package org.crosswire.utils;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.UUID;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.io.File;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.Cookie;



public class Sessions {

	static public long DEFAULT_SESSION_TIMEOUT = 1000 * 60 * 60 * 48;	// 48 hour
	public static String persistRoot = System.getProperty("catalina.base") + "/sessions";


	static Sessions systemSessions = new Sessions();
	static public Sessions getInstance() { return systemSessions; }


	private void flushExpiredSessions() {
		File repo = new File(persistRoot);
		File sessions[] = repo.listFiles();
		if (sessions != null) {
			for (File f : sessions) {
				if (f.getName().endsWith(".ser")) {
					long lastAccess = f.lastModified();
					// we've been given an explicit TTL
					long ttl = DEFAULT_SESSION_TIMEOUT;
					if (f.getName().indexOf("_") > -1) {
						try { ttl = Long.parseLong(f.getName().substring(f.getName().indexOf("_")+1, f.getName().lastIndexOf("."))); } catch (Exception e) {}
					}
					if (System.currentTimeMillis() - lastAccess > ttl) {
						f.delete();
					}
				}
			}
		}
	}


	public Map<String, Object> getSessionAttributes(String sessionHash) {
		if (sessionHash == null) return null;

		flushExpiredSessions();

		Map<String, Object> session = loadSession(sessionHash);
		return session;
	}


	public void setSessionAttributes(String sessionHash, Map<String, Object>attrs) {
		if (sessionHash == null || attrs == null) return;

		Map<String, Object> s = getSessionAttributes(sessionHash);
		if (s != null) {
			s.putAll(attrs);
			persistSession(sessionHash, s);
		}
	}


	public void setSessionAttribute(String sessionHash, String key, Object value) {
		if (sessionHash == null || key == null) return;

		Map<String, Object> s = getSessionAttributes(sessionHash);
		if (s != null) {
			s.put(key, value);
			persistSession(sessionHash, s);
		}
	}


	public Object getSessionAttribute(String sessionHash, String key) {
		if (sessionHash == null || key == null) return null;

		Map<String, Object> s = getSessionAttributes(sessionHash);
		return (s != null) ? s.get(key) : null;
	}


	public String createSession() {
		return createSession(-1);
	}
	public String createSession(long explicitTTL) {
		String sessionHash = UUID.randomUUID().toString();
		if (explicitTTL > 0) sessionHash += "_" + Long.toString(explicitTTL);
		Map<String, Object> newSession = new ConcurrentHashMap<String, Object>();
		persistSession(sessionHash, newSession);
		return sessionHash;
	}


	public void closeSession(String sessionHash) {
		if (sessionHash == null) return;
		File file = new File(persistRoot, sessionHash+".ser");
		file.delete();
	}


	private void persistSession(String sessionHash, Map<String, Object> session) {

		try {
			FileOutputStream fileOut = new FileOutputStream(persistRoot+"/"+sessionHash+".ser");
			ObjectOutputStream out = new ObjectOutputStream(fileOut);
			out.writeObject(session);
			out.close();
			fileOut.close();
		}
		catch(Exception e) { e.printStackTrace(); }
	}


	Map<String, Object> loadSession(String sessionHash) {

		if ("undefined".equals(sessionHash)) return null;

		Map<String, Object> session = null;
		File file = null;
		try {
			file = new File(persistRoot, sessionHash+".ser");
			FileInputStream fileIn = new FileInputStream(file);
			ObjectInputStream in = new ObjectInputStream(fileIn);
			session = (Map<String, Object>) in.readObject();
			in.close();
			fileIn.close();
			if (session != null) {
				file.setLastModified(System.currentTimeMillis());
			}
		}
		catch(java.io.FileNotFoundException e) { System.out.println("Session file not found: " + file.getAbsolutePath()); }
		catch(Exception e) { e.printStackTrace(); }
		return session;
	}


	// TODO: Don't use this method.  More complete and accurate impl in RightsAndRoles.getCurrentSession
	static public String getSessionHash(HttpServletRequest request) {
		String sessionHash = request.getParameter("sessionHash");
		try { if (sessionHash != null) sessionHash = new String(sessionHash.getBytes("iso8859-1"), "UTF-8"); } catch (Exception e) {}
		if (sessionHash == null) {
			Cookie cookies[] = request.getCookies();
			if (cookies != null) {
				for (Cookie c : cookies) {
					if ("ntvmrSession".equals(c.getName())) {
						sessionHash = c.getValue();
					}
				}
			}
		}
		return sessionHash;
	}


	static public Map<String, Object> getSessionAttributes(HttpServletRequest request) {
		String sessionHash = getSessionHash(request);
		return Sessions.getInstance().getSessionAttributes(sessionHash);
	}


	static public long getSessionLongValue(HttpServletRequest request, String key) {
		long retVal = -1;
		try {
			Map<String, Object> s = getSessionAttributes(request);
			if (s != null) {
				Long l = (Long)s.get(key);
				if (l != null) retVal = l.longValue();
			}
		}
		catch (Exception e) {}
		return retVal;
	}


	static public String getSessionStringValue(HttpServletRequest request, String key) {
		String retVal = null;
		try {
			Map<String, Object> s = getSessionAttributes(request);
			if (s != null) {
				retVal = (String)s.get(key);
			}
		}
		catch (Exception e) {}
		return retVal;
	}

	static public boolean hasRole(HttpServletRequest request, String role) {
		return hasRole(request, role, -1, null);
	}
	static public boolean hasRole(HttpServletRequest request, String role, int projectID) {
		return hasRole(request, role, projectID, null);
	}
	static public boolean hasRole(HttpServletRequest request, String role, int projectID, String userGroupName) {

		// TODO: VMR Impl, right now.  Extract this out somewhere
		
		boolean retVal = false;
		long userID = Sessions.getSessionLongValue(request, "userID");
		if (userID != -1) {
			try {
				String roleCheckURL = Utils.getSysConfig(request.getSession()).getProperty("VMRAPIBaseURL")+"/auth/hasrole/";
				String params = "sessionHash=" + Sessions.getSessionHash(request) + "&role=" + java.net.URLEncoder.encode(role, "UTF-8");
				if (projectID > -1) params += "&projectID=" + projectID;
				if (userGroupName != null) params += "&userGroupName=" + java.net.URLEncoder.encode(userGroupName, "UTF-8");
				StringBuffer result = HTTPUtils.postURL(roleCheckURL, params);
				retVal = result.toString().trim().indexOf("hasRole=\"true\"") > -1;
			}
			catch (Exception e) {}
		}
		return retVal;
	}
}