this.source.push('tmp1.fn = tmp1;');
        this.source.push('tmp1.inverse = ' + inverse + ';');
      }

      if(this.options.data) {
        this.source.push('tmp1.data = data;');
      }

      params.push('tmp1');

      this.populateCall(params, id, helperId || id, fn);
    },

    populateCall: function(params, id, helperId, fn) {
      var paramString = ["context"].concat(params).join(", ");
      var helperMissingString = ["context"].concat(helperId).concat(params).join(", ");

      nextStack = this.nextStack();

      this.source.push("if(typeof " + id + " === 'function') { " + nextStack + " = " + id + ".call(" + paramString + "); }");
      fn.call(this, nextStack, helperMissingString, id);
    },

    invokePartial: function(context) {
      this.pushStack("this.invokePartial(" + this.nameLookup('partials', context, 'partial') + ", '" + context + "', " + this.popStack() + ", helpers, partials);");
    },

    assignToHash: function(key) {
      var value = this.popStack();
      var hash = this.topStack();

      this.source.push(hash + "['" + key + "'] = " + value + ";");
    },

    // HELPERS

    compiler: JavaScriptCompiler,

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

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

        compiled[i] = compiler.compile(child, options);
      }

      environment.rawChildren = children;
      environment.children = compiled;
    },

    programExpression: function(guid) {
      if(guid == null) { return "this.noop"; }

      var programParams = [guid, "helpers", "partials"];

      var depths = this.environment.rawChildren[guid].depths.list;

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

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

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

      if(!this.environment.usePartial) {
        if(programParams[3]) {
          programParams[2] = "null";
        } else {
          programParams.pop();
        }
      }

      if(depths.length === 0) {
        return "this.program(" + programParams.join(", ") + ")";
      } else {
        programParams[0] = "this.children[" + guid + "]";
        return "this.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);
      }
    },

    pushStack: function(item) {
      this.source.push(this.nextStack() + " = " + item + ";");
      return "stack" + this.stackSlot;
    },

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

    popStack: function() {
      return "stack" + this.stackSlot--;
    },

    topStack: function() {
      return "stack" + this.stackSlot;
    },

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

  var reservedWords = ("break case catch continue default delete do else finally " +
                       "for function if in instanceof new return switch this throw " + 
                       "try typeof var void while with null true false").split(" ");

  compilerWords = JavaScriptCompiler.RESERVED_WORDS = {};

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

})(Handlebars.Compiler, Handlebars.JavaScriptCompiler);

Handlebars.VM = {
  programWithDepth: function(fn, helpers, partials, data, $depth) {
    var args = Array.prototype.slice.call(arguments, 4);

    return function(context, options) {
      options = options || {};

      options = {
        helpers: options.helpers || helpers,
        partials: options.partials || partials,
        data: options.data || data
      };

      return fn.apply(this, [context, options].concat(args));
    };
  },
  program: function(fn, helpers, partials, data) {
    return function(context, options) {
      options = options || {};

      return fn(context, {
        helpers: options.helpers || helpers,
        partials: options.partials || partials,
        data: options.data || data
      });
    };
  },
  noop: function() { return ""; },
  compile: function(string, options) {
    var ast = Handlebars.parse(string);
    var environment = new Handlebars.Compiler().compile(ast, options);
    return new Handlebars.JavaScriptCompiler().compile(environment, options);
  },
  invokePartial: function(partial, name, context, helpers, partials) {
    if(partial === undefined) {
      throw new Handlebars.Exception("The partial " + name + " could not be found");
    } else if(partial instanceof Function) {
      return partial(context, {helpers: helpers, partials: partials});
    } else {
      partials[name] = Handlebars.VM.compile(partial);
      return partials[name](context, {helpers: helpers, partials: partials});
    }
  }
};

Handlebars.compile = Handlebars.VM.compile;
// END(BROWSER)