"use strict";

const express = require("express"),
  config = require("config"),
  LdapAuth = require("ldapauth-fork"),
  crypto = require("crypto"),
  createTransport = require("nodemailer").createTransport,
  hb = require("handlebars");

const router = express.Router();

let userDB;

let transporter = createTransport({
  host: config.get("smtp.host"),
  pool: true,
  port: config.has("smtp.port") ? config.get("smtp.port") : 25
});

let ldap;
if (config.has("ldap.url")) {
  ldap = new LdapAuth(config.get("ldap"));
} else {
  ldap = null;
}

require("../db/users").then(function(db) {
  userDB = db;
});

router.get("/", function(req, res/*, next*/) {
  console.log("/users");
  
  if (req.session.user) {
    return res.status(200).send(req.session.user);
  }
  return res.status(200).send({});
});

const templates = {
  "html": [
    "<p>Dear {{username}},</p>",
    "",
    "<p>Welcome to <b>ketrenos.com</b>. Before you can access the system, you must authenticate",
    "your email address ({{mail}}).</p>",
    "",
    "<p>To do so, simply access this link, which contains your authentication ",
    "token: <a href=\"{{url}}{{secret}}\">{{secret}}</a></p>",
    "",
    "<p>Sincerely,</p>",
    "<p>James</p>"
  ].join("\n"),
  "text": [
    "Dear {{username}},",
    "",
    "Welcome to ketrenos.com. Before you can access the system, you must authenticate",
    "your email address ({{mail}}).",
    "",
    "To do so, simply access this link, which contains your authentication ",
    "token: {{url}}{{secret}}",
    "",
    "Sincerely,",
    "James"
  ].join("\n")
};

function ldapPromise(username, password) {
  if (!ldap) {
    return Promise.reject("LDAP not being used");
  }
  return new Promise(function(resolve, reject) {
    ldap.authenticate(username.replace(/@.*$/, ""), password, function(error, user) {
      if (error) {
        return reject(error);
      }
      return resolve(user);
    });
  });
}

router.post("/create", function(req, res) {
  let who = req.query.w || req.body.w || "",
    password = req.query.p || req.body.p || "",
    name = req.query.n || req.body.n || "",
    mail = req.query.m || req.body.m;

  if (!who || !password || !mail || !name) {
    return res.status(400).send("Missing who you know, name, password, and/or email");
  }

  let query = "SELECT * FROM users WHERE uid=:username";
  return userDB.sequelize.query(query, {
    replacements: {
      username: mail
    },
    type: userDB.Sequelize.QueryTypes.SELECT
  }).then(function(results) {
    if (results.length != 0) {
      return res.status(400).send("Email address already used.");
    }

    let re = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    if (!re.exec(mail)) {
      console.log("Invalid email address: " + mail);
      return res.status(400).send("Invalid email address.");
    }
  }).then(function() {
    return new Promise(function(resolve, reject) {
      crypto.randomBytes(16, function(error, buffer) {
        if (error) {
          return reject(error);
        }
        return resolve(buffer.toString('hex'));
      });
    });
  }).then(function(secret) {
    return userDB.sequelize.query("INSERT INTO users " + 
        "(uid,displayName,password,mail,memberSince,authenticated,notes) " +
        "VALUES(:username,:name,:password,:mail,CURRENT_TIMESTAMP,0,:notes)", {
      replacements: {
        username: mail,
        name: name,
        password: crypto.createHash('sha256').update(password).digest('base64'),
        mail: mail,
        notes: who
      }
    }).spread(function(results, metadata) {
      return userDB.sequelize.query("INSERT INTO authentications " + 
        "(userId,issued,key,type) VALUES " +
        "(:userId,CURRENT_TIMESTAMP,:key,'account-setup')", {
        replacements: {
          key: secret,
          userId: metadata.lastID
        }
      }).catch(function(error) {
        console.log(error);
        throw error;
      });
    }).then(function() {
      let data = {
        username: name,
        mail: mail,
        secret: secret,
        url: req.protocol + "://" + req.hostname + req.app.get("basePath")
      }, envelope = {
        to: mail,
        from: config.get("smtp.sender"),
        subject: "Request to ketrenos.com create account for '" + name + "'",
        cc: "",
        bcc: config.get("admin.mail"),
        text: hb.compile(templates.text)(data),
        html: hb.compile(templates.html)(data)
      };
      return new Promise(function (resolve, reject) {
        let attempts = 10;
    
        function send(envelope) {
          /* Rate limit to ten per second */
          transporter.sendMail(envelope, function (error, info) {
            if (!error) {
              console.log('Message sent: ' + info.response);
              return resolve();
            }

            if (attempts == 0) {
              console.log("Error sending email: ", error)
              return reject(error);
            }
            
            attempts--;
            console.log("Unable to send mail. Trying again in 100ms (" + attempts + " attempts remain): ", error);
            setTimeout(send.bind(undefined, envelope), 100);
          });
        }

        send(envelope);
      });
    }).then(function() {
      req.session.user = {
        name: name,
        mail: mail,
        username: mail,
        authenticated: false,
        mailVerified: false
      };
      return res.status(200).send(req.session.user);
    });
  });
});

router.post("/login", function(req, res) {
  let username = req.query.u || req.body.u || "",
    password = req.query.p || req.body.p || "";

  console.log("Login attempt");

  if (!username || !password) {
    return res.status(400).send("Missing username and/or password");
  }

  /* We use LDAP as the primary authenticator; if the user is not
   * found there, we look them up in the site-specific user database */
   
  return ldapPromise(username, password).then(function(user) {
    user.authenticated = 1;
    user.mailVerified = 1;
    return user;
  }).catch(function() {
    console.log("User not found in LDAP. Looking up in DB.");
    let query = "SELECT * FROM users WHERE uid=:username AND password=:password";
    return userDB.sequelize.query(query, {
      replacements: {
        username: username,
        password: crypto.createHash('sha256').update(password).digest('base64')
      },
      type: userDB.Sequelize.QueryTypes.SELECT
    }).then(function(users) {
      if (users.length != 1) {
        return null;
      }
      return users[0];
    });
  }).then(function(user) {
    if (!user) {
      console.log(username + " not found (or invalid password.)");
      req.session.user = {};
      return res.status(401).send("Invalid login credentials");      
    }

    req.session.user = {
      name: user.displayName,
      mail: user.mail,
      username: user.uid,
      authenticated: user.authenticated,
      mailVerified: user.mailVerified
    };

    if (!user.mailVerified) {
      console.log("Logged in as " + user.displayName + ", who is not verified email.");
    } else if (!user.authenticated) {
      console.log("Logged in as " + user.displayName + ", who is not authenticated.");
    } else {
      console.log("Logging in as " + user.displayName);
    }

    return res.status(200).send(req.session.user);
  });
});

router.get("/logout", function(req, res) {
  if (req.session && req.session.user) {
    req.session.user = {};
  }
  res.status(200).send(req.session.user);
});

module.exports = router;