"use strict";

const chokidar = require("chokidar");
const compress = require("compression");
const del = require("del");
const express = require("express");
const fs = require("fs");
const http = require("http");
const httpProxyMiddleware = require("http-proxy-middleware");
const ip = require("ip");
const serveIndex = require("serve-index");
const historyApiFallback = require("connect-history-api-fallback");
const path = require("path");
const selfsigned = require("selfsigned");
const sockjs = require("sockjs");
const spdy = require("spdy");
const webpack = require("webpack");
const webpackDevMiddleware = require("webpack-dev-middleware");

const OptionsValidationError = require("./OptionsValidationError");
const optionsSchema = require("./optionsSchema.json");

const clientStats = { errorDetails: false };

function Server(compiler, options) {
	// Default options
	if(!options) options = {};

	const validationErrors = webpack.validateSchema(optionsSchema, options);
	if(validationErrors.length) {
		throw new OptionsValidationError(validationErrors);
	}

	if(options.lazy && !options.filename) {
		throw new Error("'filename' option must be set in lazy mode.");
	}

	this.hot = options.hot || options.hotOnly;
	this.headers = options.headers;
	this.clientLogLevel = options.clientLogLevel;
	this.clientOverlay = options.overlay;
	this.disableHostCheck = !!options.disableHostCheck;
	this.publicHost = options.public;
	this.allowedHosts = options.allowedHosts;
	this.sockets = [];
	this.contentBaseWatchers = [];

	// Listening for events
	const invalidPlugin = () => {
		this.sockWrite(this.sockets, "invalid");
	};
	compiler.plugin("compile", invalidPlugin);
	compiler.plugin("invalid", invalidPlugin);
	compiler.plugin("done", (stats) => {
		this._sendStats(this.sockets, stats.toJson(clientStats));
		this._stats = stats;
	});

	// Init express server
	const app = this.app = new express();

	app.all("*", (req, res, next) => {
		if(this.checkHost(req.headers))
			return next();
		res.send("Invalid Host header");
	});

	// middleware for serving webpack bundle
	this.middleware = webpackDevMiddleware(compiler, options);

	app.get("/__webpack_dev_server__/live.bundle.js", (req, res) => {
		res.setHeader("Content-Type", "application/javascript");
		fs.createReadStream(path.join(__dirname, "..", "client", "live.bundle.js")).pipe(res);
	});

	app.get("/__webpack_dev_server__/sockjs.bundle.js", (req, res) => {
		res.setHeader("Content-Type", "application/javascript");
		fs.createReadStream(path.join(__dirname, "..", "client", "sockjs.bundle.js")).pipe(res);
	});

	app.get("/webpack-dev-server.js", (req, res) => {
		res.setHeader("Content-Type", "application/javascript");
		fs.createReadStream(path.join(__dirname, "..", "client", "index.bundle.js")).pipe(res);
	});

	app.get("/webpack-dev-server/*", (req, res) => {
		res.setHeader("Content-Type", "text/html");
		fs.createReadStream(path.join(__dirname, "..", "client", "live.html")).pipe(res);
	});

	app.get("/webpack-dev-server", (req, res) => {
		res.setHeader("Content-Type", "text/html");
		/* eslint-disable quotes */
		res.write('<!DOCTYPE html><html><head><meta charset="utf-8"/></head><body>');
		const path = this.middleware.getFilenameFromUrl(options.publicPath || "/");
		const fs = this.middleware.fileSystem;

		function writeDirectory(baseUrl, basePath) {
			const content = fs.readdirSync(basePath);
			res.write("<ul>");
			content.forEach(function(item) {
				const p = `${basePath}/${item}`;
				if(fs.statSync(p).isFile()) {
					res.write('<li><a href="');
					res.write(baseUrl + item);
					res.write('">');
					res.write(item);
					res.write('</a></li>');
					if(/\.js$/.test(item)) {
						const htmlItem = item.substr(0, item.length - 3);
						res.write('<li><a href="');
						res.write(baseUrl + htmlItem);
						res.write('">');
						res.write(htmlItem);
						res.write('</a> (magic html for ');
						res.write(item);
						res.write(') (<a href="');
						res.write(baseUrl.replace(/(^(https?:\/\/[^\/]+)?\/)/, "$1webpack-dev-server/") + htmlItem);
						res.write('">webpack-dev-server</a>)</li>');
					}
				} else {
					res.write('<li>');
					res.write(item);
					res.write('<br>');
					writeDirectory(`${baseUrl + item}/`, p);
					res.write('</li>');
				}
			});
			res.write("</ul>");
		}
		/* eslint-enable quotes */
		writeDirectory(options.publicPath || "/", path);
		res.end("</body></html>");
	});

	let contentBase;
	if(options.contentBase !== undefined) {
		contentBase = options.contentBase;
	} else {
		contentBase = process.cwd();
	}

