#!/usr/bin/env node
"use strict";
/*global Promise*/

/////////////////////////////////
// an okay vhost + api example //
/////////////////////////////////

//
// I run this on a few servers. It demonstrates dynamic virtual hosting + apis
// /srv/www -> static sites in plain folders
// ex: /srv/www/example.com
//
// /srv/api -> express apps
// ex: /srv/api/api.example.com
//

var configpath = process.argv[2] || "./config.js";
var config = require(configpath);
// The prefix where sites go by name.
// For example: whatever.com may live in /srv/www/whatever.com, thus /srv/www is our path

var path = require("path");
var fs = require("./lib/compat.js").fsAsync;
var finalhandler = require("finalhandler");
var serveStatic = require("serve-static");

//var glx = require('greenlock-express')
var glx = require("./").create({
	version: "draft-11", // Let's Encrypt v2 is ACME draft 11

	//, server: 'https://acme-staging-v02.api.letsencrypt.org/directory'
	server: "https://acme-v02.api.letsencrypt.org/directory", // If at first you don't succeed, stop and switch to staging
	// https://acme-staging-v02.api.letsencrypt.org/directory

	configDir: config.configDir, // You MUST have access to write to directory where certs
	// are saved. ex: /home/foouser/.config/acme

	approveDomains: myApproveDomains, // Greenlock's wraps around tls.SNICallback. Check the
	// domain name here and reject invalid ones

	servername: config.servername,
	app: myVhostApp, // Any node-style http app (i.e. express, koa, hapi, rill)

	/* CHANGE TO A VALID EMAIL */
	email: config.email, // Email for Let's Encrypt account and Greenlock Security
	agreeTos: true, // Accept Let's Encrypt ToS
	//, communityMember: true                                   // Join Greenlock to get important updates, no spam

	//, debug: true
	store: require("greenlock-store-fs")
});

if (require.main === module) {
	var server = glx.listen(80, 443);
	server.on("listening", function() {
		console.info(server.type + " listening on", server.address());
	});
}

function myApproveDomains(opts) {
	console.info("SNI:", opts.domain);
	// In this example the filesystem is our "database".
	// We check in /srv/www for whatever.com and if it exists, it's allowed
	// SECURITY Greenlock validates opts.domains ahead-of-time so you don't have to

	var domains = [];
	var original = opts.domain;
	var bare = original.replace(/^(www|api)\./, "");
	// The goal here is to support both bare and www domains
	//
	// dns:example.com + fs:www.example.com => both
	// dns:www.example.com + fs:example.com => both
	//
	// dns:api.example.com + fs:www.example.com => www.example.com
	// dns:api.example.com + fs:example.com => example.com
	//
	// dns:example.com + fs:example.com => example.com
	// dns:www.example.com + fs:www.example.com => www.example.com
	//
	return checkWwws(bare)
		.then(function(hostname) {
			// hostname is either example.com or www.example.com
			domains.push(hostname);
			if ("api." + bare !== original) {
				if (!domains.includes(original)) {
					domains.push(original);
				}
			}
		})
		.catch(function() {
			// ignore error
			return null;
		})
		.then(function() {
			// check for api prefix
			var apiname = bare;
			if (domains.length) {
				apiname = "api." + bare;
			}
			return checkApi(apiname)
				.then(function(app) {
					if (!app) {
						return null;
					}
					domains.push(apiname);
				})
				.catch(function() {
					return null;
				});
		})
		.then(function() {
			// It's possible that example.com could have been requested,
			// and not found, but api.example.com was found
			if (!domains.includes(original)) {
				return Promise.reject(new Error("no bare, www., or api. domain matching '" + opts.domain + "'"));
			}

			console.info("Approved domains:", domains);
			opts.domains = domains;
			//opts.email = email;
			opts.agreeTos = true;
			// pick the shortest (bare) or latest (www. instead of api.) to be the subject
			opts.subject = opts.domains.sort(function(a, b) {
				var len = a.length - b.length;
				if (0 !== len) {
					return len;
				}
				if (a < b) {
					return 1;
				} else {
					return -1;
				}
			})[0];

			if (!opts.challenges) {
				opts.challenges = {};
			}
			opts.challenges["http-01"] = require("le-challenge-fs");
			//opts.challenges['dns-01'] = require('le-challenge-dns');

