var utils = require('./utils');
/**
 * Plugin Manager
 */
var PluginManager = function(less) {
    this.less = less;
    this.visitors = [];
    this.preProcessors = [];
    this.postProcessors = [];
    this.installedPlugins = [];
    this.fileManagers = [];
    this.iterator = -1;
    this.pluginCache = {};
    this.Loader = new less.PluginLoader(less);
};

var pm, PluginManagerFactory = function(less, newFactory) {
        if (newFactory || !pm) {
            pm = new PluginManager(less);
        }
        return pm;
    };

/**
 * Adds all the plugins in the array
 * @param {Array} plugins
 */
PluginManager.prototype.addPlugins = function(plugins) {
    if (plugins) {
        for (var i = 0; i < plugins.length; i++) {
            this.addPlugin(plugins[i]);
        }
    }
};
/**
 *
 * @param plugin
 * @param {String} filename
 */
PluginManager.prototype.addPlugin = function(plugin, filename, functionRegistry) {
    this.installedPlugins.push(plugin);
    if (filename) {
        this.pluginCache[filename] = plugin;
    }
    if (plugin.install) {
        plugin.install(this.less, this, functionRegistry || this.less.functions.functionRegistry);
    }
};
/**
 *
 * @param filename
 */
PluginManager.prototype.get = function(filename) {
    return this.pluginCache[filename];
};

/**
 * Deprecate eventually 
 */
function upgradeVisitors(visitor, oldType, newType) {

    if (visitor['visit' + oldType] && !visitor['visit' + newType]) {
        visitor['visit' + newType] = visitor['visit' + oldType];
    }
    if (visitor['visit' + oldType + 'Out'] && !visitor['visit' + newType + 'Out']) {
        visitor['visit' + newType + 'Out'] = visitor['visit' + oldType + 'Out'];
    }
}
/**
 * Adds a visitor. The visitor object has options on itself to determine
 * when it should run.
 * @param visitor
 */
PluginManager.prototype.addVisitor = function(visitor) {
    var proto;
    // 2.x to 3.x visitor compatibility
    try {
        proto = utils.getPrototype(visitor);
        upgradeVisitors(proto, 'Directive', 'AtRule');
        upgradeVisitors(proto, 'Rule', 'Declaration');
    }
    catch (e) {}

    this.visitors.push(visitor);
};
/**
 * Adds a pre processor object
 * @param {object} preProcessor
 * @param {number} priority - guidelines 1 = before import, 1000 = import, 2000 = after import
 */
PluginManager.prototype.addPreProcessor = function(preProcessor, priority) {
    var indexToInsertAt;
    for (indexToInsertAt = 0; indexToInsertAt < this.preProcessors.length; indexToInsertAt++) {
        if (this.preProcessors[indexToInsertAt].priority >= priority) {
            break;
        }
    }
    this.preProcessors.splice(indexToInsertAt, 0, {preProcessor: preProcessor, priority: priority});
};
/**
 * Adds a post processor object
 * @param {object} postProcessor
 * @param {number} priority - guidelines 1 = before compression, 1000 = compression, 2000 = after compression
 */
PluginManager.prototype.addPostProcessor = function(postProcessor, priority) {
    var indexToInsertAt;
    for (indexToInsertAt = 0; indexToInsertAt < this.postProcessors.length; indexToInsertAt++) {
        if (this.postProcessors[indexToInsertAt].priority >= priority) {
            break;
        }
    }
    this.postProcessors.splice(indexToInsertAt, 0, {postProcessor: postProcessor, priority: priority});
};
/**
 *
 * @param manager
 */
PluginManager.prototype.addFileManager = function(manager) {
    this.fileManagers.push(manager);
};
/**
 *
 * @returns {Array}
 * @private
 */
PluginManager.prototype.getPreProcessors = function() {
    var preProcessors = [];
    for (var i = 0; i < this.preProcessors.length; i++) {
        preProcessors.push(this.preProcessors[i].preProcessor);
    }
    return preProcessors;
};
/**
 *
 * @returns {Array}
 * @private
 */
PluginManager.prototype.getPostProcessors = function() {
    var postProcessors = [];
    for (var i = 0; i < this.postProcessors.length; i++) {
        postProcessors.push(this.postProcessors[i].postProcessor);
    }
    return postProcessors;
};
/**
 *
 * @returns {Array}
 * @private
 */
PluginManager.prototype.getVisitors = function() {
    return this.visitors;
};

PluginManager.prototype.visitor = function() {
    var self = this;
    return {
        first: function() {
            self.iterator = -1;
            return self.visitors[self.iterator];
        },
        get: function() {
            self.iterator += 1;
            return self.visitors[self.iterator];
        }
    };
};
/**
 *
 * @returns {Array}
 * @private
 */
PluginManager.prototype.getFileManagers = function() {
    return this.fileManagers;
};

// 
module.exports = PluginManagerFactory;