	// Keep track of websocket proxies for external websocket upgrade.
	const websocketProxies = [];

	const features = {
		compress() {
			if(options.compress) {
				// Enable gzip compression.
				app.use(compress());
			}
		},

		proxy() {
			if(options.proxy) {
				/**
				 * Assume a proxy configuration specified as:
				 * proxy: {
				 *   'context': { options }
				 * }
				 * OR
				 * proxy: {
				 *   'context': 'target'
				 * }
				 */
				if(!Array.isArray(options.proxy)) {
					options.proxy = Object.keys(options.proxy).map((context) => {
						let proxyOptions;
						// For backwards compatibility reasons.
						const correctedContext = context.replace(/^\*$/, "**").replace(/\/\*$/, "");

						if(typeof options.proxy[context] === "string") {
							proxyOptions = {
								context: correctedContext,
								target: options.proxy[context]
							};
						} else {
							proxyOptions = Object.assign({}, options.proxy[context]);
							proxyOptions.context = correctedContext;
						}
						proxyOptions.logLevel = proxyOptions.logLevel || "warn";

						return proxyOptions;
					});
				}

				const getProxyMiddleware = (proxyConfig) => {
					const context = proxyConfig.context || proxyConfig.path;

					// It is possible to use the `bypass` method without a `target`.
					// However, the proxy middleware has no use in this case, and will fail to instantiate.
					if(proxyConfig.target) {
						return httpProxyMiddleware(context, proxyConfig);
					}
				}

				/**
				 * Assume a proxy configuration specified as:
				 * proxy: [
				 *   {
				 *     context: ...,
				 *     ...options...
				 *   },
				 *   // or:
				 *   function() {
				 *     return {
				 *       context: ...,
				 *       ...options...
				 *     };
				 *	 }
				 * ]
				 */
				options.proxy.forEach((proxyConfigOrCallback) => {
					let proxyConfig;
					let proxyMiddleware;

					if(typeof proxyConfigOrCallback === "function") {
						proxyConfig = proxyConfigOrCallback();
					} else {
						proxyConfig = proxyConfigOrCallback;
					}

					proxyMiddleware = getProxyMiddleware(proxyConfig);
					if(proxyConfig.ws) {
						websocketProxies.push(proxyMiddleware);
					}

					app.use((req, res, next) => {
						if(typeof proxyConfigOrCallback === "function") {
							const newProxyConfig = proxyConfigOrCallback();
							if(newProxyConfig !== proxyConfig) {
								proxyConfig = newProxyConfig;
								proxyMiddleware = getProxyMiddleware(proxyConfig);
							}
						}
						const bypass = typeof proxyConfig.bypass === "function";
						const bypassUrl = bypass && proxyConfig.bypass(req, res, proxyConfig) || false;

						if(bypassUrl) {
							req.url = bypassUrl;
							next();
						} else if(proxyMiddleware) {
							return proxyMiddleware(req, res, next);
						} else {
							next();
						}
					});
				});
			}
		},

		historyApiFallback() {
			if(options.historyApiFallback) {
				// Fall back to /index.html if nothing else matches.
				app.use(
					historyApiFallback(typeof options.historyApiFallback === "object" ? options.historyApiFallback : null)
				);
			}
		},

		contentBaseFiles() {
			if(Array.isArray(contentBase)) {
				contentBase.forEach((item) => {
					app.get("*", express.static(item));
				});
			} else if(/^(https?:)?\/\//.test(contentBase)) {
				console.log("Using a URL as contentBase is deprecated and will be removed in the next major version. Please use the proxy option instead.");
				console.log('proxy: {\n\t"*": "<your current contentBase configuration>"\n}'); // eslint-disable-line quotes
				// Redirect every request to contentBase
				app.get("*", (req, res) => {
					res.writeHead(302, {
						"Location": contentBase + req.path + (req._parsedUrl.search || "")
					});
					res.end();
				});
			} else if(typeof contentBase === "number") {
				console.log("Using a number as contentBase is deprecated and will be removed in the next major version. Please use the proxy option instead.");
				console.log('proxy: {\n\t"*": "//localhost:<your current contentBase configuration>"\n}'); // eslint-disable-line quotes
				// Redirect every request to the port contentBase
				app.get("*", (req, res) => {
					res.writeHead(302, {
						"Location": `//localhost:${contentBase}${req.path}${req._parsedUrl.search || ""}`
					});
					res.end();
				});
			} else {
				// route content request
				app.get("*", express.static(contentBase, options.staticOptions));
			}
		},

