/**
 * Copyright JS Foundation and other contributors, http://js.foundation
 *
 * 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 path = require("path");
var fs = require("fs-extra");
var os = require("os");
var util = require("@node-red/registry/lib/util");

var api;

var runtime;
var settings;
var exec;
var log;

var npmCommand = (process.platform === "win32") ? "npm.cmd" : "npm";

var metadataFileName = "npm-modules.json";

var moduleProp = {};
var moduleBase = null;

var allowInstall = true;
var allowList = ["*"];
var denyList = [];

var inProgress = {};

/**
 * Initialise npm install module.
 * @param {Object} _runtime - runtime object
 */
function init(_runtime) {
    runtime = _runtime;
    settings = _runtime.settings;
    exec = _runtime.exec;
    log = _runtime.log;

    moduleProp = {};
    inProgress = {};

    moduleBase = settings.userDir || process.env.NODE_RED_HOME || ".";

    if (settings.hasOwnProperty("externalModules")) {
        var em = settings.externalModules;
        if (em && em.hasOwnProperty("modules")) {
            var mod = em.modules;
            if (mod.hasOwnProperty("allowInstall")) {
                allowInstall = mod.allowInstall;
            }
            if (mod.hasOwnProperty("allowList")) {
                var alist = mod.allowList;
                if (Array.isArray(alist)) {
                    allowList = alist;
                }
                else {
                    log.warn("unexpected value of externalModule.allowList in settings.js");
                }
            }
            if (mod.hasOwnProperty("denyList")) {
                var dlist = mod.denyList;
                if (Array.isArray(dlist)) {
                    denyList = dlist;
                }
                else {
                    log.warn("unexpected value of externalModule.denyList in settings.js");
                }
            }
        }
    }
}

/**
 * Register dynamic module installation property.
 * @param {string} type - node type
 * @param {string} prop - property name
 */
function register(type, prop) {
    if (prop) {
        moduleProp[type] = prop;
    }
    else {
        delete moduleProp[prop]
    }
}

/**
 * Get path to install modules
 */
function modulePath() { // takes variable length arguments in `arguments`
    var result = moduleBase;
    for(var i = 0; i < arguments.length; i++) {
        result = path.join(result, arguments[i]);
    }
    return result;
}

/**
 * Decompose NPM module specification string
 * @param {string} module - module specification
 * @return {Object} array [name, version], where name is name part and version is version part of the module 
 */
function moduleName(module) {
    var match = /^([^@]+)@(.+)/.exec(module);
    if (match) {
        return [match[1], match[2]];
    }
    return [module, undefined];
}

/**
 * Get NPM module info
 * @param {string} name - module name
 * @return {Object} package.json for specified NPM module
 */
function infoNPM(name) {
    var path = modulePath("node_modules", name, "package.json");
    try {
        var pkg = fs.readFileSync(path);
        return JSON.parse(pkg);
    }
    catch (e) {
    }
    return null;
}

/**
 * Load NPM module metadata
 * @return {object} module metadata object
 */
function loadMetadata() {
    var path = modulePath(metadataFileName);
    try {
        var pkg = fs.readFileSync(path);
        return JSON.parse(pkg);
    }
    catch (e) {
    }
    return {
        modules: []
    };
}

/**
 * Save NPM module metadata
 * @param {string} data - module metadata object
 */
function saveMetadata(data) {
    var path = modulePath(metadataFileName);
    var str = JSON.stringify(data, null, 4);
    fs.writeFileSync(path, str);
}

/**
 * Find item in metadata
 * @param {Object} meta - metadata
 * @param {string} name - module name
 * @return {object} metadata item
 */
function findModule(meta, name) {
    var modules = meta.modules;
    var item = modules.find(item => (item.name === name));
    return item;
}

function setInProgress(name) {
    inProgress[name] = true;
}

function clearInProgress(name) {
    inProgress[name] = false;
}

/**
 * Install NPM module 
 * @param {string} module - module specification
 */
function installNPM(module) {
    var [name, ver] = moduleName(module);
    setInProgress(name);
    return new Promise((resolve, reject) => {
        var pkg = infoNPM(name);
        if (!pkg) {
            var args = ["install", module];
            var dir = modulePath();
            return exec.run(npmCommand, args, {
                cwd: dir
            }, true).then(result => {
                if (result && (result.code === 0)) {
                    pkg = infoNPM(name);
                    var spec = name +(pkg ? "@"+pkg.version : "");
                    log.info("successfully installed: "+spec);
                    var meta = loadMetadata();
                    var item = {
                        name: name,
                        spec: module,
                        status: "installed",
                    };
                    meta.modules.push(item);
                    saveMetadata(meta);
                    clearInProgress(name);
                    resolve(true);
                }
                else {
                    clearInProgress(name);
                    var msg = "failed to install: "+name;
                    log.warn(msg);
                    reject(msg);
                }
            }).catch(e => {
                clearInProgress(name);
                var msg = "failed to install: "+name
                log.warn(msg);
                reject(msg);
            });
        }
        else {
            var meta = loadMetadata();
            if (!findModule(meta, name)) {
                var item = {
                    name: name,
                    spec: module,
                    status: "preinstalled",
                };
                meta.modules.push(item);
                saveMetadata(meta);
            }
            clearInProgress(name);
            var spec = name +(pkg ? ("@"+pkg.version) : "");
            log.info("already installed: "+spec);
        }
        resolve(true);
    });
}

