//Explicity not strict since this file contains an eval call, and do not want
//to enforce strict on code evaluated that way. See
//https://github.com/requirejs/r.js/issues/774
/*jslint regexp: false, sloppy: true*/
/*global require: false, define: false, requirejsVars: false, process: false */

/**
 * This adapter assumes that x.js has loaded it and set up
 * some variables. This adapter just allows limited RequireJS
 * usage from within the requirejs directory. The general
 * node adapater is r.js.
 */

(function () {
    var nodeReq = requirejsVars.nodeRequire,
        req = requirejsVars.require,
        def = requirejsVars.define,
        fs = nodeReq('fs'),
        path = nodeReq('path'),
        vm = nodeReq('vm'),
        //In Node 0.7+ existsSync is on fs.
        exists = fs.existsSync || path.existsSync,
        hasOwn = Object.prototype.hasOwnProperty;

    function hasProp(obj, prop) {
        return hasOwn.call(obj, prop);
    }

    function syncTick(fn) {
        fn();
    }

    function makeError(message, moduleName) {
        var err = new Error(message);
        err.requireModules = [moduleName];
        return err;
    }

    //Supply an implementation that allows synchronous get of a module.
    req.get = function (context, moduleName, relModuleMap, localRequire) {
        if (moduleName === "require" || moduleName === "exports" || moduleName === "module") {
            context.onError(makeError("Explicit require of " + moduleName + " is not allowed.", moduleName));
        }

        var ret, oldTick,
            moduleMap = context.makeModuleMap(moduleName, relModuleMap, false, true);

        //Normalize module name, if it contains . or ..
        moduleName = moduleMap.id;

        if (hasProp(context.defined, moduleName)) {
            ret = context.defined[moduleName];
        } else {
            if (ret === undefined) {
                //Make sure nextTick for this type of call is sync-based.
                oldTick = context.nextTick;
                context.nextTick = syncTick;
                try {
                    if (moduleMap.prefix) {
                        //A plugin, call requirejs to handle it. Now that
                        //nextTick is syncTick, the require will complete
                        //synchronously.
                        localRequire([moduleMap.originalName]);

                        //Now that plugin is loaded, can regenerate the moduleMap
                        //to get the final, normalized ID.
                        moduleMap = context.makeModuleMap(moduleMap.originalName, relModuleMap, false, true);
                        moduleName = moduleMap.id;
                    } else {
                        //Try to dynamically fetch it.
                        req.load(context, moduleName, moduleMap.url);

                        //Enable the module
                        context.enable(moduleMap, relModuleMap);
                    }

                    //Break any cycles by requiring it normally, but this will
                    //finish synchronously
                    context.require([moduleName]);

                    //The above calls are sync, so can do the next thing safely.
                    ret = context.defined[moduleName];
                } finally {
                    context.nextTick = oldTick;
                }
            }
        }

        return ret;
    };

    req.nextTick = function (fn) {
        process.nextTick(fn);
    };

    //Add wrapper around the code so that it gets the requirejs
    //API instead of the Node API, and it is done lexically so
    //that it survives later execution.
    req.makeNodeWrapper = function (contents) {
        return '(function (require, requirejs, define) { ' +
                contents +
                '\n}(requirejsVars.require, requirejsVars.requirejs, requirejsVars.define));';
    };

    req.load = function (context, moduleName, url) {
        var contents, err,
            config = context.config;

        if (config.shim[moduleName] && (!config.suppress || !config.suppress.nodeShim)) {
            console.warn('Shim config not supported in Node, may or may not work. Detected ' +
                            'for module: ' + moduleName);
        }

        if (exists(url)) {
            contents = fs.readFileSync(url, 'utf8');

            contents = req.makeNodeWrapper(contents);
            try {
                vm.runInThisContext(contents, fs.realpathSync(url));
            } catch (e) {
                err = new Error('Evaluating ' + url + ' as module "' +
                                moduleName + '" failed with error: ' + e);
                err.originalError = e;
                err.moduleName = moduleName;
                err.requireModules = [moduleName];
                err.fileName = url;
                return context.onError(err);
            }
        } else {
            def(moduleName, function () {
                //Get the original name, since relative requires may be
                //resolved differently in node (issue #202). Also, if relative,
                //make it relative to the URL of the item requesting it
                //(issue #393)
                var dirName,
                    map = hasProp(context.registry, moduleName) &&
                            context.registry[moduleName].map,
                    parentMap = map && map.parentMap,
                    originalName = map && map.originalName;

                if (originalName.charAt(0) === '.' && parentMap) {
                    dirName = parentMap.url.split('/');
                    dirName.pop();
                    originalName = dirName.join('/') + '/' + originalName;
                }

                try {
                    return (context.config.nodeRequire || req.nodeRequire)(originalName);
                } catch (e) {
                    err = new Error('Tried loading "' + moduleName + '" at ' +
                                     url + ' then tried node\'s require("' +
                                        originalName + '") and it failed ' +
                                     'with error: ' + e);
                    err.originalError = e;
                    err.moduleName = originalName;
                    err.requireModules = [moduleName];
                    throw err;
                }
            });
        }

        //Support anonymous modules.
        context.completeLoad(moduleName);
    };

    //Override to provide the function wrapper for define/require.
    req.exec = function (text) {
        /*jslint evil: true */
        text = req.makeNodeWrapper(text);
        return eval(text);
    };
}());