		contentBaseIndex() {
			if(Array.isArray(contentBase)) {
				contentBase.forEach((item) => {
					app.get("*", serveIndex(item));
				});
			} else if(!/^(https?:)?\/\//.test(contentBase) && typeof contentBase !== "number") {
				app.get("*", serveIndex(contentBase));
			}
		},

		watchContentBase: () => {
			if(/^(https?:)?\/\//.test(contentBase) || typeof contentBase === "number") {
				throw new Error("Watching remote files is not supported.");
			} else if(Array.isArray(contentBase)) {
				contentBase.forEach((item) => {
					this._watch(item);
				});
			} else {
				this._watch(contentBase);
			}
		},

		middleware: () => {
			// include our middleware to ensure it is able to handle '/index.html' request after redirect
			app.use(this.middleware);
		},

		headers: () => {
			app.all("*", this.setContentHeaders.bind(this));
		},

		magicHtml: () => {
			app.get("*", this.serveMagicHtml.bind(this));
		},

		setup: () => {
			if(typeof options.setup === "function")
				options.setup(app, this);
		}
	};

	const defaultFeatures = ["setup", "headers", "middleware"];
	if(options.proxy)
		defaultFeatures.push("proxy", "middleware");
	if(contentBase !== false)
		defaultFeatures.push("contentBaseFiles");
	if(options.watchContentBase)
		defaultFeatures.push("watchContentBase");
	if(options.historyApiFallback) {
		defaultFeatures.push("historyApiFallback", "middleware");
		if(contentBase !== false)
			defaultFeatures.push("contentBaseFiles");
	}
	defaultFeatures.push("magicHtml");
	if(contentBase !== false)
		defaultFeatures.push("contentBaseIndex");
	// compress is placed last and uses unshift so that it will be the first middleware used
	if(options.compress)
		defaultFeatures.unshift("compress");

	(options.features || defaultFeatures).forEach((feature) => {
		features[feature]();
	});

	if(options.https) {
		// for keep supporting CLI parameters
		if(typeof options.https === "boolean") {
			options.https = {
				key: options.key,
				cert: options.cert,
				ca: options.ca,
				pfx: options.pfx,
				passphrase: options.pfxPassphrase
			};
		}

		// Use a self-signed certificate if no certificate was configured.
		// Cycle certs every 24 hours
		const certPath = path.join(__dirname, "../ssl/server.pem");
		let certExists = fs.existsSync(certPath);

		if(certExists) {
			const certStat = fs.statSync(certPath);
			const certTtl = 1000 * 60 * 60 * 24;
			const now = new Date();

			// cert is more than 30 days old, kill it with fire
			if((now - certStat.ctime) / certTtl > 30) {
				console.log("SSL Certificate is more than 30 days old. Removing.");
				del.sync([certPath], { force: true });
				certExists = false;
			}
		}

		if(!certExists) {
			console.log("Generating SSL Certificate");
			const attrs = [{ name: "commonName", value: "localhost" }];
			const pems = selfsigned.generate(attrs, {
				algorithm: "sha256",
				days: 30,
				keySize: 2048
			});

			fs.writeFileSync(certPath, pems.private + pems.cert, { encoding: "utf-8" });
		}

		const fakeCert = fs.readFileSync(certPath);
		options.https.key = options.https.key || fakeCert;
		options.https.cert = options.https.cert || fakeCert;

		if(!options.https.spdy) {
			options.https.spdy = {
				protocols: ["h2", "http/1.1"]
			};
		}

		this.listeningApp = spdy.createServer(options.https, app);
	} else {
		this.listeningApp = http.createServer(app);
	}

	// Proxy websockets without the initial http request
	// https://github.com/chimurai/http-proxy-middleware#external-websocket-upgrade
	websocketProxies.forEach(function(wsProxy) {
		this.listeningApp.on("upgrade", wsProxy.upgrade);
	}, this);
}

Server.prototype.use = function() {
	this.app.use.apply(this.app, arguments);
}

Server.prototype.setContentHeaders = function(req, res, next) {
	if(this.headers) {
		for(const name in this.headers) {
			res.setHeader(name, this.headers[name]);
		}
	}

	next();
}

Server.prototype.checkHost = function(headers) {
	// allow user to opt-out this security check, at own risk
	if(this.disableHostCheck) return true;

	// get the Host header and extract hostname
	// we don't care about port not matching
	const hostHeader = headers.host;
	if(!hostHeader) return false;
	const idx = hostHeader.indexOf(":");
	const hostname = idx >= 0 ? hostHeader.substr(0, idx) : hostHeader;

	// always allow requests with explicit IP-address
	if(ip.isV4Format(hostname)) return true;

	// always allow localhost host, for convience
	if(hostname === "localhost") return true;

