var util = require('util');
var _ = require('lodash');

var app = {};

/**
 * Worker
 *
 * Attaches defined data to parameter which inherit the data.
 * It uses 2 functions, preProcess and postProcess (with the result of preProcess).
 *
 * preProcess  Generates a list with [defineName][name][version] = value
 * postProcess Attach the preProcess data with the nearest version to the tree.
 *
 * @param {Object} _app
 */
function Worker(_app) {
    var self = this;

    // global variables
    app = _app;

    // class variables
    this.workers = {};

    // load worker
    var workers = Object.keys(app.workers);
    workers.forEach(function(worker) {
        if (_.isObject( app.workers[worker] )) {
            app.log.debug('inject worker: ' + worker);
            self.addWorker(worker, app.workers[worker] );
        } else {
            var filename = app.workers[worker];
            app.log.debug('load worker: ' + worker + ', ' + filename);
            self.addWorker(worker, require(filename));
        }
    });
}

/**
 * Inherit
 */
util.inherits(Worker, Object);

/**
 * Exports
 */
module.exports = Worker;

/**
 * Add Worker
 */
Worker.prototype.addWorker = function(name, worker) {
    this.workers[name] = worker;
};

/**
 * Execute worker
 *
 * @todo Add priority system (if needed), if a plugin need an other operation to be done before.
 */
Worker.prototype.process = function(parsedFiles, parsedFilenames, packageInfos) {
    // some smaller operation that are not outsourced to extra workers
    // TODO: add priority system first and outsource them then
    parsedFiles.forEach(function(parsedFile, fileIndex) {
        parsedFile.forEach(function(block) {
            if (Object.keys(block.global).length === 0 && Object.keys(block.local).length > 0) {
                if ( ! block.local.type)
                    block.local.type = '';

                if ( ! block.local.url)
                    block.local.url = '';

                if ( ! block.local.version)
                    block.local.version = packageInfos.defaultVersion;

                if ( ! block.local.filename)
                    block.local.filename = parsedFilenames[fileIndex];

                // convert dir delimeter \\ to /
                block.local.filename = block.local.filename.replace(/\\/g, '/');
            }

        });
    });

    // process transformations and assignments for each @api-Parameter
    var preProcessResults = {};

    _.each(this.workers, function(worker, name) {
        if (worker.preProcess) {
            app.log.verbose('worker preProcess: ' + name);
            var result = worker.preProcess(parsedFiles, parsedFilenames, packageInfos);
            _.extend(preProcessResults, result);
        }
    });
    _.each(this.workers, function(worker, name) {
        if (worker.postProcess) {
            app.log.verbose('worker postProcess: ' + name);
            worker.postProcess(parsedFiles, parsedFilenames, preProcessResults, packageInfos);
        }
    });
};
