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;
      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, !!mustache.hash);
      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, !!block.mustache.hash);
      this.declare('inverse', null);
      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', 'depth0');
      }

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

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

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

      if (!mustache.eligibleHelper) {
        this.simpleMustache(mustache);
      } else if (mustache.isHelper) {
        this.helperMustache(mustache);
      } else {
        var params = this.setupStackForMustache(mustache),
            name = id.parts[0];

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

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

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

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

      if (id.parts.length) {
        this.opcode('lookupOnContext', id.parts[0]);
        for(var i=1, l=id.parts.length; i<l; i++) {
          this.opcode('lookup', id.parts[i]);
        }
      } else {
        this.opcode('pushContext');
      }
      this.opcode('resolvePossibleLambda');
    },

    helperMustache: function(mustache) {
      var params = this.setupMustacheParams(mustache),
          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 if (!id.isScoped && this.options.knownHelpers[name]) {
        this.declare('usingKnownHelper', true);
        this.opcode('knownHelper', name);
      } else if (id.isScoped || this.options.knownHelpersOnly) {
        this.declare('usingKnownHelper', false);
        this.opcode('lookupOnContext', name);
      } else {
        this.declare('usingKnownHelper', false);
        this.opcode('lookupWithHelpers', name);
      }

      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
    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(depth === 0) { return; }

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

    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);
        }
      }
    },

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

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

      return params;
    },

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

      this.ID(mustache.id);

      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: { },
        registers: {list: []}
      };

      this.preamble();

      this.stackSlot = 0;
      this.stackVars = [];
      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;"; }
        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;
      if (!this.isChild) {
        locals = locals.concat(this.context.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;
      }
    },

    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) + " }");
      if (this.environment.isSimple) {
        this.source.push("else { " + this.appendToBuffer("''") + " }");
      }
    },

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

    knownHelper: function(name) {
      this.pushStackLiteral(this.nameLookup('helpers', name, 'helper'));
    },

    lookupOnContext: function(name) {
      this.pushStack(this.nameLookup('depth' + this.lastContext, name, 'context'));
    },

    pushContext: function() {
      this.pushStackLiteral('depth' + this.lastContext);
    },

    resolvePossibleLambda: function() {
      this.context.aliases.functionType = '"function"';

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

    lookupWithHelpers: function(name) {
      this.register('foundHelper', this.nameLookup('helpers', name, 'helper'));
      this.pushStack("foundHelper || " + this.nameLookup('depth' + this.lastContext, name, 'context'));
    },

    lookup: function(name) {
      this.replaceStack(function(current) {
        return current + " == null || " + current + " === false ? " + current + " : " + this.nameLookup(current, name, 'context');
      });
    },

    pushStringParam: function(string) {
      this.pushStackLiteral('depth' + this.lastContext);
      this.pushString(string);
    },

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

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

    pushLiteral: function(value) {
      this.pushStackLiteral(value);
    },

    // The rules for mustaches are:
    //
    // If the first parameter resolves to a function, call the function with the remaining parameters
    // If the first parameter resolves to undefined, call helperMissing with the string form of the
    //   first parameter and the remaining parameters
    // Otherwise, if there is only one parameter, the expression evaluates to the value of the first
    //   parameter
    invokeMustache: function(paramSize, original) {
      this.populateParams(paramSize, this.quotedString(original), [], true, function(nextStack, helperMissingString, id) {
        this.context.aliases.helperMissing = 'helpers.helperMissing';
        this.context.aliases.undef = 'void 0';

        this.source.push("else if(" + id + "=== undef) { " + nextStack + " = helperMissing.call(" + helperMissingString + "); }");
        if (nextStack !== id) {
          this.source.push("else { " + nextStack + " = " + id + "; }");
        }
      });
    },

    // The rules for mustaches containing a block are:
    //
    // If the first parameter resolves to a function, call the function with the remaining parameters
    // Otherwise, invoke blockHelperMissing with the string form of the first parameter and the
    //   remaining parameters.
    invokeProgram: function(guid, paramSize) {
      var options = [], program, inverse;

      if (inverse = this.programExpression(this.inverse)) {
        options.push("inverse:" + inverse);
      }

      if (program = this.programExpression(guid)) {
        options.push("fn:" + program);
      }

      this.populateParams(paramSize, null, options, false, function(nextStack, helperMissingString) {
        this.context.aliases.blockHelperMissing = 'helpers.blockHelperMissing';
        this.source.push("else { " + nextStack + " = blockHelperMissing.call(" + helperMissingString + "); }");
      });
    },

    invokeHelper: function(paramSize, name) {
      this.context.aliases.helperMissing = 'helpers.helperMissing';

      var helper = this.setupHelper(paramSize, name);
      this.register('foundHelper', helper.name);

      this.pushStack("foundHelper ? foundHelper.call(" +
        helper.callParams + ") " + ": helperMissing.call(" +
        helper.helperMissingParams + ")");
    },

    invokeKnownHelper: function(paramSize, name) {
      var helper = this.setupHelper(paramSize, name);
      this.pushStack(helper.name + ".call(" + helper.callParams + ")");
    },

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

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

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

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

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

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

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

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

      params.push("{" + options.join(",") + "}");
      return params.join(", ");
    },

    populateParams: function(paramSize, helperId, options, resolveLambdas, callback) {
      var id = this.popStack(), nextStack;
      var params = [], contexts = [], param, paramString, stringOptions;

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

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

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

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

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

      this.register("params", "{" + options.join(",") + "}");

      params.push("params");

      if (this.usingKnownHelper) {
        this.pushStack(id + ".call(" + ["depth0"].concat(params).join(", ") + ")");
      } else {
        this.findAndCallHelper(params, id, helperId || id, resolveLambdas, callback);
      }
    },

    findAndCallHelper: function(params, id, helperId, resolveLambdas, callback) {
      this.useRegister('foundHelper');
      this.context.aliases.functionType = '"function"';

      var paramString = ["depth0"].concat(params).join(", "), nextStack;
      var helperMissingString = ["depth0"].concat(helperId).concat(params).join(", ");

      nextStack = this.nextStack();
      var condition = resolveLambdas ? "" : "foundHelper && ";

      this.source.push("if(" + condition + "typeof " + id + " === functionType) { " +
        nextStack + " = " + id + ".call(" + paramString + "); }");

      callback.call(this, nextStack, helperMissingString, id);
    },

    invokePartial: function(context) {
      var params = [this.nameLookup('partials', context, 'partial'), "'" + context + "'", this.popStack(), "helpers", "partials"];

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

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

    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;

      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.context.registers[name]) {
        this.context.registers[name] = true;
        this.context.registers.list.push(name);
      }
    },

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

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

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

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

    nextStack: function(skipCompileStack) {
      var name = this.incrStack();
      this.compileStack.push("stack" + this.stackSlot);
      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') + '"';
    }
  };

  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) {
  options = options || {};

  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) {
  options = options || {};

  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)