/**
 * 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 events = require("../../events");

var settings;
var defaultNodesDir = path.resolve(path.join(__dirname,"..","..","..","nodes"));
var disableNodePathScan = false;

function init(_settings,_defaultNodesDir,_disableNodePathScan) {
    settings = _settings;
    if (_disableNodePathScan) {
        disableNodePathScan = _disableNodePathScan;
    }
    if (_defaultNodesDir) {
        defaultNodesDir = path.resolve(_defaultNodesDir);
    }
}


/**
 * Synchronously walks the directory looking for node files.
 * Emits 'node-icon-dir' events for an icon dirs found
 * @param dir the directory to search
 * @return an array of fully-qualified paths to .js files
 */
function getLocalNodeFiles(dir) {
    var result = [];
    var files = [];
    try {
        files = fs.readdirSync(dir);
    } catch(err) {
        return result;
    }
    files.sort();
    files.forEach(function(fn) {
        var stats = fs.statSync(path.join(dir,fn));
        if (stats.isFile()) {
            if (/\.js$/.test(fn)) {
                var valid = true;
                if (settings.nodesExcludes) {
                    for (var i=0;i<settings.nodesExcludes.length;i++) {
                        if (settings.nodesExcludes[i] == fn) {
                            valid = false;
                            break;
                        }
                    }
                }
                valid = valid && fs.existsSync(path.join(dir,fn.replace(/\.js$/,".html")));

                if (valid) {
                    result.push({
                        file:    path.join(dir,fn),
                        module:  "node-red",
                        name:    path.basename(fn).replace(/^\d+-/,"").replace(/\.js$/,""),
                        version: settings.version
                    });
                }
            }
        } else if (stats.isDirectory()) {
            // Ignore /.dirs/, /lib/ /node_modules/
            if (!/^(\..*|lib|icons|node_modules|test)$/.test(fn)) {
                result = result.concat(getLocalNodeFiles(path.join(dir,fn)));
            } else if (fn === "icons") {
                events.emit("node-icon-dir",path.join(dir,fn));
            }
        }
    });
    return result;
}

function scanDirForNodesModules(dir,moduleName) {
    var results = [];
    try {
        var files = fs.readdirSync(dir);
        for (var i=0;i<files.length;i++) {
            var fn = files[i];
            if (!moduleName || fn == moduleName) {
                var pkgfn = path.join(dir,fn,"package.json");
                try {
                    var pkg = require(pkgfn);
                    if (pkg['node-red']) {
                        var moduleDir = path.join(dir,fn);
                        results.push({dir:moduleDir,package:pkg});
                    }
                } catch(err) {
                    if (err.code != "MODULE_NOT_FOUND") {
                        // TODO: handle unexpected error
                    }
                }
                if (fn == moduleName) {
                    break;
                }
            }
        }
    } catch(err) {
    }
    return results;
}

/**
 * Scans the node_modules path for nodes
 * @param moduleName the name of the module to be found
 * @return a list of node modules: {dir,package}
 */
function scanTreeForNodesModules(moduleName) {
    var dir = __dirname+"/../../nodes";
    var results = [];
    var userDir;

    if (settings.userDir) {
        userDir = path.join(settings.userDir,"node_modules");
        results = results.concat(scanDirForNodesModules(userDir,moduleName));
    }
    
    var up = path.resolve(path.join(dir,".."));
    while (up !== dir) {
        var pm = path.join(dir,"node_modules");
        if (pm != userDir) {
            results = results.concat(scanDirForNodesModules(pm,moduleName));
        }
        dir = up;
        up = path.resolve(path.join(dir,".."));
    }
    return results;
}

function getModuleNodeFiles(module) {
    
    var moduleDir = module.dir;
    var pkg = module.package;
    
    var nodes = pkg['node-red'].nodes||{};
    var results = [];
    var iconDirs = [];
    
    for (var n in nodes) {
        /* istanbul ignore else */
        if (nodes.hasOwnProperty(n)) {
            var file = path.join(moduleDir,nodes[n]);
            results.push({
                file:    file,
                module:  pkg.name,
                name:    n,
                version: pkg.version
            });
            var iconDir = path.join(moduleDir,path.dirname(nodes[n]),"icons");
            if (iconDirs.indexOf(iconDir) == -1) {
                if (fs.existsSync(iconDir)) {
                    events.emit("node-icon-dir",iconDir);
                    iconDirs.push(iconDir);
                }
            }
        }
    }
    return results;
}

function getNodeFiles(_defaultNodesDir,disableNodePathScan) {
    
    if (_defaultNodesDir) {
        defaultNodesDir = _defaultNodesDir;
    }
    
    var dir;
    // Find all of the nodes to load
    //console.log(defaultNodesDir);
    var nodeFiles = getLocalNodeFiles(path.resolve(defaultNodesDir));
    //console.log(nodeFiles);
    
    if (settings.userDir) {
        dir = path.join(settings.userDir,"nodes");
        nodeFiles = nodeFiles.concat(getLocalNodeFiles(dir));
    }
    if (settings.nodesDir) {
        dir = settings.nodesDir;
        if (typeof settings.nodesDir == "string") {
            dir = [dir];
        }
        for (var i=0;i<dir.length;i++) {
            nodeFiles = nodeFiles.concat(getLocalNodeFiles(dir[i]));
        }
    }
    
    var nodeList = {
        "node-red": {
            name: "node-red",
            version: settings.version,
            nodes: {}
        }
    }
    nodeFiles.forEach(function(node) {
        nodeList["node-red"].nodes[node.name] = node;
    });
    
    if (!disableNodePathScan) {
        var moduleFiles = scanTreeForNodesModules();
        moduleFiles.forEach(function(moduleFile) {
            var nodeModuleFiles = getModuleNodeFiles(moduleFile);
            nodeList[moduleFile.package.name] = {
                name: moduleFile.package.name,
                version: moduleFile.package.version,
                nodes: {}
            };
            nodeModuleFiles.forEach(function(node) {
                nodeList[moduleFile.package.name].nodes[node.name] = node;
            });
            nodeFiles = nodeFiles.concat(nodeModuleFiles);
        });
    }
    return nodeList;
}

function getModuleFiles(module) {
    var nodeList = {};
    
    var moduleFiles = scanTreeForNodesModules(module);
    if (moduleFiles.length === 0) {
        var err = new Error("Cannot find module '" + module + "'");
        err.code = 'MODULE_NOT_FOUND';
        throw err;
    }

    moduleFiles.forEach(function(moduleFile) {
        var nodeModuleFiles = getModuleNodeFiles(moduleFile);
        nodeList[moduleFile.package.name] = {
            name: moduleFile.package.name,
            version: moduleFile.package.version,
            nodes: {}
        };
        nodeModuleFiles.forEach(function(node) {
            nodeList[moduleFile.package.name].nodes[node.name] = node;
        });
    });
    return nodeList;
}


module.exports = {
    init: init,
    getNodeFiles: getNodeFiles,
    getModuleFiles: getModuleFiles
}