	// allow if hostname is in allowedHosts
	if(this.allowedHosts && this.allowedHosts.length) {
		for(let hostIdx = 0; hostIdx < this.allowedHosts.length; hostIdx++) {
			const allowedHost = this.allowedHosts[hostIdx];
			if(allowedHost === hostname) return true;

			// support "." as a subdomain wildcard
			// e.g. ".example.com" will allow "example.com", "www.example.com", "subdomain.example.com", etc
			if(allowedHost[0] === ".") {
				if(hostname === allowedHost.substring(1)) return true; // "example.com"
				if(hostname.endsWith(allowedHost)) return true; // "*.example.com"
			}
		}
	}

	// allow hostname of listening adress
	if(hostname === this.listenHostname) return true;

	// also allow public hostname if provided
	if(typeof this.publicHost === "string") {
		const idxPublic = this.publicHost.indexOf(":");
		const publicHostname = idxPublic >= 0 ? this.publicHost.substr(0, idxPublic) : this.publicHost;
		if(hostname === publicHostname) return true;
	}

	// disallow
	return false;
}

// delegate listen call and init sockjs
Server.prototype.listen = function(port, hostname) {
	this.listenHostname = hostname;
	const returnValue = this.listeningApp.listen.apply(this.listeningApp, arguments);
	const sockServer = sockjs.createServer({
		// Use provided up-to-date sockjs-client
		sockjs_url: "/__webpack_dev_server__/sockjs.bundle.js",
		// Limit useless logs
		log: function(severity, line) {
			if(severity === "error") {
				console.log(line);
			}
		}
	});
	sockServer.on("connection", (conn) => {
		if(!conn) return;
		if(!this.checkHost(conn.headers)) {
			this.sockWrite([conn], "error", "Invalid Host header");
			conn.close();
			return;
		}
		this.sockets.push(conn);

		conn.on("close", () => {
			const connIndex = this.sockets.indexOf(conn);
			if(connIndex >= 0) {
				this.sockets.splice(connIndex, 1);
			}
		});

		if(this.clientLogLevel)
			this.sockWrite([conn], "log-level", this.clientLogLevel);

		if(this.clientOverlay)
			this.sockWrite([conn], "overlay", this.clientOverlay);

		if(this.hot) this.sockWrite([conn], "hot");

		if(!this._stats) return;
		this._sendStats([conn], this._stats.toJson(clientStats), true);
	});

	sockServer.installHandlers(this.listeningApp, {
		prefix: "/sockjs-node"
	});
	return returnValue;
}

Server.prototype.close = function(callback) {
	this.sockets.forEach((sock) => {
		sock.close();
	});
	this.sockets = [];
	this.listeningApp.close(() => {
		this.middleware.close(callback);
	});

	this.contentBaseWatchers.forEach((watcher) => {
		watcher.close();
	});
	this.contentBaseWatchers = [];
}

Server.prototype.sockWrite = function(sockets, type, data) {
	sockets.forEach((sock) => {
		sock.write(JSON.stringify({
			type: type,
			data: data
		}));
	});
}

Server.prototype.serveMagicHtml = function(req, res, next) {
	const _path = req.path;
	try {
		if(!this.middleware.fileSystem.statSync(this.middleware.getFilenameFromUrl(`${_path}.js`)).isFile())
			return next();
		// Serve a page that executes the javascript
		/* eslint-disable quotes */
		res.write('<!DOCTYPE html><html><head><meta charset="utf-8"/></head><body><script type="text/javascript" charset="utf-8" src="');
		res.write(_path);
		res.write('.js');
		res.write(req._parsedUrl.search || "");
		res.end('"></script></body></html>');
		/* eslint-enable quotes */
	} catch(e) {
		return next();
	}
}

// send stats to a socket or multiple sockets
Server.prototype._sendStats = function(sockets, stats, force) {
	if(!force &&
		stats &&
		(!stats.errors || stats.errors.length === 0) &&
		stats.assets &&
		stats.assets.every((asset) => !asset.emitted)
	)
		return this.sockWrite(sockets, "still-ok");
	this.sockWrite(sockets, "hash", stats.hash);
	if(stats.errors.length > 0)
		this.sockWrite(sockets, "errors", stats.errors);
	else if(stats.warnings.length > 0)
		this.sockWrite(sockets, "warnings", stats.warnings);
	else
		this.sockWrite(sockets, "ok");
}

Server.prototype._watch = function(path) {
	const watcher = chokidar.watch(path).on("change", () => {
		this.sockWrite(this.sockets, "content-changed");
	});

	this.contentBaseWatchers.push(watcher);
}

Server.prototype.invalidate = function() {
	if(this.middleware) this.middleware.invalidate();
}

// Export this logic, so that other implementations, like task-runners can use it
Server.addDevServerEntrypoints = require("./util/addDevServerEntrypoints");

module.exports = Server;
