const express = require('express');
const bodyParser = require('body-parser');
const session = require('express-session');
const QRCode=require('qrcode');
const crypto=require('crypto');
const path=require('path');

const app = express();
app.set('view engine','ejs');
app.use(express.json());
const PORT = 3000;
const PWSalt="!SaltyMagic7283715374";
const QRSalt="!SaltyMagic5392370662";

//
// ToDo, Actions:
//   + Login with Password
//   + Login with Token
//   + Email Link
//   + Signup
//     Change Password
//     Issue Tickets
//     Transfer Tickets      Complicated page. (One ticket: static with transfer and QR code. Multi: buttons to transfer or show QR code)
//     Claim Tickets 
//   + Use Ticket
//     Edit Tickets
//
// ToDo, Later
//     Use a templating engine
//     Store password hashed and salted
//     Make all HTML look nice
//     Logging and Replay system
//

function hashPW(pw) {
    const hash0=crypto.createHash('sha256');
    const hash1=hash0.update(pw+PWSalt);
    const hash=hash1.digest("base64");
    return(hash);
}

function hashQR(t,ownername) {
    const hash0=crypto.createHash('sha256');
    const hash1=hash0.update(t+QRSalt+ownername);
    const hash=hash1.digest("base64").slice(0,6);
    return(hash);
}

//
// In-memory data structures
//
// There are two ways to log in: with a username/password or with a token. 
//
const users = { "teppy@egenesis.com"    : { password: hashPW("x6321872X.1"),      superuser:true  },
	        "fallsonfire@gmail.com" : { password: hashPW("indiantreeonfire"), superuser:false }
	      };

const tickets = { "habitat-1" : { owner: "teppy@egenesis.com"  , offered: "", paid: 0.00, used: false },
		  "habitat-2" : { owner: "teppy@egenesis.com"  , offered: "", paid: 0.00 },
		  "habitat-3" : { owner: "ginachen94@gmail.com", offered: "teppy@egenesis.com", paid: 0.00 },
		  "habitat-4" : { owner: "teppy@egenesis.com"  , offered: "noahstern00@gmail.com", paid: 0.00 },
		  "habitat-5" : { owner: "teppy@egenesis.com"  , offered: "", paid: 0.00, used: true },
		  "habitat-6" : { owner: "teppy@egenesis.com"  , offered: "", paid: 0.00 },
		};

const camps = { "habitat": 0 };

const tokens = { "abc" : { username: "teppy@egenesis.com", expires: 0 }
	       };
const tokensu = { "teppy@egenesis.com" : "abc"
		};

// Middleware setup
app.use(bodyParser.urlencoded({ extended: true }));
app.use(session({
  secret: 'supersecretkey',
  resave: false,
  saveUninitialized: false,
}));

// Middleware to protect routes
function requireLogin(req, res, next) {
    if (!req.session.username) return res.redirect('/login');
    next();
    }

function requireSuperUser(req,res,next) {
    console.log(req.session);
    if (!req.session.superuser) return res.status(403).send(JSON.stringify( { error: "Forbidden without superuser flag" } ));
    else next();
    }


app.get('/styles.css', (req, res) => {
    res.setHeader('Content-Type', 'text/css');
    res.sendFile(path.join(__dirname, 'public', 'styles.css'));
    });

function generateSecureToken(length = 8) {
    const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    let token = '';
    const array = new Uint8Array(length);
    crypto.getRandomValues(array);
    for (let i = 0; i < length; i++) {
        token += characters.charAt(array[i] % characters.length);
    }
    return token;
}

const postmark = require('postmark');
const client = new postmark.ServerClient('f45bcb9f-6556-4420-9e21-05d16739b5e8');

app.get('/loginpassword',(req,res) => {
    res.send(`<h1>Sign Up</h1>
              <form method="POST" action="/loginpassword">
                <label>Username: <input type="text" name="username" required></label><br>
                <label>Password: <input type="password" name="password" required></label><br>
                <button type="submit">Log In</button>
              </form>`);
})

app.post('/loginpassword', (req, res) => {
    const { username, password } = req.body;
    if (username in users && hashPW(password)==users[username].password) {
        req.session.username=username;
        req.session.superuser=users[username].superuser;
        res.redirect('/transfer');
    } else { res.redirect('/transfer'); }
})

app.get('/logintoken', (req, res) => {
    const tok=req.query.token;
    const tokenData = tokens[tok];
    if (!consumeToken(tok)) return res.status(200).send("Missing, Invalid or Expired Token.");
    req.session.username = tokenData.username;
    req.session.superuser= users[tokenData.username].superuser;
    res.redirect('/transfer');
    });

app.get('/emaillink',(req,res) => {
    res.send(`
      <h1>Email me a login link</h1>
      <form method="POST" action="/emaillink">
        <label>Email Address: <input name="email"></label>
        <button type="submit">Submit</button>`
            )
})