			// explicitly set account id and certificate.id
			opts.account = { id: opts.email };
			opts.certificate = { id: opts.subject };

			return Promise.resolve(opts);
		});
}
exports.myApproveDomains = myApproveDomains;

function checkApi(hostname) {
	var apipath = path.join(config.api, hostname);
	var link = "";
	return fs
		.stat(apipath)
		.then(function(stats) {
			if (stats.isDirectory()) {
				return require(apipath);
			}
			return fs.readFile(apipath, "utf8").then(function(txt) {
				var linkpath = txt.split("\n")[0];
				link = " => " + linkpath + " ";
				return require(linkpath);
			});
		})
		.catch(function(e) {
			if ("ENOENT" === e.code) {
				return null;
			}
			console.error(e);
			throw new Error("rejecting '" + hostname + "' because '" + apipath + link + "' failed at require()");
		});
}
exports.checkApi = checkApi;

function checkWwws(_hostname) {
	if (!_hostname) {
		// SECURITY don't serve the whole config.srv
		return Promise.reject(new Error("missing hostname"));
	}
	var hostname = _hostname;
	var hostdir = path.join(config.srv, hostname);
	// TODO could test for www/no-www both in directory
	return fs
		.readdir(hostdir)
		.then(function() {
			// TODO check for some sort of htaccess.json and use email in that
			// NOTE: you can also change other options such as `challengeType` and `challenge`
			// opts.challengeType = 'http-01';
			// opts.challenge = require('le-challenge-fs').create({});
			return hostname;
		})
		.catch(function() {
			if ("www." === hostname.slice(0, 4)) {
				// Assume we'll redirect to non-www if it's available.
				hostname = hostname.slice(4);
				hostdir = path.join(config.srv, hostname);
				return fs.readdir(hostdir).then(function() {
					return hostname;
				});
			} else {
				// Or check and see if perhaps we should redirect non-www to www
				hostname = "www." + hostname;
				hostdir = path.join(config.srv, hostname);
				return fs.readdir(hostdir).then(function() {
					return hostname;
				});
			}
		})
		.catch(function() {
			throw new Error("rejecting '" + _hostname + "' because '" + hostdir + "' could not be read");
		});
}
exports.checkWwws = checkWwws;

function myVhostApp(req, res) {
	req.on("error", function(err) {
		console.error("HTTPS Request Network Connection Error:");
		console.error(err);
	});

	// SECURITY greenlock pre-sanitizes hostnames to prevent unauthorized fs access so you don't have to
	// (also: only domains approved above will get here)
	console.info("");
	console.info(req.method, (req.headers.host || "") + req.url);
	Object.keys(req.headers).forEach(function(key) {
		console.info(key, req.headers[key]);
	});

	// We could cache wether or not a host exists for some amount of time
	var fin = finalhandler(req, res);
	return checkWwws(req.headers.host)
		.then(function(hostname) {
			if (hostname !== req.headers.host) {
				res.statusCode = 302;
				res.setHeader("Location", "https://" + hostname);
				// SECURITY this is safe only because greenlock disallows invalid hostnames
				res.end("<!-- redirecting to https://" + hostname + "-->");
				return;
			}
			var serve = serveStatic(path.join(config.srv, hostname), { redirect: true });
			serve(req, res, fin);
		})
		.catch(function(err) {
			return checkApi(req.headers.host)
				.then(function(app) {
					if (app) {
						app(req, res);
						return;
					}
					console.error("none found", err);
					fin();
				})
				.catch(function(err) {
					console.error("api crashed error", err);
					fin(err);
				});
		});
}