package com.petukhovsky.wat.webserver;

import com.petukhovsky.wat.Tools;
import com.petukhovsky.wat.server.Account;
import com.petukhovsky.wat.server.Auth;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.handler.AbstractHandler;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.*;

/**
 * Created by Arthur on 3/30/2015.
 */
public class WebHandler extends AbstractHandler {

    @Override
    public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
        response.setContentType("text/html;charset=utf-8");
        response.setStatus(HttpServletResponse.SC_OK);
        baseRequest.setHandled(true);
        switch (target) {
            case "/login":
                CookieAuth session = CookieAuth.getCookieAuth(baseRequest);
                if (session != null) {
                    response.sendRedirect("/main");
                    break;
                }
                String username = baseRequest.getParameter("user");
                String password = baseRequest.getParameter("pass");
                if (username == null || password == null) {
                    response.getWriter().println(Tools.readFile("www/loginpage.html"));
                    break;
                }
                Account account = Auth.auth(username, password);
                if (account == null) {
                    response.getWriter().println("Wrong password or username");
                    break;
                }
                new CookieAuth(account, response);
                response.sendRedirect("/main");
                break;
            case "/logout":
                CookieAuth.clearAuth(baseRequest);
                response.sendRedirect("/login");
                break;
            default:
                session = CookieAuth.getCookieAuth(baseRequest);
                if (session == null) {
                    response.sendRedirect("/login");
                    break;
                }
                account = session.getAccount();
                response.getWriter().println("<h1>Hello World!</h1><br>You are " + account.getFormattedUsername());
        }
    }
}

class CookieAuth{
    private static char[] symbols = new char[36];
    static{
        int k = 0;
        for (char c = 'a'; c <= 'z'; c++) symbols[k++] = c;
        for (char c = '0'; c <= '9'; c++) symbols[k++] = c;
    }

    private static Random random = new Random();
    private static HashMap<String, CookieAuth> users = new HashMap<>();

    private static String getRandomString() {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < 16; i++) sb.append(symbols[random.nextInt(symbols.length)]);
        return sb.toString();
    }

    private String q;
    private String w;
    private String e;
    private String r;
    private Account account;

    CookieAuth(Account account, HttpServletResponse response) {
        q = getRandomString();
        w = getRandomString();
        e = getRandomString();
        r = getRandomString();
        this.account = account;
        users.put(q, this);
        response.addCookie(createCookie("q", q));
        response.addCookie(createCookie("w", w));
        response.addCookie(createCookie("e", e));
        response.addCookie(createCookie("r", r));
    }

    private static Cookie createCookie (String key, String value) {
        Cookie c = new Cookie(key, value);
        c.setMaxAge(2678400);
        return c;
    }

    public static CookieAuth getCookieAuth(Request baseRequest) {
        String q, w, e, r;
        q = w = e = r = null;
        if (baseRequest.getCookies() != null)
            for (Cookie c : baseRequest.getCookies()) {
                switch (c.getName()) {
                    case "q":
                        q = c.getValue();
                        break;
                    case "w":
                        w = c.getValue();
                        break;
                    case "e":
                        e = c.getValue();
                        break;
                    case "r":
                        r = c.getValue();
                        break;
                }
            }
        if (q == null || w == null || e == null || r == null) return null;
        CookieAuth cookieAuth = users.get(q);
        if (cookieAuth != null && cookieAuth.check(q, w, e, r)) return cookieAuth;
        else return null;
    }

    private boolean check(String q, String w, String e, String r) {
        return this.q.equals(q) && this.w.equals(w) && this.e.equals(e) && this.r.equals(r);
    }

    public Account getAccount() {
        return account;
    }

    public static void clearAuth(Request baseRequest) {
        String q, w, e, r;
        q = w = e = r = null;
        if (baseRequest.getCookies() != null)
            for (Cookie c : baseRequest.getCookies()) {
                switch (c.getName()) {
                    case "q":
                        q = c.getValue();
                        break;
                    case "w":
                        w = c.getValue();
                        break;
                    case "e":
                        e = c.getValue();
                        break;
                    case "r":
                        r = c.getValue();
                        break;
                }
            }
        if (q == null || w == null || e == null || r == null) return;
        CookieAuth cookieAuth = users.get(q);
        if (cookieAuth != null && cookieAuth.check(q, w, e, r)) users.remove(q);
    }
}