/**
 * Check allowance of NPM module installation
 * @param {string} name - module specification
 */
function isAllowed(name) {
    if (!allowInstall) {
        return false;
    }
    var [module, ver] = moduleName(name);
    var aList = util.parseModuleList(allowList);
    var dList = util.parseModuleList(denyList);
    return util.checkModuleAllowed(module, ver, aList, dList);
}

/**
 * Check and install NPM module according to dynamic module specification
 * @param {Object} node - node object
 */
function checkInstall(node) {
    var name = null;
    if(moduleProp.hasOwnProperty(node.type)) {
        name = moduleProp[node.type];
    }
    var promises = [];
    if (name && node.hasOwnProperty(name)) {
        var modules = node[name];
        modules.forEach(module => {
            var name = module;
            if ((typeof module === "object") &&
                module &&
                module.hasOwnProperty("name")) {
                name = module.name;
            }
            if (isAllowed(name)) {
                var [n, v] = moduleName(name);
                setInProgress(name);
                promises.push(installNPM(name));
            }
            else {
                log.info("installation not allowed: "+name);
            }
        });
    }
    return Promise.all(promises);
}

/**
 * Load NPM module
 * @param {string} module - module to load
 */
function load(module) {
    try {
        var [name, ver] = moduleName(module);
        var path = modulePath("node_modules", name);
        var npm = require(path);
        return npm;
    }
    catch (e) {
        return null;
    }
}

/**
 * Get list of installed modules
 */
function listModules() {
    return new Promise((resolve, reject) => {
        var meta = loadMetadata();
        var modules = meta.modules;
        modules.forEach(item => {
            var name = item.name;
            var info = infoNPM(name);
            if (info) {
                item.version = info.version;
            }
            item.inProgress = ((name in inProgress) && inProgress[name]);
        });
        Object.keys(inProgress).forEach(name => {
            if (inProgress[name] &&
                !modules.find(item => (item.name === name))) {
                modules.push({
                    name: name,
                    spec: name,
                    state: "inprogress",
                    inProgress: true
                });
            }
        });
        resolve(meta.modules);
    });
}

/**
 * Uninstall NPM modules
 */
function uninstall(module) {
    var [name, ver] = moduleName(module);
    setInProgress(name);
    return new Promise((resolve, reject) => {
        var pkg = infoNPM(name);
        var meta = loadMetadata();
        var item = findModule(meta, name);
        if (pkg && item) {
            if (item.status === "preinstalled") {
                clearInProgress(name);
                var msg = "can't uninstall preinstalled: "+name;
                log.warn(msg);
                reject(msg);
            }
            else {
                var args = ["uninstall", module];
                var dir = modulePath();
                return exec.run(npmCommand, args, {
                    cwd: dir
                }, true).then(result => {
                    if (result && (result.code === 0)) {
                        log.info("successfully uninstalled: "+name);
                        var meta = loadMetadata();
                        var items = meta.modules.filter(item => (item.name !== name));
                        meta.modules = items;
                        saveMetadata(meta);
                        clearInProgress(name);
                        resolve(true);
                    }
                    else {
                        clearInProgress(name);
                        var msg = "failed to uninstall: "+name;
                        log.warn(msg);
                        reject(msg);
                    }
                }).catch(e => {
                    clearInProgress(name);
                    var msg = "failed to uninstall: "+name;
                    log.warn(msg);
                    reject(msg);
                });
            }
        }
        else {
            clearInProgress(name);
            var msg = "module not installed: "+name;
            log.info(msg);
            reject(msg);
        }
    });
}

/**
 * Update NPM modules
 */
function update(module, isUpdate) {
    var act = (isUpdate ? "updated": "install")
    var acted = (isUpdate ? "updated": "installed")
    var [name, ver] = moduleName(module);
    setInProgress(name);
    return new Promise((resolve, reject) => {
        var pkg = infoNPM(name);
        if (!pkg || isUpdate) {
            var args = ["install", module];
            var dir = modulePath();
            return exec.run(npmCommand, args, {
                cwd: dir
            }, true).then(result => {
                if (result && (result.code === 0)) {
                    pkg = infoNPM(name);
                    var spec = name +(pkg ? "@"+pkg.version : "");
                    log.info("successfully "+acted+": "+spec);
                    var meta = loadMetadata();
                    var items = meta.modules.filter(item => (item.name !== name));
                    var item = {
                        name: name,
                        spec: module,
                        status: "installed",
                    };
                    items.push(item);
                    meta.modules = items;
                    saveMetadata(meta);
                    clearInProgress(name);
                    resolve(true);
                }
                else {
                    clearInProgress(name);
                    var msg = "failed to "+act+": "+name;
                    log.warn(msg);
                    reject(msg);
                }
            }).catch(e => {
                clearInProgress(name);
                var msg = "failed to "+act+": "+name;
                log.warn(msg);
                reject(msg);
            });
        }
        else {
            clearInProgress(name);
            var msg = "not "+acted+": "+name;
            log.info(msg);
            reject(msg);
        }
    });
}

api = {
    init: init,
    register: register,
    checkInstall: checkInstall,
    load: load,
    list: listModules,
    uninstall: uninstall,
    update: update
};
module.exports = api;