// These can be owned, offered, of offering
function categorizeTickets(username) {
    let rval="none";
    let numtickets=0;
    let simpleowner=0;
    let offering=0;
    let simpleoffered=0;
    let thet="";
    for (const t in tickets) if (!tickets[t].used) {
        if      (tickets[t].owner==username && tickets[t].offered=="")       simpleowner+=1;
        else if (tickets[t].owner==username && tickets[t].offered!=username) offering+=1;
        else if (tickets[t].owner!=username && tickets[t].offered==username) simpleoffered+=1;
        if (tickets[t].owner==username || tickets[t].offered==username) numtickets+=1;
        if (numtickets==1) thet=t; else thet="";
    }
    console.log("Simpleowner: "+simpleowner+" Offering "+offering+" SimpleOffered "+simpleoffered+" Numtickets "+numtickets);
    if (numtickets==0)    return [ "none", ""];
    if (numtickets >1)    return [ "complex", ""];
    if (simpleowner+offering+simpleoffered>1)
                          return [ "error", "" ]
    if (simpleowner==1)   return [ "simpleowner", thet ];
    if (offering==1)      return [ "simpleoffering", thet ];
    if (simpleoffered==1) return [ "simpleoffered", thet ];
    return [ "complex", "" ];
}


// Big Kahuna
//    If you have zero tickets, show something saying that
//    For each ticket owned, display options to offer it, use it, or (eventually) pay for it.
//    For each ticket offered, show a button to claim it.
//    Have a button to claim all tickets, if there are multiple offered to you
app.get('/transfer', requireLogin, async (req,res) => {
    let username=req.session.username;
    const [ cat, ticket ] = categorizeTickets(username);
    const simpledata={ username: username, ticket: ticket };
    console.log("Transfer type "+cat);
    if (cat=="none") return res.render("notickets",simpledata);
    if (cat=="error") return res.render("error",simpledata);
    if (cat=="simpleoffered") return res.render("claimone",simpledata);
    if (cat=="simpleoffering") return res.render("retractoffer",simpledata);
    if (cat=="complex") { 
        const edit={ username: username, tickets: {} };
        for (const t in tickets)
            if (tickets[t].owner==username || tickets[t].offered==username) {
                edit.tickets[t]={};
                edit.tickets[t].owner=tickets[t].owner;
                edit.tickets[t].offered=tickets[t].offered;
                edit.tickets[t].used=tickets[t].used;
                }
        return res.render("transfer",edit);
        }
    if (cat=="simpleowner") {
        try {
            const hash0=crypto.createHash('sha256');
            const hash1=hash0.update(ticket+QRSalt);
            const hash=hash1.digest("base64").slice(0,6);
            const dataURL=await QRCode.toDataURL('localhost:3000/useticket?t='+ticket+'&h='+hashQR(ticket,username));
            simpledata.qrcode=dataURL;
            return res.render("simpleowner",simpledata);
            }
        catch(err) {
            res.status(500).send('Error generating QR code');
            }
        }
    if (cat=="complex")     return res.render('transfer',simpledata);
})

app.post("/toggle", requireSuperUser, (req,res) => {
    const ticket=req.body.ticket;
    const isChecked = req.body.checked;
    tickets[ticket].used=isChecked; 
    // Perform any server-side logic here
    res.json({ message: 'Checkbox state received', checked: isChecked });
    })

app.post("/updateoffered", requireLogin, (req,res) => {
    const ticket=req.body.ticket;
    const offered=req.body.offered;
    console.log("Ticket: ",ticket);
    if      (tickets[ticket].owner!=req.session.username) res.status(500).send("Ticket "+ticket+" owned by someone else");
    else if (tickets[ticket].used)                        res.status(500).send("Ticket "+ticket+" has already been used");
    else {
        tickets[ticket].offered=offered;
        res.json({ message: 'Updated owner of '+ticket+' to '+offered });
        }
    })

app.get("/useticket",(req,res) => {
    let ticket=req.t;
    let hash=req.h;
    if (hashQR(ticket,req.session.username)!=hash) res.status(500).send("Ticket "+ticket+" was transferred to "+tickets[ticket].username);
    else if (tickets[ticket].used) res.status(500).send("Ticket "+ticket+" has already been used.");
    else {
        tickets[ticket].used=new Date().toISOString();
        res.send("<h1>Welcome, "+tickets[ticket].username+" to Falls on Fire! Ticket "+ticket+" has now been used.</h1>");
        }
})

    

function knownEmail(email) {
    if (users[email]) return true;
    for (const key in tickets)
        if (tickets[key].owner==email || tickets[key].offered==email) return true;
    return false;
}

app.post('emaillink',(req,res) => {
    if (!knownUser(req.email)) return res.send("Unknown User");
    const tok=createtoken(email);
    client.sendEmail({ From: 'tickets@fallsonfire.net',
                       To: 'teppy@egenesis.com',
		       Subject: 'Falls on Fire Tickets, Login Link',
		       TextBody: 'Your Login Link: http://www.fallonfire.net/longinlink?token='+tok,
		       HtmlBody: '<p>Your Login Link: </p>',
		     }).then(() => {
			 console.log('Email sent');
			 res.send("<h1>Email sent</h1>");
		     }).catch((error) => {
			 console.error('Error sending email:', error);
			 res.send("<h1>Email failed</h1>");
		     });
    res.send("Email link sent");
})
 

app.get('/testemail',
	(req,res) => {
	    client.sendEmail({ From: 'tickets@fallsonfire.net',
			       To: 'teppy@egenesis.com',
			       Subject: 'Email from Ticketing System',
			       TextBody: 'This is a test email.',
			       HtmlBody: '<p>This is a test email.</p>',
			     }).then(() => {
				 console.log('Email sent');
				 res.send("<h1>Email sent</h1>");
			     }).catch((error) => {
				 console.error('Error sending email:', error);
				 res.send("<h1>Email failed</h1>");
			     })});




