/**

* Copyright 2013 Facebook, Inc.

*

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

*

* http://www.apache.org/licenses/LICENSE-2.0

*

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

*/

'use strict';

var recast = require('recast');

exports.propagate = function(constants, source) {

var ast = recast.parse(source);

ast = new ConstantVisitor(constants).visit(ast);

return recast.print(ast);

};

var ConstantVisitor = recast.Visitor.extend({

init: function(constants) {

this.constants = constants || {};

},

visitIdentifier: function(ident) {

if (this.constants.hasOwnProperty(ident.name)) {

return recast.builder.literal(this.constants[ident.name]);

}

},

visitCallExpression: function(call) {

if (!this.constants.__DEV__) {

if (call.callee.type === 'Identifier' && call.callee.name === 'invariant') {

call.arguments.length = 1;

}

}

this.genericVisit(call);

},

visitIfStatement: function(stmt) {

// Replaces all identifiers in this.constants with literal values.

this.genericVisit(stmt);

if (stmt.test.type === recast.Syntax.Literal) {

if (stmt.test.value) {

stmt.alternate = null;

} else if (stmt.alternate) {

return stmt.alternate;

} else {

this.remove();

}

}

}

});

if (!module.parent) {

var constants = JSON.parse(process.argv[3]);

recast.run(function(ast, callback) {

callback(new ConstantVisitor(constants).visit(ast));

});

}