/**
 * Copyright 2015 IBM Corp.
 *
 * 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.
 **/

var when = require("when");
var fs = require("fs");
var path = require("path");


var localfilesystem = require("./localfilesystem");
var registry = require("./registry");

var settings;


function init(_settings) {
    settings = _settings;
    localfilesystem.init(settings);
}

function load(defaultNodesDir,disableNodePathScan) {
    var nodeFiles = localfilesystem.getNodeFiles(defaultNodesDir,disableNodePathScan);
    return loadNodeFiles(nodeFiles);
}

function loadNodeFiles(nodeFiles) {
    var promises = [];
    for (var module in nodeFiles) {
        /* istanbul ignore else */
        if (nodeFiles.hasOwnProperty(module)) {
            if (!registry.getModuleInfo(module)) {
                for (var node in nodeFiles[module].nodes) {
                    /* istanbul ignore else */
                    if (nodeFiles[module].nodes.hasOwnProperty(node)) {
                        try {
                            promises.push(loadNodeConfig(nodeFiles[module].nodes[node]))
                        } catch(err) {
                            //
                        }
                    }
                }
            }
        }
    }
    return when.settle(promises).then(function(results) {
        var nodes = results.map(function(r) { return r.value; });
        return loadNodeSetList(nodes);
    });
}

function loadNodeConfig(fileInfo) {
    return when.promise(function(resolve) {
        var file = fileInfo.file;
        var module = fileInfo.module;
        var name = fileInfo.name;
        var version = fileInfo.version;
        
        var id = module + "/" + name;
        var info = registry.getNodeInfo(id);
        var isEnabled = true;
        if (info) {
            if (info.hasOwnProperty("loaded")) {
                throw new Error(file+" already loaded");
            }
            isEnabled = info.enabled;
        }
    
        var node = {
            id: id,
            module: module,
            name: name,
            file: file,
            template: file.replace(/\.js$/,".html"),
            enabled: isEnabled,
            loaded:false
        };
    
        fs.readFile(node.template,'utf8', function(err,content) {
            if (err) {
                node.types = [];
                if (err.code === 'ENOENT') {
                    node.err = "Error: "+file+" does not exist";
                } else {
                    node.err = err.toString();
                }
            } else {                
                var types = [];
        
                var regExp = /<script ([^>]*)data-template-name=['"]([^'"]*)['"]/gi;
                var match = null;
        
                while((match = regExp.exec(content)) !== null) {
                    types.push(match[2]);
                }
                node.types = types;
                node.config = content;
        
                // TODO: parse out the javascript portion of the template
                //node.script = "";
                for (var i=0;i<node.types.length;i++) {
                    if (registry.getTypeId(node.types[i])) {
                        node.err = node.types[i]+" already registered";
                        break;
                    }
                }
            }
            registry.addNodeSet(id,node,version);
            resolve(node);
        });
    });
}



/**
 * Loads the specified node into the runtime
 * @param node a node info object - see loadNodeConfig
 * @return a promise that resolves to an update node info object. The object
 *         has the following properties added:
 *            err: any error encountered whilst loading the node
 *
 */
function loadNodeSet(node) {
    var nodeDir = path.dirname(node.file);
    var nodeFn = path.basename(node.file);
    if (!node.enabled) {
        return when.resolve(node);
    }
    try {
        var loadPromise = null;
        var r = require(node.file);
        if (typeof r === "function") {
            var promise = r(require('../../red'));
            if (promise != null && typeof promise.then === "function") {
                loadPromise = promise.then(function() {
                    node.enabled = true;
                    node.loaded = true;
                    return node;
                }).otherwise(function(err) {
                    node.err = err;
                    return node;
                });
            }
        }
        if (loadPromise == null) {
            node.enabled = true;
            node.loaded = true;
            loadPromise = when.resolve(node);
        }
        return loadPromise;
    } catch(err) {
        node.err = err;
        return when.resolve(node);
    }
}

function loadNodeSetList(nodes) {
    var promises = [];
    nodes.forEach(function(node) {
        if (!node.err) {
            promises.push(loadNodeSet(node));
        } else {
            promises.push(node);
        }
    });

    return when.settle(promises).then(function() {
        if (settings.available()) {
            return registry.saveNodeList();
        } else {
            return;
        }
    });
}

function addModule(module) {
    if (!settings.available()) {
        throw new Error("Settings unavailable");
    }
    var nodes = [];
    if (registry.getModuleInfo(module)) {
        return when.reject(new Error("Module already loaded"));
    }
    try {
        var moduleFiles = localfilesystem.getModuleFiles(module);
        return loadNodeFiles(moduleFiles);
    } catch(err) {
        return when.reject(err);
    }
}

module.exports = {
    init: init,
    load: load,
    addModule: addModule,
    loadNodeSet: loadNodeSet
}