// Routes
app.get('/', (req, res) => {
  if (req.session.username) {
    res.send(`
      <h1>Welcome, ${req.session.username}</h1>
      <a href="/products">Products</a><br>
      <a href="/faq">FAQ</a><br>
      <a href="/logout">Log Out</a>
    `);
  } else {
    res.send(`
      <h1>Welcome to our website!</h1>
      <a href="/login">Log In</a><br>
      <a href="/signup">Sign Up</a>
    `);
  }
});

app.get('/signup', (req, res) => {
  res.send(`
    <h1>Sign Up</h1>
    <form method="POST" action="/signup">
      <label>Username: <input type="text" name="username" required></label><br>
      <label>Password: <input type="password" name="password" required></label><br>
      <button type="submit">Sign Up</button>
    </form>
    <a href="/login">Log In</a>
  `);
});


function consumeToken(tok) {
    console.log("ConsumeToken 1");
    if (!(tok in tokens)) return false;
    console.log("ConsumeToken 2");
    const rval=tokens[tok].expires==0 || tokens[tok].expires>=Date.now();
    delete tokensu[tokens[tok].username];
    delete tokens[tok];
    return rval;
}

function createToken(username) {
    const token=generateSecureToken();
    tokens[token]={ username: username, expires:0 };
    tokensu[username]=token;
    return token;
}

app.get('/test', (req, res) => {
    res.send("Test worked:" + consumeToken("abc"));
})


app.post('/signup', (req, res) => {
  const { username, password } = req.body;
  if (users[username]) {
    return res.send('User already exists. <a href="/signup">Try again</a>');
  }
    users[username] = { password: hashPW(password) };
    console.log("Created new account:",username);
  res.redirect('/login');
});

app.get('/changepassword', (req, res) => {
  res.send(`
    <h1>Change Password</h1>
    <form method="POST" action="/changepassword">
      <label>Password: <input type="password" name="password1" required></label><br>
      <label>Again: <input type="password" name="password2" required></label><br>
      <button type="submit">Sign Up</button>
    </form>
    <a href="/">Home</a>
  `);
});

app.post('/changepassword', (req, res) => {
    const { password1, password2 } = req.body;
    if (!req.session.username) {
	return res.send('You are not logged in<a href="/">Back</a>');
        }
    if (password1!=password2) {
        return res.send('Passwords do not match<a href="/">Back</a>');
        }
  users[req.session.username].password=hashPW(password1);
  res.redirect('/login');
});

app.get('/login', (req, res) => {
  res.send(`
    <h1>Log In</h1>
    <form method="POST" action="/login">
      <label>Username: <input type="text" name="username" required></label><br>
      <label>Password: <input type="password" name="password" required></label><br>
      <button type="submit">Log In</button>
    </form>
    <a href="/signup">Sign Up</a>
  `);
});

app.post('/login', (req, res) => {
    const { username, password, superuser } = req.body;
    if (users[username] && users[username].password === hashPW(password)) {
        req.session.username = username;
        req.session.superuser = users[username].superuser;
        return res.redirect('/transfer');
  }
  res.send('Invalid username or password. <a href="/login">Try again</a>');
});

app.get('/logout', (req, res) => {
  req.session.destroy(() => {
    res.redirect('/');
  });
});

app.post('/qrcode',requireLogin,async (req,res) => {
    const username=req.session.username;
    const ticket=req.body.ticket;
    console.log("Body: ",req.body);
    console.log("Tickets["+ticket+"]",tickets[ticket]);
    if (tickets[ticket].owner!=username) return res.status(500).send("Only a ticket owner can generate a QR code");
    const URL=await QRCode.toDataURL('localhost:3000/useticket?t='+ticket+'&h='+hashQR(ticket,username));
    return res.send({ qrcode: URL });
    })

// Protected routes
app.get('/products', requireLogin, (req, res) => {
  res.send(`
    <h1>Products Page</h1>
    <p>Here is a list of products!</p>
    <a href="/">Home</a>
  `);
});

app.get('/tickets', requireLogin, (req, res) => {
    res.write(`<h1>Tickets for `+req.session.username+`</h1>`);
    res.write(`<a href="/">Home</a>`);
    res.end();
});

app.get('/faq', requireLogin, (req, res) => {
  res.send(`
    <h1>FAQ Page</h1>
    <p>Here are some frequently asked questions.</p>
    <a href="/">Home</a>
  `);
});

// Start the server
app.listen(PORT, () => {
  console.log(`Server is running at http://localhost:${PORT}`);
});